All you need to know about DEAD ZONES !

 ECOLOGY

DEAD ZONES

Edit credits : Diksha 

Hypoxia - reduced level of oxygen in water bodies

What is a dead zone?

A dead zone or Hypoxia, is an area of water bodies, deprived of the preferable amount of oxygen in it. Causing turbulence in aquatic life

Basic Analogy behind the water snot :

There can be two very straightforward explanations for the formation of a hypoxic region, it occurs :

• When marine adaptation dies due to the reduced amount of oxygen being supplied in the region.

• When the habitants abandon the region. 

Who is the culprit here? 

Earlier the blame was all on nature and the natural calamities but ever since humans began with the expanding industrialization, they started harming nature and hence ruining the harmony of the water bodies. Simply put, humans have contributed to the growth of dead zones around the earth. 

There are many physical, chemical, and biological factors that combine to create dead zones, but nutrient pollution is the primary cause, created by humans. For this reason, dead zones are often located near inhabited coastlines.

• THE DARK SIDE OF INDUSTRIALIZATION -

1. Excess nutrients that run off land or are piped as wastewater into rivers and coasts can stimulate an overgrowth of algae.

2. The algae then sinks in the water bodies and begins decomposing. 

3. The decomposition process consumes oxygen and depletes the supply available to healthy marine life. 

• EUTROPHICATION - 

This is also referred to as algal bloom. When a water body is supplied with excess nutrients like phosphorus and nitrogen, selective algal growth is seen. Precisely of the algae called cyanobacteria or the BGA - Blue Green Algae (from the monera kingdom of eubacteria). The cyanobacteria feed on the nutrients and divide excessively, resulting in coating the top layer of the water body. The dense algae on the surface do not allow light or oxygen to reach other aquatic organisms. In such conditions these organisms fail to grow and flourish and they eventually die.

• HUMANS ARE EVIL - 

• Agricultural practices - fossil and manure contributes to nitrogen production, which is later discharged in the atmosphere. This atmospheric nitrogen is then recoated on the surface of the land and water with the help of water cycle.

• Industrial toxins being discharged in the water bodies untreated.

• In developing countries of Latin America, Asia, and Africa, untreated wastewater from sewage and industry mainly contribute to eutrophication.

Where are they found?

The largest dead zone in the world lies in the Arabian Sea, covering almost the entire 63,700-square mile Gulf of Oman. 

The second largest sits in the Gulf of Mexico in the United States, averaging almost 6,000 square miles in size.

When was it first discovered ?

The Chesapeake Bay, on the East Coast of the United States, has one of the first dead zones ever identified, in the 1970s. 

The Chesapeake’s high levels of nitrogen are caused by two factors: 

• Urbanisation -  The western part of the bay is full of factories and urban centres that emit nitrogen into the air. 

• Agriculture -  The eastern part of the bay is a centre of poultry farming, which produces large amounts of manure.

The Chesapeake still has a dead zone, whose size varies with the season and weather.

Author : Diksha Jetly

Check out the other articles here - Click to view AMAZING articles !