Pelagic food webs
The analysis of chemical tracers, such as carbon and nitrogen stable isotopes provide a useful tool to characterize the structure of food webs. I have been using these tools to estimate the trophic position of different organisms, trophic redundancy and interspecies interactions, food web length and the level of trophic diversity within communities that compose the pelagic ecosystems.
Photos: Steve Lindley - NOAA Fisheries
I am currently investigating the structure and dynamics of the pelagic food webs that sustain salmon in the high seas of the North Pacific. This is part of the International Year of the Salmon project, which involves scientists from Canada, the United States, Russia, Japan, and North Korea. I am analysing carbon and nitrogen stable isotopes and fatty acids in the different components of these pelagic food webs to identify the main trophic pathways that support salmon, and the direct and indirect effects of inter-species interactions. More to come soon!
As part of my PhD research, I analysed stable isotopes in samples of different organisms that occur in the offshore waters of the outer continental shelf and slope in the Southwestern Atlantic Ocean. These samples included the particulate organic matter (POM, representing the primary producers), zooplankton, forage and large fishes and squids, as well as the top predator species such as cetaceans. These analyses allowed me to describe the trophic structure of these pelagic food webs, providing a baseline for future works to refer to. This work is currently in preparation for submission to a scientific journal for publication.