Ocean Acidification, Temperature and Light Effects on Carbon-use Mechanisms, Calcification, and Growth of Tropical Macroalgae: Drivers of Winners and Losers

海洋酸化、温度和光对热带大型藻类碳利用机制、钙化和生长的影响：赢家和输家的驱动因素

• 批准号: 1416376
• 负责人: Marguerite Koch-Rose
• 金额: $ 42.28万
• 依托单位: Florida Atlantic University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1416376&HistoricalAwards=false
• 关键词: Ocean; Acidification; Temperature; Light; Effects

Ocean sequestration of atmospheric CO2 enhances the availability of CO2 in seawater and lowers ocean pH, commonly referred to as 'ocean acidification'. Marine macroalgae are likely to respond to these two changes in ocean chemistry (elevated CO2 and acidification) in ways that have the potential to reduce the sustainability of coral reefs and other coastal ecosystems with potential economic consequences. There are two major forms of marine macroalgae on reefs: fleshy species that are characterized by a rapid growth potential which allows them to become 'nuisance species' and out-compete corals, and calcified species that are slower growing, but help cement the reef and promote coral larval settlement. Currently, there is very little information on fleshy macroalgal photosynthesis and growth responses to increased ocean CO2. Further, there is an inadequate understanding of ocean acidification effects on macroalgal calcification. The proposed research will examine the fundamental pathways of inorganic carbon uptake for photosynthesis across a range of pH and CO2 levels simulating ocean acidification into the future (2100). How photosynthesis, growth and calcification are modulated by light and temperature under ocean acidification will also be examined. These data will be used to identify ocean acidification effects on ecologically important macroalgae and consequential impacts to coral reef ecosystems. This research on marine macroalgae increases our understanding of ocean acidification effects on marine calcifiers, a research priority identified by the National Ocean Council. The research facility is sited at The Gumbo Limbo (GL) Nature Center that receives 100,000 visitors/yr and has educational programs supporting 15,000/yr K-12 students. This juxtaposition of research with an established outreach facility provides a unique opportunity to communicate OA science and its societal implications to a large public audience. Macroalgae responses to ocean acidification (OA) are likely to be distinctive compared to phytoplankton and microalgae due to their low surface area to volume ratios, high external boundary layer resistance to CO2 and higher irradiance requirements. Understanding specific mechanistic responses of tropical macroalgal photosynthesis and calcification to elevated pCO2, temperature and irradiance is critical to develop predictions of OA effects on macroalgal dominated communities of the tropics, including those that grow near their thermal limits. The research objectives are to (1) provide new insights into the biochemistry and physiology of photosynthesis and calcification that drive growth responses to OA and warming in ecologically important tropical macroalgal species, (2) elucidate photosynthetic C-use mechanisms in tropical species to understand OA influences on HCO3- use, (3) determine if photosynthesis-calcification processes become uncoupled by OA, (4) clarify the role of irradiance in photosynthetic and calcification responses to OA, and (5) examine the synergistic effects of OA, temperature and light on the thermal optima of photosynthesis and growth in species living close to their thermal limits. To meet these objectives, a series of short-term physiological experiments will be conducted to ascertain HCO3-use mechanisms, Ci uptake kinetics, potential to employ carbon concentrating mechanisms (CCMs), and species-specific linkages between photosynthetic C-use mechanisms and calcification in ten dominant fleshy and calcareous tropical macroalgae species. These biochemical and physiological data will subsequently be used to interpret longer-term (20 d) growth (organic and inorganic calcification and crystal formation) responses in aquaria studies conducted over three different seasons, and photosynthesis response surface experiments to gradients of pH, irradiance and temperature.

大气二氧化碳的海洋隔离可增强海水中二氧化碳的可用性，并降低海洋pH值，通常称为“海洋酸化”。 海洋宏观藻类可能会以海洋化学的这两种变化（二氧化碳和酸化升高）的反应，这些方式有可能减少珊瑚礁和其他沿海生态系统的可持续性，并带来潜在的经济后果。 礁石上有两种主要形式的海洋大藻类：具有快速生长潜力的肉体物种，使它们能够成为“滋扰物种”和兼容的珊瑚，并且钙化的物种的生长较慢，但有助于巩固礁石和礁石和珊瑚礁和促进珊瑚幼虫定居点。 当前，关于肉质大量藻类光合作用和对海洋二氧化碳增加的增长反应的信息很少。 此外，人们对海洋酸化对大藻钙化的影响的了解不足。 拟议的研究将研究在一系列pH和二氧化碳水平上模拟海洋酸化的一系列光合作用的无机碳吸收的基本途径（2100）。 还将检查如何通过海洋酸化下的光和温度调节光合作用，生长和钙化。 这些数据将用于鉴定海洋酸化对生态上重要的大藻类的影响，并对珊瑚礁生态系统产生的影响。 这项对海洋大藻类的研究增加了我们对海洋酸化对海洋钙化影响的理解，这是国家海洋委员会确定的研究优先事项。该研究机构位于Gumbo Limbo（GL）自然中心，该中心将接待100,000名游客/年，并拥有支持15,000/年K-12学生的教育计划。这种与既定的外展设施的研究并置，为大量公众观众传达OA科学及其社会影响提供了独特的机会。与浮游植物和微藻相比，大藻对海洋酸化（OA）的反应可能是与众不同的，因为它们的表面积低，体积比，高外部边界层对CO2的阻力以及更高的辐照度要求。 了解热带大藻光合作用和对PCO2升高，温度和辐照度的钙化的特定机械反应对于发展对大型宏观奥尔加尔主导的热带地区的影响，包括在热带地区生长的人，至关重要。 研究目标是（1）提供有关光合作用和钙化的生物化学和生理学的新见解，从而推动对OA的增长反应以及生态上重要的热带宏观宏观藻类物种的变暖，（2）阐明光合作用的C-C-Rese机制，以了解Tropical物种，以了解OA的OA了解OA。对HCO3的影响 - （3）确定光合作用 - 估计过程是否被OA解耦，（4）阐明辐照度在光合作用和钙化对OA中的作用，（5）检查OA的协同作用关于光合作用和生长的热最佳，靠近其热极限的物种。 为了实现这些目标，将进行一系列短期生理实验，以确定HCO3使用机制，CI摄取动力学，使用碳浓缩机制（CCMS）以及光合作用C-使用机制和钙化之间的物种特异性连接的潜力在十种主要的肉质和钙质热带大藻类中。 这些生物化学和生理数据随后将用于解释在三个不同季节进行的水族箱研究中的长期（有机和无机钙化和晶体形成）反应，以及光合作用响应响应表面实验对pH，辐照度和辐照度和辐照度和温度。