A silent yet dangerous crisis is occurring beneath the shimmering surfaces of our oceans, lakes and rivers. Scientists warn that the decline in marine dissolved oxygen levels, known as deoxygenation, is a global occurrence which is dramatically changing ecosystems and directly jeopardizing human life. Recent reports reveal that marine, coastal and freshwater bodies of the world are being oxygen-starved at a very fast pace due to anthropogenic factors like climate change, pollution, and nutrients running off from agricultural fields.
Aquatic deoxygenation doesn’t just impact marine creatures and reefs but leads to the destabilization of the entire food web. Fishes and other aquatic creatures which are adapted to the presence of a high level of oxygen will have to find new habitats or else they will die, So forming an environment where life becomes very rare (“dead zone”). Already fishers around the world are noticing fewer catches and a change in the species available, This way their incomes suffer whether through small scale farming or commercial fishing activities. For many families who mainly depend on fish as food, these developments mean higher prices at restaurants and in supermarkets, plus limited or decreased dietary access as well.
The underlying causes are intertwined with the human factor. For one, as sea surface temperatures rise, the capacity for seawater to contain dissolved oxygen goes down. Second, the nutrients like nitrogen and phosphorous are running down from the land Mainly after heavy rains which wash all fertilizers in the fields down to rivers creating algal blooms that eventually consume the dissolved oxygen. Third, coastal activities like construction and industry discharge into the waters further aggravate the situation. Marine scientists are already talking about the possibility that without drastic measures, large areas of the ocean will be rendered practically lifeless due to extreme low oxygen levels, with profound repercussions extending to life on land and even the whole biosphere. The sea not only helps us by being a sink of carbon but also it is involved in the Earth’s temperature regulation cycle; Though, if the marine ecosystem gets out of balance because of the crisis, it could lead the planet to further heating in a highly alarming manner.
On a public health level too, the consequences are serious. Low oxygen water allows the release of toxic substances such as hydrogen sulfide and methane from bottom sediments resulting in poor quality water. And, the risk of the people living near the so-called dead zones developing respiratory conditions, either as exposure through the air or contaminated seafood, will increase dramatically. In this situation of the deterioration of marine habitats, public health authorities are Mainly apprehensive about vulnerable groups of the population, like children and seniors, who may be affected through drinking water or local fisheries. Sometimes it is the crisis that brings to a head the problems of food insecurity and instability of the economy, already known in some communities.
Glacier melting has altered ocean currents and the way oceans get their oxygen supply is another factor being studied by researchers who are out to sea. But, In reality Earth is having another deoxygenation period can be inferred from the studies of sediment layers of an ancient lake. Though, because of our interference, a change like this would be much faster nowadays leaving the nature with less time to adapt as a matter of speaking. That means, scientists are coming together at various levels from national to international to get their hands on real data using both high-tech instruments and satellite imagery and the idea is to use the information for policy making as soon as they can while the damage is still not too much.
Glad to see, the situation has raised consciousness of people and there are now quite a number of initiatives being taken towards the solutions which have, for example, been a reduction in usage of fertilizer, promotion of wetlands restoration, etc. while a very large proportion of them involve a very strong component of greenhouse gas reduction. Some of the sea restoration projects have succeeded in bringing back a few areas so it gives an encouraging feeling that such a kind of effort if it is made at the right place and in the right amount will bring visible results. Also, individuals through the choice of a sustainable marine product, the elimination of ocean plastic debris or advocacy activities supporting stronger environmental laws, they are all doing something for the problem. So every one of them is playing part in the fight against depletion of oxygen in the ocean.
