ORCID Profile
0000-0002-9341-8777
Current Organisation
Griffith University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Surfacewater Hydrology | Ecology | Environmental Science and Management | Environmental Engineering Modelling | Environmental Engineering Modelling | Marine And Estuarine Ecology (Incl. Marine Ichthyology) | Water Quality Engineering | Ecological Applications | Fish physiology and genetics | Oceanography | Hydrology | Environmental Management And Rehabilitation | Population, Ecological and Evolutionary Genetics | Physical Oceanography | Ecohydrology | Ecosystem Function | Environmental Management | Freshwater Ecology | Ecological impacts of climate change and ecological adaptation | Freshwater Ecology
ANZSRC Socio-Economic Objective (SEO)
Ecosystem Adaptation to Climate Change | Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments | Estuarine and lagoon areas | Integrated (ecosystem) assessment and management | Water Services and Utilities | Land and water management | Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use) | Physical and Chemical Conditions of Water in Coastal and Estuarine Environments | Water services and utilities | Fresh, Ground and Surface Water Flora, Fauna and Biodiversity |
Related Links
Publications
Catchment land use and trophic state impacts on phytoplankton composition: a case study from the Rotorua lakes’ district, New Zealand
Publisher: Springer Science and Business Media LLC
Date: 31-05-2012
Trends and abrupt changes in 104 years of ice cover and water temperature in a dimictic lake in response to air temperature, wind speed, and water clarity drivers
Publisher: Copernicus GmbH
Date: 03-05-2016
DOI: 10.5194/HESS-20-1681-2016
Abstract: Abstract. The one-dimensional hydrodynamic ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, Wisconsin, USA, over a continuous 104-year period (1911–2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multiyear timescales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s−1 before 1994 to 3.74 m s−1 thereafter. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice-on date(9.0 days later per century), earlier ice-off date (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (−1.4 °C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911–1980, 1981–1993, and 1994–2014) delineated by abrupt changes in air temperature and wind speed. Average summer hypolimnetic temperature and fall turnover date exhibit significant differences between the third period and the first two periods. Changes in ice cover (ice-on and ice-off dates, ice cover duration, and maximum ice thickness) exhibit an abrupt change after 1994, which was related in part to the warm El Niño winter of 1997–1998. Under-ice water temperature, freeze-over water temperature, hypolimnetic temperature, fall turnover date, and stratification duration demonstrate a significant difference in the third period (1994–2014), when air temperature was warmest and wind speeds decreased rather abruptly. The trends in ice cover and water temperature demonstrate responses to both long-term and abrupt changes in meteorological conditions that can be complemented with numerical modeling to better understand how these variables will respond in a future climate.
The role of intratidal oscillations in sediment resuspension in a diurnal, partially mixed estuary
Publisher: American Geophysical Union (AGU)
Date: 29-07-2010
DOI: 10.1029/2009JC005760
Are laboratory growth rate experiments relevant to explaining bloom-forming cyanobacteria distributions at global scale?
Publisher: Elsevier BV
Date: 02-2020
Trends in water quality in a subtropical Australian river-estuary system: Responses to damming, climate variability and wastewater discharges
Publisher: Elsevier BV
Date: 09-2020
Intra-population strain variation in phosphorus storage strategies of the freshwater cyanobacterium Raphidiopsis raciborskii
Publisher: Oxford University Press (OUP)
Date: 14-05-2020
Abstract: Several cyanobacteria, including diazotrophic Raphidiopsis raciborskii, can form harmful blooms when dissolved inorganic phosphorus concentrations are very low. We hypothesized that R. raciborskii strains would vary in phosphorus (P) allocations to cell growth and storage, providing resilience of populations to continuously low or variable P supplies. We tested this hypothesis using six toxic strains (producing cylindrospermopsins) isolated from a field population using batch monocultures with and without P and dissolved inorganic nitrogen (DIN). Treatments replete with DIN, irrespective of P addition, had similar exponential growth rates for in idual strains. P storage capacity varied 4-fold among strains and was significantly higher in DIN-free treatments than in replete treatments. P was stored by all R. raciborskii strains, in preference to allocation to increase growth rates. P stores decreased with increased growth rate across strains, but weeere not related to the time to P starvation in P-free treatments. The storage capacity of R. raciborskii, combined with strategies to efficiently uptake P, means that P controls may not control R. raciborskii populations in the short term. Intra-population strain variation in P storage capacity will need to be reflected in process-based models to predict blooms of R. raciborskii and other cyanobacteria adapted to low-P conditions.
Controlling the indirect effects of flow diversions on water quality in an Australian reservoir
Publisher: Elsevier BV
Date: 1995
Summer flow event induces a cyanobacterial bloom in a seasonal Western Australian estuary
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/MF02090
Abstract: In January 2000, record rainfall led to the first recorded bloom of Microcystis aeruginosa in the Swan River estuary. A simple model is used to examine the bloom dynamics and the unusual conditions that produced it. Laboratory trials were conducted to determine the response to salinity of M. aeruginosa, while other parameters for the model were obtained from the literature. Growth was found to be optimal at salinities up to 4, and declined to zero at 25. The unseasonable summer rainfall flushed brackish and marine water from the estuary and produced a surface mixed layer with low salinity. The model simulations show that the hydrological conditions, in combination with high concentrations of inorganic nutrients (dissolved inorganic nitrogen .2 mg L–1, filterable reactive phosphorus .02 mg L–1) in river inflows, high water temperature and high daily insolation, promoted rapid phytoplankton growth, favouring dominance by M. aeruginosa. Doubling rates during the bloom were around 0.35 day–1 and cell counts exceeded 105 cells mL–1 within three weeks of the inflow event. Although this doubling rate ultimately determined the total bloom biomass, local concentrations were strongly influenced by physical processes that concentrated M. aeruginosa cells both vertically and horizontally, and advected a seed population from the upper estuary into the lower basin.
Modelling the relative importance of internal and external nutrient loads on water column nutrient concentrations and phytoplankton biomass in a shallow polymictic lake
Publisher: Elsevier BV
Date: 03-2008
A novel Eulerian approach for modelling cyanobacteria movement: Thin layer formation and recurrent risk to drinking water intakes
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.WATRES.2017.10.021
Abstract: Toxic cyanobacteria (CB) blooms are being reported in an increasing number of water bodies worldwide. As drinking water (DW) treatment can be disrupted by CB, in addition to long term management plans, short term operational decision-making tools are needed that enable an understanding of the temporal variability of CB movement in relation to drinking water intakes. In this paper, we propose a novel conservative model based on a Eulerian framework and compare results with data from CB blooms in Missisquoi Bay (Québec, Canada). The hydrodynamic model considered the effects of wind and light intensity, demonstrated that current understanding of cell buoyancy in relation to light intensity in full-scale systems is incomplete and some factors are yet to be fully characterized. Factors affecting CB buoyancy play a major role in the formation of a thin surface layer that could be of ecological importance with regards to cell concentrations and toxin production. Depending on velocities, wind contributes either to the accumulation or to the dispersion of CB. Lake recirculation effects have a tendency to create zones of low CB concentrations in a water body. Monitoring efforts and future research should focus on short-term variations of CB throughout the water column and the characterization of factors other than light intensity that affect cell buoyancy. These factors are critical for understanding the risk of breakthrough into treatment plants as well as the formation of surface scums and subsequent toxin production.
Diversity of anammox bacteria and abundance of functional genes for nitrogen cycling in the rhizosphere of submerged macrophytes in a freshwater lake in summer
Publisher: Springer Science and Business Media LLC
Date: 11-05-2019
The response of circulation and salinity in a micro-tidal estuary to sub-tidal oscillations in coastal sea surface elevation
Publisher: Elsevier BV
Date: 08-2007
Pulsed emission of methane (CH4) from a small eutrophic lake
Publisher: Unpublished
Date: 2014
Constructed treatment wetlands provide habitat for zooplankton communities in agricultural peat lake catchments
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
Derivation of lake mixing and stratification indices from high-resolution lake buoy data
Publisher: Elsevier BV
Date: 11-2011
Hypolimnetic phosphorus and nitrogen dynamics in a small, eutrophic lake with a seasonally anoxic hypolimnion
Publisher: Springer Science and Business Media LLC
Date: 11-07-2010
Intra-colony motility of Microcystis wesenbergii cells
Publisher: Figshare
Date: 2015
Spatial and temporal changes in water quality along natural and restored side‐arms of a large New Zealand river
Publisher: Wiley
Date: 02-2016
DOI: 10.1111/FWB.12716
Temporal and spatial trends in water quality of Lake Taihu, China: Analysis from a north to mid-lake transect, 1991-2011
Publisher: Springer Science and Business Media LLC
Date: 05-03-2014
DOI: 10.1007/S10661-014-3666-0
Abstract: Interpretations of state and trends in lake water quality are generally based on measurements from one or more stations that are considered representative of the response of the lake ecosystem. The objective of this study is to examine how these interpretations may be influenced by station location in a large lake. We addressed this by analyzing trends in water quality variables collected monthly from eight monitoring stations along a transect from the central lake to the north in Lake Taihu (area about 2,338 km(2)), China, from October 1991 to December 2011. The parameters examined included chlorophyll a (Chl a), total nitrogen (TN), and total phosphorus (TP) concentrations, and Secchi disk depth (SD). The in idual variables were increasingly poorly correlated among stations along the transect from the central lake to the north, particularly for Chl a and TP. The timing of peaks in in idual variables was also dependent on station location, with spectral analysis revealing a peak at annual frequency for the central lake station but absence of, or much reduced signal, at this frequency for the near-shore northern station. Percentage annual change values for each of the four variables also varied with station and indicated general improvement in water quality at northern stations, particularly for TN, but little change or decline at central lake stations. Sediment resuspension and tributary nutrient loads were considered to be responsible for some of the variability among stations. Our results indicate that temporal trends in water quality may be station specific in large lakes and that calculated whole-lake trophic status trends or responses to management actions may be specific to the station(s) selected for monitoring and analysis. These results have important implications for efficient design of monitoring programs that are intended to integrate the natural spatial variability of large lakes.
A systematic literature review of forecasting and predictive models for cyanobacteria blooms in freshwater lakes
Publisher: Elsevier BV
Date: 09-2020
Denitrification Potential in Lake Sediment Increases Across a Gradient of Catchment Agriculture
Publisher: Springer Science and Business Media LLC
Date: 02-02-2011
CDOM and its contribution to the underwater light climate of a shallow, microtidal estuary in south-western Australia
Publisher: Elsevier BV
Date: 06-2005
Comment on "Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand" by Morgenste
Publisher: Copernicus GmbH
Date: 20-06-2016
DOI: 10.5194/HESS-20-2395-2016
Abstract: Abstract. This comment addresses a key conclusion in the paper entitled "Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand" by Morgenstern et al. (2015). The authors analyse hydrochemistry data and conclude that "the only effective way to limit algae blooms and improve lake water quality in such environments is by limiting the nitrate load". We undertook the crucial task of examining this conclusion because it contradicts the current strategy of limiting both phosphorus and nitrogen loads to the lake, supported by a multi-million dollar programme of action. Following careful consideration, we believe that the conclusion is invalid and outline four reasons to support our assessment. Our comments do not relate to the methodology or results that are presented by Morgenstern et al. (2015), and we recognise that their paper makes an otherwise highly valuable contribution to understanding hydro-chemical processes in the catchment.
Structural Characterization of New Microcystins Containing Tryptophan and Oxidized Tryptophan Residues
Publisher: MDPI AG
Date: 21-08-2013
DOI: 10.3390/MD11083025
Auto-calibration of a one-dimensional hydrodynamicecological model (DYRESM 4.0-CAEDYM 3.1) using a Monte Carlo approach: simulations of hypoxic events in a polymictic lake
Publisher: Copernicus GmbH
Date: 18-09-2017
DOI: 10.5194/GMD-2017-182
Abstract: Abstract. Automated calibration of complex deterministic water quality models with a large number of biogeochemical parameters can reduce time-consuming iterative simulations involving empirical judgements of model fit. We undertook auto-calibration of the one-dimensional hydrodynamic-ecological lake model DYRESM-CAEDYM, using a Monte Carlo S ling (MCS) method, in order to test the applicability of this procedure for shallow, polymictic Lake Rotorua (New Zealand). The calibration procedure involved independently minimising the root-mean-square-error (RMSE), maximizing the Pearson correlation coefficient (r) and Nash-Sutcliffe efficient coefficient (Nr) for comparisons of model state variables against measured data. An assigned number of parameter permutations was used for 10,000 simulation iterations. The optimal temperature calibration produced a RMSE of 0.54 °C, Nr-value of 0.99 and r-value of 0.98 through the whole water column based on comparisons with 540 observed water temperatures collected between 13 July 2007–13 January 2009. The modeled bottom dissolved oxygen concentration (20.5 m below surface) was compared with 467 available observations. The calculated RMSE of the simulations compared with the measurements was 1.78 mg L−1, the Nr-value was 0.75 and the r-value was 0.87. The autocalibrated model was further tested for an independent data set by simulating bottom-water hypoxia events for the period 15 January 2009 to 8 June 2011 (875 days). This verification produced an accurate simulation of five hypoxic events corresponding to DO 2 mg L−1 during summer of 2009–2011. The RMSE was 2.07 mg L−1, Nr-value 0.62 and r-value of 0.81, based on the available data set of 738 days. The auto-calibration software of DYRESM-CAEDYM developed here is substantially less time-consuming and more efficient in parameter optimisation than traditional manual calibration which has been the standard tool practiced for similar complex water quality models.
Global data set of long-term summertime vertical temperature profiles in 153 lakes
Publisher: Springer Science and Business Media LLC
Date: 04-08-2021
DOI: 10.1038/S41597-021-00983-Y
Abstract: Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change.
The Effect of Cyanobacterial Biomass Enrichment by Centrifugation and GF/C Filtration on Subsequent Microcystin Measurement
Publisher: MDPI AG
Date: 10-03-2015
Modulation of microcystin congener abundance following nitrogen depletion of a Microcystis batch culture
Publisher: Springer Science and Business Media LLC
Date: 07-03-2016
Autocalibration of a one-dimensional hydrodynamic-ecological model (DYRESM 4.0-CAEDYM 3.1) using a Monte Carlo approach: simulations of hypoxic events in a polymictic lake
Publisher: Copernicus GmbH
Date: 09-03-2018
Abstract: Abstract. Automated calibration of complex deterministic water quality models with a large number of biogeochemical parameters can reduce time-consuming iterative simulations involving empirical judgements of model fit. We undertook autocalibration of the one-dimensional hydrodynamic-ecological lake model DYRESM-CAEDYM, using a Monte Carlo s ling (MCS) method, in order to test the applicability of this procedure for shallow, polymictic Lake Rotorua (New Zealand). The calibration procedure involved independently minimizing the root-mean-square error (RMSE), maximizing the Pearson correlation coefficient (r) and Nash–Sutcliffe efficient coefficient (Nr) for comparisons of model state variables against measured data. An assigned number of parameter permutations was used for 10 000 simulation iterations. The “optimal” temperature calibration produced a RMSE of 0.54 ∘C, Nr value of 0.99, and r value of 0.98 through the whole water column based on comparisons with 540 observed water temperatures collected between 13 July 2007 and 13 January 2009. The modeled bottom dissolved oxygen concentration (20.5 m below surface) was compared with 467 available observations. The calculated RMSE of the simulations compared with the measurements was 1.78 mg L−1, the Nr value was 0.75, and the r value was 0.87. The autocalibrated model was further tested for an independent data set by simulating bottom-water hypoxia events from 15 January 2009 to 8 June 2011 (875 days). This verification produced an accurate simulation of five hypoxic events corresponding to DO 2 mg L−1 during summer of 2009–2011. The RMSE was 2.07 mg L−1, Nr value 0.62, and r value of 0.81, based on the available data set of 738 days. The autocalibration software of DYRESM-CAEDYM developed here is substantially less time-consuming and more efficient in parameter optimization than traditional manual calibration which has been the standard tool practiced for similar complex water quality models.
Connectivity and complexity of floodplain habitats govern zooplankton dynamics in a large temperate river system
Publisher: Wiley
Date: 03-05-2013
DOI: 10.1111/FWB.12144
Effects of nutrients on algae blooms with in-situ incubation in three lakes of Wuhan in China
Publisher: IEEE
Date: 06-2010
High contribution of methane in greenhouse gas emissions from a eutrophic lake: a mass balance synthesis
Publisher: Informa UK Limited
Date: 06-08-2020
Estimation of total cloud cover from solar radiation observations at Lake Rotorua, New Zealand
Publisher: Elsevier BV
Date: 03-2010
Benthic nutrient fluxes in a eutrophic, polymictic lake
Publisher: Springer Science and Business Media LLC
Date: 06-2007
A mass balance evaluation of the ecological significance of historical nitrogen fluxes in Lake Kinneret
Publisher: Springer Science and Business Media LLC
Date: 27-08-2010
Intra-colony motility of Microcystis wesenbergii cells
Publisher: Informa UK Limited
Date: 02-01-2014
In Situ Collection and Preservation of Intact Microcystis Colonies to Assess Population Diversity and Microcystin Quotas
Publisher: MDPI AG
Date: 24-07-2019
Abstract: Understanding of colony specific properties of cyanobacteria in the natural environment has been challenging because s ling methods disaggregate colonies and there are often delays before they can be isolated and preserved. Microcystis is a ubiquitous cyanobacteria that forms large colonies in situ and often produces microcystins, a potent hepatotoxin. In the present study a new cryo-s ling technique was used to collect intact Microcystis colonies in situ by embedding them in a sheet of ice. Thirty-two of these Microcystis colonies were investigated with image analysis, liquid chromatography-mass spectrometry, quantitative polymerase chain reaction and high-throughput sequencing to assess their volume, microcystin quota and internal transcribed spacer (ITS) genotype ersity. Microcystin quotas were positively correlated to colony volume (R2 = 0.32 p = 0.004). In idual colonies had low Microcystis ITS genotype ersity and one ITS operational taxonomic unit predominated in all s les. This study demonstrates the utility of the cryo-s ling method to enhance the understanding of colony-specific properties of cyanobacteria with higher precision than previously possible.
A numerical simulation of the role of zooplankton in C, N and P cycling in Lake Kinneret, Israel
Publisher: Elsevier BV
Date: 03-2006
Seiche-induced fish-kills in the Sea of Galilee may explain the biblical miraculous catch of fish
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-5873
Abstract: On May 31, 2012, thousands of dead fish were found along the north-western shore of the Sea of Galilee. Analysis of fish gill tissue revealed no evidence of poisoning, and the fish looked healthy. This event adds to reports of similar fish kills at the same location, from the early 1990s, from May 2007, and a subsequent event on June 27, 2012, a month after the May 31 event. The common hypothesis for the massive kill suggests that a seiche induced by strong winds caused the upwelling of colder and anoxic hypolimnetic water along the western shores of the lake. Still, this hypothesis has not yet been tested.The WRF (The Weather Research and Forecasting) atmospheric model was recently coupled with the ocean model MITgcm (MIT general circulation model). The coupled model was named SKRIPS (Scripps& #8211 KAUST Regional Integrated Prediction System). The two SKRIPS model components (WRF and MITgcm) are well-tested at high resolution, allowing us to investigate the physical mechanism of the fish-kill event in an interactive system. To test the hypolimnetic water upwelling hypothesis for the massive fish-kill, we have set up and integrated the SKRIPS model for the May 31, 2012, event at a horizontal grid resolution of 400 m2, both for the atmospheric and lake component of the model.In this talk, I will present results from a high-resolution coupled atmosphere-lake regional simulation indicating an upwelling of cold anoxic hypolimnetic water into the surface during the event. The upwelling of cold water is increased close to the shore. The discussion will be supplemented by field data of temperature and oxygen concentrations, collected before, during, and after the fish-kill event. Our simulation results agree with the field observations, adding confidence to the anoxic hypolimnetic water upwelling hypothesis. Such fish-kill events may explain the biblical & #8216 miraculous catch of fish& #8217 and the & #8216 miracle of the loaves and fish& #8217 . Also, it may provide a possible seasonal time frame (spring) for their occurrence in the past.
Impacts of hydrological changes on phytoplankton succession in the Swan River, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 12-2002
DOI: 10.1007/BF02692234
Are nitrogen-to-phosphorus ratios of Chinese lakes actually increasing?
Publisher: Proceedings of the National Academy of Sciences
Date: 09-2020
Reference and current Trophic Level Index of New Zealand lakes: benchmarks to inform lake management and assessment
Publisher: Informa UK Limited
Date: 03-2020
Effect of intensive catchment and in-lake restoration procedures on phosphorus concentrations in a eutrophic lake
Publisher: Elsevier BV
Date: 04-2010
Physiological responses induced by copper bioaccumulation in Eichhornia crassipes (Mart.)
Publisher: Springer Science and Business Media LLC
Date: 02-02-2007
Transition from planktonic to benthic algal dominance along a salinity gradient
Publisher: Springer Science and Business Media LLC
Date: 02-2006
A data mining approach to evaluate suitability of dissolved oxygen sensor observations for lake metabolism analysis
Publisher: Wiley
Date: 04-10-2018
DOI: 10.1002/LOM3.10283
Mitigating harmful cyanobacterial blooms: strategies for control of nitrogen and phosphorus loads
Publisher: Springer Science and Business Media LLC
Date: 23-08-2016
Impacts of a bivalve mass mortality event on an estuarine food web and bivalve grazing pressure
Publisher: Informa UK Limited
Date: 20-10-2016
Effects of Climate Change on New Zealand Lakes
Publisher: Wiley
Date: 20-11-2012
Regulation of phosphorus bioavailability by iron nanoparticles in a monomictic lake
Publisher: Springer Science and Business Media LLC
Date: 10-12-2018
DOI: 10.1038/S41598-018-36103-X
Abstract: Dissolved reactive phosphorous (DRP) in lake systems is conventionally considered to predominate over other dissolved P species, however, this view neglects an important set of interactions that occurs between P and reactive iron hydroxide surfaces. This study addresses the coupling of P with dispersed iron nanoparticles in lakes, an interaction that may fundamentally alter the bioavailability of P to phytoplankton. We used diffusive gradients in thin films (DGT) and ultrafiltration to study Fe-P coupling in the water column of a monomictic lake over a hydrological year. Fe and P were predominantly colloidal (particle diameters ~5 nm ~20 nm) in both oxic epilimnetic and anaerobic hypolimnetic waters, but they were both DGT-labile under sub-oxic conditions, consistent with diffusion and dissolution of Fe-and-P-bearing colloids within the DGT diffusive gel. During peak stratification, increases in Fe and P bioavailability were spatially and temporally coincident with Fe nanoparticle dissolution and the formation of a deep chlorophyll maximum at 5–8 m depth. These results provide a window into the coupling and decoupling of P with mobile iron colloids, with implications for our understanding of the behaviour of nutrients and their influence on phytoplankton community dynamics.
Phytoplankton assemblages in North Island lakes of New Zealand: Is trophic state, mixing, or light climate more important?
Publisher: Informa UK Limited
Date: 09-2006
EFFECT OF BORON-DOPED GOETHITE ON SOIL ACIDITY, DIFFERENT FORMS OF MANGANESE IN RED SOIL AND THE GROWTH OF RAPE (BRASSICA NAPUS L.) SEEDLINGS
Publisher: Informa UK Limited
Date: 10-2012
Spatial heterogeneity in geothermally-influenced lakes derived from atmospherically corrected Landsat thermal imagery and three-dimensional hydrodynamic modelling
Publisher: Elsevier BV
Date: 08-2016
Quantifying temporal and spatial variations in sediment, nitrogen and phosphorus transport in stream inflows to a large eutrophic lake
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3EM00083D
Abstract: High-frequency s ling of two major stream inflows to a large eutrophic lake (Lake Rotorua, New Zealand) was conducted to measure inputs of total suspended sediment (TSS), and fractions of nitrogen and phosphorus (P). A total of 17 rain events were s led, including three during which both streams were simultaneously monitored to quantify how concentration-discharge (Q) relationships varied between catchments during similar hydrological conditions. Dissolved inorganic nitrogen (DIN) concentrations declined slightly during events, reflecting dilution of groundwater inputs by rainfall, whereas dissolved inorganic P (PO4-P) concentrations were variable and unrelated to Q, suggesting dynamic sorptive behaviour. Event loads of total nitrogen (TN) were predominantly DIN, which is available for immediate uptake by primary producers, whereas total phosphorus (TP) loads predominantly comprised particulate P (less labile). Positive correlations between Q and concentrations of TP (and to a lesser extent TN) reflected increased particulate nutrient concentrations at high flows. Consequently, load estimates based on hourly Q during storm events and concentrations of routine monthly s les (mostly base flow) under-estimated TN and TP loads by an average of 19% and 40% respectively. Hysteresis with Q was commonly observed and inclusion of hydrological variables that reflect Q history in regression models improved predictions of TN and TP concentrations. Lorenz curves describing the proportions of cumulative load versus cumulative time quantified temporal inequality in loading. In the two study streams, 50% of estimated two-year loads of TN, TP and TSS were transported in 202-207, 76-126 and 1-8 days respectively. This study quantifies how hydrological and landscape factors can interact to influence pollutant flux at the catchment scale and highlights the importance of including storm transfers in lake loading estimates.
Low dissolved inorganic nitrogen and increased heterocyte frequency: precursors to Anabaena planktonica blooms in a temperate, eutrophic reservoir
Publisher: Oxford University Press (OUP)
Date: 23-04-2010
Spatial variability in sediment phosphorus characteristics along a hydrological gradient upstream of Lake Rotorua, New Zealand
Publisher: Springer Science and Business Media LLC
Date: 10-08-2014
Biogeochemical processes and phytoplankton nutrient limitation in the inflow transition zone of a large eutrophic lake during a summer rain event
Publisher: Wiley
Date: 20-05-2014
DOI: 10.1002/ECO.1503
Economic and ecosystem costs and benefits of alternative land use and management scenarios in the Lake Rotorua, New Zealand, catchment
Publisher: Elsevier BV
Date: 2019
Conceptual Challenges and Practical Issues in Building The Global Lake Ecological Observatory Network
Publisher: IEEE
Date: 2007
Predictive Models for Determination of E. coli Concentrations at Inland Recreational Beaches
Publisher: Springer Science and Business Media LLC
Date: 29-08-2016
Interrelations between phytoplankton, submerged macrophytes, black swans (Cygnus atratus) and zooplankton in a shallow New Zealand lake
Publisher: Wiley
Date: 1988
Solid-phase photocatalytic degradation of polystyrene plastic with goethite modified by boron under UV-vis light irradiation
Publisher: Elsevier BV
Date: 02-2010
A General Lake Model (GLM 2.4) for linking with high-frequency sensor data from the Global Lake Ecological Observatory Network (GLEON)
Publisher: Copernicus GmbH
Date: 20-11-2017
DOI: 10.5194/GMD-2017-257
Abstract: Abstract. The General Lake Model (GLM) is a one-dimensional open-source model code designed to simulate the hydrodynamics of lakes, reservoirs and wetlands. GLM was developed to support the science needs of the Global Lake Ecological Observatory Network (GLEON), a network of lake sensors and researchers attempting to understand lake functioning and address questions about how lakes around the world vary in response to climate and land-use change. The scale and ersity of lake types, locations and sizes, as well as the observational data within GLEON, created the need for a robust community model of lake dynamics with sufficient flexibility to accommodate a range of scientific and management needs of the GLEON community. This paper summarises the scientific basis and numerical implementation of the model algorithms, including details of sub-models that simulate surface heat exchange and ice-cover dynamics, vertical mixing and inflow/outflow dynamics. A summary of typical parameter values for lakes and reservoirs collated from a range of sources is included. GLM supports a dynamic coupling with biogeochemical and ecological modelling libraries for integrated simulations of water quality and ecosystem health. An overview of approaches for integration with other models, and utilities for the analysis of model outputs and for undertaking sensitivity and uncertainty assessments is also provided. Finally, we discuss application of the model within a distributed cloud-computing environment, and as a tool to support learning of network participants.
Pulsed emissions of methane from a small eutrophic lake
Publisher: Unpublished
Date: 2014
Nutrients and eutrophication: Introduction
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/MF13059
Restoring shallow lakes impaired by eutrophication: Approaches, outcomes, and challenges
Publisher: Informa UK Limited
Date: 30-12-2020
Pulsed emissions of methane from a small eutrophic lake
Publisher: Unpublished
Date: 2014
Effects of benthic substrate, nutrient enrichment and predatory fish on freshwater crayfish (kōura, Paranephrops planifrons) population characteristics in seven Te Arawa (Rotorua) lakes, North Island,
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/MF14148
Abstract: Populations of kōura, or freshwater crayfish (Paranephrops planifrons White, 1842), were quantified along a eutrophication gradient in seven Te Arawa lakes using the tau kōura, a traditional Māori harvesting method, in April, July and November 2009. Six of the seven lakes contained kōura. No kōura were captured in hypertrophic Lake Ōkaro. Kōura catches were highly variable and mean catch per unit effort (CPUE) varied from 1.5 to 99.3kōura per whakaweku (fern bundle) in the six lakes with kōura present. The highest abundance of kōura was recorded in eutrophic Lake Rotorua and the highest biomass in oligotrophic Lake Rotomā. Kōura orbit carapace length (OCL) ranged from 6 to 52mm, with the largest kōura recorded in lakes Rotoiti and Rotomā. Our results suggest that benthic substrate is more important in determining kōura population abundance than nutrient enrichment (using chlorophyll-a as a proxy) or predatory fish (rainbow trout abundance). Nevertheless, lake trophic status in conjunction with lake morphology appeared to indirectly affect kōura distribution in the sheltered, steep-sided lakes, through hypolimnetic deoxygenation.
Phytoplankton succession and the formation of a deep chlorophyll maximum in a hypertrophic volcanic lake
Publisher: Springer Science and Business Media LLC
Date: 15-11-2014
Modelling classical gullies – A review
Publisher: Elsevier BV
Date: 06-2022
Parameterisation of sediment geochemistry for simulating water quality responses to long-term catchment and climate changes in polymictic, eutrophic Lake Rotorua, New Zealand
Publisher: WIT Press
Date: 10-07-2012
DOI: 10.2495/WP120151
Natural and anthropogenic lead in sediments of the Rotorua lakes, New Zealand
Publisher: Elsevier BV
Date: 09-2010
Disaggregation of Microcystis aeruginosa colonies under turbulent mixing: Laboratory experiments in a grid-stirred tank
Publisher: Springer Science and Business Media LLC
Date: 05-2004
Geo-Engineering in Lakes: A Crisis of Confidence?
Publisher: American Chemical Society (ACS)
Date: 19-08-2014
DOI: 10.1021/ES5036267
The use and value of citizen science data in New Zealand
Publisher: Informa UK Limited
Date: 03-07-2015
Carbon, Nitrogen, and Sulfur Elemental Fluxes in the Soil and Exchanges with the Atmosphere in Australian Tropical, Temperate, and Arid Wetlands
Publisher: MDPI AG
Date: 30-12-2020
Abstract: Australian ecosystems, particularly wetlands, are facing new and extreme threats due to climate change, land use, and other human interventions. However, more fundamental knowledge is required to understand how nutrient turnover in wetlands is affected. In this study, we deployed a mechanistic biogeochemical model of carbon (C), nitrogen (N), and sulfur (S) cycles at 0.25∘× 0.25∘ spatial resolution across wetlands in Australia. Our modeling was used to assess nutrient inputs to soil, elemental nutrient fluxes across the soil organic and mineral pools, and greenhouse gas (GHG) emissions in different climatic areas. In the decade 2008–2017, we estimated an average annual emission of 5.12 Tg-CH4, 90.89 Tg-CO2, and 2.34 × 10−2 Tg-N2O. Temperate wetlands in Australia have three times more N2O emissions than tropical wetlands as a result of fertilization, despite similar total area extension. Tasmania wetlands have the highest areal GHG emission rates. C fluxes in soil depend strongly on hydroclimatic factors they are mainly controlled by anaerobic respiration in temperate and tropical regions and by aerobic respiration in arid regions. In contrast, N and S fluxes are mostly governed by plant uptake regardless of the region and season. The new knowledge from this study may help design conservation and adaptation plans to climate change and better protect the Australian wetland ecosystem.
2.11 - Hydrology and Biogeochemistry Linkages.
Publisher: Elsevier
Date: 2011
Empirical and semi-analytical chlorophyll a algorithms for multi-temporal monitoring of New Zealand lakes using Landsat
Publisher: Springer Science and Business Media LLC
Date: 19-05-2015
DOI: 10.1007/S10661-015-4585-4
Abstract: The concentration of chlorophyll a (chl a as a proxy for phytoplankton biomass) provides an indication of the water quality and ecosystem health of lakes. An automated image processing method for Landsat images was used to derive chl a concentrations in 12 Rotorua lakes of North Island, New Zealand, with widely varying trophic status. Semi-analytical and empirical models were used to process 137 Landsat 7 Enhanced Thematic Mapper (ETM+) images using records from 1999 to 2013. Atmospheric correction used radiative transfer modelling, with atmospheric conditions prescribed with Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and AIRS data. The best-performing semi-analytical and empirical equations resulted in similar levels of variation explained (r (2) = 0.68 for both equations) and root-mean-square error (RMSE = 10.69 and 10.43 μg L(-1), respectively) between observed and estimated chl a. However, the symbolic regression algorithm performed better for chl a concentrations <5 μg L(-1). Our Landsat-based algorithms provide a valuable method for synoptic assessments of chl a across the 12 lakes in this region. They also provide a basis for assessing changes in chl a in idual lakes through time. Our methods provide a basis for cost-effective hindcasting of lake trophic status at a regional scale, informing on spatial variability of chl a within and between lakes.
Oxygen Nanobubbles for Lake Restoration—Where Are We at? A Review of a New-Generation Approach to Managing Lake Eutrophication
Publisher: MDPI AG
Date: 21-06-2022
DOI: 10.3390/W14131989
Abstract: Nutrient enrichment of lakes from anthropogenic activities is a significant and increasing issue globally, impairing the health, bio ersity and service provisioning from lakes, with impacts on cultural, recreational, economic and aesthetic values. Internal nutrient loads from lakebed sediment releases are a primary cause of lake eutrophication and have necessitated geoengineering methods to mitigate releases and speed up recovery from eutrophication. Our objective in this review was to evaluate the use of oxygen nanobubbles as a geoengineering technology to remediate low oxygen conditions at the lake sediment/water interface, as a precursor to alleviating eutrophication linked to high internal nutrient loads. Oxygen nanobubbles (NBs) are bubbles 1000 nm formed at the interface of solid surfaces and aqueous solutions. These bubbles have higher density than water, persist for longer and facilitate greater oxygen solubility than larger bubbles. Methods have been developed to enable NB formation at the surface of carrier materials, which are then used in conjunction with modified local soils (MLSs), to ‘floc, lock and oxygenate’ to strip nutrients from the water column, locking them in lakebed sediments and oxygenating the sediments to prevent re-release of nutrients. Most studies of NBs for lake restoration have thus far only demonstrated their potential for this purpose, using short-term, small-scale core incubations conducted mainly in laboratory settings. Work is required to (1) address scalability, including procurement and cost, (2) extend laboratory incubation studies to large outdoor enclosures and pond/lake trials, (3) examine longevity of the effects in the natural environment, including potential for MLSs to smother benthos and/or have toxic effects, and (4) extend to a range of lake environments and MLS types. Legal, cultural and social acceptance of the technology is another prerequisite of applications in the natural environment and requires in idualised analysis. Until these issues are addressed in a systematic way that addresses scalability and recommends suitable carrier materials and MLSs, NBs may continue to remain largely untried as a geoengineering method to address lake eutrophication.
Land Use and Climate Change Effects on Streamflow and Nutrient Loads in a Temperate Catchment: A Simulation Study
Publisher: MDPI AG
Date: 30-06-2023
DOI: 10.3390/LAND12071326
Abstract: Climate and land use changes impact catchment hydrology and water quality (WQ), yet few studies have investigated the amount of land use changes required to meet specific WQ targets under future climate projections. The aim of this study was to determine streamflow and nutrient load responses to future land use change (LUC) and climate change scenarios. We hypothesized that (1) increasing forest coverage would decrease nutrient loads, (2) climate change, with higher temperatures and more intense storms, would lead to increased flow and nutrient loads, and (3) LUC could moderate potential nutrient load increases associated with climate change. We tested these hypotheses with the Soil and Water Assessment Tool (SWAT), which was applied to a lake catchment in New Zealand, where LUC strategies with afforestation are employed to address lake WQ objectives. The model was calibrated from 2002 to 2005 and validated from 2006 to 2010 using measured streamflow (Q) and total nitrogen (TN), total phosphorus (TP), nitrate (NO3-N), and ammonium (NH4-N) concentrations of three streams in the catchment. The model performance across the monitored streams was evaluated using coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE) metrics to provide a basis for model projections. Future scenarios incorporated LUC and climate change (CC) based on the Representative Concentration Pathway 8.5 and were compared to the baseline streamflow and WQ indicators. Consistent with our hypotheses, Q, TN, and TP loads were predicted to decrease with afforestation. Specifically, afforestation of 1.32 km2 in one of the monitored stream sub-catchments (subbasin 3), or 8.8% of the total lake catchment area, would result in reductions of 11.9, 26.2, and 17.7% in modeled annual mean Q, TN, and TP loads, respectively. Furthermore, when comparing simulations based on baseline and projected climate, reductions of 13.6, 22.8, and 19.5% were observed for Q, TN, and TP loads, respectively. Notably, the combined implementation of LUC and CC further decreased Q, TN, and TP loads by 20.2, 36.7, and 28.5%, respectively. This study provides valuable insights into the utilization of LUC strategies to mitigate nutrient loads in lakes facing water quality challenges, and our findings could serve as a prototype for other lake catchments undergoing LUC. Contrary to our initial hypotheses, we found that higher precipitation and temperatures did not result in increased flow and nutrient loading.
Comparison of a mechanistic sediment model and a water column model for hindcasting oxygen decay in benthic chambers
Publisher: Elsevier BV
Date: 2001
Phosphorus and nitrogen loading restraints are essential for successful eutrophication control of Lake Rotorua, New Zealand
Publisher: Freshwater Biological Association
Date: 04-2016
DOI: 10.5268/IW-6.2.998
Increasing Microcystis cell density enhances microcystin synthesis: a mesocosm study
Publisher: Freshwater Biological Association
Date: 02-2012
DOI: 10.5268/IW-2.1.424
Variations in nutrient concentrations at different time scales in two shallow tidally dominated estuaries
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF11102
Abstract: Water-quality observations in estuaries can be highly variable in time and space, making it difficult to quantify nutrient fluxes and to discriminate patterns. We measured nitrate, phosphate and ammonium concentrations in two shallow tidally dominated estuaries in Tauranga Harbour, New Zealand, during four periods (winter, start of spring, end of spring and summer) within 1 year, to determine the source of variability observed in a 19-year monitoring program. These measurements consisted of high-frequency monitoring during one 24-h period (covering a daytime flood-ebb tide and a night-time flood-ebb tide) at each estuary. Concentrations of nitrate and ammonium had distinctive tidal patterns, with rising values during ebb flows. This tidal asymmetry caused a net seaward flux of dissolved inorganic nitrogen (nitrate and ammonium), with higher exports at night. Net fluxes were 34–358 kg N per tidal cycle for nitrate and 22–93 kg N per tidal cycle for ammonium. Fluxes were large relative to previously published model-based predictions for the region, particularly during winter. Our results showed that estuarine s ling strategies need to account for tidal variability and the role of episodic runoff events, and highlighted the importance of correctly validated mass fluxes from field measurements for comparisons with nutrient-loading models.
Fine‐scale cryogenic sampling of planktonic microbial communities: Application to toxic cyanobacterial blooms
Publisher: Wiley
Date: 25-06-2016
DOI: 10.1002/LOM3.10115
Influence of Hydrological Connectivity on Plankton Communities in Natural and Reconstructed Side‐Arms of a Large New Zealand River
Publisher: Wiley
Date: 29-02-2016
DOI: 10.1002/RRA.3008
Wind induced sediment resuspension: A lake-wide model
Publisher: Elsevier BV
Date: 06-1997
Effects of infaunal bivalve density and flow speed on clearance rates and near-bed hydrodynamics
Publisher: Elsevier BV
Date: 05-2011
Plastic debris in lakes and reservoirs
Publisher: Springer Science and Business Media LLC
Date: 12-07-2023
Hindcasting cyanobacterial communities in Lake Okaro with germination experiments and genetic analyses
Publisher: Oxford University Press (OUP)
Date: 02-2009
DOI: 10.1111/J.1574-6941.2008.00630.X
Abstract: Cyanobacterial blooms are becoming increasingly prevalent worldwide. Sparse historic phytoplankton records often result in uncertainty as to whether bloom-forming species have always been present and are proliferating in response to eutrophication or climate change, or if there has been a succession of new arrivals through recent history. This study evaluated the relative efficacies of germination experiments and automated rRNA intergenic spacer analysis (ARISA) assays in identifying cyanobacteria in a sediment core and thus reconstructing the historical composition of cyanobacterial communities. A core (360 mm in depth) was taken in the central, undisturbed basin of Lake Okaro, New Zealand, a lake with a rapid advance of eutrophication and increasing cyanobacteria populations. The core incorporated a tephra from an 1886 volcanic eruption that served to delineate recent sediment deposition. ARISA and germination experiments successfully detected akinete-forming nostocaleans in sediment dating 120 bp and showed little change in Nostocales species structure over this time scale. Species that had not previously been documented in the lake were identified including Aphanizomenon issatschenkoi, a potent anatoxin-a producer. The historic composition of Chrococcales and Oscillatoriales was more difficult to reconstruct, potentially due to the relatively rapid degradation of vegetative cells within sediment.
A spatially resolved model of seasonal variations in phytoplankton and clam (Tapes philippinarum) biomass in Barbamarco Lagoon, Italy
Publisher: Elsevier BV
Date: 08-2008
Temporal and spatial variations in phytoplankton productivity in surface waters of a warm-temperate, monomictic lake in New Zealand
Publisher: Springer Science and Business Media LLC
Date: 26-06-2010
Coupled use of sediment phosphorus speciation and pigment composition to infer phytoplankton phenology over 700 years in a deep oligotrophic lake
Publisher: Springer Science and Business Media LLC
Date: 19-07-2016
Vertical distributions of chlorophyll in deep, warm monomictic lakes
Publisher: Springer Science and Business Media LLC
Date: 03-03-2010
Plant availability of boron doped on iron and manganese oxides and its effect on soil acidosis
Publisher: Elsevier BV
Date: 07-2009
A multi-lake comparative analysis of the General Lake Model (GLM): Stress-testing across a global observatory network
Publisher: Elsevier BV
Date: 04-2018
A General Lake Model (GLM 3.0) for linking with high-frequency sensor data from the Global Lake Ecological Observatory Network (GLEON)
Publisher: Copernicus GmbH
Date: 29-01-2019
Abstract: Abstract. The General Lake Model (GLM) is a one-dimensional open-source code designed to simulate the hydrodynamics of lakes, reservoirs, and wetlands. GLM was developed to support the science needs of the Global Lake Ecological Observatory Network (GLEON), a network of researchers using sensors to understand lake functioning and address questions about how lakes around the world respond to climate and land use change. The scale and ersity of lake types, locations, and sizes, and the expanding observational datasets created the need for a robust community model of lake dynamics with sufficient flexibility to accommodate a range of scientific and management questions relevant to the GLEON community. This paper summarizes the scientific basis and numerical implementation of the model algorithms, including details of sub-models that simulate surface heat exchange and ice cover dynamics, vertical mixing, and inflow–outflow dynamics. We demonstrate the suitability of the model for different lake types that vary substantially in their morphology, hydrology, and climatic conditions. GLM supports a dynamic coupling with biogeochemical and ecological modelling libraries for integrated simulations of water quality and ecosystem health, and options for integration with other environmental models are outlined. Finally, we discuss utilities for the analysis of model outputs and uncertainty assessments, model operation within a distributed cloud-computing environment, and as a tool to support the learning of network participants.
The influence of water quality and sediment geochemistry on the horizontal and vertical distribution of phosphorus and nitrogen in sediments of a large, shallow lake
Publisher: Springer Science and Business Media LLC
Date: 04-02-2009
Environmental Flow Requirements of Estuaries: Providing Resilience to Current and Future Climate and Direct Anthropogenic Changes
Publisher: Frontiers Media SA
Date: 17-11-2021
DOI: 10.3389/FENVS.2021.764218
Abstract: Estuaries host unique bio ersity and deliver a range of ecosystem services at the interface between catchment and the ocean. They are also among the most degraded ecosystems on Earth. Freshwater flow regimes drive ecological processes contributing to their bio ersity and economic value, but have been modified extensively in many systems by upstream water use. Knowledge of freshwater flow requirements for estuaries (environmental flows or E-flows) lags behind that of rivers and their floodplains. Generalising estuarine E-flows is further complicated by responses that appear to be specific to each system. Here we critically review the E-flow requirements of estuaries to 1) identify the key ecosystem processes (hydrodynamics, salinity regulation, sediment dynamics, nutrient cycling and trophic transfer, and connectivity) modulated by freshwater flow regimes, 2) identify key drivers (rainfall, runoff, temperature, sea level rise and direct anthropogenic) that generate changes to the magnitude, quality and timing of flows, and 3) propose mitigation strategies (e.g., modification of dam operations and habitat restoration) to buffer against the risks of altered freshwater flows and build resilience to direct and indirect anthropogenic disturbances. These strategies support re-establishment of the natural characteristics of freshwater flow regimes which are foundational to healthy estuarine ecosystems.
What happens when you add salt: predicting impacts of secondary salinisation on shallow aquatic ecosystems by using an alternative-states model
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/BT02117
Abstract: Alternative-states theory commonly applied, for aquatic systems, to shallow lakes that may be dominated alternately by macrophytes and phytoplankton, under clear-water and enriched conditions, respectively, has been used in this study as a basis to define different states that may occur with changes in wetland salinity. Many wetlands of the south-west of Western Australia are threatened by rapidly increasing levels of salinity as well as greater water depths and permanency of water regime. We identified contrasting aquatic vegetation states that were closely associated with different salinities. Salinisation results in the loss of freshwater species of submerged macrophytes and the dominance of a small number of more salt-tolerant species. With increasing salinity, these systems may undergo further change to microbial mat-dominated systems composed mostly of cyanobacteria and halophilic bacteria. The effect of other environmental influences in mediating switches of vegetation was also examined. Colour and turbidity may play important roles at low to intermediate salinities [concentration of total dissolved solids (TDS) 000 mg L–1] however, coloured or turbid wetlands are rarely found at intermediate to high salinities ( 000 mg L–1 TDS). The role of nutrients remains largely unquantified in saline systems. We propose that alternative-states theory provides the basis of a conceptual framework for predicting impacts on wetlands affected by secondary salinisation. The ability to recognise and predict a change in state with changes in salinity adds a further tool to decision-making processes. A change in state represents a fundamental change in ecosystem function and may be difficult to reverse. This information is also important for the development of restoration strategies. Further work is required to better understand the influence of temporal variation in salinity on vegetation states and probable hysteresis effects.
Phosphorus and arsenic distributions in a seasonally stratified, iron-and manganese-rich lake: Microbiological and geochemical controls
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/EN14094
Abstract: Environmental context Despite being present at trace concentrations, arsenic and phosphorus are among the most important of freshwater contaminants. This research highlights the biogeochemical coupling of both elements in a New Zealand lake. We find that the mineralisation of organic residues coupled to the dissolution of colloidal iron and manganese hydroxides may be an important driver of the bioavailability of phosphorus and arsenic. Abstract Seasonal stratification in temperate lakes greater than a few metres deep provides conditions amenable to pronounced vertical zonation of redox chemistry. Such changes are particularly evident in eutrophic systems where high phytoplankton biomass often leads to seasonally established anaerobic hypolimnia and profound changes in geochemical conditions. In this study, we investigated the behaviour of trace elements in the water column of a seasonally stratified, eutrophic lake. Two consecutive years of data from Lake Ngapouri, North Island, New Zealand, demonstrate the occurrence of highly correlated profiles of phosphorus, arsenic, iron and manganese, all of which increased in concentration by 1–2 orders of magnitude within the anaerobic hypolimnion. Stoichiometric and mass-balance considerations demonstrate that increases in alkalinity in hypolimnetic waters were consistent with observed changes in sulfate, Fe and Mn concentrations with depth, corresponding to dissimilatory reduction of sulfate, FeIII and MnIV hydroxides. Thermodynamic constraints on Fe, Mn and Al solubility indicate that amorphous FeIII, MnIV hydroxides most probably controlled Fe and Mn in the surface mixed layer (~0 to 8m) whereas AlIII hydroxides were supersaturated throughout the entire system. Surface complexation modelling indicated that iron hydroxides (HFO) potentially dominated As speciation in the lake. It is likely that other colloidal phases such as allophanic clays also limited HPO42– activity, reducing competition for HAsO42– adsorption to iron hydroxides. This research highlights the coupling of P, As, Fe and Mn in Lake Ngapouri, and the apparent role of multiple colloidal phases in affecting P and As activity within overarching microbiological and geochemical processes.
Influence of Potamogeton crispus growth on nutrients in the sediment and water of Lake Tangxunhu
Publisher: Springer Science and Business Media LLC
Date: 25-12-2008
Ecological integrity of deep lakes in New Zealand across anthropogenic pressure gradients
Publisher: Elsevier BV
Date: 02-2014
SPATIAL VARIATION OF STRUCTURAL AND FUNCTIONAL INDICATORS IN A LARGE NEW ZEALAND RIVER
Publisher: Wiley
Date: 02-10-2012
DOI: 10.1002/RRA.2609
Ten simple rules for collaboratively writing a multi-authored paper
Publisher: Public Library of Science (PLoS)
Date: 15-11-2018
Restoration of estuary hydrological state with freshwater inflows: Non-linear processes, values-led decisions and multiple world views
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-1213
Abstract: The quantity, quality and timing of freshwater inflow into estuaries is critical for ecosystem health. Coinciding with the United Nations Decade of Restoration (2021& #8211 ), there is great interest in re-creating functional estuarine ecosystems by modifying the physio-chemical characteristics, with the premise that a functional ecosystem will follow (ecoengineering). To restore estuarine ecology, the physical processes of the system must be conductive to the re-establishment and sustenance of biota. These physical processes are generally under-monitored and often not used as a measure of restoration success. We explore ecoengineering to restore freshwater inflows to estuaries, focused on hydrological state. We use a Pressure& #8212 State& #8212 Response (PSR) framework where Pressure refers to anthropogenic pressures on freshwater inflows into estuaries such as dams and dredging. Pressure affects State & #8212 the physical estuarine condition (hydrological state), such as salinity structure, flushing time, water level and energy. A degraded state may result in information flow, such as from monitoring, and lead to a societal Response & #8211 a decision or action that attempts to prevent or reduce these pressures. Such responses may include dam removal, river re ersion, reconnection of tidal channels, dam release combined with mechanical mouth breaching and estuarine dredging. Judging restoration success remains difficult and is often a quality judgement with inherent observer bias. Most targets for improved state focus on ecological expectations and metrics, rather than hydrological state. Moreover, often the reference condition for estuaries is poorly defined, compared to rivers and lakes. & As an ex le of values-led decision making, we focus on Aotearoa New Zealand, where M& #257 ori are the Indigenous people. Here,& it is becoming more common to identify values to set environmental outcomes, including based on Te Ao M& #257 ori (M& #257 ori world view) that are holistic, and inherently include a wealth of Indigenous knowledge. Te Ao M& #257 ori is underpinned by core values engrained in an intergenerational perspective, from whakapapa (connections, genealogy between humans, ecosystems, and all flora and fauna), a theme shared by many other Indigenous Peoples, through to the concept of mauri, the life force or internal energy in living and non-living things& that can be damaged when plants, water, soils and ecosystems are degraded. Mauri has been used to guide efforts to maintain/ restore mahinga kai (traditional areas for gathering kaimoana/ sea food). For ex le, in restoration works in Te Awa o Ng& #257 toroirangi (the Maket& #363 Estuary), one of the major drivers is to restore the mauri of the river and estuary. There are many other ex les from around the world where Indigenous and Local Knowledge (ILK) and world views have been applied in environmental restoration, such as to provide baseline ecosystem information to inform restoration targets and give motivation for restoration. As values are increasingly used as a tool to frame management protocols, a more holistic approach is gradually gaining momentum. However, connecting the less quantifiable values to attributes which can be engineered is an ongoing challenge.&
Modelling the impact of zooplankton grazing on phytoplankton biomass during a dinoflagellate bloom in the Swan River Estuary, Western Australia
Publisher: Elsevier BV
Date: 2001
Growth and turion formation of Potamogeton crispus in response to different phosphorus concentrations in water
Publisher: Springer Science and Business Media LLC
Date: 04-01-2013
Rapid and highly variable warming of lake surface waters around the globe
Publisher: American Geophysical Union (AGU)
Date: 16-12-2015
DOI: 10.1002/2015GL066235
Eco-physiological adaptations that favour freshwater cyanobacteria in a changing climate
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.WATRES.2011.12.016
Abstract: Climate change scenarios predict that rivers, lakes, and reservoirs will experience increased temperatures, more intense and longer periods of thermal stratification, modified hydrology, and altered nutrient loading. These environmental drivers will have substantial effects on freshwater phytoplankton species composition and biomass, potentially favouring cyanobacteria over other phytoplankton. In this Review, we examine how several cyanobacterial eco-physiological traits, specifically, the ability to grow in warmer temperatures buoyancy high affinity for, and ability to store, phosphorus nitrogen-fixation akinete production and efficient light harvesting, vary amongst cyanobacteria genera and may enable them to dominate in future climate scenarios. We predict that spatial variation in climate change will interact with physiological variation in cyanobacteria to create differences in the dominant cyanobacterial taxa among regions. Finally, we suggest that physiological traits specific to different cyanobacterial taxa may favour certain taxa over others in different regions, but overall, cyanobacteria as a group are likely to increase in most regions in the future.
Mustering the troops toward preventative management in lakes
Publisher: Informa UK Limited
Date: 02-01-2022
The hydrology of the upper Swan River Estuary with focus on an artificial destratification trial
Publisher: Wiley
Date: 09-2001
DOI: 10.1002/HYP.298
Nitrogen transformation and transport modeling in groundwater aquifers
Publisher: Elsevier BV
Date: 02-2006
Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments
Publisher: Elsevier BV
Date: 05-2010
Phosphorus storage and utilization strategies of two bloom-forming freshwater cyanobacteria
Publisher: The Royal Society
Date: 19-07-2023
Abstract: The inter-relationships between cellular phosphorus (P) storage, dissolved inorganic P (DIP) uptake affinity, alkaline phosphatase activity (APA) and dissolved inorganic nitrogen (DIN) concentrations were studied in two ubiquitous diazotrophic freshwater cyanobacteria, Raphidiopsis raciborskii (six strains) and Chrysosporum ovalisporum (two strains). DIP uptake kinetics were measured using rates of incorporation of the radio-isotope, 33 P and APA as a proxy for DOP-ester utilization. The study showed that DIP uptake of in idual strains followed Michaelis–Menten kinetics (modified in our study to incorporate cellular P quotas), but differed with DIN and P availability, and between growth stages. High-affinity DIP uptake and APA were activated below a P quota threshold of approximately 0.01 µg P µg −1 C across the species and strains. C. ovalisporum had significantly higher APA and P quotas (per unit C and cell) but lower uptake affinity than R. raciborskii . Demand for DIP by C. ovalisporum increased when N fixation occurred, but typically not for R. raciborskii . Our results indicate that cyanobacterial species and strains differ in their strategies to P limiting conditions, and highlight the interplay between N and P. Physiological adaptations like APA and diazotrophy of cyanobacteria adapting to low DIP and/or DIN conditions may occur simultaneously and drive species dominance in oligotrophic environments.
Modelling inter-annual and spatial variability of ice cover in a temperate lake with complex morphology
Publisher: Wiley
Date: 08-12-2020
DOI: 10.1002/HYP.13618
Algebraic equilibrium solution of tissue nitrogen quota in algae and the discrepancy between calibrated parameters and physiological properties
Publisher: Elsevier BV
Date: 09-2015
Costs of harmful blooms of freshwater cyanobacteria
Publisher: Wiley
Date: 30-11-2013
Modelling interactive effects of multiple disturbances on a coastal lake ecosystem: Implications for management
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.JENVMAN.2017.11.063
Abstract: Coastal lakes, also known as temporarily open/closed estuaries or intermittently closed and open lakes and lagoons, are common worldwide, are typically sites of high bio ersity and often contain abundant macrophyte populations. Anthropogenic stressors such as increased nutrient and sediment loading have adverse effects on submerged macrophytes, and when closed, the lack of tidal flushing makes coastal lakes highly susceptible to eutrophication. Lake openings to the sea may occur naturally, but many coastal lakes are also opened artificially, often to reduce inundation of surrounding land. Here we used a coupled hydrodynamic-ecological model (DYRESM-CAEDYM), modified to include dynamic feedback between submerged macrophyte biomass and sediment resuspension, to explore the interactive effects of multiple disturbances (openings, eutrophication and climate change) on the dynamics of primary producers in a coastal lake (Waituna Lagoon) in South Island, New Zealand. Our results indicate that with exposure to high external nutrient loads, the frequent disturbances caused by artificial openings prevent sustained dominance by algae (algal biomass averaged 192 g C m
Fluorescence probes for real-time remote cyanobacteria monitoring: A review of challenges and opportunities
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.WATRES.2018.05.001
Abstract: In recent years, there has been a widespread deployment of submersible fluorescence sensors by water utilities. They are used to measure diagnostic pigments and estimate algae and cyanobacteria abundance in near real-time. Despite being useful and promising tools, operators and decision-makers often rely on the data provided by these probes without a full understanding of their limitations. As a result, this may lead to wrong and misleading estimations which, in turn, means that researchers and technicians distrust these sensors. In this review paper, we list and discuss the main limitations of such probes, as well as identifying the effect of environmental factors on pigment production, and in turn, the conversion to cyanobacteria abundance estimation. We argue that a comprehensive calibration approach to obtain reliable readings goes well beyond manufacturers' recommendations, and should involve several context-specific experiments. We also believe that if such a comprehensive set of experiments is conducted, the data collected from fluorescence sensors could be used in artificial intelligence modelling approaches to reliably predict, in near real-time, the presence and abundance of different cyanobacteria species. This would have significant benefits for both drinking and recreational water management, given that cyanobacterial toxicity, and taste and odour compounds production, are species-dependent.
Modelling the response of a highly eutrophic lake to reductions in external and internal nutrient loading
Publisher: Informa UK Limited
Date: 06-2011
Evaluating services and damage costs of degradation of a major lake ecosystem
Publisher: Elsevier BV
Date: 12-2016
Modelling hydrology and water quality in a mixed land use catchment and eutrophic lake: Effects of nutrient load reductions and climate change
Publisher: Elsevier BV
Date: 11-2018
Spatiotemporal Assessment of GHG Emissions and Nutrient Sequestration Linked to Agronutrient Runoff in Global Wetlands
Publisher: American Geophysical Union (AGU)
Date: 04-2021
DOI: 10.1029/2020GB006816
Abstract: Wetlands play a key role in regulating global greenhouse gas (GHG) emissions but anthropogenic impacts on nutrients may severely alter this balance. Recent assessments indicate that almost 22% of the global wetland area may be affected by agricultural runoff. In this work, we developed and applied a dynamic mechanistic reaction network model of soil organic matter linking the carbon (C), nitrogen (N), and sulfur (S) cycles at 0.5° × 0.5° spatial resolution across the globe. The model was used to estimate GHG emissions and nutrient sequestration rates in wetlands, driven by environmental stressors including N, P, and S fertilization. Wetland annual GHG emissions are estimated to be 136 ± 12.5 Tg C‐CH 4 , 589 ± 45.8 Tg C‐CO 2 , and 0.3 ± 0.04 Tg N‐N 2 O in contrast, C, N, and S annual sequestration rates are estimated to be 576 ± 88.1 Tg C, 20 ± 4.4 Tg N, and 7.4 ± 0.8 Tg S, between 2000 and 2017. N fertilization inputs were responsible for 13% N 2 O emissions in wetlands in the Northern Hemisphere, while tropical wetlands were major reservoirs for C, N, and S. Temperature, net primary productivity, and methanogenic microorganisms exert the major control on GHG emissions. Wetland CH 4 and CO 2 emissions were found to have a hysteretic relationship with seasonal soil temperature, but not N 2 O. A global‐scale assessment is pivotal for best nutrient management practices, reducing nutrient losses, and controlling gas emissions.
Effects of local climate and hydrological conditions on the thermal regime of a reservoir at Tropic of Cancer, in southern China
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.WATRES.2012.02.014
Abstract: Thermal regime is strongly associated with hydrodynamics in water, and it plays an important role in the dynamics of water quality and ecosystem succession of stratified reservoirs. Changes in both climate and hydrological conditions can modify thermal regimes. Liuxihe Reservoir (23°45'50″N 113°46'52″E) is a large, stratified and deep reservoir in Guangdong Province, located at the Tropic of Cancer of southern China. The reservoir is a warm monomictic water body with a long period of summer stratification and a short period of mixing in winter. The vertical distribution of suspended particulate material and nutrients are influenced strongly by the thermal structure and the associated flow fields. The hypolimnion becomes anoxic in the stratified period, increasing the release of nutrients from the bottom sediments. Fifty-one years of climate and reservoir operational observations are used here to show the marked changes in local climate and reservoir operational schemes. The data show increasing air temperature and more violent oscillations in inflow volumes in the last decade, while the inter-annual water level fluctuations tend to be more moderate. To quantify the effects of changes in climate and hydrological conditions on thermal structure, we used a numerical simulation model to create scenarios incorporating different air temperatures, inflow volumes, and water levels. The simulations indicate that water column stability, the duration of the mixing period, and surface and outflow temperatures are influenced by both natural factors and by anthropogenic factors such as climate change and reservoir operation schemes. Under continuous warming and more stable storage in recent years, the simulations indicate greater water column stability and increased duration of stratification, while irregular large discharge events may reduce stability and lead to early mixing in autumn. Our results strongly suggest that more attention should be focused on water quality in years of extreme climate variation and hydrological conditions, and selective withdrawal of deep water may provide an efficient means to reduce internal loading in warm years.
Extraction and retrieval of potassium from water hyacinth (Eichhornia crassipes)
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.BIORTECH.2005.11.011
Abstract: Studies were carried out on extraction and retrieval of potassium from water hyacinth (Eichhornia crassipes). The stem and leaf were subjected to 13 treatments. The highest rate of K removal following HCl treatment was 69.7% K. Most effective removal of suspended organic substances, Ca2+ and Mg2+ were achieved at pH approximately 13, when 88.0% of K remained in filtrate. Maximum K in precipitate following this step was achieved with tartaric acid additions at n(C4H6O6)/n(K+) of 1.72 when precipitating at 4 degrees C for 3h, which resulted in 72.3% of K removal from the solution. Over the entire process, 44.3% of K in the dried stem-leaf s le of water hyacinth was retrieved in the form of KC4H5O6. This process demonstrated the potential for use of water hyacinth as a resource of potassium to produce potassium salts and provide a valuable end use for the plant, which could be highly invasive in aquatic ecosystems.
Carbon dioxide emissions and sediment organic carbon burials across a gradient of trophic state in eleven New Zealand lakes
Publisher: Springer Science and Business Media LLC
Date: 16-03-2017
Guiding principles for the development and application of solid-phase phosphorus adsorbents for freshwater ecosystems
Publisher: Springer Science and Business Media LLC
Date: 21-03-2016
Impacts of climate change on nutrient and sediment loads from a subtropical catchment
Publisher: Elsevier BV
Date: 11-2023
Controlling metalimnetic bloom of Planktothrix rubescens by a novel water withdrawal strategy: a modelling study
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-4053
Abstract: & & Aggregations of cyanobacteria in lakes and reservoirs are commonly associated with surface blooms, but may also occur in the metalimnion as subsurface or deep chlorophyll maxima. Metalimnetic cyanobacteria blooms are of great concern when potentially toxic species, such as Planktothrix rubescens (P. rubescens), are involved. Apparently, metalimnetic blooms of P. rubescens have increased in frequency and severity in recent years so there is a strong need to establish the external factors controlling its growth. We hypothesized that P. rubescens blooms in reservoirs can be managed by modifying the water withdrawal strategy and altering the light climate experienced by the algae. We tested our hypothesis in Rappbode Reservoir by establishing a series of withdrawal and light scenarios based on a calibrated water quality model (CE-QUAL-W2). Our scenarios demonstrated that metalimnetic water withdrawal reduced P. rubescens biomass in the reservoir. According to the simulation results we defined an optimal withdrawal volume to control P. rubescens blooms in the reservoir as approximately 10 million m& sup& & /sup& during its blooming period. The numerical results also indicated that P. rubescens growth can be most effectively suppressed if the metalimnetic withdrawal is applied in the early stage of its rapid growth (i.e. before the occurrence of blooms). Additionally, the results showed that P. rubescens biomass gradually decreased with increasing light extinction and nearly disappeared when the extinction coefficient exceeded 0.55 m& sup& -1& /sup& . & Our results indicated that close linkages among in situ measurements, model simulations, empirical growth rate and flushing rate calculations could inform management strategies to minimise the harmful impacts of P. rubescens in water supplies. Such a strategy could be used in reservoir operational strategies as an adaptation way to offset the rise in P. rubescens populations that has been linked to climate change.& &
Bioavailability of phosphorus transported during storm flow to a eutrophic, polymictic lake
Publisher: Informa UK Limited
Date: 30-07-2013
Morphospecies-dependent disaggregation of colonies of the cyanobacterium Microcystis under high turbulent mixing
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.WATRES.2018.05.017
Abstract: Preventing formation of large colonies and reducing colony size of the cyanobacterium Microcystis may lead to reductions in bloom formation. Here we investigated the effects of artificial mixing on morphology and disaggregation dynamics of Microcystis colonies in vivo, using a stirring device and a laser particle analyzer. The turbulent dissipation rate (ε) was varied from 0.020 to 0.364 m
Sediment and nutrient accumulation rates in sediments of twelve New Zealand lakes: influence of lake morphology, catchment characteristics and trophic state
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/MF08131
Abstract: Intact sediment cores were collected from the deepest basins of 12 lakes in the Rotorua District, New Zealand, to test for effects of morphological features, catchment characteristics and lake trophic state on net sedimentation rates and sediment nutrient concentrations. Multiple linear regression was used to show that 68% of the variation in net sedimentation rates across the lakes could be explained by lake trophic state and catchment area. Comparison of 2006 data with results from a survey in 1995 showed that surficial sediment (0–2 cm) total phosphorus concentrations (TP) have increased in three of the 12 lakes, at rates ranging from 27.5 to 114.4 mg P kg–1 dry wt y–1. Total nitrogen (TN) concentrations in surficial sediments have increased in nine of the 12 lakes at rates ranging from 51.8 to 869.2 mg N kg–1 dry wt y–1. Temporal changes in sediment TP and TN concentrations were not significantly linearly related (P = 0.12–0.88) to catchment area or different water column indices considered to reflect lake trophic state, including annual mean water column concentrations of TP, TN or chlorophyll a. It is concluded that between-lake variations in sediment TP and TN concentrations are influenced by a range of complex interacting factors, such as sediment redox conditions (and periodic anoxia in the hypolimnion of some lakes) as well as variations in sediment mineral composition (which influences retention and release of various sediment phosphorus and nitrogen species). Subsequently, these factors cause sediment TP and TN concentrations across the 12 lakes to respond differently to temporal changes in water column TP and TN concentrations.
Predicting the effects of climate change on trophic status of three morphologically varying lakes: Implications for lake restoration and management
Publisher: Elsevier BV
Date: 04-2011
Plant availability of Boron adsorbed or occulted on Goethite to rape (Brassica napus L.) seedling
Publisher: Informa UK Limited
Date: 27-09-2010
Intracellular, environmental and biotic interactions influence recruitment of benthicMicrocystis(Cyanophyceae) in a shallow eutrophic lake
Publisher: Oxford University Press (OUP)
Date: 07-2016
Phytoplankton nutrient limitation in a polymictic eutrophic lake: Community versus species-specific responses
Publisher: Schweizerbart
Date: 2007
Modelling of cyanobacterial blooms in the mixed layer of lakes and reservoirs
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/MF9940829
Abstract: The chemical and biological components of existing water quality models are in general described by simple first-order rate equations in which the production and uptake coefficients are fixed functions of the other variables of the model. Thus although, for ex le, in a photosynthesis model the specific algal growth rate may be a function of light intensity, nutrient concentration and temperature, the form of this dependence on these variables is assumed to be fixed. In this paper, the effect on the performance of a water quality model of removing this assumption for the specific case of photosynthesis is examined. An existing coupled motion-photosynthesis model has been installed in the water quality model DYRESM-WQ and the result compared with the original model, which assumes a fixed functional dependence. The resulting model has been applied to two reservoirs, without recalibration. The result shows that the removal of the assumption of a fixed functional form for the photosynthetic growth rate may have a significant effect on the magnitude and timing of predicted cyanobacterial blooms in lakes and reservoirs, which would have important implications for reservoir and lake management. In addition, the result suggests that, in general, the validity of the assumption of fixed functional form for the rate coefficients in water quality models is not assured.
Predicting the resilience and recovery of aquatic systems: A framework for model evolution within environmental observatories
Publisher: American Geophysical Union (AGU)
Date: 09-2015
DOI: 10.1002/2015WR017175
Using the General Lake Model (GLM) to simulate water temperatures and ice cover of a medium-sized lake: a case study of Lake Ammersee, Germany
Publisher: Springer Science and Business Media LLC
Date: 07-2017
Phosphorus speciation in sediments of a deep temperate oligotrophic lake has implications for phytoplankton community
Publisher: Unpublished
Date: 2014
Trends and abrupt changes in 104-years of ice cover and water temperature in a dimictic lake in response to air temperature, wind speed, and water clarity drivers
Publisher: Copernicus GmbH
Date: 19-01-2016
Abstract: Abstract. The one-dimensional hydrodynamic-ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, WI, USA, over a continuous 104-year period (1911–2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multi-year time scales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s−1 to 3.74 m s−1 in 1994. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice on (9.0 days later per century), earlier ice-off (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of: earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (−1.4 C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911–1980, 1981–1993 and 1994–2014) delineated by abrupt changes in air temperature and wind speed. Average summer hypolimnetic temperature and fall turnover date exhibit significant differences between the third period and the first two periods. Changes in ice cover (ice-on and ice-off dates, ice cover duration, and maximum ice thickness) exhibit an abrubt change after 1994 which was related in part to the warm El Niño winter of 1997–1998. Under-ice water temperature, freeze-over water temperature, hypolimnetic temperature, fall turnover date, and stratification duration demonstrate a significant difference in the third period (1994–2014), when air temperature was warmest and wind speeds decreased rather abruptly. The trends in ice cover and water temperature demonstrate responses to both long-term and abrupt changes in meteorological conditions that can be complemented with numerical modelling to better understand how these variables will respond in a future climate.
Modelling the effects of Po River discharge, internal nutrient cycling and hydrodynamics on biogeochemistry of the Northern Adriatic Sea
Publisher: Elsevier BV
Date: 04-2017
Integration of ecology and engineering in the aquatic environment
Publisher: Elsevier BV
Date: 2001
The global Microcystis interactome
Publisher: Wiley
Date: 19-11-2019
DOI: 10.1002/LNO.11361
Low-dose alum application trialled as a management tool for internal nutrient loads in Lake Okaro, New Zealand
Publisher: Informa UK Limited
Date: 06-2008
Ecosystem respiration: Drivers of daily variability and background respiration in lakes around the globe
Publisher: Wiley
Date: 05-2013
Recent invader or indicator of environmental change? A phylogenetic and ecological study of Cylindrospermopsis raciborskii in New Zealand
Publisher: Elsevier BV
Date: 10-2014
Geographic and temporal variations in turbulent heat loss from lakes: A global analysis across 45 lakes
Publisher: Wiley
Date: 07-08-2018
DOI: 10.1002/LNO.10950
Lakes and Reservoirs of Australia and New Zealand
Publisher: Elsevier
Date: 2009
Effect of freshwater flow on the succession and biomass of phytoplankton in a seasonal estuary
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/MF00088
Abstract: Physico-chemical factors affecting phytoplankton succession and dynamics are examined in the upper Swan River estuary, Western Australia. Freshwater discharge affects the residence time available for different phytoplankton taxa to grow. It also influences succession between marine, estuarine and freshwater phytoplankton taxa according to the extent that it hinders intrusion of marine water into the estuary. The three major phytoplankton groups, Bacillariophyta, Dinophyta and Chlorophyta, are strongly separated temporally by season, and spatially along the estuary according to flow and salinity. Bacillariophyta exhibit the widest range of maximum potential growth rates and occur under a wide range of discharges. Dinophyta, dominated by relatively few brackish water species, have the lowest growth rates, and occur only at very low discharges. Chlorophyta, dominated by Chlamydomonas globulosa, are intermediate in their potential growth rates, and are restricted to freshwater conditions. In the Swan River estuary, nutrients appear to be less important than flow and salinity in regulating phytoplankton succession and biomass. It is highly likely that anthropogenic effects on freshwater discharge to Australian estuaries have had a significant impact on composition and biomass of phytoplankton communities. Control of freshwater discharge thus has the potential to control species assemblages, phytoplankton bloom potential, and eutrophication.
Phosphorus dynamics in sediments of a eutrophic lake derived from 31P nuclear magnetic resonance spectroscopy
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/MF13033
Abstract: The determination of organic phosphorus (P) compounds in lake sediments can provide information on the potential for internal P loading. Settling seston and vertical sediment core s les from highly eutrophic Lake Okaro, New Zealand, were collected during a mixed winter and stratified summer period, representing, respectively, when the water column was well oxygenated and when the bottom waters were anoxic. S les were analysed with 31P nuclear magnetic resonance (31P NMR) spectroscopy, which showed that both bottom sediments and settling seston contained orthophosphate, orthophosphate monoesters and diesters, pyrophosphates, polyphosphates and phosphonates. Phosphorus concentration in settling seston increased ~2.5-fold in winter as a result of seasonally induced changes in phytoplankton biomass, with a marked increase in the concentration of orthophosphate. Several potentially bioavailable P compounds in the bottom sediments were identified that were likely to contribute to recycling of P from the sediment to the water column. An ‘apparent half-life’ was used to quantify the time scales on which these compounds were recycled to the overlying water column. Orthophosphate monoesters that include inositol phosphates were the most persistent P compound. On the basis of half-lives, high internal P loadings may persist for more than 20 years, potentially hindering restoration efforts in Lake Okaro.
Lake management: is prevention better than cure?
Publisher: Informa UK Limited
Date: 12-07-2021
Determining the probability of cyanobacterial blooms: the application of Bayesian networks in multiple lake systems
Publisher: Figshare
Date: 2016
Tropical Coastal Wetlands Ameliorate Nitrogen Export During Floods
Publisher: Frontiers Media SA
Date: 05-11-2019
Latitude and lake size are important predictors of over‐lake atmospheric stability
Publisher: American Geophysical Union (AGU)
Date: 05-09-2017
DOI: 10.1002/2017GL073941
A short review of contemporary developments in aquatic ecosystem modelling of lakes and reservoirs
Publisher: Elsevier BV
Date: 07-2019
The role of mobile consumers in lake nutrient cycles: a brief review
Publisher: Springer Science and Business Media LLC
Date: 04-04-2018
Effects of flow on lateral interactions of fish and shrimps with off-channel habitats in a large river-floodplain system
Publisher: Springer Science and Business Media LLC
Date: 04-12-2012
Emerging Challenges for the Drinking Water Industry
Publisher: American Chemical Society (ACS)
Date: 18-02-2014
DOI: 10.1021/ES405606T
Seasonal changes in major ions, nutrients and chlorophyll a at two sites in the Swan River estuary, Western Australia
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/MF05046
Abstract: Seasonal variations in major ions, nutrients and chlorophyll a were examined at two sites in the upper reaches of the Swan River estuary, Western Australia. Intra-annual variations between the variables were strongly influenced by seasonal riverine discharge, though major ions behaved highly conservatively across a wide range of salinity. Reduced discharge following winter produced strong density stratification that coincided with upstream salt wedge propagation and produced distinct physico-chemical identities of surface and bottom waters. Anoxia of bottom waters associated with the salt wedge region induced increased concentrations of ammonium and phosphate, especially at the deeper of the two sites. Locally variable groundwater flow may have also been important in transporting sediment porewater nutrients into the water column. The seasonality of riverine discharge produced large intra-annual variations in temperature (13–29°C) and salinity (3–30). Transient increases in turbidity occurred when the salt wedge coincided with the position of s ling locations. The subsequent flocculation process likely contributed to further oxygen consumption and nutrient regeneration from the bottom sediments, while simultaneously depositing nutrient-rich flocs with low molar N:P ratios (3–8) to the sediment surface. Nutrient ratios and absolute nutrient concentrations suggest that nitrogen is the nutrient most likely to limit phytoplankton growth over most of the year.
Fate of allochthonous dissolved organic carbon in lakes: A quantitative approach
Publisher: Public Library of Science (PLoS)
Date: 14-07-2011
A review of the effects of climate change on riverine flooding in subtropical and tropical regions
Publisher: IWA Publishing
Date: 26-08-2019
DOI: 10.2166/WCC.2019.175
Abstract: Tropical and subtropical regions can be particularly severely affected by flooding. Climate change is expected to lead to more intense precipitation in many regions of the world, increasing the frequency and magnitude of flood events. This paper presents a review of studies assessing the impacts of climate change on riverine flooding in the world's tropical and subtropical regions. A systematic quantitative approach was used to evaluate the literature. The majority of studies reported increases in flooding under climate change, with the most consistent increases predicted for South Asia, South East Asia, and the western Amazon. Results were more varied for Latin America and Africa where there was a notable paucity of studies. Our review points to the need for further studies in these regions as well as in Australia, in small to mid-sized catchments, and in rapidly urbanising catchments in the developing world. Adoption of non-stationary flood analysis techniques and improved site-specific socio-economic and environmental model scenarios were identified as important future directions for research. Data accessibility and mitigation of model uncertainty were recognised as the principal issues faced by researchers investigating the impacts of climate change on tropical and subtropical rivers.
Ice cover and thermal regime in a dimictic seepage lake under climate change
Publisher: Informa UK Limited
Date: 03-07-2018
Dynamics of silicon in lakes of the Taupo Volcanic Zone, New Zealand, and implications for diatom growth
Publisher: Freshwater Biological Association
Date: 04-2016
DOI: 10.5268/IW-6.2.813
Sustainable management of freshwater crayfish (kōura, Paranephrops planifrons) in Te Arawa (Rotorua) lakes, North Island, New Zealand
Publisher: Elsevier BV
Date: 08-2015
Automated calculation of surface energy fluxes with high-frequency lake buoy data
Publisher: Elsevier BV
Date: 08-2015
Modelling and mass balance assessments of nutrient retention in a seasonally-flowing estuary (Swan River Estuary, Western Australia)
Publisher: Elsevier BV
Date: 2008
Spatial and temporal patterns of carbon flow in a temperate, large river food web
Publisher: Springer Science and Business Media LLC
Date: 18-12-2012
A comparison of bacterial community structure, activity and microcystins associated with formation and breakdown of a cyanobacterial scum
Publisher: Inter-Research Science Center
Date: 13-12-2017
DOI: 10.3354/AME01852
Prediction of water quality in lakes and reservoirs. Part I - Model description
Publisher: Elsevier BV
Date: 03-1997
Isolation and structure determination of two new hydrophobic microcystins from Microcystis sp. (CAWBG11)
Publisher: Elsevier BV
Date: 11-2013
Enhanced Sample Preparation for Quantitation of Microcystins by Matrix‐Assisted Laser Desorption/Ionisation–Time of Flight Mass Spectrometry
Publisher: Wiley
Date: 30-09-2011
DOI: 10.1002/PCA.1356
Abstract: Microcystins (MCs) are a group of cyanotoxins which pose a serious health threat when present in aquatic systems. Quantitative analysis of MCs by matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry has potential for the processing of large numbers of s les quickly and economically. The existing method uses an expensive internal standard and protocols that are incompatible with automated s le preparation and data acquisition. To produce a MALDI-TOF s le preparation technique for the quantitation of MCs that not only maintains reproducibility and sensitivity, but is also compatible with an automated work-flow. Seven different MALDI-TOF s le preparations were assessed for signal reproducibility (coefficient of variation) and sensitivity (method detection limit) using a cost-effective internal standard (angiotensin I). The best preparation was then assessed for its quantitative performance using three different MC congeners ([Dha⁷] MC-LR, MC-RR and MC-YR). The sensitivity of six of the preparations was acceptable, as was the reproducibility for two thin-layer preparations performed on a polished steel target. Both thin-layer preparations could be used with a MALDI-TOF mass spectrometer that automatically acquires data, and one could be used in an automated s le preparation work-flow. Further investigation using the thin-layer spot preparation demonstrated that linear quantification of three different MC congeners was possible. The study demonstrates that with different s le preparation methods and modern instrumentation, large numbers of s les can be analysed rapidly for MCs at low cost.
Are geothermal streams important sites of nutrient uptake in an agricultural and urbanising landscape (Rotorua, New Zealand)?
Publisher: Wiley
Date: 20-10-2011
Combating hypoxia/anoxia at sediment-water interfaces: A preliminary study of oxygen nanobubble modified clay materials
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.SCITOTENV.2018.04.284
Abstract: Combating hypoxia/anoxia is an increasingly common need for restoring natural waters suffering from eutrophication. Oxygen nanobubble modified natural particles were investigated for mitigating hypoxia/anoxia at the sediment-water interface (SWI) in a simulated column experiment. By adding oxygen nanobubble modified zeolites (ONMZ) and local soils (ONMS), the oxygen nanobubble concentrations (10
Variable littoral-pelagic coupling as a food-web response to seasonal changes in pelagic primary production
Publisher: Wiley
Date: 29-10-2017
DOI: 10.1111/FWB.13046
Influence of nitrogen on the primary and secondary metabolism and synthesis of flavonoids in Chrysanthemum morifolium Ramat
Publisher: Informa UK Limited
Date: 08-01-2010
Nutrient limitation of phytoplankton in solar salt ponds in Shark Bay, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 26-02-2009
Lake‐size dependency of wind shear and convection as controls on gas exchange
Publisher: American Geophysical Union (AGU)
Date: 05-2012
DOI: 10.1029/2012GL051886
Nitrogen-15 Isotope Enrichment in Benthic Boundary Layer Gases of a Stratified Eutrophic Iron and Manganese Rich Lake
Publisher: Springer Science and Business Media LLC
Date: 12-07-2011
Long-term changes in the water quality of a deep temperate oligotrophic lake in response to catchment disturbance: evidence from sediment cores
Publisher: Informa UK Limited
Date: 17-02-2019
Does sediment capping have post-application effects on zooplankton and phytoplankton?
Publisher: Springer Science and Business Media LLC
Date: 23-10-2009
Relationship of Attributes of Soil and Topography with Land Cover Change in the Rift Valley Basin of Ethiopia
Publisher: MDPI AG
Date: 06-07-2022
DOI: 10.3390/RS14143257
Abstract: Understanding the spatiotemporal trend of land cover (LC) change and its impact on humans and the environment is essential for decision making and ecosystem conservation. Land degradation generally accelerates overland flow, reducing soil moisture and base flow recharge, and increasing sediment erosion and transport, thereby affecting the entire basin hydrology. In this study, we analyzed watershed-scale processes in the study area, where agriculture and natural shrub land are the dominant LCs. The objective of this study was to assess the time series and spatial patterns of LCC using remotely-sensed data from 1973 to 2018, for which we used six snapshots of satellite images. The LC distribution in relation to watershed characteristics such as topography and soils was also evaluated. For LCC detection analysis, we used Landsat datasets accessed from the United States Geological Survey (USGS) archive, which were processed using remote sensing and Geographic Information System (GIS) techniques. Using these data, four major LC types were identified. The findings of an LC with an overall accuracy above 90% indicates that the area experienced an increase in agricultural LC at the expense of other LC types such as bushland, grazing land, and mixed forest, which attests to the semi-continuous nature of deforestation between 1973 and 2018. In 1973, agricultural land covered only 10% of the watershed, which later expanded to 48.4% in 2018. Bush, forest, and grazing land types, which accounted for 59.7%, 16.7%, and 13.5% of the watershed in 1973, were reduced to 45.2%, 2.3%, and 4.1%, respectively in 2018. As a result, portions of land areas, which had once been covered by pasture, bush, and forest in 1973, were identified as mixed agricultural systems in 2018. Moreover, spatial variability and distribution in LCC is significantly affected by soil type, fertility, and slope. The findings showed the need to reconsider land-use decision tradeoffs between social, economic, and environmental demands.
Reducing the external environmental costs of pastoral farming in New Zealand: Experiences from the Te Arawa lakes, Rotorua
Publisher: Informa UK Limited
Date: 09-2011
Nitrogen and Phosphorus Limitation of Phytoplankton Growth in New Zealand Lakes: Implications for Eutrophication Control
Publisher: Springer Science and Business Media LLC
Date: 06-08-2010
Effects of zinc toxicity on biochemical composition of muscle and liver of murrel (Channa punctatus)
Publisher: Elsevier BV
Date: 05-1998
Terrain Effects on the Spatial Variability of Soil Physical and Chemical Properties
Publisher: MDPI AG
Date: 20-12-2019
DOI: 10.3390/SOILSYSTEMS4010001
Abstract: Understanding topography effects on soil properties is vital to modelling landscape hydrology and establishing sustainable on-field management practices. This research focuses on an arable area (117 km2) in Southwestern Ethiopia where agricultural fields and bush cover are the dominant land uses. We postulate that adapting either of the soil data resources, coarse resolution FAO-UNESCO (Food and Agriculture Organization of the United Nations Educational, Scientific and Cultural Organization) soil data or pedo-transfer functions (PTFs) is not reliable to indicate future watershed management directions. The FAO-UNESCO data does not account for scale issues and assigns the same soil property at different landscape gradients. The PTFs, on the other hand, do not account for environmental effects and fail to provide all the required data. In this regard, mapping soil property spatial dynamics can help understand landscape physicochemical processes and corresponding land use changes. For this purpose, soil s les were collected across the watershed following a gridded s ling scheme. In areas with heterogeneous topography, soil is spatially variable as influenced by land use and slope. To understand the spatial variation, this research develops indicators, such as topographic index, soil topographic wetness index, elevation, aspect, and slope. Pearson correlation (r), among others, was used to investigate terrain effects on selected soil properties: organic matter (OM), available water content (AWC), sand content (%), clay content (%), silt content (%), electrical conductivity (EC), moist bulk density (MBD), and saturated hydraulic conductivity (Ksat). The results show that there were statistically significant correlations between elevation-based variables and soil physical properties. Among the variables considered, the ‘r’ value between topographic index and soil attributes (i.e., OM, EC, AWC, sand, clay, silt, and Ksat) were 0.66, 0.5, 0.7, 0.55, 0.62, 0.4, and 0.66, respectively. In conclusion, while understanding topography effects on soil properties is vital, implementing either FAO-UNESCO or PTFs soil data do not provide appropriate information pertaining to scale issues.
Response lags and environmental dynamics of restoration efforts for Lake Rotorua, New Zealand
Publisher: IOP Publishing
Date: 07-2015
Recent occurrence of Cylindrospermopsis raciborskii in Waikato lakes of New Zealand
Publisher: Informa UK Limited
Date: 12-2003
Global co‐occurrence of methanogenic archaea and methanotrophic bacteria in Microcystis aggregates
Publisher: Wiley
Date: 08-08-2021
Abstract: Global warming and eutrophication contribute to the worldwide increase in cyanobacterial blooms, and the level of cyanobacterial biomass is strongly associated with rises in methane emissions from surface lake waters. Hence, methane‐metabolizing microorganisms may be important for modulating carbon flow in cyanobacterial blooms. Here, we surveyed methanogenic and methanotrophic communities associated with floating Microcystis aggregates in 10 lakes spanning four continents, through sequencing of 16S rRNA and functional marker genes. Methanogenic archaea (mainly Methanoregula and Methanosaeta ) were detectable in 5 of the 10 lakes and constituted the majority (~50%–90%) of the archaeal community in these lakes. Three of the 10 lakes contained relatively more abundant methanotrophs than the other seven lakes, with the methanotrophic genera Methyloparacoccus , Crenothrix , and an uncultured species related to Methylobacter dominating and nearly exclusively found in each of those three lakes. These three are among the five lakes in which methanogens were observed. Operational taxonomic unit (OTU) richness and abundance of methanotrophs were strongly positively correlated with those of methanogens, suggesting that their activities may be coupled. These Microcystis ‐aggregate‐associated methanotrophs may be responsible for a hitherto overlooked sink for methane in surface freshwaters, and their co‐occurrence with methanogens sheds light on the methane cycle in cyanobacterial aggregates.
Relationships between land use and nitrogen and phosphorus in New Zealand lakes
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/MF10180
Abstract: Developing policies to address lake eutrophication requires an understanding of the relative contribution of different nutrient sources and of how lake and catchment characteristics interact to mediate the source–receptor pathway. We analysed total nitrogen (TN) and total phosphorus (TP) data for 101 New Zealand lakes and related these to land use and edaphic sources of phosphorus (P). We then analysed a sub-s le of lakes in agricultural catchments to investigate how lake and catchment variables influence the relationship between land use and in-lake nutrients. Following correction for the effect of co-variation amongst predictor variables, high producing grassland (intensive pasture) was the best predictor of TN and TP, accounting for 38.6% and 41.0% of variation, respectively. Exotic forestry and urban area accounted for a further 18.8% and 3.6% of variation in TP and TN, respectively. Soil P (representing naturally-occurring edaphic P) was negatively correlated with TP, owing to the confounding effect of pastoral land use. Lake and catchment morphology (zmax and lake : catchment area) and catchment connectivity (lake order) mediated the relationship between intensive pasture and in-lake nutrients. Mitigating eutrophication in New Zealand lakes requires action to reduce nutrient export from intensive pasture and quantifying P export from plantation forestry requires further consideration.
Contrasting cyanobacterial communities and microcystin concentrations in summers with extreme weather events: insights into potential effects of climate change
Publisher: Springer Science and Business Media LLC
Date: 09-07-2016
Ten steps applied to development and evaluation of process-based biogeochemical models of estuaries
Publisher: Elsevier BV
Date: 04-2008
HARP: A suite of parameters to describe the hysteresis of streamflow and water quality constituents
Publisher: Elsevier BV
Date: 11-2023
Three-dimensional modelling of a Microcystis bloom event in the Swan River estuary, Western Australia
Publisher: Elsevier BV
Date: 05-2004
Switching toxin production on and off: intermittent microcystin synthesis in a Microcystis bloom
Publisher: Wiley
Date: 02-2011
DOI: 10.1111/J.1758-2229.2010.00196.X
Abstract: Toxic cyanobacterial blooms are increasing in prevalence. Microcystins are the most commonly produced cyanotoxin. Despite extensive research the variables regulating microcystin production remain unclear. Using a RT-QPCR assay that allowed the precise measurement of mcyE transcriptional gene expression and an ELISA that enabled small changes in total microcystin concentrations to be monitored, we demonstrate for the first time that microcystin production is not always constitutive and that significant up- and downregulation in microcystin synthesis can occur on time scales of 2-6 h. S les were collected over 3 days from a small eutrophic lake during a dense microcystin-producing Microcystis bloom. McyE gene transcripts were detected in only four out of 14 s les. Vicissitudes in both microcystin quotas and extracellular microcystin levels corresponded with changes in mcyE expression. During the period of exalted microcystin synthesis Microcystis sp. cell concentrations increased from 70 000 cells ml(-1) to 4 000 000 cells ml(-1) . These data provide compelling evidence that changes in Microcystis cell concentrations influence microcystin production.
Phycocyanin sensors as an early warning system for cyanobacteria blooms concentrations: a case study in the Rotorua lakes
Publisher: Informa UK Limited
Date: 19-05-2019
Multiple lines of evidence determine robust nutrient load limits required to safeguard a threatened lake/lagoon system
Publisher: Informa UK Limited
Date: 02-01-2017
Wind forced circulation and sediment disturbance in a temperate lake
Publisher: Informa UK Limited
Date: 02-04-2016
Variations in the Distribution of Chl-a and Simulation Using a Multiple Regression Model
Publisher: MDPI AG
Date: 18-11-2019
Abstract: Chlorophyll a (Chl-a) is an important indicator of algal biomass in aquatic ecosystems. In this study, monthly monitoring data for Chl-a concentration were collected between 2005 and 2015 at four stations in Meiliang Bay, a eutrophic bay in Lake Taihu, China. The spatiotemporal distribution of Chl-a in the bay was investigated, and a statistical model to relate the Chl-a concentration to key driving variables was also developed. The monthly Chl-a concentration in Meiliang Bay changed from 2.6 to 330.0 μg/L, and the monthly mean Chl-a concentration over 11 years was found to be higher at s ling site 1, the northernmost site near Liangxihe River, than at the three other s ling sites. The annual mean Chl-a concentration fluctuated greatly over time and exhibited an upward trend at all sites except s ling site 3 in the middle of Meiliang Bay. The Chl-a concentration was positively correlated with total phosphorus (TP r = 0.57, p 0.01), dissolved organic matter (DOM r = 0.73, p 0.01), pH (r = 0.44, p 0.01), and water temperature (WT r = 0.37, p 0.01), and negatively correlated with nitrate (NO3−-N r = −0.28, p 0.01), dissolved oxygen (DO r = −0.12, p 0.01), and Secchi depth (ln(SD) r = −0.11, p 0.05). A multiple linear regression model integrating the interactive effects of TP, DOM, WT, and pH on Chl-a concentrations was established (R = 0.80, F = 230.7, p 0.01) and was found to adequately simulate the spatiotemporal dynamics of the Chl-a concentrations in other regions of Lake Taihu. This model provides lake managers with an alternative for the control of eutrophication and the suppression of aggregations of phytoplankton biomass at the water surface.
High Levels of Structural Diversity Observed in Microcystins from Microcystis CAWBG11 and Characterization of Six New Microcystin Congeners
Publisher: MDPI AG
Date: 13-11-2014
DOI: 10.3390/MD12115372
Temporal changes between ecological regimes in a range of primary and secondary salinised wetlands
Publisher: Springer Science and Business Media LLC
Date: 12-2005
Effects of hydrologic conditions on SWAT model performance and parameter sensitivity for a small, mixed land use catchment in New Zealand
Publisher: Copernicus GmbH
Date: 13-10-2015
DOI: 10.5194/HESS-19-4127-2015
Abstract: Abstract. The Soil Water Assessment Tool (SWAT) was configured for the Puarenga Stream catchment (77 km2), Rotorua, New Zealand. The catchment land use is mostly plantation forest, some of which is spray-irrigated with treated wastewater. A Sequential Uncertainty Fitting (SUFI-2) procedure was used to auto-calibrate unknown parameter values in the SWAT model. Model validation was performed using two data sets: (1) monthly instantaneous measurements of suspended sediment (SS), total phosphorus (TP) and total nitrogen (TN) concentrations and (2) high-frequency (1–2 h) data measured during rainfall events. Monthly instantaneous TP and TN concentrations were generally not reproduced well (24 % bias for TP, 27 % bias for TN, and R2 0.1, NSE 0 for both TP and TN), in contrast to SS concentrations ( 1 % bias R2 and NSE both 0.75) during model validation. Comparison of simulated daily mean SS, TP and TN concentrations with daily mean discharge-weighted high-frequency measurements during storm events indicated that model predictions during the high rainfall period considerably underestimated concentrations of SS (44 % bias) and TP (70 % bias), while TN concentrations were comparable ( 1 % bias R2 and NSE both ~ 0.5). This comparison highlighted the potential for model error associated with quick flow fluxes in flashy lower-order streams to be underestimated compared with low-frequency (e.g. monthly) measurements derived predominantly from base flow measurements. To address this, we recommend that high-frequency, event-based monitoring data are used to support calibration and validation. Simulated discharge, SS, TP and TN loads were partitioned into two components (base flow and quick flow) based on hydrograph separation. A manual procedure (one-at-a-time sensitivity analysis) was used to quantify parameter sensitivity for the two hydrologically separated regimes. Several SWAT parameters were found to have different sensitivities between base flow and quick flow. Parameters relating to main channel processes were more sensitive for the base flow estimates, while those relating to overland processes were more sensitive for the quick flow estimates. This study has important implications for identifying uncertainties in parameter sensitivity and performance of hydrological models applied to catchments with large fluctuations in stream flow and in cases where models are used to examine scenarios that involve substantial changes to the existing flow regime.
Quantifying the Extent of Anthropogenic Eutrophication of Lakes at a National Scale in New Zealand
Publisher: American Chemical Society (ACS)
Date: 08-2019
Abstract: Quantifying environmental changes relative to ecosystem reference conditions (baseline or natural states) can inform assessment of anthropogenic impacts and the development of restoration objectives and targets. We developed statistical models to predict current and reference concentrations of total nitrogen (TN) and total phosphorus (TP) in surface waters for a nationally representative s le of ≥1033 New Zealand lakes. The lake-specific nutrient concentrations reflected variation in factors including anthropogenic nutrient loads, hydrology, geology, elevation, climate, and lake and catchment morphology. Changes between reference and current concentrations were expressed to quantify the magnitude of anthropogenic eutrophication. Overall, there was a clear increase in lake trophic status, with the most common trophic status being oligotrophic under a reference state and mesotrophic under current conditions. The magnitude of departure from reference state varied considerably within the s le however, on average, the mean TN concentration approximately doubled between reference and current states, whereas the mean TP concentration increased approximately 4-fold. This study quantified the extent of water quality degradation across lake types at a national scale, thereby informing ecological restoration objectives and the potential to reduce anthropogenic nutrient loads, while also providing a modeling framework that can be applied to lakes elsewhere.
Coupling high-resolution measurements to a three-dimensional lake model to assess the spatial and temporal dynamics of the cyanobacterium Planktothrix rubescens in a medium-sized lake
Publisher: Springer Science and Business Media LLC
Date: 05-04-2012
High- and low-affinity phosphate uptake and its effect on phytoplankton dominance in a phosphate-depauperate lake
Publisher: Inter-Research Science Center
Date: 24-06-2015
DOI: 10.3354/AME01751
Quantifying the role of organic phosphorus mineralisation on phytoplankton communities in a warm-monomictic lake
Publisher: Informa UK Limited
Date: 02-01-2019
Prediction of water quality in lakes and reservoirs: Part II - Model calibration, sensitivity analysis and application
Publisher: Elsevier BV
Date: 03-1997
Calibrating the Dynamic Reservoir Simulation Model (DYRESM) and filling required data gaps for one-dimensional thermal profile predictions in a boreal lake
Publisher: Wiley
Date: 12-2007
Physiology, blooms and prediction of planktonic cyanobacteria
Publisher: Springer Netherlands
Date: 2012
Preface: Lake restoration: An experimental ecosystem approach for eutrophication control
Publisher: Springer Science and Business Media LLC
Date: 29-11-2011
Supplementary material to "Auto-calibration of a one-dimensional hydrodynamicecological model (DYRESM 4.0-CAEDYM 3.1) using a Monte Carlo approach: simulations of hypoxic events in a polymictic lake"
Publisher: Copernicus GmbH
Date: 18-09-2017
Management strategies to optimise sustainable clam (Tapes philippinarum) harvests in Barbamarco Lagoon, Italy
Publisher: Elsevier BV
Date: 2009
Application of flow cytometry for examining phytoplankton succession in two eutrophic lakes
Publisher: IWA Publishing
Date: 08-2011
DOI: 10.2166/WST.2011.099
Abstract: Flow cytometry has potential as a rapid assessment technique to evaluate phytoplankton biomass and species composition. It facilitates for multi-parameter analysis of in idual cells on the basis of light scattering effects induced from cellular constituents, as well as auto-fluorescence. Fluorescence emission characteristics may be especially useful in classifying cyanobacteria as they contain phycoerythrin which emits light predominantly in the 550–600 nm waveband, chlorophyll-a (650–700 nm emission) and allophycocyanin (660 nm emission). The objective of our study was to assess the utility of flow cytometry for the rapid identification and sorting of freshwater algae and cyanobacteria species. Using a selection of laboratory-cultured freshwater algae and cyanobacteria species, this study demonstrated unique light scatter and fluorescent characteristics for each species examined, allowing for rapid species identification and sorting of mixed populations of laboratory cultures and s les from two lakes in the Rotorua region (New Zealand). Analysis of lake water s les collected over seven months demonstrated changes in abundance and community composition of phytoplankton in the two lakes and demonstrates that flow cytometry may be a useful technique for examining seasonal changes in phytoplankton composition.
Diel Surface Temperature Range Scales with Lake Size
Publisher: Public Library of Science (PLoS)
Date: 29-03-2016
In-situ fluorescence monitoring of cyanobacteria: Laboratory-based quantification of species-specific measurement accuracy
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.HAL.2019.101625
Abstract: In recent years, in-situ fluorometers have been extensively deployed to monitor cyanobacteria in near real-time. Acceptable accuracy can be achieved between measured pigments and cyanobacteria biovolume provided the cyanobacteria species are known. However, cellular photosynthetic pigment content and measurement interferences are site and species specific and can dramatically affect sensor reliability. We quantified the accuracy of an in-situ fluorometer compared with traditional methods using mono- and mixed cultures of four different cyanobacterial species. We found: (1) lower pigment content in cultures in stationary phase, (2) higher precision with the sensor compared to traditional pigment quantification methods of measuring phycocyanin and chlorophyll a, (3) species-specific relationships between sensor readings and measurements related to biovolume, (4) overestimation of pigments in mixed compared with mono cultures, (5) dissolved organic matter causing a loss in signal proportional to its degree of aromaticity, and (6) potential to quantify the degree of cell lysis with a fluorescent dissolved organic matter sensor. This study has provided important new information on the strengths and limitations of fluorescence sensors. The sensor readings can provide accurate biovolume quantification and species determination for a number of bloom-forming species when sensors are properly compensated and calibrated.
Perspective: Advancing the research agenda for improving understanding of cyanobacteria in a future of global change
Publisher: Elsevier BV
Date: 2020
A Global Lake Ecological Observatory Network (GLEON) for synthesising high–frequency sensor data for validation of deterministic ecological models
Publisher: Freshwater Biological Association
Date: 2015
DOI: 10.5268/IW-5.1.566
Impacts of atmospheric stilling and climate warming on cyanobacterial blooms: An individual-based modelling approach
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.WATRES.2022.118814
Abstract: Harmful algal blooms of the freshwater cyanobacteria genus Microcystis are a global problem and are expected to intensify with climate change. In studies of climate change impacts on Microcystis blooms, atmospheric stilling has not been considered. Stilling is expected to occur in some regions of the world with climate warming, and it will affect lake stratification regimes. We tested if stilling could affect water column Microcystis distributions using a novel in idual-based model (IBM). Using the IBM coupled to a three-dimensional hydrodynamic model, we assessed responses of colonial Microcystis biomass to wind speed decrease and air temperature increase projected under a future climate. The IBM altered Microcystis colony size using relationships with turbulence from the literature, and included light, temperature, and nutrient effects on Microcystis growth using input data from a shallow urban lake. The model results show that dynamic variations in colony size are critical for accurate prediction of cyanobacterial bloom development and decay. Colony size (mean and variability) increased more than six-fold for a 20% decrease in wind speed compared with a 2 °C increase in air temperature. Our results suggest that atmospheric stilling needs to be included in projections of changes in the frequency, distribution and magnitude of blooms of buoyant, colony-forming cyanobacteria under climate change.
Sensor manufacturer, temperature, and cyanobacteria morphology affect phycocyanin fluorescence measurements
Publisher: Springer Science and Business Media LLC
Date: 27-10-2017
DOI: 10.1007/S11356-017-0473-5
Abstract: Sensors to measure phycocyanin fluorescence in situ are becoming widely used as they may provide useful proxies for cyanobacterial biomass. In this study, we assessed five phycocyanin sensors from three different manufacturers. A combination of culture-based experiments and a 30-s le field study was used to examine the effect of temperature and cyanobacteria morphology on phycocyanin fluorescence. Phycocyanin fluorescence increased with decrease in temperature, although this varied with manufacturer and cyanobacterial density. Phycocyanin fluorescence and cyanobacterial biovolume were strongly correlated (R
Flushing of dense, hypoxic water from a cavity of the Swan River estuary, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 10-2002
DOI: 10.1007/BF02691339
Further Characterization of Glycine-Containing Microcystins from the McMurdo Dry Valleys of Antarctica
Publisher: MDPI AG
Date: 10-02-2015
Application of a Three-Dimensional Water Quality Model as a Decision Support Tool for the Management of Land-Use Changes in the Catchment of an Oligotrophic Lake
Publisher: Springer Science and Business Media LLC
Date: 19-06-2014
DOI: 10.1007/S00267-014-0306-Y
Abstract: While expansion of agricultural land area and intensification of agricultural practices through irrigation and fertilizer use can bring many benefits to communities, intensifying land use also causes more contaminants, such as nutrients and pesticides, to enter rivers, lakes, and groundwater. For lakes such as Benmore in the Waitaki catchment, South Island, New Zealand, an area which is currently undergoing agricultural intensification, this could potentially lead to marked degradation of water clarity as well as effects on ecological, recreational, commercial, and tourism values. We undertook a modeling study to demonstrate science-based options for consideration of agricultural intensification in the catchment of Lake Benmore. Based on model simulations of a range of potential future nutrient loadings, it is clear that different areas within Lake Benmore may respond differently to increased nutrient loadings. A western arm (Ahuriri) could be most severely affected by land-use changes and associated increases in nutrient loadings. Lake-wide annual averages of an eutrophication indicator, the trophic level index (TLI) were derived from simulated chlorophyll a, total nitrogen, and total phosphorus concentrations. Results suggest that the lake will shift from oligotrophic (TLI = 2-3) to eutrophic (TLI = 4-5) as external loadings are increased eightfold over current baseline loads, corresponding to the potential land-use intensification in the catchment. This study provides a basis for use of model results in a decision-making process by outlining the environmental consequences of a series of land-use management options, and quantifying nutrient load limits needed to achieve defined trophic state objectives.
Latitudinal variation in nutrient stoichiometry and chlorophyll-nutrient relationships in lakes: A global study
Publisher: Schweizerbart
Date: 06-2012
A framework for testing the ability of models to project climate change and its impacts
Publisher: Springer Science and Business Media LLC
Date: 11-2013
Geoengineering in lakes: welcome attraction or fatal distraction?
Publisher: Freshwater Biological Association
Date: 10-2014
DOI: 10.5268/IW-4.4.769
Light attenuation characteristics of glacially‐fed lakes
Publisher: American Geophysical Union (AGU)
Date: 07-2014
DOI: 10.1002/2014JG002674
Related Organisations
Related Funding Activities
Toxic In Crowds: The Triggers Of Toxin Production In Planktonic Cyanobacteria
Start Date: 2013
End Date: 2016
Funder: Marsden Fund
View Funded ActivityExploring The Utility Of Stable State Theory In Real-world Environmental Problems
Start Date: 2021
End Date: 2024
Funder: Marsden Fund
View Funded ActivityDiscovery Projects - Grant ID: DP210102575
Start Date: 04-2021
End Date: 04-2024
Amount: $390,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP190101848
Start Date: 04-2019
End Date: 04-2023
Amount: $475,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP0776375
Start Date: 05-2008
End Date: 05-2011
Amount: $120,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0211475
Start Date: 05-2002
End Date: 12-2002
Amount: $50,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP130104078
Start Date: 2013
End Date: 12-2015
Amount: $360,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP0219300
Start Date: 06-2002
End Date: 12-2005
Amount: $108,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP220200882
Start Date: 07-2023
End Date: 06-2026
Amount: $565,671.00
Funder: Australian Research Council
View Funded Activity