Collaborative Research: Effects of multiple stressors on Marine Phytoplankton

该项目的总体目标是建立一个框架，以了解浮游植物对多种环境胁迫的反应。海洋浮游植物是一种微小的藻类，它们产生的氧气和陆地植物一样多，并直接或间接地为所有海洋动物提供食物。因此，它们的生产力对全球氧和碳元素循环以及海洋的生产力都很重要。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一次对一个环境参数（如温度）变化的响应有一些了解，但对它们对几个参数同时变化的响应知之甚少。大气中二氧化碳浓度的增加导致海洋酸化和地表水温度的升高。后者反过来导致更大的海洋分层，以及与之相关的浮游生物光照和营养可利用性的变化。近年来，浮游植物对这些生长参数同时变化的反应显然不是加性的。例如，海洋酸化的影响在一种温度-光组合下可能是严重的，而在另一种温度-光组合下可以忽略不计。该项目的研究人员将进行实验，为相关相互作用提供理论理解，以便以知情的方式预测气候变化对海洋浮游植物的影响。这个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研究。漫画记者将根据研究结果创作漫画故事，将研究结果转化为更广泛的公众受众。每一种浮游植物都有能力适应温度、光照、二氧化碳分压和营养物质的变化——至少在有限的范围内。然而，浮游植物对多个同时发生的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充分测试浮游植物适应多种环境压力的现有模型的假设和影响。研究人员将把建模分析与实验室实验结合起来，利用开放海洋和沿海硅藻菌株（假海藻）和开放海洋蓝藻物种（聚藻球菌）的培养物，研究二氧化碳分压、温度、光照和硝酸盐可用性变化对浮游植物生长的综合影响。计划中的实验代表了环境条件对生物的复杂和相互作用的理想案例研究，其结果将为浮游植物分类群对多种环境胁迫的响应预测建模提供基础。

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.