Logo image
Back
Can export of organic matter from estuaries support zooplankton in nearshore, marine plumes?
Journal article   Peer reviewed

Can export of organic matter from estuaries support zooplankton in nearshore, marine plumes?

Thomas Schlacher, R M Connolly, Anna J Skillington and Troy F Gaston
Aquatic Ecology: a multidisciplinary journal relating to processes and structures at different organizational levels, Vol.43(2), pp.383-393
2009
DOI: https://doi.org/10.1007/s10452-008-9196-5
url
https://doi.org/10.1007/s10452-008-9196-5View
Published Version

Abstract

land-ocean coupling plumes tropic subsidy stable isotope food webs
Marine and terrestrial ecosystems are connected via transfers of nutrients and organic matter in river discharges. In coastal seas, such freshwater outflows create prominent turbidity plumes. These plumes are areas of high biological activity in the pelagos, of which zooplankton is a key element. Conceptually, the increased biomass of zooplankton consumers in plumes can be supported by two alternative trophic pathways-consumption of fresh marine phytoplankton production stimulated by riverine nutrients, or direct trophic subsidies through the uptake of terrestrial and estuarine organic matter flushed to sea. The relative importance of these two pathways has not been established previously. Isotopic tracing (carbon and nitrogen) was used to measure the extent of incorporation of marine versus terrestrial matter into mesozooplankton consumers in the plumes off a small estuary in eastern Australia. Replicate zooplankton samples were taken during baseflow conditions with minimal freshwater influence to the sea, and during pulsed discharge events that generated turbidity plumes in coastal waters. Food sources utilized by zooplankton differed among locations and with the strength of freshwater flow. Terrestrial and estuarine carbon only made a sizeable contribution (47%) to the carbon demands of zooplankton in the lower estuary during pulsed freshwater flows. By contrast, in plumes that developed in nearshore marine waters, phytoplankton supplied up to 90% of the dietary carbon of zooplankton feeding in the plumes. Overall, it was "fresh" carbon, fixed by marine phytoplankton, the growth of which became stimulated by fluvial nutrient exports, that dominated energy flows in plume regions. The trophic role of terrestrial and estuarine organic exports was comparatively minor. The trophic dynamics of plankton in small coastal plumes is closely linked to variations in freshwater flow, but this coupling operates mainly through the enhancement of in-situ phytoplankton production rather than cross-boundary transfers of organic matter to marine food webs in the pelagos.

Details

Metrics

3 File views/ downloads
1154 Record Views
37 Times Cited - Web of Science

InCites Highlights

These are selected metrics from InCites Benchmarking & Analytics tool, related to this output

Collaboration types
Domestic collaboration
Web Of Science research areas
Ecology
Limnology
Marine & Freshwater Biology
Logo image