Hobbies And Interests
Plastic
The large volume of plastic produced by human activity and its persistence in the environment make it a harmful marine pollutant whose effects only build over time. Americans alone put about 2.5 million plastic bottles per hour into the ocean, according to the Icelandic environmental consulting group Beluga. That is only a small part. About 70 percent of global plastic pollution comes from industry rather than from consumers. Currents tend to concentrate the plastic into debris fields. Marine animals can become tangled in plastics and die. Sea turtles eat plastic bags, confusing them with jellyfish. Sea birds also eat plastic, confusing pellets with fish eggs. The plastics can clog the animals' digestive tracts, causing them to starve to death. As plastic ages, it breaks down into particles and chemicals that pollute the waters beyond the debris fields. Microplastics also wash directly into the ocean in cleaning products. The tiny plastic pellets act as carriers for toxic chemicals.
Oil
Major oil spills can devastate many square miles of ocean. Oil spreads out on the surface of the water and affects all of the marine life in its path. Some petroleum products are toxic or caustic, and they harm animals with which they come into contact. Marine mammals and sea birds can inhale oil, rendering them vulnerable to pneumonia. Sea birds also get oil in their feathers, which can decrease their buoyancy and cause them to drown.
Oil spills are featured in news reports because of the environmental damage that they wreak. However, major spills are only a part of global oil pollution. Around the docks frequented by oil tankers, oil constantly makes its way to the sea from minor spills and tanker cleaning. These areas have low levels of oil pollution, but it is harmful nevertheless. For example, just 4 microliters of petroleum will render a seabird egg infertile. In addition to its biological effects, oil takes an economic toll. Exposure to oil ruins the taste of fish and other seafood, crippling fisheries in polluted areas.
Bioaccumulants
Too many toxic chemicals to list pollute the oceans. They come from human activities: agricultural runoff, dumping and even the burning of waste contaminate the seas. The poisons sometimes flood ecosystems, but at other times they enter the water in trace amounts. The lowest levels of toxins can still have devastating effects because of bioaccumulation. The chemicals build up in the tissues of marine animals. The concentrations are highest in the predatory animals that take in the accumulated substances in the flesh of their prey. As they build, they can harm the animals and creatures that consume them, including humans. Polychlorinated biphenyls (PCBs) are a class of chemicals that are particularly toxic to marine life. Researchers have discovered evidence of hermaphroditism in polar bears that they believe to be caused by PCB buildup.