Alpine wetlands play a sensitive function in global carbon cycle during the ongoing climate warming, yet the temporal patterns of carbon dynamics from in situ ground‐based long‐term observations remain unclear. Here, we analyzed the continuous net ecosystem CO₂ exchange (NEE) measured with the eddy covariance technique over an alpine peatland on the northeastern Qinghai‐Tibetan Plateau from 2007 to 2016. The wetland acted as a net CO₂ source with a positive NEE (120.4 ± 34.8 gC m⁻² year⁻¹, Mean ± SD), with the mean annual gross primary productivity (GPP) of 500.3 ± 59.4 gC m⁻² year⁻¹ and annual ecosystem respiration (RES) of 620.7 ± 74.2 gC m⁻² year⁻¹. At the seasonal scale, the classification and regression trees (CART) analysis showed that aggregated growing season degree days (GDDs) were the predominant determinant on variations in monthly NEE and monthly GPP. Variations in monthly RES were determined by soil temperature (Ts). Furthermore, nongrowing season Ts had a significant positive correlation with the following year annual GPP (p < 0.05). Nongrowing season RES only accounted for about 25% of annual RES but had significant correlation with annual RES and annual NEE (p < 0.05). The further partial correlation analysis showed that nongrowing season air temperature (Ta, p = 0.05), rather than precipitation (PPT, p = 0.25) was a predominant determinant on variations in annual NEE. Our results highlighted the importance in carbon dynamics of climate fluctuations and CO₂ emission from the nongrowing season in alpine wetlands. We speculated that the vast peadlands would positively feedback to climate change on the Tibetan plateau where the nongrowing season warming was significant.

中文翻译：

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青藏高原高山湿地10年间CO2通量的季节变化和年际变化

在持续的气候变暖过程中，高山湿地在全球碳循环中起着敏感的作用，但是来自地面长期实地观测的碳动态的时间模式仍然不清楚。在这里，我们分析了从2007年至2016年，用涡度协方差技术对东北青藏高原高寒泥炭地进行的连续净生态系统CO ₂交换（NEE）。湿地作为净CO ₂源，其NEE为正值（ 120.4±34.8 gC m - ² 年^-1，平均值±SD），年平均总初级生产力（GPP）为500.3±59.4 gC m - ² 年- ^1年，年度生态系统呼吸（RES）为620.7±74.2 gC m ⁻² 年^-1。在季节尺度上，分类树和回归树（CART）分析显示，聚集的生长季节度日（GDD）是每月NEE和GPP月度变化的主要决定因素。每月RES的变化由土壤温度（Ts）确定。此外，非生长季节Ts与次年的年度GPP呈显着正相关（p  <0.05）。非生长季节的RES仅占年度RES的25％左右，但与年度RES和年度NEE有显着相关性（p  <0.05）。进一步的偏相关分析表明，非生长季节的气温（Ta，p  = 0.05），而不是降水（PPT，p = 0.25）是决定年度NEE变化的主要因素。我们的结果强调了高山湿地非生长季节的气候波动和CO ₂排放对碳动态的重要性。我们推测，在非生长季节明显变暖的青藏高原上，广大的豌豆田将对气候变化产生积极的反馈。