Researchers from American institutions along with scientists from the University of Utah and NASA have identified a powerful new source of carbon dioxide release from the seas. The culprit is bottom trawling, a fishing method that drags heavy nets along the ocean floor. The updated findings appear in a peer reviewed journal focused on marine sciences.
Past work has shown that vast stores of carbon lie in seabed sediments. Experts note that when bottom soil is disturbed by trawling, as much as sixty percent of stored carbon can be released as carbon dioxide, which gradually makes its way to the atmosphere over a multi year timeline.
People estimate that emissions from trawlers may be double the carbon output of the global fishing fleet, which comprises millions of vessels. The new study highlights ocean regions where bottom trawling contributes most to carbon release, pointing to vulnerable zones in the East China Sea, the Baltic and North Seas, and the Greenland Sea as particularly impacted areas.
Additional potential hotspots include parts of Southeast Asia, the Bay of Bengal, the Arabian Sea, portions of Europe’s marine waters, and the Gulf of Mexico. At present, researchers lack precise data on the scale and intensity of trawling in these regions, making exact comparisons difficult.
One of the study’s authors described the discovery as showing that seabed disturbance creates plumes of carbon that can become stored in the ocean floor for thousands of years, akin to effects seen in other land use changes. The finding underscores a broader message about how activities on the sea bed can affect climate, ecosystems and coastal communities over the long term.
Earlier warnings from scientists about the risks of carbon release from methane rich formations undersea, sometimes called fire ice, add to the urgency of understanding how bottom fishing activities influence atmospheric carbon levels and climate dynamics.