Environmental forcing of primary production in arctic and subarctic seas

北方海洋生态系统对气候变化高度敏感。扰动在北极最为严重，那里的气温稳步上升，冰盖迅速下降。海洋水团环流的半球变化、极端天气事件的发生以及上层海洋的淡水含量改变了表层水域的垂直混合和营养物质和生物的远距离扩散。通过它们对浮游植物生长条件的影响，这些变化可能会影响食物网和海洋大气二氧化碳的减少(减缓全球变暖)。我们目前对浮游植物生态与气候变异性和变化有关的知识不足以评估北部海洋生态系统的当前和未来状况。拟议研究的长期目标是量化和预测环境强迫对北极和亚北极海域初级生产的主要影响。最初的五年计划将解决两个基本问题：是什么控制着(1)物种优势和(2)初级生产力的规模？来自船舶工艺研究、现场采样观测站和浮游植物培养对照实验的数据将结合在一起，以检验工作假设。一系列关键的浮游植物变量将在光、温度和营养物质进行和不进行实验操作的情况下进行量化。形成水华的浮游植物将被分离并带到家庭实验室，以量化它们在光、温度和营养的梯度上的生长动力学。总而言之，这些结果有望增加我们对浮游植物过程的基本理解，并提供必要的数据来对环境强迫的模型和模拟进行参数化。对加拿大的好处将是更多地了解关键的生态系统过程，从长远来看，更有能力预测和管理气候和海洋可再生资源的变化。

Boreal marine ecosystems are highly sensitive to climate change. Perturbations are most acute in the Arctic, where temperature increases steadily and the ice cover declines rapidly. Hemispheric changes in the circulation of oceanic water masses, the incidence of extreme weather events and the freshwater content of the upper ocean alter vertical mixing in surface waters and the long-range dispersal of nutrients and organisms. Through their effects on the growth conditions of phytoplankton, these changes are likely to affect food webs and the oceanic drawdown of atmospheric CO2 (which mitigates global warming). Our present knowledge of phytoplankton ecology in relation to climate variability and change is insufficient to assess the current and future state of northern marine ecosystems. The long-term objective of the proposed research is to quantify and predict the major effects of environmental forcing on primary production in Arctic and subarctic seas. Two fundamental questions will be addressed by the initial five-year plan: what controls the (1) species dominance and (2) magnitude of primary production? Data from ship-based process studies, in situ sampling observatories and controlled experiments with phytoplankton cultures will be combined to test the working hypotheses. A suite of key phytoplankton variables will be quantified with and without experimental manipulations of light, temperature and nutrients. Bloom-forming phytoplankton will be isolated and taken to the home laboratory to quantify their growth dynamics across gradients of light, temperature and nutrients. Collectively, the results are expected to increase our fundamental understanding of phytoplankton processes and provide the data necessary to parameterize models and simulations of environmental forcing. The benefit to Canada will be greater knowledge of critical ecosystem processes and, in the longer term, greater capacity to anticipate and manage change in climate and marine renewable resources.