Collaborative Research: Illuminating Cave Benthos in Subterranean Estuaries- Biodiversity, Ecology, and Role in Coastal Ecosystem Functioning

合作研究：阐明地下河口的洞穴底栖动物——生物多样性、生态学以及在沿海生态系统功能中的作用

• 批准号: 2136377
• 负责人: Joan Bernhard
• 金额: $ 62.03万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2136377&HistoricalAwards=false
• 关键词: Collaborative; Research; Illuminating; Cave; Benthos

Karst subterranean estuaries (KSEs) occur worldwide where fresh and marine-derived waters mix within coastal aquifers, creating a chemical reaction zone that alters the composition of materials transported to the sea and sustains characteristic aquatic communities. Approximately one quarter of Earth’s population depends on karst (eroded limestone) water supplies that – within coastal regions – are directly threatened by rising sea level, uncontrolled groundwater extraction, and rapid coastal development. Yet, the role of these ecosystems in coastal biogeochemical cycling and groundwater health remains unknown. While pelagic constituents of flooded caves in KSEs have been studied for decades, the living benthic (cave floor / seafloor-hosted) fauna of these caves and caverns remains understudied. The overarching goal of this project is to better understand how benthic biodiversity affects ecosystem functioning across subsurface environmental gradients between freshwater aquifers and the marine environment. Flooded coastal caves allow the team to access the KSEs and make direct observations. Results of this work benefit marine benthic ecology and biology, biogeochemistry, paleoecology and biodiversity assessments. This interdisciplinary project establishes a multinational, multi-institutional collaboration, enhance research and scholarship opportunities at a predominantly undergraduate Hispanic-serving institution in Texas and support young investigators from under-represented groups in the sciences. For outreach, the project-associated PhD student, who is an African American female, is co-authoring a semi-autobiographical children’s book about cave diving and the wonders of cave-associated organisms. KSEs influence coastal carbon and nitrogen cycling because they buffer terrestrial material inputs with groundwater discharge into the oceans. While pelagic communities of flooded cave environments in KSEs have been studied for decades due to their adaptations, biogeography, and evolutionary origin, the living benthic fauna and their role in KSE elemental cycling remains understudied. The overall aim of this project is to establish the diversity and ecology of benthic eukaryotes across environmental gradients in extensive coastal caves flooded by the KSE in the Yucatan Peninsula and Cozumel Island (Mexico) and determine how they interact with benthic elemental cycles. This study provides a holistic characterization of KSE benthos using interdisciplinary field- and lab-based approaches including barcoding/meta-barcoding, meta-transcriptomics, ultrastructural analysis, and lab culturing that are being integrated with biogeochemical and hydrological measurements. Specifically, the investigators are characterizing (1) the drivers of spatial biodiversity patterns in coastal cave eukaryotic benthic communities across salinity/oxygen gradients, relative to organic inputs; (2) the role of benthic meiofauna (to nanobiota) communities, with emphasis on foraminifera, in ecosystem function relative to dominant biogeochemical processes that mediate organic matter transformations and nitrogen cycling; and (3) the temporal constraints of benthic meiofauna (to nanobiota) biodiversity and ecosystem resilience in response to seasonal hydrological variation associated with meteorological events.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.

岩溶地下河口(KSE)在世界范围内存在，淡水和海洋来源的水在沿海含水层中混合，形成化学反应区，改变输送到海洋的物质组成，并维持独特的水生群落。大约四分之一的地球人口依赖于喀斯特(被侵蚀的石灰岩)供水，而在沿海地区，这些供水直接受到海平面上升、地下水开采失控和沿海快速发展的威胁。然而，这些生态系统在沿海生物地球化学循环和地下水健康中的作用尚不清楚。虽然对KSE被淹洞穴的远洋成分进行了几十年的研究，但这些洞穴和洞穴的活的底栖生物(洞底/海底宿主)动物仍然没有得到充分的研究。该项目的首要目标是更好地了解底栖生物多样性如何跨越淡水含水层和海洋环境之间的地下环境梯度影响生态系统的功能。被洪水淹没的沿海洞穴使研究小组能够进入KSE并进行直接观察。这项工作的结果有助于海洋底栖生态和生物学、生物地球化学、古生态学和生物多样性评估。这个跨学科项目建立了一个跨国、多机构合作，在德克萨斯州一所以本科生为主的拉美裔服务机构加强研究和奖学金机会，并支持来自科学界代表性不足群体的年轻研究人员。为了扩大影响，这位与该项目相关的博士生是一名非裔美国女性，她正在与人合著一本关于洞穴潜水和洞穴相关生物奇观的半自传体儿童书籍。KSE影响沿海的碳和氮循环，因为它们通过向海洋排放地下水来缓冲陆地物质的输入。由于KSE的适应性、生物地理学和进化起源，人们对KSE淹没洞穴环境中的远洋群落进行了数十年的研究，但对KSE中活的底栖动物及其在KSE元素循环中的作用仍未得到充分的研究。该项目的总体目标是在尤卡坦半岛和科祖梅尔岛(墨西哥)被KSE淹没的大片沿海洞穴中建立跨越环境梯度的底栖真核生物的多样性和生态，并确定它们如何与底栖元素循环相互作用。这项研究使用跨学科的现场和实验室方法提供了KSE底栖生物的整体特征，包括条形码/元条形码、元转录组学、超微结构分析和实验室培养，这些方法正在与生物地球化学和水文测量相结合。具体地说，研究人员正在描述(1)相对于有机投入，跨越盐度/氧气梯度的沿海洞穴真核底栖生物群落空间生物多样性格局的驱动因素；(2)底栖小型动物(对纳米生物群)在生态系统功能中的作用，重点是有孔虫，相对于主导的生物地球化学过程，调节有机物转化和氮循环；以及(3)底栖小型动物(对纳米生物群)生物多样性和生态系统弹性对与气象事件相关的季节性水文变化的时间限制。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的审查标准进行评估，认为值得支持。