Eight Mile Lake Research Watershed, Carbon in Permafrost Experimental Heating and Drying Research (DryPEHR): Annual and growing season decomposition of a common substrate, 2012-2019

This drying and warming experiment addresses the following questions: 1) Does ecosystem drying, warming and permafrost thaw cause a net release or uptake of C from the ecosystem to the atmosphere?, 2) Does the decomposition of old C that comprises the bulk of the soil C pool influence ecosystem C loss? 3) How do drying and warmign affect plant communities and ecosystem properties? We are answering these questions using a combined warming and drying experiment (DryPEHR), which is situated with the Carbon in Permafrost Experimental Heating Research (CiPEHR) project and located in an upland tundra field site near Healy, Alaska in the foothills of the Alaska Range. Warming treatment here refers to growing season air temperature warming (~1C) using open top chambers (OTC) combined with soil 'warming' using snow fences during the snow covered months. Drying is achieve using an automated pumping system that lowers the water table in the dry plots. Soil warming began in 2008; OTCs and drying in 2011.

本干湿增温实验旨在解答以下科学问题：1）生态系统干旱化、增温与永久冻土融化，是否会引发碳从生态系统向大气的净释放或固存？2）占土壤碳库主体的老碳分解，是否会对生态系统碳流失产生影响？3）干旱化与增温会如何作用于植物群落与生态系统属性？本研究依托联合增温-干旱实验平台DryPEHR开展相关研究，该平台与永久冻土碳实验加热研究（Carbon in Permafrost Experimental Heating Research, CiPEHR）项目共建，选址于阿拉斯加山脉山麓、阿拉斯加希利附近的高地苔原野外站点。本实验的增温处理具体为：在生长季利用开顶箱（open top chambers, OTC）实现约1℃的空气温度增温，并在积雪期通过雪堤实现土壤增温；干旱处理则通过自动化抽水系统降低干旱样地的地下水位。土壤增温实验于2008年启动，开顶箱布设与干旱处理则于2011年实施。