OCE-PRF Track 2 (International) - Plasticity of Inorganic Carbon Use in Marine Calcifying Macroalgae Across a Latitudinal Gradient and Consequences of Global Change

壳珊瑚藻（CCA）是一种钙化藻类，对海岸稳定、海滩形成和珊瑚礁结构非常重要。人们越来越担心，这些生物对全球气候变化很敏感，这将对沿海和珊瑚礁的稳定性产生重要影响。尽管它们的意义和敏感性，其基本的光合作用和钙化机制还没有得到很好的理解。在这个项目中，该研究员将通过研究东北大西洋沿着纬度梯度的CCA标本，更好地了解这些机制。这项研究将在德国不莱梅的马克斯·普朗克海洋微生物学研究所由德克·德·比尔博士领导的微传感器研究小组内进行。该项目的活动和成果将在博客和Facebook页面上分享，以提高公众对该项目的认识。此外，该研究员还将促进建立一个虚拟CCA研究小组，以促进世界各地与CCA合作的科学家之间的交流，这将把该项目的影响提升到全球范围。本研究采用野外采样和室内实验相结合的方法，旨在实现以下目标：（1）确定影响石藻稳定碳同位素特征的环境因子;沿着纬度梯度，2）以确定响应于光和温度的溶解无机碳（DIC）吸收机制的可塑性和3）以确定光合作用和钙化如何与DIC吸收机制相关联。纬度梯度包括北大西洋从斯瓦尔巴特群岛到佛得角东部和从佛罗里达到加勒比西部的八个取样点。测量收集的样品的稳定碳同位素特征，以确定DIC吸收的可塑性沿着纬度梯度在长期监测站测量的环境条件。在实验室中，微传感器用于测量藻类表面扩散边界层（DBL）内的pH值、氧气和钙通量。由于DIC的摄取在很大程度上取决于DBL，微传感器提供了一种独特的方法，用于确定温度和光对光合作用和钙化内的微环境中的外部海水和藻类表面之间的界面。该项目的成功完成将提供第一项关于钙化宏生物体中DIC吸收机制的纬度模式和灵活性的研究，并将提高对DIC吸收、光合作用和钙化在不断变化的环境条件下和跨地理范围之间关系的科学知识。

Crustose coralline algae (CCA) are calcifying algae that are important to coastal stability, beach formation, and coral reef structure. There is growing concern that these organisms are sensitive to global climate change, which will have important consequences for coastal and reef stability. Despite their significance and sensitivity, their basic photosynthetic and calcification mechanisms are not well understood. In this project, the fellow will establish a better understanding of these mechanisms by studying CCA specimens along a latitudinal gradient in the Northeast Atlantic. The research will be conducted at the Max Planck Institute for Marine Microbiology in Bremen, Germany within the Microsensor Research Group led by Dr. Dirk de Beer. The activities and results of this project will be shared on a Blog and Facebook page to enhance public awareness of the project. Furthermore, the fellow will facilitate development of a Virtual CCA Research Group to foster communication among scientists world-wide working with CCA which will elevate the impacts of this project to a global scale. Both field sampling and laboratory experiments are used to pursue the goals of the project, which are: 1) to determine the environmental factors influencing the stable carbon isotope signatures of Lithothamnion spp. along a latitudinal gradient, 2) to determine the plasticity of dissolved inorganic carbon (DIC) uptake mechanisms in response to light and temperature and 3) to determine how photosynthesis and calcification are linked to DIC uptake mechanisms. The latitudinal gradient consists of eight sampling locations in the North Atlantic from Svalbard to Cape Verde in the east and from Florida to the Caribbean in the west. The stable carbon isotope signatures of collected samples are measured to determine the plasticity of DIC uptake along the latitudinal gradient in relation to environmental conditions measured at long-term monitoring stations. In the lab, microsensors are used to measure pH, oxygen and calcium fluxes within the diffusive boundary layer (DBL) at the surface of the algae. Because DIC uptake depends heavily on the DBL, microsensors provide a unique method for determining the effects of temperature and light on photosynthesis and calcification within the microenvironment at the interface between the external seawater and the algal surface. Successful completion of the project will provide the first study on latitudinal patterns and the flexibility of DIC uptake mechanisms in a calcifying macroalga and will improve the scientific knowledge of the relationship between DIC uptake, photosynthesis and calcification under changing environmental conditions and across biogeographical ranges.