Climate change is likely to impact the production of omega-3 fatty acids produced by plankton at the base of the food web in the ocean bed, according to a study.
This means less omega-3 fatty acids available for fish and for people. Omega-3 fatty acid is an essential fat that the human body cannot produce on its own, and is widely regarded as a "good" fat that links seafood consumption to heart health.
The first-ever survey of planktonic lipids in the global ocean predicts a temperature-linked decrease in the production of essential omega-3 fatty acids, an important subset of lipid molecules.
The survey analyzed 930 lipid samples across the global ocean using a uniform high-resolution accurate mass spectrometry analytical workflow, "revealing heretofore unknown characteristics of ocean planktonic lipidomes," which is the entirety of hundreds to thousands of lipid species in a sample, according to a new paper led by authors from the Woods Hole Oceanographic Institution (WHOI).
"Focusing on ten molecularly diverse glycerolipid classes we identified 1,151 distinct lipid species, finding that fatty acid unsaturation (i.e., number of carbon to carbon double bonds) is fundamentally constrained by temperature. We predict significant declines in the essential fatty acid eicosapentaenoic acid [EPA] over the next century, which are likely to have serious deleterious effects on economically critical fisheries," states the paper, Global ocean lipidomes show a universal relationship between temperature and lipid unsaturation, published in Science.
EPA is one of the most nutritious omega-3 fatty acids, has been linked to numerous health benefits, and is widely available as a dietary supplement. "The lipids in the ocean affect your life," says journal article co-author Benjamin Van Mooy, senior scientist in WHOI's Marine Chemistry and Geochemistry Department. "We found that the composition of lipids in the ocean is going to change as the ocean warms. That is a cause for concern. We need those lipids that are in the ocean because they influence the quality of the food that the ocean produces for humanity."
"All organisms in the ocean have to contend with water temperatures. With this study, we have revealed one of the important biochemical ways cells are doing that," says journal article lead author Henry C. Holm, a doctoral student in the Massachusetts Institute of Technology (MIT) -- WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering.
"These findings about EPA were made possible by using a method that gives us a very complete picture of the gylcerolipids in each sample. We saw that temperature was linked with the saturation of cell membranes everywhere we looked in the ocean."
"These trends are also evident in all the other glycerolipid classes as well as the total aggregated lipidomes of all glycerolipid classes," the paper states. "Indeed, it is striking that the relationship between temperature and unsaturation emerges from our dataset despite spanning such diverse and disparate planktonic communities, from the nutrient-depleted subtropical gyres to the highly-productive Antarctic coastal shelf," says the study.