Climate change

Climate change to foster algae blooms and disrupt ocean food chains, study finds

written by Oceanographic Staff

A recent study published in the journal Nature Communications by the University of East Anglia and the Earlham Institute found that global warming that already extends the warm hemisphere is likely to foster algae blooms and change algae communities that are vital for maintaining global ocean health.

According to the study this is happening because of shifting biodiversity ‘break point’ boundaries. These ‘break points’ describe areas where the upper ocean temperature is approximately 15 degrees on an annual average, separating cold and warm waters. Instead of a gradual microbial diversity change due to warming oceans, we will see more algae blooms and abrupt changes at the ‘break points’, the study suggest.

Prof Thomas Mock, from UEA’s School of Environmental Sciences, said: “Algae are essential in maintaining a healthy ecosystem to balance ocean life. By absorbing energy from sunlight, carbon dioxide and water, they produce organic compounds for marine life to live off. These organisms underpin some of the largest food webs on Earth and drive global biogeochemical cycles.

“Accountable for at least 20 percent of annual global carbon fixation, temperature changes could have a significant impact upon the algae that our marine systems, fisheries and ocean biodiversity depend on. We wanted to better-understand how the climate crisis is impacting algae worldwide from the Arctic to the Antarctic.”

The study was conducted by an international team of 32 researchers over more than 10 years, involving the first pole-to-pole analysis of how algae are distributed in the oceans. Another key pillar of the research was looking into how the algae’s gene activity changes due to environment changes in upper ocean zones.

Prof Mock said: “Significant international efforts have provided insights into what drives the diversity of these organisms and their global biogeography in the global ocean, however, there is still limited understanding of environmental conditions responsible for differences between local species communities on a large scale from pole to pole.

“Our results provide new insights into how changing environmental conditions correlate with biodiversity changes subject to large-scale environmental fluctuation and disturbances. This knowledge is essential for predicting the consequences of global warming and therefore may guide environmental management.

“We can expect the marine systems around the UK and other countries on this latitude to be severely affected, and more suddenly than previously thought. The largest ecosystem change will occur when marine microalgal communities and their associated bacteria around the UK will be replaced by their warm-water counterparts.”

Because microalgae form such an important part of the food chain, major changes in the rest of marine ecosystems can be expected which can affect marine conservation effects and fisheries. On the other hand, the shift in microalgal communities could make algae’s ability to take up carbon dioxide less effective which in turn could exacerbate global warming.

The researchers urged that this is not irreversible yet – if countries and governments work quickly and efficiently on preventing global warming now.

For the full study, ‘The biogeographic differentiation of algal microbiomes in the upper ocean from pole to pole’, click here

For more from our Ocean Newsroom, click here.

Photography courtesy of Unsplash.

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