Далайн гадаргын метан ялгаруулалтын нууцыг тайллаа

For decades, oceanographers measured something that did not make sense. Surface ocean waters, saturated with oxygen, were consistently releasing methane into the atmosphere. Methane production has always been associated with airless environments: wetland sediments, deep-sea mud, waterlogged soils. Oxygen-rich seawater was supposed to suppress it. Yet the readings kept coming, and nobody could explain where the gas was coming from.

A study published in the Proceedings of the National Academy of Sciences by researchers at the University of Rochester now resolves that contradiction. The explanation centers on a single missing nutrient, a microbial switch that flips when it runs out, and a warming mechanism that will increasingly create the conditions for that switch to stay on.

When Phosphate Drops, Marine Bacteria Switch to Methane

The Rochester team, led by Thomas Weber, an associate professor in the Department of Earth and Environmental Sciences, working with graduate student Shengyu Wang and postdoctoral research associate Hairong Xu, assembled a global dataset of ocean measurements and ran computer simulations to isolate what drives methane production in surface waters.

The answer was a specific microbial process tied to nutrient stress. Certain marine bacteria generate methane as a metabolic byproduct when they break down organic compounds, but only when phosphate, an essential nutrient, drops below a critical threshold. In waters where phosphate is available, those bacteria follow a different metabolic path and produce no methane. Starve them of it, and methane output switches on.

Large stretches of the open ocean, particularly the subtropical gyres, where surface waters are already nutrient-poor, have been doing this continuously. “This means that phosphate scarcity is the primary control knob for methane production and emissions in the open ocean,” Weber said.

The finding reframes how researchers understand marine methane. Rather than being a rare or localized phenomenon, production in oxygenated surface water may be widespread across any region where phosphate depletion takes hold.

Warming Cuts the Deep-Water Nutrient Supply

Identifying phosphate as the trigger also reveals why a warming climate makes the problem harder to contain. Phosphate does not naturally accumulate in surface waters. It arrives from depth through vertical mixing, the process by which cold, dense, nutrient-rich water rises toward the surface and exchanges with the warmer layer above. That circulation keeps surface phosphate levels high enough to keep the methane pathway suppressed.

Warming disrupts it at the source. As greenhouse gases trap heat, the ocean absorbs the bulk of it, and that warming concentrates near the top. Warmer water is less dense than cold water, so the surface layer grows buoyant and increasingly resistant to exchange with the water below. The result is ocean stratification: the surface and the deep become more physically separated, and the upward delivery of nutrients slows.

“Climate change is warming the ocean from the top down, increasing the density difference between surface and deep waters,” Weber said. “This is expected to slow the vertical mixing that carries nutrients like phosphate up from depth.” According to the team’s model, surface waters will become progressively more phosphate-depleted as stratification intensifies, widening the zones where methane-producing microbes find the conditions they need.

A Self-Reinforcing Loop That Current Models Ignore

The sequence closes on itself in a way that makes it particularly difficult to contain. Warming strengthens stratification. Stratification cuts phosphate delivery to the surface. Phosphate-starved bacteria produce more methane. Methane is a far more potent greenhouse gas than carbon dioxide over short timescales, warming the atmosphere further, which in turn drives more stratification. Each step feeds the next.

What makes this finding consequential beyond the mechanism itself is that this feedback is absent from most major climate projection models. The Rochester team’s work establishes the confirmed biological and physical pathway, giving modelers the foundation they need to incorporate it.

The study does not calculate how much additional methane a specific warming scenario would produce; that quantification was outside its scope. But without a confirmed mechanism, any such estimate would be extrapolation. The paper provides the wiring diagram. “Our work will help fill a key gap in climate predictions, which often overlook interactions between the changing environment and natural greenhouse gas sources to the atmosphere,” Weber said.

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