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.

喀斯特地下河口 (KSE) 遍布世界各地，淡水和海洋水在沿海含水层内混合，形成化学反应区，改变输送到海洋的物质的成分并维持特有的水生群落。地球上大约四分之一的人口依赖于喀斯特（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、不受控制的地下水开采和快速沿海开发的威胁。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仍然未知。虽然 KSE 中被淹没的洞穴的中上层成分已经被研究了几十年，但这些洞穴和洞穴中的活底栖（洞穴底部/海底）动物群仍然没有得到充分研究。该项目的总体目标是更好地了解底栖生物多样性如何影响淡水含水层和海洋环境之间地下环境梯度的生态系统功能。被洪水淹没的沿海洞穴使团队能够进入 KSE 并进行直接观察。这项工作的结果有利于海洋底栖生态学和生物学、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跨国、多机构合作，增加了德克萨斯州一所主要为西班牙裔本科生服务的机构的研究和奖学金机会，并支持来自科学领域代表性不足群体的年轻研究人员。为了进行推广，这位与项目相关的博士生（一名非裔美国女性）正在与人合着一本关于洞穴潜水和洞穴相关生物奇迹的半自传儿童读物。 KSE 影响沿海碳和氮循环，因为它们通过地下水排放到海洋来缓冲陆地物质输入。虽然 KSE 中被淹没的洞穴环境中的上层群落因其适应性、生物地理学和进化起源而被研究了数十年，但现存的底栖动物群及其在 KSE 元素循环中的作用仍然没有得到充分研究。该项目的总体目标是在尤卡坦半岛和科苏梅尔岛（墨西哥）被 KSE 淹没的广阔沿海洞穴中跨环境梯度建立底栖真核生物的多样性和生态学，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，包括条形码/元条形码、元转录组学、超微结构分析和与生物地球化学和水文测量相结合的实验室培养，提供了 KSE 底栖生物的整体特征。具体来说，研究人员正在表征（1）相对于有机输入，沿海洞穴真核底栖群落跨盐度/氧气梯度的空间生物多样性模式的驱动因素； (2) 底栖小型动物（纳米生物群）群落（重点是有孔虫）在生态系统功能中相对于介导有机质转化和氮循环的主要生物地球化学过程的作用； (3) 底栖小型动物（纳米生物群）生物多样性和生态系统复原力的时间限制，以应对与气象事件相关的季节性水文变化。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。