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Climate change could lead to a dramatic temperature-linked decrease in essential omega-3 fatty acids

Climate change could lead to a dramatic temperature-related decrease in essential omega-3 fatty acids, according to a new study

MIT-WHOI Joint Program student Henry Holm pumps seawater for lipid samples from under sea ice in the western Antarctic Peninsula, 2018. This is for a WHOI-led study that conducted a global survey of lipids in the ocean to extract omega-3 fatty acids to be analysed. Credit: Benjamin Van Mooy / © Woods Hole Oceanographic Institution

The effects of global climate change are already leading to the loss of sea ice, accelerated sea level rise and longer and more intense heat waves, among other threats.

Now, the first-ever study of planktonic lipids in the global ocean predicts a temperature-related decrease in the production of essential omega-3 fatty acids, an important subset of lipid molecules.

A key implication of the research is that as global warming progresses, fewer and fewer omega-3 fatty acids will be produced by plankton at the base of the food web, meaning fewer omega-3 fatty acids will be available to consumers. fishing 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 linking seafood consumption to heart health.

The study analyzed 930 lipid samples across the global ocean using a uniform, high-resolution, high-resolution mass spectrometry analysis workflow, “revealing hitherto unknown features of ocean planktonic lipidomes,” which is the aggregate 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).

“By focusing on ten molecularly diverse glycerolipid classes, we identified 1,151 different lipid species, finding that fatty acid unsaturation (i.e., the number of carbon-carbon double bonds) is fundamentally limited by temperature. We predict significant decreases in the essential fatty acid eicosapentaenoic acid. [EPA] in the next century, likely to have serious deleterious effects on economically critical fisheries,” states the article, “Lippomes in the Global Ocean Exhibit a Universal Relationship Between Temperature and Lipid Unsaturation,” published in Science

EPA is one of the most nutritious omega-3 fatty acids, has been associated with numerous health benefits and is widely available as a dietary supplement. “The lipids in the ocean affect your life,” said co-author of the journal article Benjamin Van Mooy, senior scientist in WHOI’s Division of Marine Chemistry and Geochemistry. “We found that the composition of lipids in the ocean starts to change as the ocean warms. That is a cause for concern. We need the lipids in the ocean because they affect the quality of the food the ocean produces for humanity.”

“All organisms in the ocean deal with water temperatures. With this study, we have revealed one of the important biochemical ways cells do that,” said lead author of the journal article Henry C. Holm, a doctoral student at 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 glycerolipids in each sample. We saw that temperature was linked to the saturation of cell membranes everywhere we looked in the ocean.”

Lipids are a class of biomolecules produced and used by organisms from all domains of life for energy storage, membrane structure and signalling. They make up about 10-20 percent of the plankton in the ocean’s surface, where lipid production and supplies are greatest. Oceanographers have used lipids as biomarkers for chemical and biological processes for decades, and their biogeochemistry has been well researched. Only recently, however, has the combination of high-resolution mass spectrometry and downstream analytical tools enabled the comprehensive untargeted assessments of ocean lipids at scales comparable to studies of other molecules such as nucleic acids and proteins.

In this new study, researchers examined a global mass spectral dataset of planktonic lipidomes from 146 sites, collected during seven oceanographic research cruises from 2013-2018. The researchers note that while the planktonic community’s lipidomes are influenced by numerous environmental factors, such as nutrient availability, the paper reports on “the relationship between lipids and perhaps the most fundamental control over their composition: temperature.”

Researchers examined the state of saturation for the 10 major classes of lipids with glycerol (i.e., glycerolipids) and found that of those classes, “temperature was highly influential in structuring the relative abundance of fatty acid species.” In addition, researchers found a clear transition from lipid species with more unsaturated fatty acids at colder temperatures to fully saturated species at the highest temperatures.

“These trends are also evident in all other glycerolipid classes and in the total aggregated lipidomes of all glycerolipid classes,” the paper states. “It is indeed striking that the relationship between temperature and unsaturation emerges from our dataset, despite covering such diverse and disparate plankton communities, from the nutrient-poor subtropical gyres to the highly productive Antarctic coastal shelf.”

The researchers also found that percentage abundance for eicosapentaenoic acid (EPA) species showed a strong relationship with temperature. To determine how the upper and lower limits for EPA’s composition might shift under future warming conditions, researchers created maps using end-of-century sea surface temperatures for various climate scenarios. Under climate scenario SSP5-85, which the paper says is considered a worst-case scenario with persistently high greenhouse gas emissions, some ocean regions — especially at higher latitudes — see a drastic drop to -25% in the EPA from the amount they have now. , according to the newspaper.

Van Mooy said the study is “another example of how human activities are disrupting the oceans in ways we never expected, and of the uncertainty about how the ocean will respond to warming.”

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More information:
Henry C. Holm et al, Global ocean lipidomes show a universal relationship between temperature and lipid unsaturation, Science (2022). DOI: 10.1126/science.abn7455

Provided by Woods Hole Oceanographic Institution

Quote: Climate change could lead to dramatic temperature-related decline in essential omega-3 fatty acids (2022, June 23) retrieved June 23, 2022 from https://phys.org/news/2022-06-climate-temperature-linked-decrease- essential-omega-.html

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