Abstract
Estuaries are crucial biogeochemical filters at the land-ocean interface that are strongly impacted by anthropogenic nutrient inputs. Here, we investigate benthic nitrogen (N) and phosphorus (P) dynamics in relation to physicochemical surface sediment properties and bottom water mixing in the shallow, eutrophic Peel-Harvey Estuary. Our results show the strong dependence of sedimentary P release on Fe and S redox cycling. The estuary contains surface sediments that are strongly reducing and act as net P source, despite physical sediment mixing under an oxygenated water column. This decoupling between water column oxygenation and benthic P dynamics is of great importance to understand the evolution of nutrient dynamics in marine systems in response to increasing nutrient loadings. In addition, the findings show that the relationship between P burial efficiency and bottom water oxygenation depends on local conditions; sediment properties rather than oxygen availability may control benthic P recycling. Overall, our results illustrate the complex response of an estuary to environmental change because of interacting physical and biogeochemical processes.
| Original language | English |
|---|---|
| Pages (from-to) | 3114-3121 |
| Number of pages | 8 |
| Journal | Environmental Science and Technology |
| Volume | 47 |
| Issue number | 7 |
| Early online date | 11 Mar 2013 |
| DOIs | |
| Publication status | Published - 2 Apr 2013 |
Funding
This research is part of a Linkage Project (LP0991658) cofunded by the Australian Research Council. A.L.R. also acknowledges funding support from ARC project DP0987351. E.D.B. also acknowledges funding support from ARC project DP110100519, The <SUP>210</SUP>Pb analyses were funded by the Australian Institute of Nuclear Science and Engineering (AINGRA11P070) and performed with the help of Atun Zawadzki, Henk Heijnis, and Daniela Fierro. We thank the Department of Water in Western Australia, in particular Zitty Wesolowski and John Pszczola, for their help with sample collection. Dirk Erler and Damien Maher from the Centre for Coastal Biogeochemistry Research at Southern Cross University are gratefully acknowledged for help with the incubation experiments. William Bredenbac assisted with the sequential iron and sulfur extractions. Our partners at the Western Australian Organic and Isotope Geochemistry Centre, Department of Chemistry, Curtin University, in particular Kliti Grice and Robert Lockhart, are thanked for their assistance during core processing.
Keywords
- BALTIC SEA SEDIMENTS
- GREEN-ALGAL BLOOMS
- MARINE-SEDIMENTS
- ECOLOGICAL SIGNIFICANCE
- REDUCTION MEASUREMENTS
- NUTRIENT REGENERATION
- AUSTRALIAN ESTUARY
- SULFATE REDUCTION
- IRON MONOSULFIDE
- PALMONES RIVER
