On 16th January, 2001, oil tanker 'Jessica', with 160,000 gallons of diesel oil and 80,000 gallons of intermediate fuel oil on board, ran aground at Wreck bay near Galapagos Islands. The repercussions of the oil spill triggered by this accident affected the biodiversity rich Galapagos Islands big time killing several sea lions and sea birds - resulting in big loss for the ecosystem of this region.
In 2002, a study published in Nature - an interdisciplinary journal of science, revealed that the 2001 Galapagos Islands oil spill resulted in death of around 60 percent of the iguanas which were found on these islands, all of which died within a year of the oil spill. The researchers at the Princeton University who carried out this study added that the oil ingestion killed the digestion-assisting microbes in the gut of these iguanas, as a result of which they eventually died of starvation.
Are Oil Spills the Only Culprits?
The 2001 Galapagos Islands oil spill is just one of the numerous oil spills that various oceans of the world have been subjected to over the last decade or so, and the iguana is just one of the numerous species which have been affected by ocean pollution caused by these oil spills. Statistics reveal that around 3-4 oil spills occur in some or the other part of the world every year. Though these oil spills are responsible for marine pollution to a great extent, the pollution of this water is not just restricted to them. Approximately, 80 percent of the ocean pollution recorded is attributed to land-based activities.
Different Types of Ocean Pollution
Basically, ocean pollution refers to the contamination of ocean water by harmful chemicals which are discharged into these ocean bodies as a result of human or natural activities. When we say different types of ocean pollution, we refer to the different methods by which the harmful chemicals (pollutants) are introduced into the oceans. Sewage waste discharge into the oceans is one of the major source of pollution in this case. Sewage is either discharged into the oceans directly, or dumped into the rivers from it is carried to the oceans. Even today, several countries continue to dump sewage waste in oceans without subjecting it to proper treatment which is required to get rid of harmful matter in the same. Sewage waste discharge into the oceans is not just restricted to land-based structures, as large vessels also dump tons of garbage into the oceans every single day. In fact, a single cruise ship is known to generate, and dump, more than a million gallons of waste water into the ocean on a single trip.
Industrial waste is one of the most prominent causes of ocean pollution. In fact, it is much more harmful as compared to sewage water pollution as the pollutants in this case include toxic metals such as cadmium, mercury, lead, polychlorinated biphenyl (PCB), polycyclic aromatic hydrocarbon (PAH), etc. These toxic metals which are suspended in the waste water are also introduced into the oceans either directly or through the rivers. While the problem of industrial waste threatens the oceans around developed countries, it is the problem of agricultural waste that threatens the oceans around the countries which still rely on agriculture to a certain extent. The chemicals used in agricultural practices most often make it to the oceans in form of surface runoff following heavy rains. At times these chemicals can also seep into the ground, get mixed into ground water, and make it to the oceans eventually.
Contamination of oceans by oil is not just restricted to oil spills. In fact, oil is introduced into these oceans by means of surface runoff, marine transportation and routine maintenance of ships, natural oil seeps, offshore oil drilling, etc. Experts argue that marine transportation in itself is a far bigger threat than the oil spills which are caused as a result of accidents in oceans once in a while. Huge containers of toxic material accidentally fall in the oceans when they are being transported from one place to another. As a part of routine maintenance, these ships flush out significant amount of oil - which is eventually dumped into the oceans. While natural oil seeps are triggered as a result of the crustal movements of the Earth, oil seeps can also occur as result of off-shore drilling.
This may come as a surprise for many, but air pollution/atmospheric pollution is also known to fuel ocean pollution. Carbon dioxide and carbon monoxide which are released in the atmosphere get dissolved into the ocean water in course of time, in a process which is by and large similar to oxygen getting dissolved in water. More importantly, oceans absorb carbon dioxide from the atmosphere, and that happens to be a serious issue if you take into consideration the fact that the atmospheric concentration of carbon dioxide is on a rise as a result of various human activities. Deep sea mining is also believed to be one of the causes of ocean pollution, but the impact of the same is yet to be ascertained as it is a relatively new concept.
Though the effects of ocean pollution on marine organisms and plants are more than obvious, they are not restricted to these marine species alone - but are also known to affect us humans in the long run. There is no dearth of laws prohibiting dumping of all these pollutants in the oceans. The problem lies with the process of implementation of these laws which is very poor at the grass-root level, and that's where we need to put in some efforts if we are to save the marine ecosystem.