{"id":217985,"date":"2025-10-16T19:04:18","date_gmt":"2025-10-16T19:04:18","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/217985\/"},"modified":"2025-10-16T19:04:18","modified_gmt":"2025-10-16T19:04:18","slug":"the-permafrosts-revenant-microbes-are-slowly-awaking-this-is-bad-news-for-climate-change","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/217985\/","title":{"rendered":"The Permafrost’s “Revenant” Microbes Are Slowly Awaking. This Is Bad News for Climate Change"},"content":{"rendered":"

\"\" <\/a>Thawing permafrost in Alaska. Image credits: Brandt Meixell\/USGS.<\/p>\n

The frozen, barren soil of the Arctic isn\u2019t as lifeless as it looks. Locked inside the permafrost is a strikingly diverse community of microbes. They\u2019ve been asleep for millennia, alive, but inactive, in a kind of suspended animation. As the ice begins to thaw, these ancient organisms start to stir. What happens then?<\/p>\n

A team of researchers decided to find out. They reanimated microbes from Arctic permafrost and, after a sluggish start, the organisms began to thrive \u2014 producing methane and carbon dioxide in the process.<\/p>\n

\u201cThese are not dead samples by any means,\u201d said Tristan Caro, lead author of the study and a former graduate student in geological sciences at CU Boulder. \u201cThey\u2019re still very much capable of hosting robust life that can break down organic matter and release it as carbon dioxide.\u201d<\/p>\n

Finding Ancient Microbes<\/p>\n

Permafrost is, technically speaking, a mix of soil, rocks, and ice that has been frozen solid for at least two consecutive years. Around 15% of the Northern Hemisphere, or 11% of the global land surface, is underlain by permafrost. There\u2019s a lot of it, and it hosts many microbes we know very little about.<\/p>\n

To peer into this frozen world, a team of scientists ventured to the Permafrost Research Tunnel near Fox, Alaska. Operated by the U.S. Army Cold Regions Research and Engineering Laboratory, the tunnel offers a unique window into the past. It provides access to deep layers of permafrost that have been frozen since the late Pleistocene, some for more than 40,000 years.<\/p>\n

The researchers collected cores of permafrost from the surface, about 4,200 years old, and from deep within the tunnel at depths of 35, 54, and 83 meters.<\/p>\n

\u201cThe first thing you notice when you walk in there is that it smells really bad. It smells like a musty basement that\u2019s been left to sit for way too long,\u201d said Caro, now a postdoctoral researcher at the California Institute of Technology. \u201cTo a microbiologist, that\u2019s very exciting because interesting smells are often microbial.\u201d<\/p>\n

\"The <\/a>The U.S. Army Corps of Engineers\u2019 Permafrost Tunnel near Fairbanks, Alaska. Image credits: Tristan Caro.<\/p>\n

So, they gathered their samples and gently thawed the ancient soil under controlled anaerobic (oxygen-free) conditions and at different temperatures, from just below freezing at -4 degrees Celsius to a warmer 12 degrees Celsius. They gave the microbes \u201cheavy\u201d hydrogen atoms, called deuterium, to track how the microorganisms drank water and then used the hydrogen to build cellular membranes. Essentially, the deuterium was a way to track microbial activity.<\/p>\n

First Slow, Then Fast<\/p>\n

At first, the microbes moved incredibly slowly. Sometimes, it was barely detectable.<\/p>\n

They would replace only about 1 in 100,000 cells per day. At this rate, the average time for the microbial community to double, known as its generation time, was estimated to be between 3 and 57 years. For most active microbes, this period is less than a day. This \u201cslow reawakening\u201d suggests a natural buffer: even if a sudden heatwave hits, it might take years before microbial activity really takes off, especially if the ground refreezes in winter.<\/p>\n

But after 6 months, their activity drastically changed. <\/p>\n

\"A <\/a>Robyn Barbato of the Cold Regions Research and Engineering Laboratory drills a sample from the walls of the Permafrost Tunnel. Image credits: Tristan Caro.<\/p>\n

They didn\u2019t act like modern microbes, but they weren\u2019t so sluggish either. Instead, they morphed into a novel ecosystem, which the researchers term a \u201crevenant\u201d microbial community \u2014 a community returned from a long-dormant past, but fundamentally changed by the experience.<\/p>\n

Some of them produced gooey structures called \u201cbiofilms\u201d that could be seen with the naked eye, which typically grant added resilience powers to the microbial community. The temperature at which they awakened didn\u2019t seem to affect the growth rate. How long they were exposed to a non-freezing period seemed to be the key element. In other words, the longer the Arctic summers last, the more likely it is for microbes to revive.<\/p>\n

\u201cYou might have a single hot day in the Alaskan summer, but what matters much more is the lengthening of the summer season to where these warm temperatures extend into the autumn and spring,\u201d Caro said.<\/p>\n

Why This Is Even Worse for Climate<\/p>\n

We often hear that climate change triggers feedback loops, and this is a good example of that.<\/p>\n

The permafrost holds a lot of greenhouse gases (particularly methane) trapped within. If it melts, then this methane reaches the atmosphere, generates more heating, which melts more permafrost, and so on.<\/p>\n

But there\u2019s another mechanism at play. Permafrost contains vast amounts of organic matter, like plants and animals. If the microbes wake up, they start consuming the existing organic matter and then release methane. <\/p>\n

\"A <\/a>Permafrost thawing often looks like this site in Alaska. Image via Wiki Commons.<\/p>\n

This finding complicates predictions for how permafrost thaw will impact the climate. It suggests that the initial pulse of greenhouse gases may be physical, while the biological contribution will follow a significant delay. But ultimately, both will play a role in our planet\u2019s climate.<\/p>\n

\u201cThere\u2019s so much permafrost in the world \u2014 in Alaska, Siberia and in other northern cold regions,\u201d Caro said. \u201cWe\u2019ve only sampled one tiny slice of that.\u201d<\/p>\n

There is, of course, the concern of some of these microbes becoming pathogens. Caro said it\u2019s unlikely that these microbes could infect people, but the team kept them in sealed chambers regardless. Yet as the permafrost melts, many of these microbes could simply escape into ecosystems.<\/p>\n

The full consequences of the melting permafrost are not yet understood. For now, this research reveals that the duration of the thaw season may be a more critical factor than the intensity of warming. As long as the ground refreezes before the microbes fully wake up and proliferate, the vast stores of carbon may remain relatively safe. However, with longer and warmer summers, these ancient, revenant communities will have the time they need to establish themselves.<\/p>\n

The study was published<\/a> in JGR Biosciences.<\/p>\n","protected":false},"excerpt":{"rendered":"Thawing permafrost in Alaska. Image credits: Brandt Meixell\/USGS. The frozen, barren soil of the Arctic isn\u2019t as lifeless…\n","protected":false},"author":2,"featured_media":217986,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[105218,16167,11541,49,48,32427,6093,105219,105220,6092,17021,58130,65772,95195,105221,66],"class_list":["post-217985","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-alaska-research","tag-arctic","tag-biodiversity","tag-ca","tag-canada","tag-carbon-dioxide","tag-climate-change","tag-feedback-loop","tag-frozen-soil","tag-global-warming","tag-greenhouse-gases","tag-methane","tag-microbes","tag-permafrost","tag-revenant-microbes","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/217985","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=217985"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/217985\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/217986"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=217985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=217985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=217985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}