Climate change reduces nutritional value of algae

March 11, 2009 |

Dutch researchers wanted to know whether an increased CO2 concentration exerted an influence on underwater life. They therefore examined freshwater micro-algae: small, floating and mostly unicellular algae. The experiments were performed in large tanks called limnotrons. These were aerated with ordinary air or with air containing an elevated concentration of CO2. The researchers then examined the ratio between the important elements carbon, nitrogen and phosphorous.

First link in the food chain

The micro-algae grew faster at a higher CO2 concentration, exactly as the researchers had expected. Yet this growth was also associated with a change in the composition of the algae. The algae cultured at a higher CO2 concentration contained relatively more carbon and relatively less phosphorous. This meant a reduction in the nutritional value, which could have detrimental effects upon the small animals that eat the algae such as water fleas. These in turn form food for fish, for example. As they are the first link in the underwater food chain, the algae ultimately influence the entire ecosystem.

In a follow-up study, the Centre for Limnology (NIOO-KNAW) and the Department of Aquatic Microbiology at Universiteit van Amsterdam will examine what effects the reduced nutritional value of the algae can have in real ecosystems. Meanwhile, it is already clear that the effects can become more pronounced as a result of higher water temperatures.

The best-know effects of climate change are shifts in the habitats of animals and plants, for example, species that spread further northwards. This research has shown that climate change can also exert significant effects on the underwater food chain.

One Response to Climate change reduces nutritional value of algae

  1. Anonymous March 11, 2009 at 11:32 am #

    If anyone can cite evidence or experiments that conclusively link CO2 to the greenhouse effect, please do so. I have been unable to find it on the Internet.

    What I have found, though, is that Carbon Dioxide gas is a tiny, tiny component of the Earth’s atmosphere. The fraction of CO2 in the air is 1 over 2632. To put that in perspective, a column of Earth atmosphere ten thousand inches long, (833 feet), only has enough CO2 to make 3 of those inches. It seems everyone has swallowed the idea that CO2 makes a difference. Absent evidence or experiments to the contrary, I say it doesn’t, there’s just not enough of it.

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