Jul 29, 2026 02:07 AM
(This post was last modified: Jul 29, 2026 02:09 AM by C C.)
A new way that a cow’s inner world shapes Earth’s atmosphere
https://www.quantamagazine.org/a-new-way...-20260727/
INTRO: Within every cow is a thriving ecosystem. Churning deep in its intestines, a massive fermentation chamber known as the rumen hosts a robust microbiome that can consume up to 100 pounds of feed daily. Inside this gut pouch, tens of millions of bacteria scavenge for scraps of fiber, starch, and other nutrients, and break down cellulose and proteins. They get a hand from microbial fungi, whose enzymes demolish stiff cell walls, and all are ruled by ciliates: large, predatory microbes that gorge themselves on bacteria.
This complex food web transforms a bounty of compounds to fuel the cow’s metabolism. Little goes to waste: Even hydrogen gas and carbon dioxide, the byproducts of fermentation, are scavenged by opportunists in this dark, warm, oxygen-free world. Those opportunists are rumen microbes called methanogens, and their waste product is methane, a notoriously powerful heat-trapping greenhouse gas.
In this way, the inner world of a cow has global significance. Ruminant livestock, including cows, goats, and sheep, have burped out about a third of all methane gas in the atmosphere. All told, when combined with more methane from landfills and fossil fuels, the gas is responsible for around 30% of the rise in global temperatures over the past 150 years. But it has a weak spot: It decays more quickly than carbon dioxide. That’s why cow gas has attracted interest from researchers across the globe. They are looking into livestock’s specialized stomachs to identify the biological mechanisms that produce methane, which could be targeted to slow global warming within our lifetimes.
A recent study published in Science has revealed a clue wrapped in a membrane. Amid new genome sequences for 450 ciliates — the rumen’s apex predators — researchers followed a trail that led them to an organelle, new to science, that is essential to the biochemical process of rebuilding atoms into compounds that are heating the planet. They named it the “hydrogenobody” because it produces hydrogen gas, which methanogens then turn into methane.
The findings offer new ideas for managing this pervasive source of warming, said Juan Tricarico, who researches enteric, or intestinal, methane at Dairy Management Inc., a nonprofit trade association for dairy farmers, and was not involved in the recent study. “Just targeting the methanogens is probably not enough.”
Understanding how microscopic organisms lead to changes at a planetary scale will require further disentangling of the rumen’s microbial food web and the specific mechanisms by which they produce methane, he added. “We want to understand the environment under which these microbes thrive.” (MORE - details)
https://www.quantamagazine.org/a-new-way...-20260727/
INTRO: Within every cow is a thriving ecosystem. Churning deep in its intestines, a massive fermentation chamber known as the rumen hosts a robust microbiome that can consume up to 100 pounds of feed daily. Inside this gut pouch, tens of millions of bacteria scavenge for scraps of fiber, starch, and other nutrients, and break down cellulose and proteins. They get a hand from microbial fungi, whose enzymes demolish stiff cell walls, and all are ruled by ciliates: large, predatory microbes that gorge themselves on bacteria.
This complex food web transforms a bounty of compounds to fuel the cow’s metabolism. Little goes to waste: Even hydrogen gas and carbon dioxide, the byproducts of fermentation, are scavenged by opportunists in this dark, warm, oxygen-free world. Those opportunists are rumen microbes called methanogens, and their waste product is methane, a notoriously powerful heat-trapping greenhouse gas.
In this way, the inner world of a cow has global significance. Ruminant livestock, including cows, goats, and sheep, have burped out about a third of all methane gas in the atmosphere. All told, when combined with more methane from landfills and fossil fuels, the gas is responsible for around 30% of the rise in global temperatures over the past 150 years. But it has a weak spot: It decays more quickly than carbon dioxide. That’s why cow gas has attracted interest from researchers across the globe. They are looking into livestock’s specialized stomachs to identify the biological mechanisms that produce methane, which could be targeted to slow global warming within our lifetimes.
A recent study published in Science has revealed a clue wrapped in a membrane. Amid new genome sequences for 450 ciliates — the rumen’s apex predators — researchers followed a trail that led them to an organelle, new to science, that is essential to the biochemical process of rebuilding atoms into compounds that are heating the planet. They named it the “hydrogenobody” because it produces hydrogen gas, which methanogens then turn into methane.
The findings offer new ideas for managing this pervasive source of warming, said Juan Tricarico, who researches enteric, or intestinal, methane at Dairy Management Inc., a nonprofit trade association for dairy farmers, and was not involved in the recent study. “Just targeting the methanogens is probably not enough.”
Understanding how microscopic organisms lead to changes at a planetary scale will require further disentangling of the rumen’s microbial food web and the specific mechanisms by which they produce methane, he added. “We want to understand the environment under which these microbes thrive.” (MORE - details)