Benthic foraminifera

Abstract

The world's oceans have an abundance of organisms thriving in their waters and sediments. A few kinds of these marine organisms have a hard skeleton protecting a soft body. Benthic foraminifera are one such group. They are marine unicellular microorganisms, a majority of which have a hard exoskeleton. Their single cell is enclosed in a microscopic shell made up of either calcite or sediments accumulated from the nearby environment. Foraminifera evolved during the Cambrian (541 to 485 million years ago [mya]) and inhabit the full range of marine environments from shallow water intertidal regions to deep trenches. Benthic foraminifera are very sensitive to the changes in physico-chemical and biological characteristics (sediment texture, seawater temperature, salinity, pH, dissolved oxygen, availability of food) of the ambient environment. The signatures of the changes in the ambient environment are incorporated in benthic foraminiferal shells, which have high preservation potential. Therefore, the composition of foraminifera species assemblages, as well as the characteristics of benthic foraminiferal shells, including their morphology, abundance, stable isotopic and trace element composition, provide valuable information about the past climatic and oceanographic changes, including sea-level, monsoon intensity, temperature, salinity, and ocean circulation patterns.