气候变化领域集成服务门户(CCPortal): Dominance of net autotrophy in arid landscape low relief polar lakes, Nunavut, Canada

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DOI	10.1111/gcb.17193
	Dominance of net autotrophy in arid landscape low relief polar lakes, Nunavut, Canada
发表日期	2024
ISSN	1354-1013
EISSN	1365-2486
起始页码	30
结束页码	2
卷号	30 期号:2
英文摘要	The Arctic is the fastest warming biome on the planet, and environmental changes are having striking effects on freshwater ecosystems that may impact the regional carbon cycle. The metabolic state of Arctic lakes is often considered net heterotrophic, due to an assumed supply of allochthonous organic matter that supports ecosystem respiration and carbon mineralization in excess of rates of primary production. However, lake metabolic patterns vary according to regional climatic characteristics, hydrological connectivity, organic matter sources and intrinsic lake properties, and the metabolism of most Arctic lakes is unknown. We sampled 35 waterbodies along a connectivity gradient from headwater to downstream lakes, on southern Victoria Island, Nunavut, in an area characterized by low precipitation, organic-poor soils, and high evaporation rates. We evaluated whether lakes were net autotrophic or heterotrophic during the open water period using an oxygen isotopic mass balance approach. Most of the waterbodies were autotrophic and sites of net organic matter production or close to metabolic equilibrium. Autotrophy was associated with higher benthic primary production, as compared to its pelagic counterpart, due to the high irradiance reaching the bottom and efficient internal carbon and nutrient cycling. Highly connected midstream and downstream lakes showed efficient organic matter cycling, as evidenced by the strong coupling between gross primary production (GPP) and ecosystem respiration, while decoupling was observed in some headwater lakes with significantly higher GPP. The shallow nature of lakes in the flat, arid region of southern Victoria Island supports net autotrophy in most lakes during the open water season. Ongoing climate changes that lengthen the ice-free irradiance period and increase rates of nutrient evapoconcentration may further promote net autotrophy, with uncertain long-term effects for lake functioning. We studied the metabolic state of 35 lakes in the Canadian Arctic along a hydrological connectivity gradient. Our findings indicate that the metabolic state of lakes was mostly net autotrophic or in metabolic equilibrium. The metabolic rates were associated with the degree of hydrological connectivity, the position of the lake in the watershed, and lake size, which were determinant factors for the chemical composition and light penetration in the water column. Consequently, higher GPP values were measured in small headwater lakes compared to larger midstream and downstream lakes. Our findings highlight the importance of shallow Arctic lakes as climate regulators.image
英文关键词	Arctic lakes; evaporation; hydrology; internal carbon cycling; metabolism; net ecosystem production
语种	英语
WOS研究方向	Biodiversity & Conservation ; Environmental Sciences & Ecology
WOS类目	Biodiversity Conservation ; Ecology ; Environmental Sciences
WOS记录号	WOS:001177413700008
来源期刊	GLOBAL CHANGE BIOLOGY
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/305916
作者单位	University of Quebec; University of Quebec Chicoutimi; University of Lethbridge; Wilfrid Laurier University; Wilfrid Laurier University; University of Waterloo; University of Quebec; University of Quebec Chicoutimi; University of Quebec; University Quebec Abitibi-Temiscamingue
推荐引用方式 GB/T 7714	. Dominance of net autotrophy in arid landscape low relief polar lakes, Nunavut, Canada[J],2024,30(2).
APA	(2024).Dominance of net autotrophy in arid landscape low relief polar lakes, Nunavut, Canada.GLOBAL CHANGE BIOLOGY,30(2).
MLA	"Dominance of net autotrophy in arid landscape low relief polar lakes, Nunavut, Canada".GLOBAL CHANGE BIOLOGY 30.2(2024).

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