What’s The Problem? During the 20th century, as consumers became accustomed to having every type of fish available, large commercial fleets began depleting fish populations to meet consumers’ expectations. In 2003, a report estimated commercial fishing had reduced big sea fish to just 10% of their previous population. A study in Science predicts that if overfishing continues at its current rate, then the world’s fisheries will collapse by 2048.
What Can Be Done? Scientists say some fish populations could be restored with better fishing practices and laws. Alternatives, such as aquaculture, would reduce overfishing in the ocean. Also, individuals must take for granted eating a wide variety of seafood.
2. Ocean Acidification
What’s The Problem? For millions of years, the ocean has maintained a steady balance of acidity, which life has flourished in. But the ocean has been absorbing nearly half of the carbon dioxide released into the air since the Industrial Revolution, altering surface-level acidity and causing many problems for marine life.
What Can Be Done? Ocean acidification is caused by many factors, but scientists say that a reduction in fossil fuels will have the greatest power to slow its effects.
3. Coral Bleaching
What’s The Problem? Rises in temperature cause massive coral die-offs, because they trigger the reefs to expel their symbiotic food-producing algae in response to the heat. This also happens to make reefs look white, which is why the phenomena is called coral bleaching. In 1998, an El Niño weather pattern caused one of the world’s worst coral bleaching: 16% of reefs died. Some reefs recover from such events, but many do not.
What Can Be Done? The Nature Conservancy assists reefs in recovery efforts after a coral bleaching. No one can predict when a coral bleaching is going to occur, but environmental groups work with communities to better protect reefs before such events happen.
4. Oil Spills
What’s The Problem? Oil spills from tanker ship accidents have damaged ecosystems around Alaska, in the Gulf of Mexico, and many other places. The oil kills animals by ruining fur and feathers, by being ingested by them, and by ruining the reproductive cycles of fish. It can also contaminate drinking water.
What Can Be Done? Cleanup after a spill is very difficult, because oil can spread in the ocean for hundreds of miles. Once a spill happens, response crews must determine where it is moving and how to contain it. The best thing though is to prevent an oil spill before it happens through better protocol and equipment, but ultimately by eliminating the shipment of oil.
5. Shark Finning
What’s The Problem? Up to 73 million sharks are caught each year for the global fin trade, which is fueled by shark-fin soup, a traditional delicacy in many parts of the world. The sharks are caught and their fins are sliced off. Then the shark’s body, alive or dead, is thrown back in the water. This practice is drastically decreasing populations of sharks, who are key members of the ocean ecosystem.
What Can Be Done? Pew Environment advocates for international shark conservation and for areas with diverse shark populations to be declared sanctuaries. Also, people must not insist on having shark-fin soup.
6. Harmful Algal Blooms
What’s The Problem? An algal bloom happens in all coastal states when there is a rapid increase in algae, the small organisms that function at the bottom of the food chain. In large numbers, the algae clogs the gills of fish, smothers coral, and is also toxic to a lot of marine life. Algal blooms are caused by many things, one of which is nutrient pollution that comes from runoff.
What Can Be Done? Federal government groups study algal blooms in hopes of learning more about what causes them and work with coastal communities to set up plans for prevention and mitigation.
7. Ocean Dead Zones
What’s The Problem? When there is no oxygen in the air, ocean dead zones form because all the marine life either leaves or dies off. Some ocean dead zones happen naturally, but scientists are especially worried about those that are accelerated by human activity. Runoff that includes nitrogen and phosphorus causes harmful algae or bacteria blooms, which often become ocean dead zones. In Hawaii, an ocean dead zone formed in Honolulu Harbor, when a massive molasses spill killed off all marine life.
What Can Be Done? Nutrient pollution is caused by runoff from chemically based fertilizers and pesticides, which should be avoided or not used altogether. Shipment of harmful products should also be well regulated or banned.
8. Mercury Pollution
What’s The Problem? Mercury enters the water from industrial sources, like coal plants. Once in the ocean, it bioaccumulates in marine animals, meaning the higher up on the food chain the animal then the more mercury it is likely to have (e.g., tuna and swordfish). Exposure to mercury, even in small doses, is extremely harmful for wildlife and humans. Once mercury enters the water, it can travel across great distances, making contamination a global problem.
What Can Be Done? Treaty discussions involving the United Nations are underway, which include measures that would use non-mercury alternatives when possible and reduce mercury emissions. Although not a cure all, the European Union enacted an export ban beginning in 2011 and the U.S. Congress enacted a similar export ban in 2013.
9. Marine Invasive Species
What’s The Problem? In the ocean, marine life has always moved around, but now plants and animals hitch rides on boats, traveling across great distances to new areas. Invasive species in new ocean ecosystems compromise or even wipe out entire populations. One example is the zebra mussel from the Black Sea that was accidentally introduced by a cargo ship into the Great Lakes in 1988. The little mollusk thrived and starved out many of the native mussels. It has now spread to Canada and Mexico, where it is considered a pest.
What Can Be Done? A lot of money is invested in the eradication of the zebra mussel every year. To avoid this, governments must invest in prevention and require ships to exchange their ballast water while out at sea or kill stowaway species before they are released.
10. PCBs, or polychlorinated biphenyls
What’s The Problem? An estimated 1.5 billion pounds of PCBs were made until these chemicals were banned in the U.S. in 1979. PCBs and their byproducts leaked into the air, ground, and water, and were discovered in far-reaching places, such as the Arctic, meaning that they can travel great distances. PCBs breakdown, but not very quickly, and many still remain.
What Can Be Done? Even though PCBs were banned decades ago, they remain in the ocean because they take so long to break down. The PCBs settle in the sediments, making them difficult to clean up without dredging everything.
11. The Great Garbage Patch
What’s The Problem? Plastic never goes away. Once in the ocean, it floats on the top moving with the currents across vast distances. The garbage patch is made up of tiny microplastics that are so small you can’t see them, but animals choke on them or harmed by them in other ways.
What Can Be Done? There is still more to be learned, but we do know that plastic arrives in the ocean through the storm drains and sewers, as well as from trash left behind by beach goers. Plastic bans have spread across the U.S., which have helped reduce plastic bag usage, but always remember to recycle, reuse, and reduce.
What’s The Problem? The U.S. Navy uses sonar for military applications, but it interferes with the sonar used by whales and dolphins. No one knows how bad the impact is, but sonar is the language whales use to communicate with each other and mass whale strandings have become more frequent. Scientists believe the sonar may scare the animals, leading them to swim to shallow areas, where they die. Biologists are also concerned marine mammals may suffer prolonged stress caused by sonar.
What Can Be Done? The U.S. Navy plans to increase its use of sonar over the next few years, but environmental groups have filed lawsuits against the military’s sonar use and you can write Secretary of Defense Chuck Hagel to let him know your position.
13. Nuclear Radiation
What’s The Problem? Nuclear is so scary, because once it’s out there it can remain radioactive for hundreds of thousands of years. The ocean is threatened by the nuclear radiation leaking from Japan’s reactor in Fukushima. The plume of radiation from Fukushima is set to hit the U.S. West Coast in 2014, peaking in 2016, but the level of radiation is expected to be below World Health Organization’s safe levels. There are also the tens of thousands of steel drums of atomic waste dumped into the water by the U.S. and other nations up until the 1970s, which remain at the bottom of the ocean.
What Can Be Done? Many of the U.S. dump sites were off California and the East Coast, and officials have issued an advisory against fishing for bottom-dwelling creatures in Massachusetts Bay, but overall little has been done to deal with safety concerns. Alternative energy sources are a way to avoid making atomic waste, which needs to be stored or dumped somewhere after it is created.