气候变化领域集成服务门户(CCPortal): Peatland evaporation across hemispheres: contrasting controls and sensitivity to climate warming driven by plant functional types

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DOI	10.5194/bg-21-1173-2024
	Peatland evaporation across hemispheres: contrasting controls and sensitivity to climate warming driven by plant functional types
	Speranskaya, Leeza; Campbell, David I.; Lafleur, Peter M.; Humphreys, Elyn R.
发表日期	2024
ISSN	1726-4170
EISSN	1726-4189
起始页码	21
结束页码	5
卷号	21 期号:5
英文摘要	Peatlands store disproportionally large amounts of carbon per unit area, a function that is dependent on maintaining high and stable water tables. Climate change is likely to negatively impact carbon storage in peatlands, in part due to increases in vapour pressure deficit (VPD) driving higher evaporation ( E ) rates. However, the response of E to increasing VPD depends on the dominant vegetation type within peatlands. In this study, we used multiple years of eddy covariance (EC) measurements to compare E regimes at two peatlands with contrasting vegetation types - Kopuatai bog in Aotearoa / New Zealand, dominated by the vascular wire rush Empodisma robustum, and Mer Bleue bog in Canada, a typical shrub- and moss-dominated Northern Hemisphere peatland. We examined seasonal variability in E and equilibrium E ( E eq ), energy balance partitioning, and the response of E , evaporative fraction (EF), and canopy conductance ( g c ) to VPD. Mean annual E was 45 % lower than mean annual E eq at Kopuatai but only 16 % lower at Mer Bleue, demonstrating much greater limitations on E at Kopuatai. In addition, the mean midday (10:00-14:30 local standard time) dry-canopy Bowen ratio ( beta ) at Kopuatai was 2.0 compared to 0.8 at Mer Bleue; therefore, the sensible heat flux ( H ) dominated over the latent heat flux (LE) at Kopuatai and vice versa at Mer Bleue. The responses of E , EF, and g c to increasing VPD at Kopuatai demonstrated stronger limitations on evaporative water loss for VPD > 0.7 kPa compared to Mer Bleue. The observed limitations at Kopuatai were attributed to strong stomatal control by E. robustum due to the rapid decrease in g c with increasing VPD; however, surface E could also be limited by its dense standing litter. At Mer Bleue, however, E was only weakly limited at VPD > 2 kPa, likely due to weak stomatal control over transpiration by the sparse shrub canopy and relatively large surface E from Sphagnum carpets. As such, the results of this study suggest that E. robustum drives a greater hydrological resistance to increasing VPD than the vegetation at Mer Bleue, leading to greater water retention at Kopuatai. This may enable greater resilience of the carbon sink function at Kopuatai to climatic warming and drying than at Mer Bleue.
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Geology
WOS类目	Ecology ; Geosciences, Multidisciplinary
WOS记录号	WOS:001190653500001
来源期刊	BIOGEOSCIENCES
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/305964
作者单位	University of Waikato; Trent University; Carleton University
推荐引用方式 GB/T 7714	Speranskaya, Leeza,Campbell, David I.,Lafleur, Peter M.,et al. Peatland evaporation across hemispheres: contrasting controls and sensitivity to climate warming driven by plant functional types[J],2024,21(5).
APA	Speranskaya, Leeza,Campbell, David I.,Lafleur, Peter M.,&Humphreys, Elyn R..(2024).Peatland evaporation across hemispheres: contrasting controls and sensitivity to climate warming driven by plant functional types.BIOGEOSCIENCES,21(5).
MLA	Speranskaya, Leeza,et al."Peatland evaporation across hemispheres: contrasting controls and sensitivity to climate warming driven by plant functional types".BIOGEOSCIENCES 21.5(2024).