Gulf of Mexico Hypoxic Zone Resulting in Loss of Wildlife

Posted: August 12, 2021 1:05 am

Lack of Hurricane Activity in Gulf Partly to Blame for Dead Zone

A large hypoxic zone in the Gulf of Mexico is creating an environment that does not support healthy marine life. This so-called “dead zone” is dangerous to the local wildlife while simultaneously delivering a financial blow to the fishing industry along the US Gulf Coast.

Details of the Hypoxic Zone

A hypoxic zone occurs when an excess amount of nutrients from farming zones and sewage flow downstream into the Gulf of Mexico. As the temperature rises, the algae in the water begin to feed on these nutrients. The algae then inevitably die and drop to the floor of the Gulf where bacteria in the water sucks up the oxygen in the area. Without the necessary oxygen in the water, marine life is not able to thrive and replicate.

Dangers of a Hypoxic Zone

According to the National Oceanic and Atmospheric Administration (NOAA), this type of dead zone can lead to a host of disastrous effects on the wildlife that call this water home. The lack of available oxygen can negatively affect reproduction and growth rates and change the way that fish are forced to eat. A large hypoxic zone can also sink the availability of commercially harvested marine life that people consume.

This decrease in the availability of species such as shrimp is already affecting the fishery industry along the Gulf Coast, particularly in Louisiana. For example, approximately half of the Louisiana coast is showing oxygen levels that are too low to maintain the usual harvest of penaeid shrimp, one of the most significant economic fisheries in the region. Without the necessary habitat for the shrimp to thrive, experts are predicting that the catches may plummet in the coming weeks, delivering a significant financial blow to the industry.

Why This Summer’s Hypoxic Zone is So Concerning

The current dead zone has ballooned to an area equivalent to the size of Connecticut. While it is certainly not an anomaly for the hypoxic zone to form in the Gulf during this time of the year, this year’s zone is larger than usual.

Earlier predictions detailed that the hypoxic area would reach 4,880 square miles, however, the zone had reached 6,334 miles during the last survey of the area. The scientists are blaming the increase from the initial forecast on a greater than average amount of water flowing from the Mississippi River. This larger than normal output produced more of the nutrients that algae feed on. In addition, less oxygen was delivered from the surface of the Gulf to the bottom.

Quiet Hurricane Season Also to Blame

The lack of tropical activity in the Gulf has also been to blame for the increase in the size of the dead zone. The last few years have brought a high number of tropical storms and hurricanes to the region, disrupting the ability of hypoxia to set into the Gulf. However, a calmer hurricane season thus far has led to an increase in hypoxic activity.

Hurricane Elsa was the last tropical feature to visit the Gulf of Mexico, making landfall in Florida on July 5. Since Elsa made its way up the west coast of Florida, it never was able to disturb the hypoxic activity farther into the interior of the Gulf. While Tropical Storm Claudette landed close to the current dead zone at the end of June, its effects were not enough to prevent the hypoxic activity.

It is not unusual for hurricanes to tamper with the ability of a dead zone to expand. During the year 2020, the mixing attributed to Hurricane Hanna in the Gulf caused a dead zone that was smaller than originally forecast. While it was predicted to balloon to 6,700 square miles, the 2020 hypoxic zone only measured 2,116 square miles. This was the third smallest area in the 34 years since the phenomenon has been tracked.

The largest dead zone on record reached 8,777 miles during the year 2017. The average measurement over the last five years has been 5,380 miles.

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