{"id":3767,"date":"2026-02-03T23:47:00","date_gmt":"2026-02-03T21:47:00","guid":{"rendered":"https:\/\/arcticwatch.info\/?p=3767"},"modified":"2026-03-21T21:58:49","modified_gmt":"2026-03-21T19:58:49","slug":"greenland-will-release-more-sediment-into-the-ocean-as-the-climate-warms","status":"publish","type":"post","link":"https:\/\/arcticwatch.info\/index.php\/2026\/02\/03\/greenland-will-release-more-sediment-into-the-ocean-as-the-climate-warms\/","title":{"rendered":"Greenland will release more sediment into the ocean as the climate warms"},"content":{"rendered":"\n

Greenland\u2019s winding, rocky fjords are no strangers to research vessels. Usually, these boats give icebergs a wide berth, because they can roll over unexpectedly. <\/p>\n\n\n\n

That wasn\u2019t the case, though, for the boats carrying INSTAAR fellow and CU associate professor Irina Overeem<\/a> and her former PhD student Ethan Pierce<\/a> during the 2019 and 2022 summer field seasons. They were there for the icebergs. <\/p>\n\n\n\n

Relying on the caution and expertise of Greenlander captains, the scientists sidled up to the floating monoliths aboard small dinghies and carefully chipped off samples before returning to the main boat.<\/p>\n\n\n\n

\"An<\/figure>\n\n\n\n

A small dinghy carries Irina Overeem, Tom Marchitto, and Mia, a Greenlandic deckhand, out to sample an iceberg. (Nora Matell)<\/em><\/p>\n\n\n\n

\u201cWe really were relying on the Greenlanders a lot for their sense of what was safe and what was not,\u201d Pierce said. <\/p>\n\n\n\n

\u201cThey fish in that environment themselves, so they have a ton of experience doing that risk calculation,\u201d Overeem added. <\/p>\n\n\n\n

Five years later, that calculated risk is paying off. Pierce, Overeem and University of Copenhagen associate professor emeritus Bent Hasholt<\/a> published a new paper in Nature Communications documenting how icebergs bring sediment from Greenland out to sea<\/a>. <\/p>\n\n\n\n

\"A<\/figure>\n\n\n\n

Tom Marchitto paddles a packraft out to sample a dirty iceberg in Nuup Kangerlua (Irina Overeem)<\/em>
 <\/p>\n\n\n\n

The investigation is the first to unravel the complex process underlying a phenomenon that has an outsized impact on the Arctic Ocean\u2019s chemistry. The scientists estimate that icebergs account for around one third of all of the sediment leaving Greenland (the rest comes from meltwater). That sediment unloads nutrients into Arctic waters, which support organisms at every scale \u2014 from phytoplankton to whales.<\/p>\n\n\n\n

\"A<\/figure>\n\n\n\n

Irina Overeem poses with her catch in a Greenlandic fjord. (Tom Marchitto)<\/em><\/p>\n\n\n\n

Importantly, the scientists were also able to determine the effect of climate change on this process. As the planet warms, icebergs will deposit more and more sediment into the ocean.<\/p>\n\n\n\n

\u201cThis is the first modern study of this process that can say, \u2018with a warming climate we\u2019re going to see more transport of ice-rafted debris,\u2019\u201d Pierce said.<\/p>\n\n\n\n

A back-of-the-envelope calculation<\/h2>\n\n\n\n

Greenland contributes around 15 percent of the sediment that ends up in the ocean each year \u2014 an exceptionally high figure for a landmass of its size. Nearly a decade ago, Overeem published another paper<\/a> characterizing the amount of sediment coming from Greenlandic meltwater rivers. She found that these waterways were unloading a vast amount, but they didn\u2019t account for all of Greenland’s sediment export.<\/p>\n\n\n\n

At the time, Overeem already knew that icebergs might be the missing piece of the puzzle. For years, she had seen dark stripes of debris crisscrossing icebergs in Greenlandic fjords. And, ice-derived debris has long been found in sediment cores pulled from the bottom of the Atlantic Ocean. But, scientists had yet to figure out how exactly the debris got in the ice or how much of it left the continent this way. <\/p>\n\n\n\n

On the flight home from her 2016 field season, Overeem started jotting down rough equations based on previous research from colleagues. The numbers shocked her.<\/p>\n\n\n\n

\u201cAt the time, I did a back-of-the-envelope calculation,\u201d she said. \u201cI was shocked at how much it could be.\u201d \u201cI pitched the idea to the CU Research and Innovation Office and they funded a pilot project.\u201d<\/p>\n\n\n\n

By 2019, Overeem brought Pierce on as a PhD student and put him on the project. Unfortunately, the pandemic delayed multiple field seasons, but Pierce used the extra time to drill down on a mathematical model of how the debris ends up in the ice in the first place.<\/p>\n\n\n\n

According to Pierce\u2019s model, the weight of the massive Greenland ice sheet creates pressure points where the ice comes into contact with individual grains of sand on the earth below. These pressure points create heat, which melts the ice. The meltwater then refreezes around the grain of sand. As the ice sheet slides downhill toward the ocean, this process sucks up more and more sediment into the bottom layer of ice. Eventually, the ice reaches the waters edge and breaks off, forming a sediment-laden ice berg.<\/p>\n\n\n\n

Pierce’s model combined with the field sample data produce the central insight of the new paper \u2014 that icebergs contribute about one third of Greenland\u2019s sediment export.<\/p>\n\n\n\n

\u201cThere are lab experiments and grain-scale models that show that these processes happen, but Ethan is the first person who put together a numerical model that can then be extrapolated out on the scale of the Greenland ice sheet,\u201d Overeem said. <\/p>\n\n\n\n

Powering new research<\/h2>\n\n\n\n

Now that Overeem\u2019s back-of-the-envelope calculation has grown into a sophisticated model, it\u2019s time for the researchers to pass their data on to other scientists. The model could be useful for myriad other projects, including offering hints into ancient climatic conditions.<\/p>\n\n\n\n

Another potential application is more forward looking. As sediment in the Arctic Ocean increases, it will increase the abundance of minerals like iron and silicon. Those are minerals used by phytoplankton, the microscopic foundation of the Arctic marine food web.<\/p>\n\n\n\n

\u201cPeople who are good at observing phytoplankton over the long-term record have seen an uptick in Greenland,\u201d Overeem said. \u201cThere\u2019s definitely some interest in this from that community.\u201d<\/p>\n\n\n\n

It\u2019s not yet clear exactly how an increase in sediment might affect life in the ocean, but the question could spark further collaborations within the Institute of Arctic and Alpine Research. Tom Marchitto\u2019s laboratory excels at precise measurements of dissolved chemicals, a capability that could further resolve the contents of Greenlandic sediment. On the biological side of things, INSTAAR director Nicole Lovenduski\u2019s lab specializes in modeling phytoplankton blooms in the Arctic.<\/p>\n\n\n\n

\u201cThis is just one part of a number of potential connections,\u201d Overeem said.<\/p>\n\n\n\n

For now, Pierce will move onto other projects as a postdoctoral researcher at Dartmouth, and Overeem will turn her attention to other pressing surface process models. Both can rest easy knowing they placed another puzzle piece in the answer to a question that has loomed over generations of Greenlandic science.<\/p>\n\n\n\n

Source – https:\/\/www.colorado.edu\/instaar\/2026\/02\/02\/breaking-ice-moving-earth-greenland-will-release-more-sediment-ocean-climate-warms<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Greenland\u2019s winding, rocky fjords are no strangers to research vessels. Usually, these boats give icebergs a wide berth, because they can roll over unexpectedly.\u00a0<\/p>\n","protected":false},"author":2,"featured_media":3768,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"yes","rop_publish_now_accounts":[],"rop_publish_now_history":[],"rop_publish_now_status":"pending","_themeisle_gutenberg_block_has_review":false,"footnotes":""},"categories":[5],"tags":[],"class_list":["post-3767","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-climate"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/posts\/3767","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/comments?post=3767"}],"version-history":[{"count":1,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/posts\/3767\/revisions"}],"predecessor-version":[{"id":3769,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/posts\/3767\/revisions\/3769"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/media\/3768"}],"wp:attachment":[{"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/media?parent=3767"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/categories?post=3767"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/arcticwatch.info\/index.php\/wp-json\/wp\/v2\/tags?post=3767"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}