Oceans are large bodies of water that contain most of the earth's water. Up to 71 % of the earth's surface is made up of oceans and contains up to 90 % of the earth's biosphere. So, these are huge areas teeming with life. The oceans are absolutely crucial to our lives. Why do we treat them so indifferently and why do we destroy them?
The oceans are crucial to humans in many ways. They make a living from fishing, make it easier to transport goods over long distances, sea currents help to transfer heat from the tropics to the polar, they generate about half the oxygen, absorb large amounts of carbon dioxide, evaporated water from their surface brings moisture and last but not least they are praised for our recreation and economic benefit. Even life on planet Earth penetrated the oceans and did not reach the mainland until 3 billion years later.
Man pollutes the oceans in various ways. The obvious causes are oil extraction and oil accidents, waste ending up in rivers flowing into the oceans, frequent shipping, but also overfishing, global warming, or tourism. For example, it is estimated that if consumption and pollution increase at the same rate as now, by 2050 the oceans will contain more plastics than fish in terms of total weight.
Overfishing is one of the major problems of today's oceans. The data show that over the last 50 years, fish and other aquatic animal populations have fallen by more than half. However, the problem is not only the ever lower and lower catch for small-scale fishermen, for whom fishing is the only means of subsistence. Higher demand, together with a lower number of fish, forces companies to use more efficient methods, which, however, have an increasingly negative impact on the ecosystem. Many rare animals such as sharks, rays, turtles and dolphins die in fishing nets. In addition, fishing boats often throw unsaleable fish back into the sea, which can be up to two-thirds of all fish caught.
Man-made global warming has a much greater impact on the oceans than on land. The oceans absorb up to about half of all greenhouse gases. On the one hand, they are warming up, as a result of which, among other things, sea levels are rising, and they are further acidifying. These phenomena are so rapid that many marine animals are unable to adapt to change, which will mean their extinction. Currently, a much-discussed topic is the so-called whitening of corals, which in extreme cases leads to their death. Coral bleaching occurs, among other things, due to over-acidification of the water and an increase in its temperature.
Shipping also has a significant impact on ocean pollution. Ships often discharge waste directly into the sea, contaminate water with toxic varnishes, disrupt natural fish spawning grounds, transmit diseases and invasive plant and animal species. In the event of an accident, oil or transported cargo may leak into the water. Transmissible invasive species can disrupt the local ecosystem. In addition to the ships themselves, they can be even transported on garbage.
Plastic waste pollution is considered to be one of the biggest causes of ocean pollution. Plastics can now be found virtually anywhere, on the ocean floor, in Antarctica, hundreds of miles from the mainland. Often already in the form of so-called microplastics and nanoplastics, particles smaller than 5 millimeters. Recently, there have been more and more projects to clean the oceans of waste. Many projects are also very promising. However, these projects also present a major pitfall in that they can give us a false idea that we can behave as we have done so far, and that someone will clean up our mess anyway. Therefore, it is crucial to change individual behavior in waste management and waste generation in general, and to establish these practices at national and international level through appropriate legislation.
Oceans can also be polluted by noise. Because light does not reach deep underwater, many marine animals have developed the ability to forage, communicate, and orient themselves using sound. However, human activity fundamentally impairs the ability of animals to rely on sound. This is visibly reflected, for example, in the increasingly frequent trapping of whales on beaches. The consequence, which is already less visible, is the damage to the sensitive auditory organs of marine animals, which can either be disoriented and frightened, or can easily become the food of another animal. A person pollutes the oceans with noise, for example by ship sirens, sonar, frequent traffic, or exploration of oil deposits. One of the advantages of noise pollution in the oceans, compared to all other pollution, is that it can be eliminated immediately. If man stops generating noise, the ocean will also stop being polluted by noise.
The oceans are essential to our lives, whether we feel it or not. Our daily decisions also affect life in the oceans. Buying goods from distant lands, buying a product in packaging, traveling by car or plane, wasting, all this and much more exacerbates the great problem of pollution of the world's oceans. So, it is up to us how we approach this issue.