Balance of ocean food web at risk as jellyfish blooms increase
By Summit Voice
SUMMIT COUNTY — Warmer water temperatures, over-fishing and nutrient loading in coastal areas could result in a jellyfish takeover, according to a team of biologists who studied the role of the slimy floaters in marine ecosystems.
The scenario might be good for a jellyfish lover like the cartoon character Spongebob Squarepants, but as numbers of jellyfish increase, they could tip the balance of ocean food chains away from fish and toward bacteria, the scientists with the Virginia Institute of Marine Science wrote in a paper recently published in the Proceedings of the National Academy of Sciences.
Jellyfish eat huge amounts of plankton, which is also the most important food for small fish at the base of ocean food chains. But jellyfish are not a significant food source for other animals and their waste products add almost nothing useful to marine ecosystems.
The research team was led by Rob Condon, now a researcher at the Dauphin Island Sea Lab. His research partners included VIMS professors Deborah Steinberg and Deborah Bronk, Paul del Giorgio of the Université du Québec à Montréal, Thierry Bouvier of Université Montpellier in France, Monty Graham of DISL, and Hugh Ducklow of the Marine Biological Laboratory in Woods Hole, Massachusetts.
Condon studied two species of jellyfish in the York River, flowing into Chesapeake Bay, and observed a significant top-down changes to the zooplankton community.
“Blooms of both Mnemiopsis and Chrysaora (along with other members of the Pelagiidae) have been recorded worldwide as causing major problems for marine food webs and human activities (including tourism) … and their increased abundance in … the Baltic Sea and … the Mediterranean … suggests that these jellyfish have considerable invasive capabilities. The inclusion of these jellyfish species in this study is therefore relevant from a global perspective and serves as a relevant model to represent possible jellyfish-mediated changes to coastal bio-geochemical pathways,” the researchers wrote.
In what could become a climate-change bio-feedback loop, the research also suggests that bacteria consuming carbon-rich jellyfish waste and byproducts end up converting the carbon back to another form carbon instead of using to grow or reproduce.
Altogether, the changes could lead to major changes in some marine ecosystems, the researcher concluded.
“Our findings suggest major shifts in microbial structure and function associated with jellyfish blooms, and a large detour of (carbon_ toward bacterial CO2 production and away from higher trophic levels. These results further suggest fundamental transformations in the biogeochemical functioning and biological structure of food webs associated with jellyfish blooms,” they wrote.
Filed under: biodiversity, climate and weather, Environment, global warming, Marine biology Tagged: | Chesapeake Bay, Environment, jellyfish, marine biology, Proceedings of the National Academy of Sciences, Summit County News, Virginia Institute of Marine Science