Some great news: annual Gulf of Mexico ‘dead zone’ 3rd-smallest on record

Back in early June, NOAA predicted a larger-than-average 'dead zone' to develop this summer

Some great news: annual Gulf of Mexico ‘dead zone’ 3rd-smallest on record

MONTGOMERY, Ala. (WSFA) - In a year with a whole bunch going on across the country, many of us are trying to find some positive news. While that may be easier said than done, there is some phenomenal news coming from the Gulf of Mexico this summer!

The National Oceanic and Atmospheric Administration has reported that the annual Gulf of Mexico ‘dead zone’ measured in late July was the 3rd-smallest on record! This comes after NOAA originally projected a larger-than-average dead zone -- also called hypoxic zone -- back on June 3rd.

Every summer a zone that is unfit for nearly all marine life and bottom dwellers forms in the northern Gulf of Mexico. It is usually forced off the coasts of Louisiana and southeastern Texas. This is due to the little to no oxygen present in those areas.

The entirety of the Mississippi River Watershed flows into the Mississippi River and eventually to the Gulf.
The entirety of the Mississippi River Watershed flows into the Mississippi River and eventually to the Gulf. (Source: WSFA 12 News/NOAA)

According to NOAA, the annual dead zone forms as “excess nutrients from cities, farms and other sources in upland watersheds drain into the Gulf and stimulate algal growth during the spring and summer.” The algae eventually die, sink and thus decompose. As that happens, oxygen-consuming bacteria decay the algae. This results in very low oxygen levels near the bottom of the Gulf, leading to a habitat not supportive of most marine life.

This year’s dead zone came in measuring 2,116 square miles, which is “equivalent to 1.4 million acres of habitat potentially unavailable to fish and bottom species,” according to NOAA. That puts 2020′s Gulf of Mexico hypoxic zone as the 3rd-smallest to be recorded in the 34 years of data-keeping.

The reasoning behind it being so small is likely the passage of Tropical Storm/Hurricane Hanna across the Gulf. Hanna sent large waves into the hypoxic zone, mixing the water around. This happened just days prior to when the measurements were taken in late July, likely resulting in the patchy and much smaller size according to NOAA.

For perspective on size, the 5-year running average for Gulf dead zones is 5,408 square miles. The largest Gulf of Mexico dead zone ever measured came back in 2017 at a staggering 8,776 square miles.

The most expansive Gulf of Mexico 'dead zone' was measured in 2017. Notice the expansiveness of the red color.
The most expansive Gulf of Mexico 'dead zone' was measured in 2017. Notice the expansiveness of the red color. (Source: WSFA 12 News/NOAA)

That year’s incredibly large dead zone is outlined immediately above. Just look at the amount of red compared to this year’s dead zone delineation above; it makes this year’s zone look very small.

Despite it being the 3rd-smallest dead zone on record, it was still above the goal set forth by the Hypoxia Task Force of 1,900 square miles.

2020 saw the 3rd-smallest Gulf of Mexico 'Dead Zone' in the 34 years of record-keeping.
2020 saw the 3rd-smallest Gulf of Mexico 'Dead Zone' in the 34 years of record-keeping. (Source: WSFA 12 News/NOAA)

That goal has only been achieved twice: back in 1988 and 2000.

Even so, the goal set forth by the Hypoxia Task Force is to have the size of the dead zone not exceed that 1,900 square mile threshold by the year 2035.

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