Emiliania

Emiliania is a genus of coccolithophores, single-celled marine algae within the phylum Haptophyta. Members produce coccoliths, tiny calcium carbonate plates that surround the cell or are shed into surrounding water, contributing to marine sediment when cells die.

The most extensively studied species is Emiliania huxleyi, which is widespread in nutrient-rich surface waters of temperate and tropical oceans. E. huxleyi forms large, optically bright blooms that can cover vast areas and are detectable from space as milky patches. Other species in the genus are less well known and show greater morphological and ecological variability.

Ecologically, Emiliania spp. are important primary producers, using photosynthesis to fix carbon dioxide and form a base for marine food webs. The coccoliths they produce contribute to the ocean’s calcite sink and to the global carbon cycle. In paleoclimatology, coccolith fossils and the lipid biomarkers produced by Emiliania, such as alkenones, are used to reconstruct past sea surface temperatures and ocean chemistry.

Morphologically, coccolithophores are typically a few micrometers in diameter and have a calcium carbonate external covering. They reproduce mainly by asexual division, though some life cycles include sexual stages. Blooms can influence light scattering in surface waters and may affect local albedo and carbonate chemistry.

Distribution and significance: Emiliania is widely distributed in modern oceans, with species diversity greatest in upper, sunlit waters of many seas. The genus is studied for its ecological role, biogeochemical impact, and usefulness in paleoceanography and climate research.