Marine pollution is a primary cause of eutrophication of surface waters, in which excess nutrients, usually nitrates or phosphates, stimulate algae growth. Many potentially toxic chemicals adhere to tiny particles which are then taken up by plankton and benthic animals, most of which are either deposit feeders or filter feeders. In this way, the toxins are concentrated upward within ocean food chains. Many particles combine chemically in a manner highly depletive of oxygen, causing estuaries to become anoxic. When pesticides are incorporated into the marine ecosystem, they quickly become absorbed into marine food webs. Once in the food webs, these pesticides can
Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2013 accumulation in the population of algae (typically microscopic) in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Freshwater algal blooms are the result of an excess of nutrients, particularly some phosphates. Harmful algal blooms are algal bloom events involving toxic or otherwise harmful phytoplankton such as dinoflagellates of the genus "Alexandrium" and "Karenia" or diatoms of the genus "Pseudo-nitzschia". is an algal bloom that causes negative impacts to other organisms via production of natural toxins, mechanical damage to other organisms, or by other means. HABs are often associated with large-scale marine mortality events and