![\"Net](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/09\/trawl-net.jpg\")
<\/p>\n
A trawl net, full of fish, as it is hauled to the surface within the English Channel.<\/p>\n
A heavy metal net is dragged across the seafloor at breakneck speed, churning up dark clouds of sediment and swallowing everything in its path. A blue-spotted stingray tries to flee, flailing its winglike pectoral fins as the trawl closes in from behind, but its efforts are in vain. This unprecedented footage\u2014a scene in David Attenborough\u2019s latest documentary Ocean\u2014is the first time bottom trawling has been captured in high definition, exposing a practice rarely seen by the public.<\/p>\n
Bottom trawling<\/a> is a highly controversial fishing method, but it provides a quarter of the world\u2019s seafood. It involves a vessel pulling a weighted net and other heavy gear, blindly and fast, along vast stretches of seabed\u2014often in pursuit of only one or two commercially valuable species. It traps huge numbers of other organisms and bulldozes over fragile habitats, destroying centuries-old coral, scallop gardens and seagrass beds. \u201cIt\u2019s hard to imagine a more wasteful way to catch fish,\u201d Attenborough narrates somberly as viewers watch a pile of dead juvenile sharks and rays get swept off the deck of the fishing vessel in Ocean.<\/p>\n But ecological destruction is not the only concern. Emerging research points to another lesser-known problem with bottom trawling: its potential to unleash climate-warming gases by disturbing carbon stored in seafloor sediments.<\/p>\n On supporting science journalism<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n The ocean is the world’s largest single carbon sink, absorbing around 30 percent of the carbon dioxide that human activity<\/a> pumps into the atmosphere. Phytoplankton\u2014microscopic plants and algae drifting near the ocean\u2019s surface\u2014take in CO\u2082 during photosynthesis, converting it into organic carbon that gets stored in their tissues. Many sink to the seafloor when they die; sediments eventually bury them and the carbon they contain, effectively locking it away.<\/p>\n A view of fishes seized December 27, 2007, at the port of Abidjan, from two Chinese ships, “Far East I” and “Far East II” (seen in background), which were intercepted using ‘bottom trawling,’ disregarding the national fishing laws.<\/p>\n Kambou Sia\/AFP via Getty Images<\/p>\n Bottom trawling stirs massive clouds of this carbon-rich sediment back into the water column. There the organic matter is exposed to oxygen and microbial activity that converts some of the carbon into other chemical forms, which can worsen ocean acidification or escape into the atmosphere as CO\u2082.<\/p>\n But how much of this dredged-up carbon is actually released into the atmosphere by bottom trawling\u2014and how quickly\u2014remains a matter of debate.<\/p>\n Some scientists argue that a significant portion of the carbon released by bottom trawling<\/a> makes its way into the atmosphere\u2014at levels that rival some of the world\u2019s worst emitters. \u201cIf all the disturbed carbon entered the atmosphere, it would rival aviation\u2019s emissions,\u201d says Utah State University ecologist Trisha Atwood, who co-authored a 2021 study<\/a> and a 2024 follow-up<\/a> that quantified trawling emissions by using statistical models. \u201cOur latest research shows that 55 to 60 percent of the resuspended carbon is actually released into the atmosphere over seven to nine years, which is around 340 [million] to 370 million metric tons of CO\u2082 annually.\u201d That\u2019s more than the entire annual emissions of countries such as Italy or Spain.<\/p>\n But other experts disagree with such high estimates, explaining that the ocean\u2019s carbon cycle is governed by complex biogeochemical processes that naturally absorb, convert or sequester much of the carbon that gets resuspended in the water column. \u201cIt is important to note that some of the CO\u2082 released from organic matter mineralization [microbial decomposition] ends up as bicarbonate, which is dissolved in seawater and does not exchange with the atmosphere,\u201d says Volker Br\u00fcchert, an associate professor of biogeochemistry at Stockholm University. This input of bicarbonate contributes to acidification and hinders some of the ocean\u2019s ability to absorb additional CO\u2082, he says\u2014\u201cbut direct corresponding data for such a large CO\u2082 emission from oceanic shelves into the atmosphere has not been demonstrated.\u201d<\/p>\n There is, however, general consensus that frequent trawling makes it harder for carbon to remain sequestered in seafloor sediments. \u201cIt\u2019s difficult to measure the exact scale of greenhouse gas emissions, but we know carbon on the seabed is more likely to be preserved if it\u2019s not continually resuspended by bottom trawling activity. There is growing evidence to support this,\u201d says William Austin, a paleooceanographer at the University of St. Andrews in Scotland and chair of the United Nations Ocean Decade Program for Blue Carbon<\/a>.<\/p>\n Methane, a greenhouse gas far more potent than CO<\/a>\u2082<\/a>, adds another variable that is difficult to account for in seafloor disturbance. Most oceanic methane is stored as methane hydrates<\/a>\u2014icelike compounds formed under high pressure and low temperatures\u2014which are typically scattered over seabed areas too deep for trawling to reach. But in regions with shallow, nearshore methane deposits (such as the Siberian Shelf), bottom trawling could pose a risk, particularly as receding sea ice leads to new fishing grounds above methane hotspots.<\/p>\n This possibility is drawing much scientific interest, especially in light of past climate events. Around 56 million years ago, during an interval called the Paleocene-Eocene Thermal Maximum<\/a> (PETM), the planet warmed by up to eight degrees Celsius in under 200,000 years\u2014a blink in geological time and one of the closest analogues researchers have to help them understand modern climate change. Though the exact cause of that warming event remains uncertain, one hypothesis is that warming waters destabilized and melted seafloor methane hydrates, triggering an unprecedented release of methane into the atmosphere. Whether modern, human-driven warming could trigger similar processes, even at a much smaller scale, is still unclear.<\/p>\n \u201cIf we\u2019re going to start trawling the seabed in a rapidly warming and transitioning Arctic,\u201d Austin says, \u201cwe may need to stop and think first.\u201d<\/p>\n It\u2019s Time to Stand Up for Science<\/p>\n If you enjoyed this article, I\u2019d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n I\u2019ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n If you subscribe to Scientific American<\/a>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n In return, you get essential news, captivating podcasts<\/a>, brilliant infographics, can’t-miss newsletters<\/a>, must-watch videos, challenging games<\/a>, and the science world’s best writing and reporting. You can even gift someone a subscription<\/a>.<\/p>\n There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":"August 28, 2025 4 min read A Controversial Fishing Method May Dredge Up a Climate Time Bomb Bottom…\n","protected":false},"author":2,"featured_media":125305,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[192,79],"class_list":{"0":"post-125304","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-environment","9":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/125304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=125304"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/125304\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/125305"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=125304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=125304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=125304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Large](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/09\/fish-and-trawling-ship.jpg\")
<\/p>\n