Water circulation is an essential component for global climate system. A new study has been published in Proceedings of the National Academy of Science, where researchers showed that water circulation in deep ocean has been slowed down during the last glacial period.
Research shows that decomposition of organic carbon in water has consumed the oxygen availability in the water. Scientists from Oklahoma State University and GEOMAR Helmholtz Centre for Ocean Research Kiel and MARUM has conducted this research.
Ocean is a natural sink for carbon and also an important element of the Earth’s climate system. Seabed consumes particles containing carbon and oxygen plays a vital role in the consumption and forming microbial decomposition. The distribution of oxygen in the water mainly depends on vertical circulation.
The researchers have studied sediment samples to find out the answer of whether the corresponding conditions in the deep ocean can be changed or not. Chemical elements have been preserved over thousands of years in sediments has been analysed by the researchers.
The team of researchers have examined the sediment cores from Cape Basin of the west coast of southern Africa. The depth of the water was between 1,000 and 2,500 meters. This area is one of the most biologically productive area because of the ocean currents. The depth has also increased the productivity of phytoplankton.
In the water, dead organic material is processed by microorganisms. This is the process that consumes oxygen. If the organic material is large then it consumes more oxygen. Then the water becomes oxygen-free.
The researchers have used geochemical signatures in the sediments and proved that less oxygen is available in the deep ocean during the last glacial period.
Till now researchers thought glacial periods have stronger temperature gradient between the poles which increases wind circulation and as a result of this nutrient-rich water comes.