U Tikhole, K Balasubramanian and KB Bhushan

Today’s ocean is dominated by eukaryotic phytoplankton such as diatoms, dinoflagellates, and coccolithophores. According to fossil records, diatoms were a minor component of the sea until the Cretaceous Era (145.5-66 mya). Modern continents formed when the supercontinent Pangea broke down, creating much space in the marine ecosystem and delivering more nutrients to the oceans. The increase in ocean nutrients favoured the selection of large-celled phytoplankton such as diatoms and other algae. In the Cenozoic era (66-0 mya), diatom diversity increased, and two major speciation events occurred, namely in the boundary interval of the Eocene/Oligocene (33.9-23 mya) and in the mid-to-late Miocene (16-5.3 mya). These events took place because of environmental changes such as changes in ocean chemistry, the availability of silica, a rise in sea level, and predation…read more on NOPR