Skeletonema Costatum

Skeletonema costatum is a cosmopolitan centric diatom that forms chains of six to twenty four cells, occasionally as many as sixty, each cell about eight to twelve micrometers across and holding up to two chloroplasts. It lives in coastal waters worldwide except around Antarctica, favoring brackish and estuarine conditions with salinity between eighteen and thirty five practical salinity units, though it can tolerate the full range from zero to thirty five, and it grows best around twenty five degrees Celsius, often dominating phytoplankton in nearshore waters. As one of the most abundant bloom-forming diatoms, it is a major oxygen producer, drawing carbon dioxide out of the atmosphere and helping offset ocean acidification, though its blooms can also deplete phosphate and crowd out other phytoplankton in nutrient-rich water.