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

在过去的几十年里，世界各地的珊瑚礁经历了从以珊瑚本身为主到以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应激源，也包括沿海开发和气候变化等人类活动的影响。加勒比珊瑚礁上有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庇护所，并产生大量多样化的化合物，这些化合物对控制珊瑚礁上的物种相互作用非常重要，并可能成为潜在的新药。尽管它们在珊瑚礁上很重要，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源。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，这取决于它们与沿海开发的距离，这些珊瑚礁上的海绵组合也因人类影响的程度而不同。2017年9月，圣托马斯连续遭受两次5级飓风袭击。由于与珊瑚不同，人们几乎对飓风过后海绵群落的情况一无所知，研究小组将结合野外生态学和种群遗传学的方法来确定海绵群落如何应对和从这些毁灭性的风暴中恢复，以及之前暴露在陆地上的压力源是否会影响它们的恢复。密西西比大学、阿拉巴马大学和维尔京群岛大学的研究人员将参与这一快速项目，并将为学生和博士后研究人员提供培训机会，特别是来自代表性不足群体的培训机会。信息将提供给维尔京群岛的资源管理者，以及对圣托马斯社区团体的外联计划。该项目的目标是评估单一(例如飓风)和多个(例如飓风和陆上污染源)应激源对美国圣托马斯海绵群落的复原力、恢复和招募的影响。鉴于全球珊瑚礁上海绵的日益主导地位，了解海绵对自然和人为应激源的反应越来越重要。调查人员将利用圣托马岛周围几个地点多年的海绵组合数据，这些海绵组合在飓风伊尔玛和玛丽亚之前暴露于当地陆地应激源的程度不同，并评估这些不同组合随着时间的变化，从这些毁灭性风暴后3个月内开始。使用自然和实验清理的地块相结合，调查人员将评估海绵演替的进展，以及藻类的存在是否干扰海绵的补充和恢复。将收集新兵的亚样本和附近的同种生物，以评估种群遗传多样性和新个体的潜在来源。该项目产生的数据将为海绵应对飓风的应变能力、海绵群落内演替的启动、演替轨迹的潜在预测因子以及风暴事件后海绵种群内的遗传多样性提供关键的见解。这些信息将有助于查明阻碍珊瑚恢复的因素和提高珊瑚礁复原力的可能方法。

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.