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
Arctic National Wildlife Refuge Wildlife Refuge is the only refuge that regularly dens polar bears in that local region, and contains the most consistent amount polar bears in the area. The Arctic basin is the shallowest ocean basin on Earth. It is the least salty, because of low evaporation and large current of freshwater from rivers and glaciers. River mouths and calving glaciers, are continually moving ocean currents contribute to a unique marine ecosystem in the Arctic. The cold, circulating water is rich in minerals, as well as the microscopic organisms (such as phytoplankton and algae) that need them to grow. Marine animals thrive