Short-term nitrogen and phosphorus release during the disturbance of surface sediments: a case study in an urbanised estuarine system (Gold Coast Broadwater, Australia)
Dunn, Ryan J.K., Waltham, Nathan, Teasdale, Peter R., Roberston, David, and Welsh, David T. (2017) Short-term nitrogen and phosphorus release during the disturbance of surface sediments: a case study in an urbanised estuarine system (Gold Coast Broadwater, Australia). Journal of Marine Science and Engineering, 5 (2). pp. 1-13.
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Abstract
Understanding the effects of sediment disturbances on nutrient loadings is important for the management of estuarine settings. This study investigated the initial influence of sediment disturbance on water column nutrient concentrations in a shallow estuarine setting within the Gold Coast Broadwater, using a laboratory-based approach. Undisturbed sediment cores (200 mm Ø × 330 mm length, plexiglass) were incubated before and after being subjected to a disturbance event, to investigate the effect on the immediate and subsequent short-term water column nutrient concentrations. Sediment NH4+bio and PO43−bio concentrations ranged from 150 to 478 and 1.50 to 8.56 nmol g−1 dry wt, respectively. Water column NH4+ concentrations underwent the greatest increase (>1000% or approx. 14 times greater) immediately following disturbance, with mean effluxes increasing by >300%. Thereafter, water column NH4+ concentrations and efflux rates declined to near initial pre-disturbance concentrations. Water column NH4+ concentrations accounted for 0.58%–5.50% of the depth-integrated sediment NH4+bio concentration, indicating mobilization of the sediment bound exchangeable NH4+. The observed changes in PO43− concentrations and fluxes were much lower in comparison to those observed for N-species. Following disturbance, increases in the water column PO43− concentration accounted for 7.16%–8.22% depth-integrated sediment bioavailable PO43− at +1 and +2 hours, and 5.65% at +7 hours, respectively. These results provide important insight into the potential implications of disturbance events, such as vessel activities and dredging operations, within the case study region, providing information for potential management options and relevant water quality concerns
| Item ID: | 48557 |
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| Item Type: | Article (Research - C1) |
| ISSN: | 2077-1312 |
| Keywords: | nutrients; sediment disturbance; water quality |
| Additional Information: | © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution(CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
| Funders: | Gold Coast City Council, Griffith University |
| Date Deposited: | 20 Apr 2017 04:31 |
| FoR Codes: | 41 ENVIRONMENTAL SCIENCES > 4105 Pollution and contamination > 410501 Environmental biogeochemistry @ 50% 41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring @ 50% |
| SEO Codes: | 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960507 Ecosystem Assessment and Management of Marine Environments @ 50% 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 50% |
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