A temperature & irradiance controlled growth chamber for phytoplankton physiological research

海洋浮游植物，单细胞藻类，通过将大气中的二氧化碳固定为有机碳，对全球碳循环产生重大影响，从而对气候产生重大影响。很大一部分有机碳通过所谓的“生物泵”被输送到深海。如今海洋吸收大气中二氧化碳的能力比上一个冰河期要低，因为30%的海洋中铁供应不足，限制了浮游植物的生长。尽管在广阔的海洋区域长期存在铁限制，但一些浮游植物物种在这些水域中丰富，而其他浮游植物物种保持低“种子”种群，它们可以对零星的铁输入做出积极反应。因此，很明显，不同的浮游植物有不同的策略来获取和储存铁，并可能有能力以铁代替更丰富的微量元素。这些不同的生理适应在广泛缺铁或零星铁输入期间具有重要的生态意义。为了提高我们对碳循环的认识，研究微量金属和二氧化碳在控制海洋生产力和生态中的作用是必要的。我们的研究小组通过实验室和实地研究，通过确定各种代谢过程的速率，以及检测参与光合作用、碳获取/固定和微量金属获取/代谢/储存的基因和蛋白质的表达，研究海洋浮游植物对光介导的氧化应激、可变二氧化碳浓度和限制微量金属浓度的生理适应。我们的研究方法包括a)阐明浮游植物在严格控制的实验室培养条件下的生理反应，b)检查这些反应是否在海洋中起作用。我们的研究在很大程度上依赖于在控制良好的温度和光照条件下培养浮游植物的环境生长室。该提案要求为一个新的、最先进的培养室提供资金，以支持我们的实验室研究计划。

Marine phytoplankton, unicellular algae, have a major impact on the global carbon cycle-and hence climate-by fixing atmospheric carbon dioxide to organic carbon. A significant fraction of this organic C is transported to the deep ocean via the so-called 'biological pump'. The ocean's capacity to sequester atmospheric carbon dioxide today is lower than during the last ice-ages, as phytoplankton growth is limited by inadequate Fe supply in 30% of the ocean. Despite chronic Fe limitation in vast oceanic regions, some phytoplankton species are abundant in these waters, while others maintain low 'seed' populations which can respond vigorously to sporadic Fe inputs. It is thus clear that different phytoplankton have distinct strategies to acquire and store Fe, and may have the ability to substitute Fe for a more abundant trace element. These different physiological adaptations have important ecological implications during periods of extensive Fe starvation or sporadic Fe inputs. To improve our understanding of the carbon cycle, it is imperative to investigate the role of trace metals and pCO2 in controlling marine productivity and ecology. Our research groups, through laboratory and field studies, investigate the physiological adaptations of marine phytoplankton to light-mediated oxidative stress, variable carbon dioxide concentrations, and limiting trace metals concentrations by determining the rates of various metabolic processes, and examining the expression of genes and proteins involved in photosynthesis, C acquisition/fixation and trace metal acquisition/metabolism/storage. Our research approach consists of a) elucidating phytoplankton physiological responses under tightly controlled laboratory culture conditions and b) examining whether these responses operate at sea. Our research depends critically on environmental growth chambers for culturing phytoplankton under well controlled temperature and light regimes. This proposal requests funds for a new, state of the art, culturing chamber to support our laboratory research program.