RAPID: Here we go again - The fate of Diadema antillarum and Caribbean reefs in the 21st century

RAPID：我们又来了 - 21 世纪 Diadema antillarum 和加勒比珊瑚礁的命运

• 批准号: 2235138
• 负责人: Rolando Santos
• 金额: $ 19.97万
• 依托单位: Florida International University
• 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: 2022-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2235138&HistoricalAwards=false
• 关键词: RAPID; Here; go; again; fate

Coral reef benthic community assemblage and functioning are controlled in part by herbivores that graze on algae, which compete for space with various taxa, including coral and sponge species. In the Caribbean, it is hypothesized that the black sea urchin, Diadema antillarum, is a keystone grazer that controls macroalgae species composition and biomass at low levels and facilitates the recruitment and survival of reef-building corals, leading to a coral-dominated state of reefs. The recent D. antillarum die-off provides the conditions of a natural removal experiment useful to understand the top-down control exertion of this herbivore, especially by quantifying the spatial arrangement progression of benthic functional groups across urchin abundances. This study is assessing the impact of the loss of this keystone species on reef community structure and function using innovative imaging tools to quantify the fine-scale changes in the community structure, the size distribution, and spatial dispersion of D. antillarum, the dominant coral species (Porites), and turf-algae and macroalgae on the reefs of Culebra, Puerto Rico, during the initial phase of the Diadema die-off in the Caribbean. The Caribbean-wide D. antillarum die-off highlights the importance of understanding how and when herbivores play a role in shaping reef communities. This RAPID award is creating a rich digital dataset that will be leveraged to assess multiple ecological questions and provide numerous opportunities for undergraduate and graduate research studies.The loss of this keystone species is expected to impact overall reef community structure and function and the abundance and distribution of coral turf-algae and macroalgae. The project uses innovative spatially explicit tools to quantify the fine-scale spatiotemporal changes in the community structure, size distribution, and spatial dispersion of D. antillarum, Porites astreoides (dominant coral species), and turf-algae and macroalgae (Dictyota spp.) on the reefs of Culebra, Puerto Rico, during the initial phase of the Diadema die-off in the Caribbean. Based on top-down control, competition, and percolation theory, the investigators hypothesize (H1) a strong relationship between D. antillarum and the community structure of reefs, (H2) an increase in macroalgae/turf algae cover starting with a non-uniform dispersion of algae clumps, followed by the coalescing of algae clumps percolated across the reefs and around P. asteroides colonies, which will result in (H3) a decrease of P. asteroides demographic parameters (e.g., growth, size-structure, recruitment) due to smothering, shading, and interactive effects with algae. They hypothesize (H4) that the trophic dynamics of reefs will shift, especially by the diversification of basal resources and expansion of trophic niches of consumers. The investigators are using Structure-from-Motion software to create large-area images that reproduce a digital reconstruction of reef plots. They leverage data from an existing project in Culebra (Puerto Rico) that has collected over 90 high resolution (cm-scale), large-area images (LAIs, 100 m2) since 2020. They are generating bi-monthly LAIs (8 time points) to assess the fine-scale and fast responses as a function of the die-off. Samples across different basal resources and trophic guilds/levels are being collected to perform stable isotope analysis and Bayesian mixing models to quantify shifts in trophic dynamics due to the response of the reef community to the urchin die-off. These research activities follow an analytical framework based on a before-and-after experimental approach and high-resolution temporal trends. Different statistical modeling techniques are being incorporated in this framework to address the projects' hypotheses and synergistic activities.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.

珊瑚礁底栖生物群落的组合和功能在一定程度上受到食草动物的控制，食草动物以藻类为食，与包括珊瑚和海绵物种在内的各种分类群争夺空间。在加勒比，据推测，黑海胆迪亚德马antillarum是一种关键的食草动物，控制大型藻类的物种组成和生物量，并促进造礁珊瑚的补充和生存，导致珊瑚礁占主导地位。最近的D. antillarum死亡提供了一个自然的去除实验的条件，有助于了解这种食草动物的自上而下的控制发挥，特别是通过量化的海胆丰度的底栖功能群的空间排列进展。这项研究正在评估这种关键物种的损失对珊瑚礁群落结构和功能的影响，使用创新的成像工具来量化群落结构，大小分布和空间分散的细微变化。在加勒比地区迪亚德马灭绝的最初阶段，在波多黎各的库莱布拉的珊瑚礁上，主要珊瑚物种（滨珊瑚）、草坪藻类和大型藻类。 加勒比地区的D. antillarum死亡突出了了解食草动物如何以及何时在塑造珊瑚礁群落方面发挥作用的重要性。该RAPID奖项正在创建一个丰富的数字数据集，将被用来评估多个生态问题，并为本科生和研究生的研究提供大量的机会。这一关键物种的损失预计将影响整体珊瑚礁群落结构和功能以及珊瑚礁藻类和大型藻类的丰度和分布。 该项目使用创新的空间明确的工具来量化群落结构，大小分布和空间分散的细尺度时空变化。antillarum、滨珊瑚（Porites astreoides）（优势种）、草坪藻类和大型藻类（网藻属（Dictyota spp.）在加勒比海迪亚德马灭绝的最初阶段，在波多黎各的库莱布拉的珊瑚礁上。基于自上而下的控制、竞争和渗透理论，研究者假设（H1）D。antillarum和珊瑚礁的群落结构，（H2）大型藻类/草皮藻类覆盖的增加，开始于藻类团块的不均匀分散，随后是跨越珊瑚礁和P. asteroides菌落周围的藻类团块的合并，这将导致（H3）P. asteroides人口统计参数的降低（例如，生长、大小结构、补充），这是由于窒息、遮蔽以及与藻类的相互作用。他们假设（H4），珊瑚礁的营养动态将发生变化，特别是通过基础资源的多样化和消费者营养生态位的扩大。调查人员正在使用运动结构软件创建大面积图像，再现珊瑚礁地块的数字重建。他们利用了库莱布拉（波多黎各）现有项目的数据，该项目自2020年以来收集了90多幅高分辨率（厘米级）大面积图像（莱什，100平方米）。 他们正在生成每两个月一次的莱什（8个时间点），以评估作为死亡函数的精细尺度和快速反应。正在收集不同基底资源和营养行会/水平的样本，以进行稳定同位素分析和贝叶斯混合模型，以量化由于珊瑚礁群落对海胆死亡的反应而引起的营养动态变化。这些研究活动遵循一个基于前后实验方法和高分辨率时间趋势的分析框架。不同的统计建模技术被纳入这个框架，以解决项目的假设和协同活动。这个奖项反映了NSF的法定使命，并已被认为是值得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的支持。