For hundreds of millions of years, the tiny shells of single-celled marine organisms called foraminifera have been accumulating on the ocean floor. Their shells contain clues about the composition of the seawater they lived in. In a recent cooperation between EPFL and the Alfred Wegener Institute, researchers lay out a new explanation for how these organisms take up the elements they use to grow their shells, offering climatologists a better understanding into a common tool to study the Earth’s climate history. Their results were published in the journal Biogeosciences in late October, and highlighted in the November 22 issue of Science.
Scientists often rely on secondary evidence, from ice or sediment cores, to reconstruct the prehistoric climate. Studying sediment cores containing foraminifera, scientists have reconstructed temperature timelines and analyzed the planet’s ice cover based on the composition of the shells. But as coauthor Anders Meibom explains, because they are the result of complex biological processes, foraminifer from sediment cores cannot be interpreted easily using data from inorganically formed minerals.
Not just passive transport
Foraminifera build their shells by using calcium, carbon, and oxygen that they find in seawater. Until now, scientists thought that the microorganisms used tiny “carrier bubbles,” or vacuoles, to transport seawater into them. There, calcium carbonate would precipitate from the water, forming the shell.
Read more at: Phys.org