Saturday, October 23, 2021

Climate change lowers nutrition, increases toxicity at base of food web

 

https://www.eurekalert.org/news-releases/932391

 

 News Release 22-Oct-2021
Research looks at warming, browning effects on freshwater systems
Peer-Reviewed Publication
Dartmouth College

 

HANOVER, N.H. – October 25, 2021 – Climate change impacts on freshwater systems can lower nutrition and increase toxicity at the base of the food web, according to research from Dartmouth College and the Swedish University of Agricultural Sciences.

The research, published in Scientific Reports, focused on the effects of warming water temperatures and browning—a discoloration of water caused by increased dissolved organic matter—using controlled outdoor environments known as mesocosms.

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 The research found that a combination of warmer, browner water resulted in the higher transfer of methylmercury from water to phytoplankton at the base of food web. Lower concentrations of essential polyunsaturated fatty acids in phytoplankton were also observed.

Long-chain polyunsaturated fatty acids—such as omega-3 and omega-6—support the growth and survival of animal and plant life by providing energy and by regulating immune systems. Methylmercury is a form of mercury that is easily absorbed by living organisms and acts a potent neurotoxin.

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Phytoplankton are the main suppliers of polyunsaturated fatty acids in aquatic ecosystems. According to the study, the less nutritious phytoplankton that result from browning and warmer water cause higher-level organisms—such as zooplankton, fish, other wildlife, and humans—to be exposed to more methylmercury as they consume more to achieve fatty acid quotas. 

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