Environmental disturbances such as El Niño shake up the marine food web off Southern California, new research shows, countering conventional thinking that the hierarchy of who-eats-who in the ocean remains largely constant over time.
(From Phys.org) — The new research published in the journal Science Advances examined the skin cells of common dolphins for chemical clues about the length of the marine food chain, which begins with tiny plankton and continues as species eat them, and other species eat those species. Large predators such as dolphins occupy the top of the food chain, their cells carrying chemical information from all the species beneath them.
Many scientists have long considered the length of the food chain in the open sea to be relatively stable, with roughly the same animal species feeding on each other through time. But the chemical signatures in the skin of Southern California dolphins collected over two decades now show otherwise, report scientists from NOAA Fisheries, Moss Landing Marine Laboratories and the Scripps Institution of Oceanography.
“We documented for first time marked changes in the pelagic food web length in response to various natural and anthropogenic related stressors,” said lead author Rocio I. Ruiz-Cooley, formerly of NOAA Fisheries’ Southwest Fisheries Science Center and now at Moss Landing Marine Laboratories. “This tells us that the food web is very dynamic, and reveals changes with the ecosystem around it.”
The finding helps scientists understand the health and resilience of the ecosystem, she said. A longer food chain is more typical, and reflects a relatively diverse community, while shorter chains occur during extreme environmental conditions and suggest a decline in that diversity.
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