COLLEGE STATION, Texas, July 14 (UPI) -- Researchers measuring the "dead zone" in the Gulf of Mexico say it is currently about 3,300 square miles but some scientists say it could become much larger.
The so-called "dead zone," caused by nitrogen levels in the gulf related to human activities such as agricultural runoff, occurs when oxygen levels in seawater drop to dangerously low levels, causing severe hypoxia that can potentially result in fish kills and harm marine life.