What are Oceanic Dead Zones and Why Should You Care?

What are Oceanic Dead Zones and Why Should You Care?

What happens when we run out of oxygen? We die! But death is not only specific to living creatures. 


Oceans can also run out of oxygen and result in ocean dead zones – patches in the oceans where no life exists. The largest oceanic dead zone in the world is in the Pacific Ocean and is almost 2700 square miles, nearly as big as Ireland!

Now let me tell you how this works. 

Did you know that the Gulf of Mexico in the Atlantic Ocean is brimming with marine life from tiny crabs to gigantic whales throughout the year? But, at the onset of summer, they start fleeing the area, and the creatures that can’t swim fast enough suffocate and die! This phase continues till early autumn, during which thousands of square kilometers of the ocean turn into dead zones and cannot support marine life. 


This is just one instance. Numerous dead zones form all over the world during this time of the year. But before we get into the details of what causes these lethal conditions, let’s have a look at how a healthy marine ecosystem works.


Healthy Marine Ecosystems

What are Oceanic Dead Zones and Why Should You Care?

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Two factors determine whether an oceanic ecosystem is healthy or not:

1. Sufficient sunlight 

2. Plant-like organisms like algae and cyanobacteria

How, you ask?

Well, the algae are scattered across the surface of deep waters providing just the right amount of sunlight to the plants below, while cyanobacteria serve as the basis of the local food chain for the sea creatures. Moreover, they carry out photosynthesis that balances the amount of oxygen required for the aquatic creatures to survive. 

But did you know that algae can also play a role in creating oceanic dead zones, among other factors?  Here’s how:


What Causes Ocean Dead Zones?

1. Excessive Algae

What are Oceanic Dead Zones and Why Should You Care?

Photo credit: Pexels

Excess of something is never beneficial. The algae on the surface of the water lets in only a fraction of the sunlight, which helps the marine ecosystem thrive. But, the same algae can create dead zones. 


During rainstorms, nutrient-rich sediments from the forest can wash up in the ocean, which in return cause the algae to grow at a rapid speed, covering the entire water surface and blocking the sunlight. This kills the underwater plants due to light deprivation and further reduces the oxygen levels. The outcome? An inhabitable dead zone!


2. Global Warming

Another factor behind the ever-growing oceanic dead zones is global warming. 

Come to think of it; global warming is the contributing factor in everything that’s wrong with our planet!

What are Oceanic Dead Zones and Why Should You Care?

Photo credit: Pexels 

90% of the heat due to global warming goes into the oceans, increasing the water temperature. Warm water cannot hold as much oxygen as cooler water, depriving the fish of oxygen, causing them to suffocate and die. 

Similarly, phytoplanktons – microscopic organisms in the ocean that account for more than half of the world’s oxygen, cannot survive in warm waters and retreat to cooler temperatures, causing a massive drop in the oxygen level of the ocean patch they abandoned. The fish follow them in an attempt to get oxygen to survive. The result? Another oceanic dead zone!


Why Should You Care?

The number of ocean dead zones has gone up from only 49 to more than 400 in the past 50 years or so. The increasing number of these dead zones will eventually create water bodies with below-normal oxygen levels, leading to the extinction of all sorts of species and aquatic creatures that live in the ocean. 

What are Oceanic Dead Zones and Why Should You Care?

Photo credit: Pexels


Global warming not only takes oxygen from the water but also prevents it from reaching us. With the unbalanced and low oxygen levels in the atmosphere, the danger is not only looming upon the sea creatures but also living beings on land – including us!

Your Contribution

At the Purpose For Earth Foundation, we work on ocean conservation and want to create awareness among the masses to opt for a sustainable lifestyle.

This is where we need your help! 

We know that it would be devastating for you to see ocean life diminish, and that also due to human activities that can be controlled. You can help us create awareness by volunteering for beach clean-up events and holding inspirational meetings, teaching people how to implement sustainable practices in their daily life.

Even if we manage to change the mindset of one person, we will count it as success! 

But the question is, how? 

Let’s make a difference by teaching the people to:

  • Use renewable energy
  • Invest in energy-efficient appliances
  • Save water
  • Stop using chemical-laden products

Healing the planet starts from home!

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