Descent into Madness: Dealing with the dead zones

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EMBSdiaries

5 min readAug 18, 2021

On our mission of deep oceanic exploration, we have admired the reefs, dived deep between the marine environment, and befriended the creatures it shelters. We now take a cautious step to explore the darker parts of this heavenly environment. Read the blog to know more about what is rightly called “a DEAD zone.”

Do you know what is more alarming than a dead species of fish? A dead zone. it is claimed by few marine biologists that there are chances that marine life will decrease by 90% by 2050. And the most underlying cause is active dead zones.

What are dead zones?

Dead zones are low-oxygen or hypoxic, areas in the world’s oceans and lakes. Because most organisms need oxygen to live, few organisms can survive in hypoxic conditions. That is why these areas are called dead zones.

Dead zones occur because of a process called eutrophication, which happens when a body of water gets too many nutrients, such as phosphorus and nitrogen. At normal levels, these nutrients feed the growth of an organism called cyanobacteria, or blue-green algae. With too many nutrients, however, cyanobacteria grow out of control, which can be harmful. Human activities are the main cause of these excess nutrients being washed into the ocean. For this reason, dead zones are often located near inhabited coastlines.

Causes of Eutrophication

The enrichment of water by nutrients can be of a natural origin (natural eutrophication) but is often dramatically increased by human activities (anthropogenic eutrophication). Causes of eutrophication by human activities can be characterized into point source and non-point source.

Point source pollution: Pollution that comes from contaminants that enter a waterway from a single identifiable source such as stationary locations or fixed facilities. Examples are discharges from sewage treatment plants or industrial plants and fish farms.

Non-point source pollution: Pollution from widespread including human activities with no specific point of discharge or entry into receiving watercourses. Examples are leaching out of nitrogen compounds from fertilized agricultural lands and losses from atmospheric deposition.

Natural eutrophication has been occurring for millennia. It is the process of adding, flowing, and accumulating nutrients to water bodies, resulting in changes to the community's primary production and species composition. Cultural eutrophication is the process that speeds up natural eutrophication because of human activity.

Prevention and elimination of these dead zones

It is a goal to eliminate ocean dead zones by implementing these methods and tactics. The Black Sea dead zone is an example of how what was once a large problematic region of dead zones, became a clean sea again with the collaboration of all those who wished to have a cleaner environment.

Decreasing usage of chemical fertilizer and better processing of chemical waste can contribute much to the prevention of dead zones.

The Baltic Sea is home to seven of the world’s 10 largest marine dead zones. Increased runoff from agricultural fertilizers and sewage has sped up the eutrophication process. Overfishing of Baltic cod has intensified the problem. Cod eat sprats, a small, herring-like species that eat microscopic zooplankton, which in turn eat algae. Fewer cod and more sprats mean more algae and less oxygen. The spreading dead zones are starting to reach the cod’s deep-water breeding grounds, further endangering the species.

The Baltic Sea has become the first “macro-region” targeted by the European Union to combat pollution, dead zones, overfishing, and regional disputes. The EU is coordinating the Baltic Sea Strategy with eight EU member countries that border the Baltic Sea: Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, and Sweden.

Categorizing Eutrophic Systems

Scientists have identified 415 dead zones worldwide. Hypoxic areas have increased dramatically during the past 50 years, from about 10 documented cases in 1960 to at least 169 in 2007. Most of the world’s dead zones are located along the eastern coast of the United States, and the coastlines of the Baltic States, Japan, and the Korean Peninsula. As a result of the dramatic increase in dead zones, scientists have categorized coastal systems experiencing any symptoms of eutrophication.

An area of concern is a coastal system that exhibits effects of eutrophication, such as elevated nutrient levels, harmful algal blooms, and negative changes in the benthic community. Areas of concern are at the most risk of developing hypoxia. Major concentrations of areas of concern are located along the western coast of Central and South America, and the coastlines of Great Britain and Australia. There are 233 areas of concern around the world.

A system in recovery is one that once exhibited low oxygen levels and hypoxia, but is now improving. For example, the Black Sea once experienced annual hypoxic events but is now in a state of recovery. Like Boston Harbor in the United States and the Mersey Estuary in the United Kingdom, others also have improved water quality. These are the results of better industrial and wastewater controls. There are only 13 coastal systems in recovery around the world. Term Part of Speech Definition

Here is a graph showing the bottom water area of hypoxia from 1985 to 2021 in the Gulf of Mexico.

The dead zone has increased nutrients that before are limited leading to algae blooms. These algae blooms can disastrously affect marine life. This made the dead zone one of the leading problems of marine life extinction. A new report from the World Wildlife Fund indicates a nearly 50% decline in marine life populations between 1970 and 2012! What do you think the future beholds for all the water that surrounds us?

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Descent into Madness: Dealing with the dead zones

Written by AKKIREDDI SV RAMAPRSADA RAO 20BCE2460