Oceanic Dead Zones Part 2

Updated: Jan 29

In part one of this series, we discussed oceanic dead zones: what they are, what causes them, why they are harmful, and whether or not they can be reversed. In part two we explore the process of denitrification, responses to oceanic dead zones, and alternatives to reduce the likelihood of dead zone formation.


According to Scientific American, the denitrification process uses bacteria to remove excess fertilizer from water, converting nitrates into nitrogen. The bacteria then releases the gas into the atmosphere. Denitrification remains the only process guaranteed to remove nitrogen from water. However, research found that this process only eliminates 16% of nitrogen pollution on average. In undisturbed streams, denitrification removes approximately 43% of nitrogen pollution. Algae and other organisms consume the remaining nitrogen pollution, sink, and when they die, “suck” oxygen out of the coastal waters.

Unfortunately, nitrogen cannot be easily extracted or eliminated from water sources. To reduce the amount of potential nitrogen in bodies of water, we outlined various responses below.

Global Responses to Oceanic Dead Zones

The majority of dead zones can be traced back to nitrogen fertilizer runoff from agriculture fields and farmland. By curtaining nitrogen use in agricultural land we can weaken “the point of entry” or the original source of oceanic dead zones. By virtually eliminating nitrogen, it disrupts the pollution cycle and cuts the dead zone cultivation potential. Farmers must adapt and change their ways and move away from nitrogen fertilizers. Unfortunately, many farmers have been using nitrogen-based fertilizers for so long that they are reliant on it. The soils require more and more fertilizer to be productive and many farmers are hesitant and fearful of changing their ways. Rather than adopt regenerative agriculture practices, many farmers continue to use nitrogen fertilizers knowing they are expensive and environmentally degradative. With this being said, we compiled some alternatives to nitrogen fertilizer.

Alternatives to Try

Meat consumption and food demand in general complicates the above argument. For some farmers, reducing or eliminating nitrogen fertilizers altogether is merely impossible. Project Drawdown, a nonprofit organization dedicated to reaching “drawdown” or the point when greenhouse gas emissions peak and start to decline, outlines an alternative: nutrient management. Nutrient management focuses on improving fertilizer-use efficiency to ensure that plants absorb the nitrogen and do not release exorbitant amounts into the environment. Farmers often overuse fertilizers thinking that it stimulates crop growth and productivity. In reality, overuse of fertilizers weakens soil productivity overtime and provides little short-term benefit.

Adopting nutrient management requires education about fertilizer usage and government regulations to reduce fertilizer rates. Currently, few countries have fertilizer regulations in place. Nitrogen pollution in bodies of water is generally considered a “nonpoint source pollution” which means that the pollution is not easily traced back to one source. With this being said, it is very difficult to enforce pollution and waste regulations since we cannot pinpoint the source. Additionally, because of food insecurity, many nations prioritize food productivity over sustainability. However, some governing bodies are attempting to regulate waste and pollution. In instituting nutrient management worldwide, it seems easiest to start in countries where fertilizer has little impact on agricultural yield protecting farmers from failures.

Eliminating nitrogen fertilizer usage, while not easy, avoids emissions and protects our oceans from becoming dead zones. To protect our oceans and preserve the integrity of our planet, we need to advocate for waste and pollution regulation and educate on nutrient management.

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