Seventy-five scientists from around the globe on Thursday sent a letter to President Barack Obama, urging the federal government not to move ahead with use of seismic airguns in the Atlantic Ocean for oil and gas exploration. They say the use of the guns, which create canonlike air blasts underwater, represents a "significant threat to marine life throughout the region." The air blasts fire every 10-12 seconds for weeks or months at a time, which the scientists say can harm marine mammals such as whales that rely on sound waves to communicate, feed, mate and travel. The blasting can disrupt the reproduction and feeding of blue whales and other endangered whales "over vast ocean areas," the letter says.

Nine permits are before the Bureau of Ocean Energy Management, which must also be approved by NOAA Fisheries before being finalized. The government says no seismic applications will be approved without measures meant to mitigate harm to marine life.

IN-DEPTH

SOCIAL

75 marine scientists sound the alarm on oil & gas airgun exploration in Atlantic. http://t.co/sxFEJKWk4e pic.twitter.com/CSVamr541u — Earthjustice (@Earthjustice) March 5, 2015

Obama Administration Criticized For Seismic Airgun Blasting In The Atlantic - http://t.co/pCANNiLhTk pic.twitter.com/3pvsRvBhmS — DianeN56 (@DianeN56) March 5, 2015

— The Associated Press and NBC News staff