Woods Hole Oceanographic Institution Marine paleoecologist Marco Coolen was mining through vast amounts of genetic information from the Black Sea sediment record, when he got surprised by the variety of past plankton species. The plankton species left behind their genetic makeup.
The Black Sea is semi-isolated and is highly sensitive to climate driven environmental changes. The Black Sea is currently receiving salty Mediterranean waters through the narrow Strait of Bosphorus. Also, freshwater is supplied by rivers via precipitation.
"However, during glacial sea level lowstands, the marine connection was hindered, and the Black Sea functioned as a giant lake", said WHOI geologist Liviu Giosan.
Coolen, Giosan, and their colleagues used a combination of advanced ancient DNA techniques and tools to reconstruct the past climate. This helped them determine the way communities of plankton responded to changes in climate and the influence of humans over the last 11,400 years.
Researchers generally make use of a microscope to reconstruct the makeup of plankton in order to count the fossil skeletons found in sediment cores. However, this method has various limitations as most plankton do not leave any fossils. This led Coolen to look for sedimentary genomic remains of the past inhabitants of the Black Sea water column.
The findings of the study will be published in the Proceedings of the National Academy of Sciences, USA and will be available online on May 6.