Soil Chemistry and Moisture in Macrosystems Biodiversity Project at Harvard Forest 2012

Patterns of biodiversity, such as the increase toward the tropics and the peaked curve during ecological succession, are fundamental phenomena for ecology. Such patterns have multiple, interacting causes, but temperature emerges as a dominant factor across organisms from microbes to trees and mammals, and across terrestrial, marine, and freshwater environments. However, there is little consensus on the underlying mechanisms, even as global temperatures increase and the need to predict their effects becomes more pressing. The purpose of this project is to generate and test theory for how temperature impacts biodiversity through its effect on biochemical processes and metabolic rate. A combination of standardized surveys in the field and controlled experiments in the field and laboratory measure diversity of three taxa -- trees, invertebrates, and microbes -- and key biogeochemical processes of decomposition in seven forests distributed along a geographic gradient of increasing temperature from cold temperate to warm tropical. Soil chemistry (TN, TC, NH4-N, NO3-N, and pH) and moisture measurements were taken from soil cores from an array of 21 1m2 subplots and processed by the University of Oklahoma Institute for Environmental Genomics as part of a macrosystems biodiversity and latitude project supported by the National Science Foundation under Cooperative Agreement DEB#1065836.

生物多样性格局——如向热带地区递增的分布模式与生态演替过程中的单峰曲线格局——是生态学的核心基础现象。此类格局的成因多元且相互作用，但温度始终是支配从微生物、林木到哺乳类等各类生物，以及陆地、海洋与淡水生境的核心影响因素。然而，即便全球气温持续攀升、预测其生态影响的需求愈发迫切，学界对其背后的作用机制仍未达成广泛共识。
本项目旨在构建并验证相关理论，以阐明温度如何通过影响生化过程与代谢速率，进而作用于生物多样性。本研究结合野外标准化调查与野外、实验室控制实验，对沿温度梯度（从寒温带至暖热带）分布的7处森林中的3类生物类群（林木、无脊椎动物与微生物）的多样性，以及关键的分解相关生物地球化学过程开展测定。
本研究从21个1平方米样方的土壤钻芯中采集样本，测定了土壤化学指标（TN、TC、NH4-N、NO3-N及pH）与土壤湿度，相关样本由俄克拉荷马大学环境基因组学研究所完成分析，该工作是由美国国家科学基金会（National Science Foundation）通过合作协议DEB#1065836资助的大尺度系统生物多样性与纬度项目的组成部分。