气候变化领域集成服务门户(CCPortal): Peatlands Versus Permafrost: Landscape Features as Drivers of Dissolved Organic Matter Composition in West Siberian Rivers

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DOI	10.1029/2023JG007797
	Peatlands Versus Permafrost: Landscape Features as Drivers of Dissolved Organic Matter Composition in West Siberian Rivers
	Starr, Sommer F.; Frey, Karen E.; Smith, Laurence C.; Kellerman, Anne M.; Mckenna, Amy M.; Spencer, Robert G. M.
发表日期	2024
ISSN	2169-8953
EISSN	2169-8961
起始页码	129
结束页码	2
卷号	129 期号:2
英文摘要	West Siberia contains some of the largest soil carbon stores on Earth owing to vast areas of peatlands and permafrost, with the region warming far faster than the global average. Organic matter transported in fluvial systems is likely to undergo distinct compositional changes as peatlands and permafrost warm. However, the influence of peatlands and permafrost on future dissolved organic matter (DOM) composition is not well characterized. To better understand how these environmental drivers may impact DOM composition in warming Arctic rivers, we used ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry to analyze riverine DOM composition across a latitudinal gradient of West Siberia spanning both permafrost-influenced and permafrost-free watersheds and varying proportions of peatland cover. We find that peatland cover explains much of the variance in DOM composition in permafrost-free watersheds in West Siberia, but this effect is suppressed in permafrost-influenced watersheds. DOM from warm permafrost-free watersheds was more heterogenous, higher molecular weight, and relatively nitrogen enriched in comparison to DOM from cold permafrost-influenced watersheds, which were relatively enriched in energy-rich peptide-like and aliphatic compounds. Therefore, we predict that as these watersheds warm, West Siberian rivers will export more heterogeneous DOM with higher average molecular weight than at present. Such compositional shifts have been linked to different fates of DOM in downstream ecosystems. For example, a shift toward higher molecular weight, less energy-rich DOM may lead to a change in the fate of this material, making it more susceptible to photochemical degradation processes, particularly in the receiving Arctic Ocean. West Siberia is warming faster than other regions and contains vast areas of peatlands and permafrost, which contain vast stores of carbon. This carbon is transported off the landscape by rivers and the composition of this exported carbon is likely to change with continued warming, but there is no consensus on exactly what changes will occur. To study these potential changes, we used ultrahigh resolution mass spectrometry to analyze molecular-level organic matter composition across a gradient of permafrost influence and peatland cover in West Siberian watersheds. Warm permafrost-free watersheds had organic matter that was more diverse, of higher molecular weight, and had unique molecular composition compared to cold permafrost-influenced watersheds. We also found that while peatland cover explained much of the compositional diversity between rivers, permafrost ultimately controlled the influence of peatland cover on dissolved organic matter composition, effectively acting as a switch on the compositional signal from peatlands. We predict that as West Siberia warms, the fate of organic matter transported by rivers in the region will thus change and the role of photochemical degradation processes may become more important. West Siberian watersheds exhibit distinct dissolved organic matter (DOM) composition related to permafrost influence and peatland cover Permafrost acts as a switch controlling the influence of peatland cover on the molecular composition of watershed DOM Warming West Siberian watersheds may export more heterogeneous DOM with ramifications for its fate in the Arctic Ocean
英文关键词	West Siberian Lowland; permafrost; peatlands; DOM; surface water; climate change
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Geology
WOS类目	Environmental Sciences ; Geosciences, Multidisciplinary
WOS记录号	WOS:001169244000001
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/294967
作者单位	State University System of Florida; Florida State University; State University System of Florida; Florida State University; Clark University; Brown University; State University System of Florida; Florida State University; Colorado State University
推荐引用方式 GB/T 7714	Starr, Sommer F.,Frey, Karen E.,Smith, Laurence C.,et al. Peatlands Versus Permafrost: Landscape Features as Drivers of Dissolved Organic Matter Composition in West Siberian Rivers[J],2024,129(2).
APA	Starr, Sommer F.,Frey, Karen E.,Smith, Laurence C.,Kellerman, Anne M.,Mckenna, Amy M.,&Spencer, Robert G. M..(2024).Peatlands Versus Permafrost: Landscape Features as Drivers of Dissolved Organic Matter Composition in West Siberian Rivers.JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES,129(2).
MLA	Starr, Sommer F.,et al."Peatlands Versus Permafrost: Landscape Features as Drivers of Dissolved Organic Matter Composition in West Siberian Rivers".JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 129.2(2024).