Antarctic phytoplankton in response to environmental change studied by a synergistic approach using multi- and hyper-spectral satellite data

气候模型表明，南大洋将在不久的将来受到对流层释放温室气体，特别是化石燃料燃烧产生的二氧化碳所造成的温度和pH值变化的重大影响和冲击。这些变化将影响浮游植物的组成，从而影响碳，氮和相关化合物的循环。这一跨学科项目的目标是评估南大洋浮游植物类型的空间和时间变异性，以更好地了解它们在南大洋生态系统中的差异，并改善我们对南极浮游植物对全球碳循环贡献的定量估计。将利用两个不同卫星仪器提供的独特数据组合，首次以合理的时间和空间覆盖范围评估南大洋不同浮游植物类型的浓度。这种协同方法将是通用的，适用于类似的即将到来的卫星任务，因此，确保一个独特的浮游植物类型的数据集，涵盖几十年的前景。浮游植物总生物量数据将通过多光谱成像仪器对南极条件的适应来检索，而最重要的浮游植物类型在总生物量中所占的比例将通过使用我们的研究小组开发的PhytoDOAS方法对高光谱卫星测量中的特征吸收特征进行分析来确定。由此产生的长期卫星数据集是未来变化的必要基准。然后，它将被用来研究南极浮游植物的变化，在过去的十年中，他们与不断变化的环境因素的相关性。此外，我们的浮游植物组成数据集将被用来评估在南大洋的生态系统模型的性能，该模型评估浮游植物类型的生理特性的基础上，在一个模拟的海洋。这一研究工作将提出改进模型参数化的建议。有了这一长期浮游植物类型数据集和对南极浮游植物变异性的了解，我们将有一个评估气候变化对南大洋影响的基础。

Climate models indicate that the Southern Ocean will significantly be affected and impacted by changes in temperature and pH in the near future resulting from the tropospheric release of greenhouse gases and in particular carbon dioxide from fossil fuel combustion. Such changes will impact on the phytoplankton composition and thus affect the cycling of carbon, nitrogen and related compounds. The objectives of this interdisciplinary project are to assess the spatial and temporal variability of phytoplankton types in the Southern Ocean, to better understand their different in the Southern Ocean ecosystem, and to improve our quantitative estimates of the contribution of Antarctic phytoplankton to the global carbon cycle. Using a unique combination of data from two different satellite instruments, the concentration of different phytoplankton types will be assessed for the first time in the Southern Ocean with reasonable temporal and spatial coverage. This synergistic method will be generic and applicable to similar upcoming satellite missions and therefore secure a perspective for a unique phytoplankton type data set covering decades. The total phytoplankton biomass data will be retrieved by adaptation to the Antarctic conditions from multi-spectral imaging instruments, whereas the fractions of the most important phytoplankton types within the total biomass will be determined from the analysis of their characteristic absorption features in hyper-spectral satellite measurements using the PhytoDOAS method developed by our research team. The resulting long term satellite data set is a necessary benchmark for future change. It will then be used to study the Antarctic phytoplankton varibility over the last ten years and their correlation with changing environmental factors. In addition, our phytoplankton composition data set will be used to evaluate in the Southern Ocean the performance of a ecosystem model which assesses the biogeography of phytoplankton types based on their physiological traits in a modeled ocean. Recommendations for improved model parameterizations will result from this research exercise. With this long-term phytoplankton type data set and the acquired knowledge of Antarctic phytoplankton variability, we will have a basis to assess the influence of climate change on the Southern Ocean.