Seasonal variations in carbon dioxide exchange fluxes at a taiga?tundra boundary ecosystem in Northeastern Siberia
Seasonal variations in carbon dioxide exchange fluxes at a taiga?tundra boundary ecosystem in Northeastern Siberia
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西伯利亚东北部针叶林苔原边界生态系统二氧化碳交换通量的季节变化
DOI：
10.1016/j.polar.2021.100644
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发表时间：
2021
期刊：
影响因子：
1.8
通讯作者：
Maximov Trofim
中科院分区：
文献类型：
--
作者：
Tei Shunsuke;Morozumi Tomoki;Kotani Ayumi;Takano Shinya;Sugimoto Atsuko;Miyazaki Shin;Shingubara Ryo;Fan Rong;Petrov Roman;Starostin Egor;Shakhmatov Ruslan;Nogovitcyn Aleksandr;Maximov Trofim
东西伯利亚的北极和北方永冻土生态系统被认为对气候系统和全球碳循环至关重要，特别容易受到气候变化的影响。本研究调查了2013年至2015年西伯利亚东北部针叶林-苔原边界生态系统的二氧化碳（CO2）交换通量，这种测量是稀缺的。生长季（5月至9月）的净CO2交换通量（NEE）为−39.4（−60.1至−20.2）gCm−2，生态系统呼吸（RE）为306.2（288.1至317.9）gCm− 2，初级生产总值（GPP）为−345.5（−372.5至−317.7）gCm−2。决定这些CO2交换通量的小气候因子随季节变化。这些通量显着影响的C吸收，这是反映在土壤温度的变化，在春季和初夏的时间开始，随后通量响应以及光合光子通量密度，特别是对于NEE。这些CO2交换通量在东北西伯利亚针叶林-苔原边界生态系统显着小于以前报道的南方针叶林网站。春雪融水丰富的土壤水分条件，使南部针叶林网站作为更强的CO2汇在6月比针叶林-苔原边界生态系统，这可能是在很大程度上负责明显的南北梯度生长季节NEE。
Arctic and boreal permafrost ecosystems in Eastern Siberia, considered crucial to the climate system and global carbon cycle, are particularly vulnerable to climate change. This study investigates carbon dioxide (CO2) exchange fluxes over northeastern Siberia from 2013 to 2015 in a taiga–tundra boundary ecosystem for which such measurements are scarce. The growing season (May–September) net CO2exchange flux (NEE) was −39.4 (−60.1 to −20.2) gCm−2, with ecosystem respiration (RE) = 306.2 (288.1–317.9) gCm−2and gross primary production (GPP) = −345.5 (−372.5 to −317.7) gCm−2. Microclimatic factors determining these CO2exchange fluxes change seasonally. These fluxes are significantly affected by the timing of the onset of C uptake, which is reflected by changes in the soil temperature in spring and early summer, following which fluxes respond well to the photosynthetic photon flux density, especially for NEE. These CO2exchange fluxes at the northeastern Siberian taiga–tundra boundary ecosystem are significantly smaller than those previously reported at southern-taiga forest sites. Spring snow meltwater-rich soil moisture conditions render southern-taiga sites as stronger CO2sinks in June than taiga–tundra boundary ecosystem, which may be largely responsible for the pronounced north–south gradient in growing season NEE.