Postdoctoral Fellowship: CREST-PRP: Ecophysiological response of tidal freshwater tree ecosystem engineers to chronic thermal, hydric, and salinity stressors in the Caribbean.

在热带生态系统中，天气通常是稳定和温暖的，但在过去十年中，气候变化导致了沿海湿地的温度变化、降雨和海平面的变化，这些变化正在影响热带动植物。由于缺乏适应这些变化的工具，热带植物可能难以生存。本研究将探讨两种树种——翼树（Pterocarpus officinalis）和黄檀（Dalbergia ecastaphyllum）如何应对温度和水供应的变化，以及这些变化如何影响它们的生理机能。研究地点位于Corredor Ecológico del Noreste，这是加勒比地区的一个自然保护区，代表着淡水海岸湿地。与自然资源管理者、社区和科学家合作，将收集数据来描述气候变化对这些树木的影响，目的是提高知识水平，从而为沿海湿地恢复的管理决策提供信息。在过去的十年里，波多黎各和更广阔的加勒比地区见证了历史性的气温上升。趋势表明，这一变暖轨迹将持续下去，并伴随着其他极端气候，包括海平面上升、极端降水事件和大气扰动加剧。沿海热带植被正处于危险的境地，在地球变暖和海平面上升的背景下，植被可能没有适应环境的生理机制。本研究的目的是评估在相同的中气候条件下，潮汐淡水湿地固氮物种对温度升高和盐度升高的生态生理反应。本研究将探讨1)气候变暖和盐度升高对光合作用和渗透平衡调节的影响；2)这些环境变化对固氮活性和效率的影响。该研究采用跨学科的方法，涉及植物生理学、生态学、气候变化科学和代谢组学，将包括对具有相同中气候但不同水文条件的两种树种——翼树（Pterocarpus officinalis）和黄檀（Dalbergia ecastaphyllum）的实地观察，以及对气温和盐分条件进行调整的温室实验。研究数据将包括光和温度响应曲线，用于评估叶片耐热性、植物形态特征、水力导度、渗透势、13C和15N固氮同位素分析，以及营养分析和非靶向代谢组学分析，以创建与盐胁迫和温度变化相关的代谢物概况。这种综合方法将适用于为保护管理工作中的植物选择提供信息，从而提高这些关键生态系统提供的潜在效益。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In tropical ecosystems the weather is typically stable and warm but in the past decade climate change has been causing changes in temperature and shifts in rain and sea level in coastal wetlands that are impacting tropical flora and fauna. Lacking tools to adjust to these changes, tropical plants might struggle to survive. This study will investigate how two tree species, Pterocarpus officinalis and Dalbergia ecastaphyllum, cope with changes in temperatures and water supply and how these changes are affecting their physiology. The study site is located in the Corredor Ecológico del Noreste, a natural reserve in the Caribbean that represents freshwater coastal wetlands. Working with natural resource managers, community, and scientists, data will be collected to characterize the effects of climate change on these trees with the goal of advance knowledging that can be applied to inform management decisions about coastal wetlands restoration.In the past decade, Puerto Rico and the broader Caribbean region have witnessed a historical increase in temperature. Trends suggest that this warming trajectory will continue, accompanied by other climatic extremes, including rising sea levels, extreme precipitation events, and intensified atmospheric disturbances. Coastal tropical vegetation is in a perilous situation, where in the context of a warmer planet and rising sea levels, vegetation might not have the physiological mechanisms for acclimation. This study’s goal is to assess the ecophysiological responses of nitrogen-fixing species in tidal freshwater wetlands in response to warmer temperatures and increased salinity under the same mesoclimate conditions. The research will investigate 1) how warmer climate and increased salinity affects photosynthesis and regulation of osmotic balance, and 2) how these environmental changes affect activity and efficiency of nitrogen fixation. Using an interdisciplinary approach involving plant physiology, ecology, climate change science and metabolomics, the study will include field observations of two tree species, Pterocarpus officinalis and Dalbergia ecastaphyllum, that share the same mesoclimate but different hydrologic conditions, and greenhouse experiments in which air temperature and saline conditions will be modified. Data examined will include light and temperature response curves to assess leaf thermal tolerance, plant morphological traits, hydraulic conductance, osmotic potential, 13C and 15N isotopic analyses for nitrogen fixation, as well as nutrient analysis and non-targeted metabolomic analyses to create a profile of metabolites related to salt stress and temperature changes. The combined approach will be applicable to informing plant selection in conservation management efforts, thus enhancing the potential benefits these critical ecosystems provide.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.