Winter C-Flux in Arctic Ecosystems Under Changing Climate: Effects of Soil Carbon and Active Layer Dynamics

SCHIMEL， WELKER, PING university of CALIFORNIA, university of WYOMING， university of ALASKA本项目旨在充分了解北极土壤冬季碳动态，从而有效地模拟冬季二氧化碳通量的空间动态，以及它们如何随气候变化而变化。这项工作将包括二氧化碳通量和可能控制它们的环境因素的实地测量，再加上建模和机理研究。该项目有四个主要目标：1)量化一系列北极冻土带类型的冬季二氧化碳通量的大小和时间；2)确定冬季呼吸是如何受土壤物理状况控制的；3)评价有机质组成对冬季碳循环的控制作用；4)建立冬季微生物活动的简单模型。这些目标将把土壤热水和不冻水制度与微生物活动和基质利用联系起来。总体目标是开发尽可能简单的模型，这些模型可以由广泛的尺度参数驱动，同时保留必要的机制信息，以提供可靠的碳动力学估计。

ABSTRACT OPP-9713999, 9732732 SCHIMEL, WELKER, PING UNIV. CALIFORNIA, UNIV. WYOMING, UNIV. ALASKA This project is designed to develop a sufficient understanding of winter carbon dynamics in arctic soils to model effectively the spatial dynamics of winter carbon dioxide fluxes, and how they will vary with altered climate. The work will involve field measurements of carbon dioxide fluxes and environmental factors likely to control them coupled to modeling and mechanistic studies. The project has four main objectives: 1) to quantify the magnitude and timing of winter carbon dioxide fluxes across a range of arctic tundra types; 2) to determine how winter respiration is controlled by the physical regime of the soils; 3) to evaluate how organic matter composition control winter carbon cycling; and 4) to develop simple models of winter microbial activity. These objectives will link the soil thermal and unfrozen water regimes to microbial activity and substrate use. The overarching goal is to develop the simplest possible models that can be driven by broad scale parameters while retaining necessary mechanistic information to provide reliable estimates of carbon dynamics.