Ancient Marine Algae May Reveal the Impact of Climate Change

Ancient marine algae could give us a glimpse into how climate change has impacted our environment over time. Researchers have taken a closer look at coccolithophores, a type of marine algae, and have found that a changing environment has affected both their growth and skeleton structure.

Coccolithophores are prolific in the ocean today and have been for millions of years. These single-celled plankton produce calcite skeletons that are preserved in seafloor sediments after death. Although coccolithophores are microscopic, their abundance makes them key contributors to marine ecosystems and the global carbon cycle.

In this case, the scientists examined preserved fossil remains of coccolithophores from a period of climate warming and ocean acidification that occurred about 56 million years ago during the Paleocene Eocene Thermal Maximum (PETM). More specifically, they found that two key PETM coccolithophores, Cocolithus pelagicus and Toweius pertusus had calcification rates that halved during the PETM. That said, the response of each species was different and involved intervals of slowed growth in C. pelagicus and an overall reduction in the size of the skeletal components in T. pertusus. Surprisingly, though, there was very little evidence for any response to ocean acidification.

"our results show that climate change significantly altered coccolithophore calcification rates at the PETM and has the potential to be just as significant, perhaps even more so, today," said Sarah O'Dea, one of the researchers, in a news release. "Ultimately then, it is the factors that influence where species live, their abundance, how fast they grow and their ability to adapt to environmental change that is likely to control future coccolithophore calcite production."

The findings have implication for what might happen as our climate continues to change. By studying the past, the researchers can predict what will happen in the future.

The findings are published in the journal Nature Communications.