近日，英国利兹大学Taylor Maavara团队报道了河流代谢是全球碳循环中最不确定的通量之一。该项研究成果发表在2025年11月6日出版的《科学》杂志上。

研究组提出了横跨美国（CONUS）的超过175,000条河流的总初级生产力（GPP）和生态系统呼吸（ER）的估计，包括对极端水文条件的代谢反应。他们的模型预测CONUS河流的年GPP为每年10.1太克碳，ER为每年18.7太克碳，这意味着净生态系统生产力（NEP; NEP = GPP - ER）是河流二氧化碳排放的一个小贡献者。

超过70%的河流代谢发生在西部，那里同时存在极端异养和自养区域。自养在整个西方都很突出，对干旱很敏感，特别是在研究不足的生物群落中，如干旱的沙漠灌木地，这可能表明全球河流对二氧化碳的吸收比假设的要高。

附：英文原文

Title: River metabolism in the contiguous United States: A West of extremes

Author: Taylor Maavara, Zimin Yuan, Andrew M. Johnson, Shuang Zhang, Kelly S. Aho, Craig B. Brinkerhoff, Laura A. Logozzo, Peter Raymond

Issue&Volume: 2025-11-06

Abstract: River metabolism is among the most uncertain fluxes in the global carbon cycle. We present estimates for gross primary productivity (GPP) and ecosystem respiration (ER) for more than 175,000 rivers across the contiguous United States (CONUS), including metabolic responses to extreme hydrological conditions. Our model predicts an annual GPP in CONUS rivers of 10.1 teragrams of carbon per year and an ER of 18.7 teragrams of carbon per year, which implies that net ecosystem productivity (NEP; where NEP = GPP – ER) is a small contributor to river carbon dioxide emissions. More than 70% of river metabolism occurs in the West, where regions of both extreme heterotrophy and autotrophy exist. Autotrophy is prominent across the West and is sensitive to drought, particularly in understudied biomes such as arid desert shrublands, which may indicate that global riverine uptake of carbon dioxide is higher than hypothesized.

DOI: adu9843

Source: https://www.science.org/doi/10.1126/science.adu9843