High nitrate blamed for rise in shark attacks


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Elevated levels of nitrate from agricultural fertilisers are being blamed for an increase in shark attacks off the Texas coast.

According to the BBC, the use of nitrogen-based fertilisers by farmers around the Gulf of Mexico has caused an annual "dead zone" to form in the waters.

The 5800 square mile dead zone contains water with a very low oxygen level, making it inhospitable to fish.

Experts now believe that the dead zone is causing an increase in the number of shark attacks in the Gulf of Mexico, with three recorded casualties already this year.

Dr Nancy Rabalais from the Louisiana Universities Marine Consortium told the BBC that the dead zone has become a summer phenomena due to the popularity of nitrate-based fertilisers with farmers in the area.

The nitrates cause algae to take over via a process called eutrophication.

It's believed that the sharks are moving further inshore to areas where the dissolved oxygen levels are greater. The dead zone has decreased the amount of habitat available to them, thus causing an increase in their abundance in human populated areas and more attacks on humans.