Collaborative Research: Effects of multiple stressors on Marine Phytoplankton

该项目的总体目标是开发一个框架，用于了解浮游植物对多种环境压力的反应。海洋浮游植物是一种微小的藻类，它产生的氧气与陆地植物一样多，并直接或间接地为所有海洋动物提供食物。因此，它们的生产力对于全球氧和碳的元素循环以及海洋的生产力都是重要的。在全球范围内，海洋浮游植物的生产力似乎正在发生变化，但尽管我们对浮游植物对一次一个环境参数变化的反应有了一些了解，如温度，但对它们对几个参数同时变化的反应知之甚少。大气中二氧化碳浓度的增加会导致海洋酸化和地表水温升高。后者反过来导致更大的海洋分层和相关的光暴露和浮游生物营养可获得性的变化。最近，浮游植物对这些生长参数的同时变化的反应变得明显不是相加的。例如，海洋酸化的影响在一种温光组合下可能是严重的，而在另一种温度-光照组合下可以忽略不计。该项目的研究人员将开展实验，为相关相互作用提供理论上的了解，以便能够在知情的情况下预测气候变化对海洋浮游植物的影响。该项目将通过培训一名教师和发展一个教学单位来吸引高中生。本科生和研究生将直接参与这项研究。一名卡通记者将根据研究结果制作一篇卡通故事，将研究结果传达给更广泛的公众。每种浮游植物都有能力适应温度、光线、二氧化碳和养分供应的变化-至少在有限的范围内。然而，浮游植物对多种同时应激源的反应往往是复杂的，因为对生理反应的影响是相互作用的。到目前为止，甚至没有一个单一物种的数据集可以完全测试现有浮游植物适应多种环境压力的模型的假设和含义。研究人员将把模拟分析与实验室实验相结合，利用公海和沿海硅藻菌株(假海链藻)和公海蓝藻物种(聚球藻)的培养，研究二氧化碳、温度、光照和硝酸盐有效性的变化对浮游植物生长的综合影响。计划中的实验是对环境条件对生物的复杂和交互影响的理想案例研究，结果将为预测浮游植物类群对多种环境压力的反应提供基础。

The overarching goal of this project is to develop a framework for understanding the response of phytoplankton to multiple environmental stresses. Marine phytoplankton, which are tiny algae, produce as much oxygen as terrestrial plants and provide food, directly or indirectly, to all marine animals. Their productivity is thus important both for global elemental cycles of oxygen and carbon, as well as for the productivity of the ocean. Globally the productivity of marine phytoplankton appears to be changing, but while we have some understanding of the response of phytoplankton to shifts in one environmental parameter at a time, like temperature, there is very little knowledge of their response to simultaneous changes in several parameters. Increased atmospheric carbon dioxide concentrations result in both ocean acidification and increased surface water temperatures. The latter in turn leads to greater ocean stratification and associated changes in light exposure and nutrient availability for the plankton. Recently it has become apparent that the response of phytoplankton to simultaneous changes in these growth parameters is not additive. For example, the effect of ocean acidification may be severe at one temperature-light combination and negligible at another. The researchers of this project will carry out experiments that will provide a theoretical understanding of the relevant interactions so that the impact of climate change on marine phytoplankton can be predicted in an informed way. This project will engage high schools students through training of a teacher and the development of a teaching unit. Undergraduate and graduate students will work directly on the research. A cartoon journalist will create a cartoon story on the research results to translate the findings to a broader general public audience.Each phytoplankton species has the capability to acclimatize to changes in temperature, light, pCO2, and nutrient availability - at least within a finite range. However, the response of phytoplankton to multiple simultaneous stressors is frequently complex, because the effects on physiological responses are interactive. To date, no datasets exist for even a single species that could fully test the assumptions and implications of existing models of phytoplankton acclimation to multiple environmental stressors. The investigators will combine modeling analysis with laboratory experiments to investigate the combined influences of changes in pCO2, temperature, light, and nitrate availability on phytoplankton growth using cultures of open ocean and coastal diatom strains (Thalassiosira pseudonana) and an open ocean cyanobacteria species (Synechococcus sp.). The planned experiments represent ideal case studies of the complex and interactive effects of environmental conditions on organisms, and results will provide the basis for predictive modeling of the response of phytoplankton taxa to multiple environmental stresses.