The oceans, covering some 71% of the Earth’s surface, are the foundation of human life. They have always been a prime source of nourishment for the life it helped generate and served as well for trade and commerce. Climate and weather, even the quality of the air people breathe, depend in great measure on interplay between the ocean and the atmosphere. However, human activity has finally pushed oceans to their limit.
In 2008, the United Nations General Assembly decided that, as from 8 June 2009 would be designated by the United Nations as “World Oceans Day”. The official designation of World Oceans Day is an opportunity to celebrate the importance of our planet’s largest bodies of water and raise global awareness of the current challenges faced by the international community in connection with the oceans.
The biggest threat to our Ocean’s health is climate change, with its twin super-dangers of rising sea temperatures and acidification. Both rising sea temperatures and acidification are due to become increasingly extreme throughout this century, along with other climate change impacts such as rising sea levels and more frequent, and more severe, storms.
Rising sea temperatures are already having a major influence on the distribution of marine species and are also partly responsible for the phenomenon of coral bleaching, devastating large areas of the world’s coral reefs.
Ocean acidification is a direct result of the absorption of carbon dioxide by the Ocean. This threatens all marine animals and plants that secrete calcium carbonate as part of their structure. It is believed that this has already caused a reduction in the size and growth rates of some marine animals.
Overfishing is another threat to life in the oceans. Entire populations of fish are being targeted and destroyed, disrupting the food chain from top to bottom. Overfishing happens when the amount of fish caught exceeds the amount of fish needed to sustain fish stocks in a given region. Giant factory ships are using state-of-the-art equipment to locate and literally vacuum entire schools of fish out of the water. These industrial fishing fleets target one species at a time, until numbers are so low, that they turn to another species, decimating the entire ocean food chain and threatening the very future of our oceans.
On the other hand, bottom trawling, a form of industrial fishing method that drags large, heavy nets across the seafloor kills vast numbers of corals, sponges, fish and other animals, bottom trawling has been banned in a growing number of places in recent years. Biologists estimate that somewhere between 500,000 and 5,000,000 marine species have yet to be discovered. Many of these species are in serious danger from the world’s most destructive fishing practice, bottom trawling.
Fish farming or aquaculture (farming fish and shellfish) is often called the future of the seafood industry. However, shrimp farming is perhaps the most destructive, unsustainable and unjust fishery in the world. The salmon farming industry also proves fish farming is no solution, it takes approximately 4 kg of wild caught fish to produce 1 kg of farmed salmon.
Marine pollution mainly comes from the land. Our oceans have become a dumping ground for a wide variety of pollutants, including pesticides and nutrients from agriculture, sewage, industrial discharges, urban and industrial run-off, accidents, spillage, explosions, sea dumping operations, mining, waste heat sources, and radioactive discharges. Solid waste such as bags, foam, and other items dumped into the oceans from land or by ships at sea are frequently consumed, with often fatal effects, by marine mammals, fish, and birds that mistake it for food.
The protection of the oceans calls for collective action. We can each make a difference, by understanding the issues and focusing on sustainable solutions that we can apply to our lives.
References
un.org
ocean.nationalgeographic.com
greenpeace.org