ORCID Profile
0000-0002-6929-6626
Current Organisation
James Cook University
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Publisher: Elsevier BV
Date: 11-2016
Publisher: Public Library of Science (PLoS)
Date: 27-09-2013
Publisher: Elsevier BV
Date: 2016
Publisher: Wiley
Date: 22-01-2008
Publisher: Elsevier BV
Date: 02-2016
Publisher: MDPI AG
Date: 12-03-2017
DOI: 10.3390/D9010017
Publisher: Elsevier BV
Date: 08-2009
Publisher: Elsevier BV
Date: 12-2015
Publisher: American Geophysical Union (AGU)
Date: 06-2014
DOI: 10.1002/2014PA002630
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.10.029
Abstract: Photosystem II (PSII) herbicides are used in large quantities on agricultural lands adjoining the Great Barrier Reef (GBR). Routine monitoring at 14 sites in inshore waters of the GBR using passive s ling techniques detected diuron (32-94% of s ling periods) at maximum concentrations of 1.7-430ng L(-1) in the relatively pristine Cape York Region to the Mackay Whitsunday Region, respectively. A PSII herbicide equivalent (PSII-HEq) index developed as an indicator for reporting was dominated by diuron (average contribution 89%) and typically increased during the wet season. The maximum PSII-HEq indicates the potential for photosynthetic inhibition of diatoms, seagrass and coral-symbionts. PSII herbicides were significantly positively correlated with remotely sensed coloured dissolved organic matter, a proxy for freshwater extent. Combining these methods provides for the first time the potential to cost-effectively monitor improvements in water quality entering the GBR with respect to exposure to PSII herbicides.
Publisher: American Chemical Society (ACS)
Date: 09-02-2016
Abstract: Pesticide exposure threatens many freshwater and estuarine ecosystems around the world. This study examined the temporal and spatial trends of pesticide concentrations in a waterway within an agriculturally developed dry-tropics catchment using a combination of grab and passive s ling methods over a continuous two-year monitoring program. A total of 43 pesticide residues were detected with 7 pesticides exceeding ecologically relevant water quality guidelines/trigger values during the study period and 4 (ametryn, atrazine, diuron, and metolachlor) of these exceeding guidelines for several months. The presence and concentration of the pesticides in the stream coincided with seasonal variability in rainfall, harvest timing/cropping cycle, and management changes. The s ling approach used demonstrates that the application of these complementary s ling techniques (both grab and passive s ling methods) was effective in establishing pesticide usage patterns in upstream locations where application data are unavailable.
Publisher: Wiley
Date: 09-08-2013
DOI: 10.1002/JOC.3799
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.MARPOLBUL.2018.08.002
Abstract: Studies documenting the effects of land-derived suspended particulate matter (SPM, i.e., particulate organic matter and mineral sediment) on marine ecosystems are typically disconnected from terrestrial studies that determine their origin, transport and fate. This study reviews sources, transport, transformations, fate and effects of SPM along the 'ridge-to-reef' continuum. We show that some of the SPM can be transported over long distances and transformed into large and easily resuspendible organic-rich sediment flocs. These flocs may lead to prolonged reductions in water clarity, impacting upon coral reef, seagrass and fish communities. Using the Great Barrier Reef (NE Australia) as a case study, we identify the latest research tools to determine thresholds of SPM exposure, allowing for an improved appreciation of marine risk. These tools are used to determine ecologically-relevant end-of-basin load targets and reliable marine water quality guidelines, thereby enabling enhanced prioritisation and management of SPM export from ridge-to-reef.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.JENVMAN.2019.07.026
Abstract: An operational method to assess trends in marine water composition and ecosystem health during flood periods has been developed for the Great Barrier Reef (GBR), Queensland, Australia. This method integrates satellite water colour data with field water quality and ecosystem monitoring data and involves the classification of Moderate-Resolution Imaging Spectroradiometer (MODIS satellite) pixels into six distinct water bodies using a "wet season" colour scale developed specifically for the GBR. Using this information, several monitoring and reporting products have been derived and are operationally implemented into a long-term water quality monitoring program for the GBR. However, MODIS sensors are aging and a long-term monitoring solution is needed. This study reviewed the water colour monitoring products currently used in the GBR. It tested the feasibility to transition these methods from historical MODIS satellite imagery to the new Sentinel-3 satellite of the European Space Agency and from the wet season colour scale to the historical Forel-Ule colour scale, using a freely-distributed Forel Ule (FU) Satellite Toolbox. Monitoring products derived from both satellites and colour scales showed very similar patterns across two case study regions of the GBR, the Wet Tropics and Burdekin marine regions, over the 2017-18 wet season. The results obtained in this study highlighted the potential of using FU Sentinel-3 imagery for the mapping of GBR marine water bodies, including flood conditions. Furthermore, the operational monitoring products and frameworks developed for the GBR are likely to provide valuable foundations for analysis of FU Sentinel-3 data in the future. Such satellite water colour datasets and frameworks will be instrumental to better understand the impact of floods and reduced water clarity on marine ecosystems, as well as to support water quality management and facilitate catchment management policy in the GBR and worldwide.
Publisher: Elsevier BV
Date: 05-2016
Publisher: Springer Netherlands
Date: 25-07-2013
Publisher: Elsevier BV
Date: 08-2016
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.WATRES.2017.12.055
Abstract: The aim of this study was to understand the uncertainty of estimating loads for observed herbicides and nutrients during a flood event and provide guidance on estimator selection. A high-resolution grab s ling c aign (258 s les over 100 h) was conducted during a flood event in a tropical waterway in Queensland, Australia. Ten herbicides and three nutrient compounds were detected at elevated concentrations. Each had a unique chemograph with differences in transport processes (e.g. dependence on flow, dilution processes and timing of concentration pulses). Res ling from the data set was used to assess uncertainty. Bias existed at lower s ling efforts but depended on estimator properties as s ling effort increased: the interpolation, ratio and regression estimators became unbiased. Large differences were observed in precision and the importance of s ling effort and estimator selection depended on the relationship between the chemograph and hydrograph. The variety of transport processes observed and the resultant variability in uncertainty suggest that useful load estimates can only be obtained with sufficient s les and appropriate estimator selection. We provide a rationale to show the latter can be guided across s ling periods by selecting an estimator where the s ling regime or the relationship between the chemograph and hydrograph meet its assumptions: interpolation becomes more correct as s ling effort increases and the ratio becomes more correct as the r
Publisher: Institute of Mathematical Statistics
Date: 09-2016
DOI: 10.1214/16-AOAS950
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.JENVMAN.2018.02.028
Abstract: Optically active water quality components (OAC) transported by flood plumes to nearshore marine environments affect light levels. The definition of minimum OAC concentrations that must be maintained to sustain sufficient light levels for conservation of light-dependant coastal ecosystems exposed to flood waters is necessary to guide management actions in adjacent catchments. In this study, a framework for defining OAC target concentrations using empirical light attenuation models is proposed and applied to the Wet Tropics region of the Great Barrier Reef (GBR) (Queensland, Australia). This framework comprises several steps: (i) light attenuation (Kd(PAR)) profiles and OAC measurements, including coloured dissolved organic matter (CDOM), chlorophyll-a (Chl-a) and suspended particulate matter (SPM) concentrations collected in flood waters (ii) empirical light attenuation models used to define the contribution of CDOM, Chl-a and SPM to the light attenuation, and (iii) translation of empirical models into manageable OAC target concentrations specific for wet season conditions. Results showed that (i) Kd(PAR) variability in the Wet Tropics flood waters is driven primarily by SPM and CDOM, with a lower contribution from Chl-a (r2 = 0.5, p < 0.01), (ii) the relative contributions of each OAC varies across the different water bodies existing along flood waters and strongest Kd(PAR) predictions were achieved when the in-situ data were clustered into water bodies with similar satellite-derived colour characteristics ('brownish flood waters', r2 = 0.8, p < 0.01, 'greenish flood waters', r2 = 0.5, p < 0.01), and (iii) that Kd(PAR) simulations are sensitive to the angular distribution of the light field in the clearest flood water bodies. Empirical models developed were used to translate regional light guidelines (established for the GBR) into manageable OAC target concentrations. Preliminary results suggested that a 90th percentile SPM concentration of 11.4 mg L
Publisher: Elsevier BV
Date: 06-2019
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.SCITOTENV.2014.04.005
Abstract: Industry transitions away from traditional photosystem II inhibiting (PSII) herbicides towards an 'alternative' herbicide suite are now widely advocated as a key component of improved environmental outcomes for Australia's Great Barrier Reef and improved environmental stewardship on the part of the Queensland sugar industry. A systematic desktop risk analysis found that based on current farming practices, traditional PSII herbicides can pose significant environmental risks. Several of the 'alternatives' that can directly fill a specific pre-emergent ('soil residual') weed control function similar to regulated PSII herbicides also, however, presented a similar environmental risk profile, regardless of farming systems and bio-climatic zones being considered. Several alternatives with a pre-emergent residual function as well as alternative post-emergent (contact or 'knockdown') herbicides were, predicted to pose lower environmental risks than the regulated PSII herbicides to most trophic levels, although environmental risks could still be present. While several herbicides may well be viable alternatives in terms of weed control, they can still present equal or possibly higher risks to the environment. Imposing additional regulations (or even de-registrations) on particular herbicides could result in marginal, and possibly perverse environmental impacts in the long term, if usage shifts to alternative herbicides with similar risk profiles. Regardless of any regulatory efforts, improved environmental sustainability outcomes in pesticide practices within the Great Barrier Reef catchment area will hinge primarily on the continuing adoption of integrated, strategic pest management systems and technologies applied to both traditional and 'alternative' herbicides. One of the emerging policy challenges is ensuring the requisite technical and extension support for cane growers to ensure effective adoption of rapidly evolving farming system technologies, in a very dynamic and scrutinised herbicide management environment.
Publisher: American Geophysical Union (AGU)
Date: 26-04-2021
DOI: 10.1029/2021GL092708
Abstract: The contrasting responses of ice core δ 18 O records (δ 18 O ice ) from the northern and southern Tibetan Plateau (TP) to the El Niño Southern Oscillation (ENSO) complicate δ 18 O ice ‐based temperature reconstructions. These contrasting responses were explored using stable hydrogen isotopes in water vapor (δD v ). We found that the interannual variation in δD v from the northern TP is influenced by midtropospheric moisture sources from the Indo‐Pacific Warm Pool, with enriched (depleted) δD v values in La Niña (El Niño) years due to enhanced (weakened) deep convection. In comparison, the interannual δD v variation in the southern TP is mainly influenced by low‐tropospheric moisture from the central Indian Continent, whose δD v is depleted (enriched) in La Niña (El Niño) years. These results demonstrate that moisture transported from different altitudes can lead to opposite isotopic signals of water vapor over the northern and southern TP and can be used to reconcile the contrasting responses of δ 18 O ice to ENSO.
Publisher: Elsevier BV
Date: 2012
Publisher: American Geophysical Union (AGU)
Date: 07-03-2023
DOI: 10.1029/2022GL102229
Abstract: Stable hydrogen isotopes in monsoonal precipitation (δD p ) at three sites (Port Blair, Barisal and Darjeeling) reveal the factors governing δD p variations over a south‐north gradient across the Bay of Bengal. We found that the δD p at each site continuously decreases from May to September and these trends become more pronounced from south to north. The decreasing trends of downstream δD p closely follow the decreasing trends of upstream stable hydrogen isotopes in water vapor (δD v ), which indicates that upstream δD v properties shape initial spatiotemporal patterns of the downstream δD p (“shaping effect”). Additionally, our results demonstrate that, during moisture transport, upstream vertical air motions (convection and downward motion) and topographic relief magnify the litude of the decreasing trends of downstream δD p (“magnifying effect”). Our findings imply that upstream δD v properties and relevant atmospheric and topographical conditions along the moisture transport pathway need to be considered collectively to better interpret paleoclimate records.
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.MARPOLBUL.2018.04.069
Abstract: Dissolved inorganic nitrogen (DIN) runoff from Great Barrier Reef (GBR) catchments is a threat to coral reef health. Several initiatives address this threat, including the Australian Government's Reef 2050 Plan. However, environmental decision makers face an unsolved prioritization challenge: determining the exposure of reefs to DIN from in idual rivers. Here, we use virtual river tracers embedded within a GBR-wide hydrodynamic model to resolve the spatial and temporal dynamics of 16 in idual river plumes during three wet seasons (2011-2013). We then used in-situ DIN observations to calibrate tracer values, allowing us to estimate the contribution of each river to reef-scale DIN exposure during each season. Results indicate that the Burdekin, Fitzroy, Tully and Daintree rivers pose the greatest DIN exposure risk to coral reefs during the three seasons examined. Results were used to demonstrate a decision support framework that combines reef exposure risk with river dominance (threat ersity).
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.JENVMAN.2010.05.007
Abstract: Herbicide contamination from agriculture is a major issue worldwide, and has been identified as a threat to freshwater and marine environments in the Great Barrier Reef World Heritage Area in Australia. The triazine herbicides are of particular concern because of potential adverse effects, both on photosynthetic organisms and upon vertebrate development. To date a number of bioremediation strategies have been proposed for triazine herbicides, but are unlikely to be implemented due to their reliance upon the release of genetically modified organisms. We propose an alternative strategy using a free-enzyme bioremediant, which is unconstrained by the issues surrounding the use of live organisms. Here we report an initial field trial with an enzyme-based product, demonstrating that the technology is technically capable of remediating water bodies contaminated with the most common triazine herbicide, atrazine.
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.08.025
Abstract: This study examined the temporal variability in herbicide delivery to the Great Barrier Reef (GBR) lagoon (Australia) from one of the GBR catchment's major sugarcane growing regions. Annual loads of measured herbicides were consistently in the order of 200+kg. Atrazine, it's degradate desethylatrazine, and diuron contributed approximately 90% of annual herbicide load, with early 'first-flush' events accounting for the majority of herbicide loads leaving the catchment. Assessment of herbicide water-sediment partitioning in flood runoff highlighted the majority of herbicides were transported in predominantly dissolved form, although a considerable fraction of diuron was transported in particulate-bound form (ca. 33%). Diuron was also the herbicide demonstrating the highest concentrations and frequency of detection in sediments collected from catchment waterways and adjacent estuarine-marine environments, an outcome aligning with previous research. Herbicide physico-chemical properties appear to play a crucial role in partitioning between water column and sediment habitat types in GBR receiving ecosystems.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/MF08333
Abstract: To assist in the development of the Tully Water Quality Improvement Plan, a subcatchment water quality monitoring program was undertaken to identify the pollutants of concern and their land-based sources. Monitoring of suspended sediments, nutrients and pesticides in subcatchment waterways was conducted during the 2005–06 and 2006–07 wet seasons, which both had above average annual flows. We found distinct water quality signals from the basin’s major land uses (forest, grazing, urban, sugarcane and banana cultivation), except for suspended sediment concentrations, which were low across all land uses when compared with neighbouring river catchments. This reflects the high ground cover of the basin and the location of intensive agriculture on low sloping areas of the floodplain, minimising the potential for erosion. Nitrate concentrations were elevated in streams draining sugarcane, indicating fertiliser export from intensive agricultural landscapes. Residues of the herbicides diuron and atrazine were detected at sites draining sugarcane, and on occasion exceeded national ecological protection trigger values, which highlights a potential threat to downstream wetlands of recognised national significance. Herbicides were also detectable offshore in flood plumes of the Tully–Murray Rivers, with some concentrations of diuron above lowest observable effect concentrations for specific species of seagrass and corals. Run-off of nitrate and diuron were identified as key water quality issues in the Tully–Murray basin.
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.09.030
Abstract: Coral cores were collected along an environmental and water quality gradient through the Whitsunday Island group, Great Barrier Reef (Australia), for trace element and stable isotope analysis. The primary aim of the study was to examine if this gradient could be detected in coral records and, if so, whether the gradient has changed over time with changing land use in the adjacent river catchments. Y/Ca was the trace element ratio which varied spatially across the gradient, with concentrations progressively decreasing away from the river mouths. The Ba/Ca and Y/Ca ratios were the only indicators of change in the gradient through time, increasing shortly after European settlement. The Mn/Ca ratio responded to local disturbance related to the construction of tourism infrastructure. Nitrogen isotope ratios showed no apparent trend over time. This study highlights the importance of site selection when using coral records to record regional environmental signals.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.09.031
Abstract: Development of the Great Barrier Reef (GBR) catchments in the last 150 years has increased the loads of suspended sediment, nutrients and pesticides ('pollutants') delivered to the GBR. The scale and type of development, the pollutants generated and the ecosystems offshore vary regionally. We analysed the relative risk of pollutants from agricultural land uses and identified the sources of these pollutants from different land uses for each region to develop priorities for management. The assessment showed the Wet Tropics and Mackay Whitsunday regions to be of relatively high risk dominated by sugarcane cultivation, contributing pesticide and dissolved inorganic nitrogen (DIN). The Burdekin and Fitzroy ranked medium-high risk dominated by grazing suspended sediment inputs for both, and additionally sugarcane DIN and pesticide inputs for the Burdekin. The Burnett Mary ranked medium risk, dominated by grazing and sugarcane. Cape York was not formally ranked but is considered to be low risk.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.12.011
Abstract: We argue that the residence times of key pollutants exported to the Great Barrier Reef (GBR) are greater in the GBR lagoon than those of the water itself, in contradiction to some previous assumptions. Adverse effects of the pollutant discharge will be greater and longer lasting than previously considered, in turn requiring stronger or more urgent action to remediate land practices. Residence times of fine sediments, nitrogen and phosphorus, pesticides and trace metals are suggested to be from years to decades in the GBR lagoon and highly likely to be greater than the residence time of water, estimated at around 15-365days. The recovery of corals and seagrass in the central region of the GBR following current land-use remediation in the catchment depends on the residence time of these contaminants. Ecohydrological modeling suggests that this recovery may take decades even with adequate levels of improved land management practices.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 06-07-2018
Abstract: The GBR is losing its ability to recover from disturbances, but local management action can help partially restore this ability.
Publisher: Wiley
Date: 08-03-2016
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.MARPOLBUL.2012.05.014
Abstract: The 2010-2011 wet season was one of extreme weather for the State of Queensland, Australia. Major rivers adjacent to the Great Barrier Reef (GBR) were discharging at rates 1.5 to >3 times higher than their long term median. Exposure to photosystem II herbicides has been routinely monitored over a period of up to 5 years at 12 inshore GBR sites. The influence of this wet season on exposure to photosystem II herbicides was examined in the context of this long-term monitoring record and during flood plume events in specific regions. Median exposures expressed as diuron equivalent concentration were an average factor of 2.3 times higher but mostly not significantly different (p<0.05) to the median for the long-term monitoring record. The herbicides metolachlor and tebuthiuron were frequently detected in flood plume waters at concentrations that reached or exceeded relevant water quality guidelines (by up to 4.5 times).
Publisher: No publisher found
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2012.01.043
Abstract: The extreme 2010-2011 wet season resulted in highly elevated Burdekin River discharge into the Great Barrier Reef lagoon for a period of 200 days, resulting in a large flood plume extending >50km offshore and >100km north during peak conditions. Export of suspended sediment was dominated by clay and fine silt fractions and most sediment initially settled within ∼10km of the river mouth. Biologically-mediated flocculation of these particles enhanced deposition in the initial low salinity zone. Fine silt and clay particles and nutrients remaining in suspension, were carried as far as 100km northward from the mouth, binding with planktonic and transparent exopolymer particulate matter to form large floc aggregates (muddy marine snow). These aggregates, due to their sticky nature, likely pose a risk to benthic organisms e.g. coral and seagrass through smothering, and also by contributing to increased turbidity during wind-induced resuspension events.
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.11.009
Abstract: Herbicide residues have been measured in the Great Barrier Reef lagoon at concentrations which have the potential to harm marine plant communities. Monitoring on the Great Barrier Reef lagoon following wet season discharge show that 80% of the time when herbicides are detected, more than one are present. These herbicides have been shown to act in an additive manner with regards to photosystem-II inhibition. In this study, the area of the Great Barrier Reef considered to be at risk from herbicides is compared when exposures are considered for each herbicide in idually and also for herbicide mixtures. Two normalisation indices for herbicide mixtures were calculated based on current guidelines and PSII inhibition thresholds. The results show that the area of risk for most regions is greatly increased under the proposed additive PSII inhibition threshold and that the resilience of this important ecosystem could be reduced by exposure to these herbicides.
Publisher: Springer Science and Business Media LLC
Date: 12-09-2023
Publisher: MDPI AG
Date: 11-10-2018
DOI: 10.3390/D10040110
Abstract: Coral reefs globally are impacted by natural and anthropogenic stressors that are compounded by climate change. Understanding past reef responses to natural stressors (cyclones, sea-level change, freshwater inputs, and sedimentation) can provide important insights to further understand recent (within the past century) trends in coral cover and ersity. Here we use a compilation of recently published data to investigate the Holocene development of five fringing reefs that are located on a cross-shelf transect on the central Great Barrier Reef, and that are exposed to varying degrees of natural and anthropogenic sedimentation, storm exposure, and Holocene sea-level change. Forty-two reef cores collected using a combination of manual percussion coring and hydraulic drilling techniques, were analysed and dated using uranium-thorium methods. The chronostratigraphic records of reef development established using 105 recently published radiometric ages and seven new uranium-thorium ages from the reef cores and fossil microatolls preserved across the reef flats were compared to investigate cross-shelf variations in reef development. This is the first study to conduct an internal investigation of reef framework across an inshore–offshore gradient to examine the varying levels of influence of sedimentation, sea level and cyclones. Our observations from the central Great Barrier Reef show that reefs furthest offshore from the mainland coast were typically initiated earliest after the post-glacial marine transgression. Reef flat size, morphology, and growth style varied according to constraints placed on reef development by the composition, depth, shape, and relief of the underlying substrate. We establish that terrigenous sedimentation had a marked effect on the development of inshore reefs closest to the mainland (within 10 km of the mainland coast). Periods of relatively high terrigenous sedimentation correspond with enhanced reef accretion rates, and also resulted in a superior record of palaeo-ecological coral composition (i.e., better preservation) at inshore sites. In contrast, mid-Holocene cyclones played a seemingly more important role in the development of reefs km from the mainland although cyclones clearly affect reefs closer inshore, their geomorphology is affected by a range of controlling factors. Insights provided by these five Holocene reef chronostratigraphies provide useful baseline understanding of reef condition and growth along a cross-shelf transect where the reefs are exposed to variable stressors.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.SCITOTENV.2018.11.084
Abstract: Determining the source of sediments and associated nutrients from terrestrial to aquatic environments is critical for managing the detrimental impacts of soil erosion and loss of nutrients from terrestrial into aquatic environment. However, tracing the source of particulate nutrients from different land uses has not been adequately carried out due to methodological difficulties in separating sources, particularly in the Great Barrier Reef (GBR) catchment. The objective of this study was to develop a method to differentiate the sources of particulate nutrients from soils collected from different land uses (combination of beef and dairy grazing, sugarcane, forest and banana) using both geochemical and isotopic signatures. In order to select a discriminative group of signatures, all soil s les collected from each of the land use areas were fractionated to <63 μm size fraction and were analysed for both isotopic (δ
Publisher: Springer Science and Business Media LLC
Date: 28-07-2022
DOI: 10.1038/S41467-022-32172-9
Abstract: Stable isotope paleoaltimetry that reconstructs paleoelevation requires stable isotope (δD or δ 18 O) values to follow the altitude effect. Some studies found that the δD or δ 18 O values of surface isotopic carriers in some regions increase with increasing altitude, which is defined as an “inverse altitude effect” (IAE). The IAE directly contradicts the basic theory of stable isotope paleoaltimetry. However, the causes of the IAE remain unclear. Here, we explore the mechanisms of the IAE from an atmospheric circulation perspective using δD in water vapor on a global scale. We find that two processes cause the IAE: (1) the supply of moisture with higher isotopic values from distant source regions, and (2) intense lateral mixing between the lower and mid-troposphere along the moisture transport pathway. Therefore, we caution that the influences of those two processes need careful consideration for different mountain uplift stages before using stable isotope palaeoaltimetry.
Publisher: Springer Science and Business Media LLC
Date: 11-07-2010
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.12.012
Abstract: The Great Barrier Reef (GBR) is a World Heritage Area and contains extensive areas of coral reef, seagrass meadows and fisheries resources. From adjacent catchments, numerous rivers discharge pollutants from agricultural, urban, mining and industrial activity. Pollutant sources have been identified and include suspended sediment from erosion in cattle grazing areas nitrate from fertiliser application on crop lands and herbicides from various land uses. The fate and effects of these pollutants in the receiving marine environment are relatively well understood. The Australian and Queensland Governments responded to the concerns of pollution of the GBR from catchment runoff with a plan to address this issue in 2003 (Reef Plan updated 2009), incentive-based voluntary management initiatives in 2007 (Reef Rescue) and a State regulatory approach in 2009, the Reef Protection Package. This paper reviews new research relevant to the catchment to GBR continuum and evaluates the appropriateness of current management responses.
Publisher: American Geophysical Union (AGU)
Date: 11-2014
DOI: 10.1002/2013WR014386
Publisher: Elsevier BV
Date: 06-2020
Publisher: American Chemical Society (ACS)
Date: 28-10-2016
Abstract: Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations.
Publisher: Elsevier BV
Date: 10-2023
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/MF08339
Abstract: Water Quality Improvement Plans (WQIPs) are being developed for in idual river basins on the Great Barrier Reef (GBR) catchment associated with the GBR Water Quality Protection Plan. Within each WQIP, marine ecosystem targets are linked to end-of-river pollutant (suspended sediments, nutrients and pesticides) load targets and to farm level management practice targets. The targets are linked through quantitative models e.g. one model connects GBR chlorophyll concentrations (marine target) to end-of-river nitrate loads, a second connects the end-of-river nitrate loads to fertiliser management targets in the catchment, whereas a third model links fertiliser application to nitrate loss at the farm scale. The difficulties of applying these linked models to derive credible and practical management targets are great, given the high degree of uncertainty in each model. Our understanding of the generation of suspended sediments, nutrients and pesticides in catchments and the relationship to on-farm management, the transport of these materials to the ocean, their transport in coastal waters and their effects on marine ecosystems is incomplete. The challenge is to produce estimates from the models, with known levels of uncertainty, but robust enough for management purposes. Case studies from the Tully–Murray basin and the Burdekin basin in north Queensland are discussed.
Publisher: Elsevier BV
Date: 09-2010
Publisher: Elsevier BV
Date: 08-2013
Publisher: Springer Science and Business Media LLC
Date: 02-05-2016
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.SCITOTENV.2013.09.030
Abstract: Modification of terrestrial sediment fluxes can result in increased sedimentation and turbidity in receiving waters, with detrimental impacts on coral reef ecosystems. Preventing anthropogenic sediment reaching coral reefs requires a better understanding of the specific characteristics, sources and processes generating the anthropogenic sediment, so that effective watershed management strategies can be implemented. Here, we review and synthesise research on measured runoff, sediment erosion and sediment delivery from watersheds to near-shore marine areas, with a strong focus on the Burdekin watershed in the Great Barrier Reef region, Australia. We first investigate the characteristics of sediment that pose the greatest risk to coral reef ecosystems. Next we track this sediment back from the marine system into the watershed to determine the storage zones, source areas and processes responsible for sediment generation and run-off. The review determined that only a small proportion of the sediment that has been eroded from the watershed makes it to the mid and outer reefs. The sediment transported >1 km offshore is generally the clay to fine silt (<4-16 μm) fraction, yet there is considerable potential for other terrestrially derived sediment fractions ( 75% will likely be required to reduce runoff and prevent sub-soil erosion however, it is not known whether ground cover management alone will reduce sediment supply to ecologically acceptable levels.
Publisher: American Geophysical Union (AGU)
Date: 02-2013
DOI: 10.1002/WRCR.20117
Publisher: Elsevier BV
Date: 08-2013
Publisher: Springer Science and Business Media LLC
Date: 27-10-2015
Publisher: American Chemical Society (ACS)
Date: 10-03-2017
Abstract: The suitability of passive s lers (Chemcatcher) as an alternative to grab s ling in estimating time-weighted average (TWA) concentrations and total loads of herbicides was assessed. Grab s ling complemented deployments of passive s lers in a tropical waterway in Queensland, Australia, before, during and after a flood event. Good agreement was observed between the two s ling modes in estimating TWA concentrations that was independent of herbicide concentrations ranging over 2 orders of magnitude. In a flood-specific deployment, passive s ler TWA concentrations underestimated mean grab s ler (n = 258) derived concentrations of atrazine, diuron, ametryn, and metolachlor by an average factor of 1.29. No clear trends were evident in the ratios of load estimates from passive s lers relative to grab s les that ranged between 0.3 and 1.8 for these analytes because of the limitations of using TWA concentrations to derive flow-weighted loads. Stratification of deployments by flow however generally resulted in noticeable improvements in passive s ler load estimates. By considering the magnitude of the uncertainty (interquartile range and the root-mean-squared error) of load estimates a modeling exercise showed that passive s lers were a viable alternative to grab s ling since between 3 and 17 grab s les were needed before grab s ling results had less uncertainty.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.SCITOTENV.2013.07.117
Abstract: Runoff from farm fields is a common source of herbicide residues in surface waters in many agricultural industries around the world. In Queensland, Australia, the runoff of PSII inhibitor herbicides (in particular diuron and atrazine) is a major concern due to their potential impact on the Great Barrier Reef. This study compared the conventional practice of broadcast application of herbicides in sugarcane production across the whole field with the banded application of particular herbicides onto raised beds only using a shielded sprayer. This study found that the application of two moderately soluble herbicides, diuron and atrazine, to only the raised beds decreased the average total load of both herbicides moving off-site by >90% compared with the conventional treatment. This was despite the area being covered with the herbicides by the banded application being only 60% less than with the conventional treatment. The average total amount of atrazine in drainage water was 7.5% of the active ingredient applied in the conventional treatment compared with 1.8% of the active ingredient applied in the banded application treatment. Similarly, the average total amount of diuron in drainage water was 4.6% of that applied in the conventional treatment compared with 0.9% of that applied in the banded application treatment. This study demonstrates that the application of diuron and atrazine to raised beds only is a highly effective way of minimising migration of these herbicides in drainage water from furrow irrigated sugarcane.
Publisher: American Geophysical Union (AGU)
Date: 04-2012
DOI: 10.1029/2011WR011080
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 07-2017
Publisher: Elsevier BV
Date: 02-2018
Publisher: Springer Science and Business Media LLC
Date: 10-04-2015
Publisher: Elsevier BV
Date: 04-2007
Publisher: American Chemical Society (ACS)
Date: 13-05-2016
Abstract: This special issue presents a collection of papers covering the environmental fate, effects, and risk of pesticides in tropical environments, which is expected to facilitate improved management of pesticides. Environmental monitoring programs of surface and ground waters in the tropics, including areas of high ecological value, have detected several relatively polar pesticides at concentrations that are of ecological concern. Novel monitoring techniques have the capacity to reveal the spatial and temporal extent of such risks. To best manage these pesticides, their sorption, dissipation rates, leaching, and runoff potential need to be better understood. On these aspects, important insights have been provided by several studies within this issue. Improved understanding of the environmental fate, effects, and risks through studies presented in this special issue is crucial for minimizing the nontarget impacts of pesticides on bio ersity-rich tropical regions.
Publisher: Elsevier BV
Date: 03-2012
No related grants have been discovered for Stephen Lewis.