Collaborative Research: Arctic to the Amazon: Physical Processes Controlling Gas Exchange from Freshwater Ecosystems

二氧化碳和甲烷排放估算表明，内陆水生生态系统在从本地生态系统尺度到区域和全球尺度的多个尺度上的碳平衡中发挥着重要作用。由于全球变暖和人类活动导致生物地球化学循环不断发生变化，世界各地正在开展研究，以更准确地评估湖泊和水库在区域和全球碳循环中的作用，并估计湖泊的代谢活动。这些努力的关键是准确估计空气和水界面的气体通量，但目前的模型并未包括调解气体交换的所有物理过程。这项多尺度模拟研究包括气体交换和控制气体交换过程的现场测量，这些过程跨越了从北极小湖泊到亚马逊河大漫滩湖泊的一系列淡水水体。这些数据将用于开发淡水生态系统的气体交换模型，该模型不仅包括风速，还包括使空气和水之间的界面具有通量的所有物理过程。他们还将考虑到温水湖和冷水湖中主导过程的差异。这些新模式，加上对促进气体交换的基本动力有了更好的了解，将能够改进对全世界各个淡水水体的温室气体通量的估计，并准确地按比例扩大对广大地区的估计。结果将通知全球湖泊生态观测站网络在世界各地的站点和国家生态观测站网络内拟议的湖泊站点的程序。美国和国外的博士后和研究生将接受微气象学、湖沼学和生物地球化学方面的培训。主要研究人员将在美国、瑞典和巴西的实地课程和国家会议上为技术讲习班作出贡献或举办讲习班。

Estimates of carbon dioxide and methane emissions indicate inland aquatic ecosystems play an important role in carbon balances across multiple scales ranging from the local ecosystem scale to regional and global scales. Given ongoing changes in biogeochemical cycles due to global warming and human activities, studies are being conducted worldwide to more accurately assess the role of lakes and reservoirs in regional and global carbon cycles and to estimate metabolic activity in lakes. Essential to these efforts are accurate estimates of gas fluxes at the air and water interface, yet current models do not include all the physical processes which mediate gas exchange. This multiscale modeling research includes field measurements of gas exchange and of processes controlling gas exchange across a range of freshwater bodies from small arctic lakes to the large floodplain lakes of the Amazon. These data will be used to develop gas exchange models for freshwater ecosystems that include not just wind speed but the full range of physical processes that enable fluxes across the interface between air and water. They will also take into account the differences in dominant processes in warm versus cold water lakes. The new models, combined with improved understanding of the underlying dynamics enabling gas exchange, will enable improved estimates of greenhouse gases fluxes from individual freshwater bodies worldwide and accurate scaling up of estimated over broad regions.Results will inform procedures at Global Lake Ecological Observatory Network sites worldwide and proposed lake sites within the National Ecological Observatory Network. Postdoctoral fellows and graduate students in the United States and abroad will receive training in micrometeorology, limnology and biogeochemistry. The principle investigators will contribute to or conduct workshops on techniques for field courses and at national meetings in the United States, Sweden and Brazil.