RAPID: Collaborative Research: Sponge resilience in the face of multiple stressors

在过去几十年中，世界各地的珊瑚礁经历了从珊瑚本身为主到海绵或藻类为主的转变。这些变化的原因很复杂，但既包括疾病和飓风等自然压力，也包括沿海开发和气候变化等人类活动的影响。加勒比海珊瑚礁上有600多种海绵，它们发挥着许多重要的生态作用，包括营养循环，为其他珊瑚礁动物提供食物和住所，并产生对控制珊瑚礁上物种相互作用至关重要的多种多样的化学化合物，并可能成为潜在的新药。尽管它们对珊瑚礁很重要，但海绵生物学的许多方面仍然未知，包括它们如何应对不同类型的压力。美属维尔京群岛圣托马斯的珊瑚礁受到不同程度的人为压力，这取决于它们是否接近沿海开发区，这些珊瑚礁上的海绵组合也随着人类影响的程度而变化。2017年9月，圣托马斯连续遭受两次5级飓风的破坏。由于与珊瑚不同，人们对飓风过后海绵群落的变化几乎一无所知，研究小组将结合实地生态学和种群遗传学方法来确定海绵群落如何从这些毁灭性的风暴中应对和恢复，以及先前暴露于陆地压力是否会影响它们的恢复。密西西比大学、亚拉巴马大学和维尔京群岛大学的研究人员将参加这一快速项目，并将为学生和博士后研究人员，特别是代表性不足的群体的研究人员提供培训机会。将向维尔京群岛的资源管理人员提供信息，沿着向圣托马斯社区团体的外联方案。本项目的目标是评估单一（例如，飓风）与多个（例如，飓风和陆基污染源）对美国圣托马斯海绵群落的恢复力、恢复和补充的压力。 鉴于海绵在全世界珊瑚礁上的主导地位日益增加，了解海绵对自然和人为压力的反应越来越重要。研究人员将利用多年来关于圣托马斯岛周围几个地点的海绵组合的数据，这些地点在飓风伊尔玛和玛丽亚之前暴露于当地陆基压力源的水平不同，并评估这些不同组合随时间的变化，从这些破坏性风暴的3个月内开始。 使用自然和实验清除的地块相结合，研究人员将评估海绵演替的进展，以及藻类的存在是否会干扰海绵的招募和恢复。将收集新兵和附近同种的子样本，以评估种群遗传多样性和新个体的潜在来源。从这个项目产生的数据将提供关键的见解海绵弹性在应对飓风在以前暴露于陆基压力，海绵社区内的继承，继承轨迹的潜在预测因子，和海绵种群内的遗传多样性风暴事件后的网站。这些信息将有助于确定阻碍珊瑚恢复的因素和加强珊瑚礁复原力的潜在办法。

Over the past several decades, coral reefs worldwide have undergone a transition from being dominated by the corals themselves to being dominated by sponges or algae. The causes of these changes are complex, but they include both natural stressors, such as diseases and hurricanes, and impacts from human activities, such as coastal development and climate change. There are over 600 species of sponges on Caribbean coral reefs, and they serve many important ecological roles, including nutrient cycling, providing food and shelter for other reef animals, and producing a tremendous diversity of chemical compounds that are important for controlling species interactions on the reef, and may serve as potential new drugs. In spite of their importance on coral reefs, there are many aspects of sponge biology that remain unknown, including how they respond to different types of stressors. Coral reefs in St. Thomas, in the U.S. Virgin Islands, are exposed to different levels of man-made stressors, depending upon their proximity to coastal development, and the sponge assemblages on these reefs also vary with levels of human impacts. In September 2017, St. Thomas was devastated by two Category 5 hurricanes in a row. Since, unlike corals, virtually nothing is known about what happens to sponge communities in the aftermath of hurricanes, the research team will use a combination of field ecology and population genetics approaches to determine how sponge communities respond and recover from these devastating storms and whether prior exposure to land-based stressors affects their recovery. Researchers at the Universities of Mississippi, Alabama and the Virgin Islands will participate in this RAPID project, and will provide training opportunities for students and postdoctoral researchers, especially from underrepresented groups. Information will be provided to resource managers in the Virgin Islands, along with outreach programs to community groups in St. Thomas.The goal of this project is to assess the impacts of single (e.g., hurricanes) versus multiple (e.g., hurricanes and land-based sources of pollution) stressors on the resilience, recovery, and recruitment of sponge communities in St. Thomas, U.S.V.I. Given the growing dominance of sponges on coral reefs worldwide, understanding the responses of sponges to natural and anthropogenic stressors is increasingly important. The investigators will leverage multiple years of data on sponge assemblages from several sites around the island of St. Thomas that varied in their levels of exposure to local land-based stressors prior to Hurricanes Irma and Maria, and evaluate changes to these diverse assemblages over time, beginning within 3 months of these devastating storms. Using a combination of natural and experimentally cleared plots, the investigators will assess the progress of sponge succession and whether the presence of algae interferes with sponge recruitment and recovery. Subsamples of recruits and nearby conspecifics will be collected to evaluate population genetic diversity and potential sources of new individuals. The data resulting from this project will provide critical insights into sponge resilience in response to hurricanes at sites previously exposed to land-based stressors, the initiation of succession within sponge communities, potential predictors of successional trajectory, and genetic diversity within sponge populations following a storm event. This information will help identify factors that inhibit coral recovery and potential approaches to enhance resilience of coral reefs.