EAPSI: Do Symbiodinium Exhibit Species-specific Responses to Iron Availability?

共生藻属中造礁珊瑚和它们的光合共生体之间的互惠共生关系形成了许多浅水热带海洋生态系统的基础。与气候变化有关的严重海洋变暖的发生已经导致许多热带和亚热带地区的珊瑚种群大规模减少。虽然许多共生体容易受到热应激的影响，但各种物种和菌落在视觉上似乎不受影响，这促使许多研究人员了解解释这种抗性的潜在生物学属性。共生藻和宿主珊瑚的持续存在和生长需要微量金属，这些金属对光合作用和氮同化等重要过程至关重要。以前的研究表明，微量金属的可用性，特别是铁，影响海洋浮游植物的生长，并有助于应激反应。微量金属的可用性影响共生珊瑚对热应力的抵抗力的可能性目前尚未探讨。主持人科学家何东源博士（台湾中央研究院）最近描述了共生藻生长所需的微量金属，发现铁的可用性增加与藻类生长呈正相关。为了建立在这项研究的基础上，本项目将通过评估共生藻的远亲和近亲物种之间的铁需求来扩展这项研究，并利用我对何博士微量金属清洁实验室的访问。铁的需求的多样性的共生藻物种（在文化）的知识将奠定基础，为今后的调查是否可用性和随后收购的铁影响珊瑚共生期间的热stress.During本实验期间，10种共生藻将在环境条件下生长，暴露于各种微量铁浓度。将使用细胞密度对生长速率进行定量和比较。为了确定共生藻属的铁需要量，在生长实验期间的多个点使用元素分析来定量细胞铁水平。研究微量铁的可用性如何改变许多共生藻物种的生长动力学将确定铁的需求是否遵循系统发育模式，并在热水和冷水适应共生藻属物种是独一无二的。该奖项，根据东亚和太平洋夏季研究所计划，支持美国研究生的夏季研究，并由NSF和台湾科技部共同资助。

The mutualistic symbiosis between reef-building corals and their photosynthetic symbionts in the genus Symbiodinium form the basis of many shallow water tropical marine ecosystems. Episodes of severe ocean warming linked to climate change has driven largescale declines of coral populations in many tropical and subtropical regions. While many symbioses are susceptible to heat stress, various species and colonies appear unaffected visually, spurring many investigations into learning the underlying biological attributes that explain this resistance. The persistence and growth of Symbiodinium and host coral requires trace metals which are essential to vital processes such as photosynthesis and nitrogen assimilation. Previous studies have shown that the availability of trace metals, most notably iron, influences marine phytoplankton growth and assists in stress responses. The possibility that trace metal availability affects resistance to thermal stress in symbiotic corals is currently unexplored. The host scientist, Dr. Tung-Yuan Ho (Academia Sinica, Taiwan) recently described the trace metal requirements for growth by Symbiodinium kawagutii finding that increased iron availability was positively correlated with algal growth. To build upon this study, this project will expand upon this study by evaluating iron requirements among distantly and closely-related species of Symbiodinium and capitalize upon my access to Dr. Ho's trace metal clean laboratory. Knowledge of iron requirements for a diversity of Symbiodinium species (in culture) will lay the foundation for future investigation on whether the availability and subsequent acquisition of iron affects corals in symbiosis during periods of thermal stress.During this experiment, ten species of Symbiodinium will be grown in ambient conditions and exposed to various trace iron concentrations. Growth rates will be quantified and compared using cell density. To determine the iron requirement of Symbiodinium spp., cellular iron levels will be quantified using elemental analysis at multiple points during the growth experiment. Examining how trace iron availability alters the growth kinetics of numerous Symbiodinium species will determine whether iron requirements follow phylogenetic patterns and are unique in hot- and cold-water adapted Symbiodinium spp.This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of Taiwan.