Carbon dioxide fluxes on canadian arctic tundra

由于全球变暖，北极正在经历前所未有的变化。生态系统过程，如冻土带和大气之间的二氧化碳交换，受到了这种变暖的影响。我们预测未来气候的能力取决于对这些变化的了解。在过去的八年里，我一直在与我的学生和合作者建立一个研究项目，调查西北地区达林湖附近的北极苔原-大气二氧化碳交换，在那里，二氧化碳通量站建立在四个不同的苔原环境中。它现在是加拿大北极地区运行时间最长、范围最广的碳通量测量项目。我提议扩大这项研究，以解决新的关键科学问题，这些问题将提高我们对北极冻原过程的理解，从而产生有助于预测未来气候变化的知识。我将研究植物生长的变化（以叶面积表示）如何控制二氧化碳通量的季节和年际变化，并将其与温度和降水等气候因素进行比较。假设植物因子与气候因子仅间接相关，在决定冻土带吸收大气二氧化碳总量方面比气候更为重要。我还将探索监测这些植被变化的新方法，最终可以推断出大地理区域的二氧化碳通量。我将把测量扩展到冬末和秋季，那时我们认为冻土带上的二氧化碳损失是显著的。过去，由于技术限制，测量主要局限于无雪生长季节，但现在可以通过更新的设备克服这一问题，并将为我们提供构建准确的苔原生态系统年度碳预算所需的信息。这项研究将提高我们对冻原过程和气候反馈的认识，解决加拿大北极地区碳通量研究的不足，培养北极环境科学方面的新学生，并最终通过改进气候预测使北方人受益，这将有助于社区规划和适应气候变化。

The Arctic is experiencing unprecedented change due to global warming. Ecosystem processes, such as the exchange of carbon dioxide between tundra and atmosphere, are impacted by this warming. Our ability to predict future climate rests on understanding these changes. For the past eight years I have been building a research program with my students and collaborators to investigate Arctic tundra-atmosphere carbon dioxide exchange near Daring Lake, NWT, where carbon dioxide flux stations are set up in four different tundra environments. It is now the longest running and most extensive carbon flux measurement program in Arctic Canada. I am proposing to expand this research to address new crucial scientific issues that will improve out understanding of Arctic tundra processes and thus, generate knowledge that will assist in predictions of future climatic change. I will investigate how variations in plant growth, expressed as leaf area, control seasonal and interannual variations in carbon dioxide fluxes and compare these with climate factors such as temperature and precipitation. It is hypothesized that the plant factors are only indirectly related to climate factors and are more important than climate for determining the total amount of atmospheric carbon dioxide absorbed by the tundra. I will also explore novel ways for monitoring these vegetation changes, and ultimately carbon dioxide fluxes, which can be extrapolated to large geographic areas. I will extend the measurements into the late-winter and autumn seasons when we believe that the loss of carbon dioxide from the tundra is significant. In the past, due to technological limitations, measurements were primarily restricted to the snow-free growing season, but this can now be overcome with updated equipment and will give us the information needed to construct accurate annual carbon budgets for tundra ecosystems. This research will advance our knowledge of tundra processes and climate feedbacks, address the lack of carbon flux research in the Canadian Arctic, train new students in Arctic environmental science and ultimately, benefit northerners by improving climate predictions that will help communities plan for and adapt to climate change.