Acclimation and adaptation of phytoplankton to changing climate

下个世纪的气候变化预计将改变海洋的基本物理和化学性质，包括水温、pH值、环流以及表层海洋的光和营养状况。环境条件的这种变化预计将改变浮游植物群落的结构和功能。浮游植物的光合作用生产为海洋食物网提供燃料，并调节海洋作为碳汇的能力。目前，对于气候变化将如何改变浮游植物群落结构、净初级生产量以及碳向海洋的运输速度，模型预测之间缺乏共识。模型预测从根本上受到目前对浮游植物适应能力和适应环境条件变化能力的缺乏的了解，时间跨度从几小时到几年不等。我们建议通过测量暴露在不同温度和温度制度下的硅藻菌株在几个小时到几年的时间尺度上的整个基因表达序列、生长速度和生理特征的差异，来评估浮游植物适应和适应不同时间尺度上的温度变化的能力。这项工作的目的是i)确定浮游植物生理适应和适应不同时间尺度温度变化的能力，ii)确定与温度适应和适应有关的基因和生理机制，以及iii)确定是否存在与温度适应和适应有关的能量(光子或碳)或营养(氮或磷)成本。这项工作的发现对于理解浮游植物群落、海洋食物网和海洋碳汇可能如何应对未来的气候变化具有重要意义。

Climate change over the next century is projected to alter fundamental physical and chemical properties of the ocean including water temperature, pH, circulation, and light and nutrient regimes in the surface ocean. Such changes in environmental conditions are expected to transform the structure and function of phytoplankton communities. Photosynthetic production by phytoplankton fuels the marine food web and regulates the ocean's capacity to act as a carbon sink. Currently there is a lack of consensus amongst model projections for exactly how climate change will alter phytoplankton community structure, net primary production, and the rate of transport of carbon into the ocean. Model projections are fundamentally limited by the current lack of understanding of the capacity of phytoplankton to both acclimate and to adapt to changes in environmental conditions over a range of different timescales from hours to years. We propose to assess the capacity of phytoplankton to acclimate and adapt to temperature change over different timescales by measuring differences in whole gene expression sequences, growth rate, and physiological traits across diatom strains exposed to different temperatures and temperature regimes over timescales of hours to years. The objective of this work is to I) determine the capacity of phytoplankton to physiologically acclimate and adapt to changes in temperature over different timescales, II) identify genes and physiological mechanisms associated with temperature acclimation and adaptation, and III) determine if there is an energy (photon or carbon) or nutrient (nitrogen or phosphorus) cost associated with temperature acclimation and adaptation. The findings from this work has significant implications for understanding how phytoplankton communities, the marine food web, and the ocean carbon sink are likely to respond to future climate change.