Dead Zone has Deadly Consequences

A Dead zone is an inhabitable area in the ocean. This occurs because the oxygen level is below 2 milliliters per liter. Such a phenomenon is threatening the biodiversity of the marine ecosystem as well as worsening climate change, as the ocean plays a big role against climate by absorbing excess heat and carbon dioxide. This issue has also caused an economic loss of over 80 million a year.

How dead zone occurs?
Low oxygen beneath the ocean happens as oxygen is blocked by the rapid growth of organisms such as cyanobacteria. Its exponential growth is mainly due to the increase of nutrition dumped into the ocean waters. This nutrition-rich fertilizer comes from many sources, one of them are from agriculture. Our agriculture practices still rely heavily on animal manure, which contains high nitrogen and phosphorus. The nutrition flows from agricultural fields to the ocean by rain or irrigation. The second-largest source found from untreated wastewater (from sewage and waste industries). This happen usually in developing countries where wastewater management tends to be managed poorly.

What problems have occurred?
The Dead zone is affecting us and the planet. Shellfish, such as oysters, absorb microbes associated with cyanobacteria, which are toxic to humans. The biotoxin produced by the shellfish can affect the nervous system, making people pose a severe illness condition or even death. The National Oceanic and Atmospheric Admission (NOAA), estimates that the dead zone costs the U.S seafood and tourism industries $82 million a year, and the figure is rising as the dead zone area is increasing. In 1998, Hongkong’s fish farms suffered from stock decline. The stock went down drastically by 40%, estimated economic loss of $40 million.

Currently, the biggest size of dead zone is located in the Baltic sea, approximately 70,000 square kilometers, roughly the same area as Ireland. The second biggest area has approximately the same size area as New Jersey, its Gulf of Mexico. In 2019 the size had already grown to over 22,000 square kilometers.

Our ocean has been doing an excellent job at diminishing carbon dioxide (CO2) from our planet (30% of CO2 has been absorbed by the ocean), but in doing so, the ocean is becoming acidic and that leads to a problem for marine life such as oyster.

What can be done?
As nutrition (Nitrogen and Phosphorus) has been the root cause of this problem, we have to be more careful about what goes into our ocean. Tighter regulations against industrial run-off should be enforced. The way we deal with wastewater should also be managed more properly. In the long term, we could revolutionize the way we farm by cutting off our reliance on nitrogen-rich fertilizer.




Leave a Reply

Your email address will not be published.