Researchers from the Institute for the Oceans and Fisheries (IOF) at the University of British Columbia, used two biochemical tools, stable isotopes and fatty acids, to unlock the secrets of jellyfish feeding.
They published their findings recently in the Journal of Experimental Marine Biology and Ecology. Jellyfish have voracious appetites, and they aren't considered the most selective eaters. Almost anything that gets stuck to their tentacles winds up in the gelatinous sack that they use to digest their food.
This 'take what comes' feeding strategy has clouded our understanding of which foods jellyfish survive on and how they fit in food webs. The team sought to solve this mystery using stable isotopes and fatty acids.
Stable isotopes are naturally occurring isotopes of elements like carbon and nitrogen that exist in certain ratios in all living tissue. Similarly, fatty acids, which perform several critical physiological functions in the body, are produced in unique compositions by plants at the base of the food web.
Unique isotope and fatty acid "signatures," also known as "biomarkers," get passed from prey to predator and can be used to trace food web connections and illuminate the makeup of an animal's diet.
Scientists cultured jellyfish and fed them two unique crustaceans, krill and artemia, but they didn't really incorporate the krill. Scientists believe jellyfish can be picky eaters.
"They didn't really incorporate the krill because it seemed that they didn't like feeding on a single diet. Either it didn't meet their nutritional needs, or they preferred the live artemia over the dead, frozen krill," said Jessica Schaub, the study's lead author in a report posted on the university's website.
The study also found that jellyfish may be able to create their own essential omega-3 and omega-6 fatty acids, which are important for healthy body function.