Coupling of benthic and pelagic food webs to land derived N sources in Waquoit Bay, Massachussetts.

PAULINA MARTINETTO; MIRTA TEICHBERG; IVAN VALIELA

Santiago de Compostela, España

Conferencia; ASLO Summer Meeting, 2005; 2005

American Society of Limnolgy and Oceanography

The land-derived source of nutrients promoting eutrophication in the receiving coastal waters imply coupling between land and marine environments. Increasing nitrogen inputs in the estuaries are followed by major shifts in biota composition and abundances. In shallow coastal waters benthic and pelagic coupling is also important, yet the influences that eutrophication has on benthic-pelagic coupling are unclear. We used N and C isotopes ratios to analyze the degree of land-estuary and benthic-pelagic coupling in estuaries receiving different N loads. We found that primary producers, benthic taxa, and fishes were coupled to the watersheds and estuaries where they were collected. In contrast, zooplankton was uncoupled. Primary consumers and predators feeding on benthic prey within the estuaries were also coupled to the watershed and estuaries, but predators feeding on zooplankton were not. Our results suggest that there are strong links between land use and those parts of the estuarine food webs associated with the benthos. Pelagic components feeding on zooplankton seem to be uncoupled to land.