ORCID Profile
0000-0001-8950-5176
Current Organisation
University of Tasmania
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.
Publisher: MDPI AG
Date: 23-11-2022
Abstract: The longspined sea urchin, Centrostephanus rodgersii, is a climate-driven pest species in south-eastern Australia. The harvest of this species is highly encouraged and in Tasmania, the existing fishery is expanding resulting in a large amount of waste that needs disposal. Research into use of waste products as inputs for organic or biodynamic farming systems can help reduce costs of disposal and keep the industry profitable by sustaining or incrementing sea urchin harvest the industry can assist in their control. In the current study, urchin waste was dried and finely ground to a powder and applied to tomato plants in a greenhouse to examine the effect on growth and productivity. Urchin waste powder (UWP) had a mineral composition of Ca (40 g 100 g−1), Mg (1.7 g 100 g−1), P (0.03 g 100 g−1), Fe (19.34 mg kg−1) and B (38 mg kg−1), a pH 8.06 in water and an Electrical Conductivity (EC) value of 7.64 dSm−1. Seven different treatment rates of UWP (0.3% 0.5% 0.8% 1% 2% 3% 5%), were added to 10 replicate pots containing 4 kg nutrient-poor potting mix planted with tomato (Variety K1) seedlings. Plant growth, yield, quality attributes and mineral content of tomato were measured under UWP treatments with comparison against a Hoagland solution control. UWP influenced tomato growth and productivity proportional to the quantity applied, however, the Hoagland solution control had a significantly greater yield. Potting mix pH increased from 6.8 to 7 and higher available P was detected in potting mix receiving higher rates of UWP. No phytotoxic effects were detected. The highest UWP treatment matched the Hoagland control in fruit quality and nutritional composition. Processing waste from the sea urchin fishery has potential as organic fertiliser or amendment providing plant-available Ca and some microelements such as Boron.
Publisher: Springer Science and Business Media LLC
Date: 09-10-2023
Publisher: Frontiers Media SA
Date: 28-06-2019
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.MARPOLBUL.2013.01.002
Abstract: We investigated the effects of the burrowing cirratulid polychaete Cirriformia filigera (Delle Chiaje, 1828) on benthic respiration and nitrogen regeneration in metal-contaminated estuarine sediments using laboratory mesocosms. C. filigera is a dominant component of assemblages in the most severely contaminated sediments within the Derwent estuary, southern Australia. In the presence of C. filigera sediment O2 consumption doubled, with approximately 55% of this increase due to their respiration and the remaining 45% attributable to oxidation reactions and increased microbial respiration associated with burrow walls. Combined NO3 and NO2 fluxes were unaffected. The addition of labile organic matter did not affect benthic fluxes, in the presence or absence of C. filigera, presumably due to the short timeframe of the experiment and naturally enriched test sediments. The results suggest that a combination of tolerance and burrowing activity enables this species to provide an ecosystem service in the removal of N from contaminated sites.
Publisher: Oxford University Press (OUP)
Date: 09-2023
Publisher: Oxford University Press (OUP)
Date: 13-01-0088
Abstract: Climate change increases the need to control range-extending species, which adversely impact their recipient ecosystem. Increasing populations of resident predators may be effective to counter such range-extension, but only if they consume the novel invaders at sufficient rates. In South-East Australia, poleward range-extending Longspined Sea Urchins (Centrostephanus rodgersii) are causing catastrophic ecological habitat transition to extensive urchin barrens. Tasmanian native Southern Rock Lobster (Jasus edwardsii) is a potential predator that could control further urchin expansion. Experimental feeding trials showed that range-extending Longspined Sea Urchins are the least preferred prey choice for Southern Rock Lobsters (3.8% predation events), when compared to three local species: abalone, urchins, and snails (36.6, 32.6, and 27%). Interestingly, habitat origin and naivete of lobsters to urchins affected urchin consumption with 85% being consumed by lobsters originating from urchin barrens. Low predation rates on Longspined Sea Urchin suggest that resident lobsters are unlikely to control further barren expansion unless a behavioural shift occurs. Results imply that potential control of Longspined Sea Urchins by Southern Rock Lobsters has previously been overestimated. Additional control methods are needed to safeguard ecological communities and important commercial stocks from this climate change-induced, range-extending pest species.
Publisher: Wiley
Date: 07-2008
Publisher: Informa UK Limited
Date: 12-2004
Publisher: Springer Science and Business Media LLC
Date: 16-10-2018
Abstract: Larval fishes are a useful metric of marine ecosystem state and change, as well as species-specific patterns in phenology. The high level of taxonomic expertise required to identify larval fishes to species level, and the considerable effort required to collect s les, make these data very valuable. Here we collate 3178 s les of larval fish assemblages, from 12 research projects from 1983-present, from temperate and subtropical Australian pelagic waters. This forms a benchmark for the larval fish assemblage for the region, and includes recent monitoring of larval fishes at coastal oceanographic reference stations. Comparing larval fishes among projects can be problematic due to differences in taxonomic resolution, and identifying all taxa to species is challenging, so this study reports a standard taxonomic resolution (of 218 taxa) for this region to help guide future research. This larval fish database serves as a data repository for surveys of larval fish assemblages in the region, and can contribute to analysis of climate-driven changes in the location and timing of the spawning of marine fishes.
Publisher: Oxford University Press (OUP)
Date: 16-11-2011
DOI: 10.1111/J.1574-6941.2010.00988.X
Abstract: The effects of sediment hypoxia, resulting from increased carbon loads or decreased dissolved oxygen (DO), on nitrogen cycling in estuarine environments is poorly understood. The important role played by bacterial and archaeal ammonia oxidizers in the eventual removal of nitrogen from estuarine environments is likely to be strongly affected by hypoxic events. In this study, an analysis of the effects of different levels of sediment hypoxia (5%, 20% and 75% DO) was performed in a microcosm experiment. Changes in the nutrient fluxes related to nitrification at 5% DO were observed after 4 h. Quantification of the key nitrification gene ammonium monooxygenase (amoA) in both DNA and RNA extracts suggests that bacterial amoA transcription was reduced at both of the lower DO concentrations, while changes in DO had no significant effect on archaeal amoA transcription. There was no change in the ersity of expressed archaeal amoA, but significant change in bacterial amoA transcriptional ersity, indicative of low- and high-DO phylotypes. This study suggests that groups of ammonia oxidizers demonstrate differential responses to changes in sediment DO, which may be a significant factor in niche partitioning of different ammonia oxidizer groups.
Publisher: Wiley
Date: 07-2008
Publisher: Elsevier BV
Date: 03-2009
Publisher: Elsevier BV
Date: 07-2016
Publisher: Inter-Research Science Center
Date: 06-08-2013
DOI: 10.3354/AME01642
Publisher: Oxford University Press (OUP)
Date: 11-09-2014
Abstract: A molecular approach was successfully developed to discriminate between spawned eggs of the pelagic carangids Trachurus declivis and Trachurus novaezelandiae collected during ichthyoplankton surveys conducted in October 2002 and 2003 along shelf waters of Queensland (Qld) and New South Wales (NSW), in southeastern Australia (25o50′–37o30′S). Visually identified Trachurus eggs were subjected to mtDNA analysis by targeting specific fragments of the cytochrome oxidase subunit 1 (CO1) and cytochrome b (Cyt b) genes, with three diagnostic sites (single-nucleotide polymorphisms) within a 297 bp segment of Cyt b (558, 588, 825) providing the best approach to discriminate between species. Polymerase chain reaction lification and sequencing of 608 suspected Trachurus eggs resulted in 586 (96.4%) high-quality sequences that unequivocally identified 315 and 207 eggs as T. declivis and T. novaezelandiae, respectively, as well as 18 “variant haplotype” eggs that exhibited a base substitution at one of the diagnostic sites the remaining 46 sequences aligned to three different genera in GenBank including two carangids, thus highlighting the effectiveness of molecular methods for egg identification. Rehydrated, mtDNA-verified eggs of T. declivis were significantly larger (0.97 ± 0.01 mm) than those of T. novaezelandiae (0.82 ± 0.01 mm), though still proved problematic to identify to species when relying on morphology alone. Egg distributions showed main spawning areas of T. declivis and T. novaezelandiae confined mostly to southern NSW (& °S) and northern NSW/southern Qld (& °S), respectively, with T. novaezelandiae likely to continue spawning further south during summer with the gradual temperature increase associated with the south-flowing East Australian Current. Overall findings support the adoption of comparable molecular protocols to verify identification of wild spawned eggs to species level, especially eggs collected during the application of the daily egg production method to estimate spawning biomass of pelagic species, as well as biological fish studies.
Publisher: Elsevier BV
Date: 08-2008
Publisher: Springer Science and Business Media LLC
Date: 16-05-2019
Publisher: Frontiers Media SA
Date: 17-04-2023
DOI: 10.3389/FRSEN.2023.1149900
Abstract: Robust definition of the spatial extent of seafloor habitats and how they may be changing through time is a holy grail for ecosystem management, particularly if an ecosystem is approaching a tipping point beyond which irreversible changes may occur. Here we generate and explore a new data set for the management of warming reefs in eastern Tasmania, Australia that will significantly improve the baseline maps required for fine-scaled spatial modelling and management that is, both robust at regional scales and is highly resolved within the water column. This procedure enabled the relative density of kelp vegetation to be identified in a region that is being overwhelmed by the range extension of a destructive grazer, the Longspined Sea Urchin, Centrostephanus rodgersii. We present a new online tool to visualize multibeam water column acoustic data as surfaces of kelp density at high resolution (50 cm) scale over seafloor terrain maps (spanning a total straight-line distance of 594 km and a total area of 29.14 km 2 ) to reveal the types of reef structure on the East Coast of Tasmania where abalone habitat is threatened by kelp loss.
Publisher: Springer Science and Business Media LLC
Date: 22-02-2014
DOI: 10.1007/S00248-014-0376-7
Abstract: Sediment organic loading has been shown to affect estuarine nitrification and denitrification, resulting in changes to sediment biogeochemistry and nutrient fluxes detrimental to estuarine health. This study examined the effects of organic loading on nutrient fluxes and microbial communities in sediments receiving effluent from a paper and pulp mill (PPM) by applying microcosm studies and molecular microbial ecology techniques. Three sites near the PPM outfall were compared to three control sites, one upstream and two downstream of the outfall. The control sites showed coupled nitrification-denitrification with minimal ammonia release from the sediment. In contrast, the impacted sites were characterised by nitrate uptake and substantial ammonia efflux from the sediments, consistent with a decoupling of nitrification and denitrification. Analysis of gene ersity demonstrated that the composition of nitrifier communities was not significantly different at the impacted sites compared to the control sites however, analysis of gene abundance indicated that whilst there was no difference in total bacteria, total archaea or ammonia-oxidising archaea (AOA) abundance between the control and impacted sites, there was a significant reduction in ammonia-oxidising bacteria (AOB) at the impacted sites. The results of this study demonstrate an effect of organic loading on estuarine sediment biogeochemistry and highlight an apparent niche differentiation between AOA and AOB.
No related grants have been discovered for John Patrick Keane.