FN Archimer Export Format PT J TI Modelling ecological change over half a century in a subtropical estuary: impacts of climate change, land-use, urbanization and freshwater extraction BT AF CONDIE, Scott A. HAYES, Donna FULTON, Elizabeth A. SAVINA, Marie AS 1:1;2:1;3:1;4:2; FF 1:;2:;3:;4:; C1 CSIRO, Wealth Oceans Flagship, Hobart, Tas 7004, Australia. CSIRO, Wealth Oceans Flagship, Brisbane, Qld 4001, Australia. C2 CSIRO, AUSTRALIA CSIRO, AUSTRALIA IF 2.55 TC 13 UR https://archimer.ifremer.fr/doc/00175/28673/27113.pdf LA English DT Article DE ;Coastal lagoon;Flushing;Land-use;Climate impacts;Nutrients;Phytoplankton;Zooplankton AB 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. PY 2012 PD JUL SO Marine Ecology Progress Series SN 0171-8630 PU Inter-research VL 457 UT 000306755000005 BP 43 EP 66 DI 10.3354/meps09718 ID 28673 ER EF