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Modelling ecological change over half a century in a subtropical estuary: impacts of climate change, land-use, urbanization and freshwater extraction
Citation
Condie, SA and Hayes, D and Fulton, EA and Savina, M, Modelling ecological change over half a century in a subtropical estuary: impacts of climate change, land-use, urbanization and freshwater extraction, Marine Ecology - Progress Series, 457 pp. 43-66. ISSN 0171-8630 (2012) [Refereed Article]
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Copyright Statement
Copyright 2012 Inter-Research
Abstract
The Clarence River Estuary is the largest estuary in southeast Australia, with an
extensive floodplain encompassing multiple river channels and a large coastal lagoon. It is the
focus of major commercial and recreational fisheries and there is pressure to divert its freshwater
inputs for agricultural and domestic uses. We used a spatial biogeochemical model to simulate the
variability and evolution of this system on timescales from days to decades over the past half
century. Like most tropical and subtropical estuaries, the Clarence River Estuary is strongly influenced by river discharge, sediment and nutrient loads. Given the high nutrient loads arriving
from the upper catchment, plankton biomasses in the model were typically limited by flushing
through the estuary channels. However, the longer residence times of the lagoons produced a profoundly
different regime where higher zooplankton concentrations were supported by recycling
of nutrients and detritus. Using alternative model scenarios, it was found that the ecology of the
lagoon was sensitive to changes in land-use and urbanization within the local sub-catchment, but
was largely insensitive to changes in upstream river discharge (i.e. rainfall or freshwater extraction).
The opposite was true in the estuary channels, where changes in land-use or urbanisation in
the populated lower catchment had little effect on the estuarine ecology, while even modest
reductions in river discharges dramatically increased the biomass of the smaller phytoplankton
and zooplankton groups, and favoured benthic algae over seagrass and macroalgae. The contrasting
responses of these 2 estuarine environments suggests the need for distinct management
approaches, with stringent controls on nutrient loads into coastal lagoons and protection of
environmental flows into estuary channels.
Item Details
Item Type: | Refereed Article |
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Keywords: | climate impacts, coastal lagoon, flushing, land-use, nutrients, phytoplankton, zooplankton |
Research Division: | Biological Sciences |
Research Group: | Ecology |
Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the environmental sciences |
UTAS Author: | Fulton, EA (Dr Elizabeth Fulton) |
ID Code: | 119021 |
Year Published: | 2012 |
Web of Science® Times Cited: | 15 |
Deposited By: | Sustainable Marine Research Collaboration |
Deposited On: | 2017-07-25 |
Last Modified: | 2017-09-13 |
Downloads: | 119 View Download Statistics |
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