Postdoctoral Fellowship: OCE-PRF: Do dead shells make good homes? Assessing the Development, Stability, and Evolution of Shell Gravel Habitats Across Space and Time

该项目的目的是评估底栖无脊椎动物群落和贝壳砾石生境沿着纬度梯度的共同进化。底栖生物群落直接改变其物理栖息地的骨骼碎片（贝壳，骨头，骨片等）。许多代的死亡生物在沉积物中积累，形成粗糙的基质斑块，底栖（表面活的）生物可以在其上定居。尽管是罕见的现代大陆架，贝壳砾石栖息地是生物多样性的热点，也许是最好的现代类似物的早期化石组合之前，普遍的软沉积物动物群落（6500万年前）。此外，虽然全球纬度梯度的进化起源和生态后果已被严格评估，以解释现代和深时间的生物多样性，我们仍然知道很少的纬度变化的过程中，确定生产，持久性和保存的化石组合。PI将收集并评估来自北美东太平洋沿岸沿着两个著名贝壳砾石环境的各种基底条件（砾石与泥浆，浅与深）的沉积物样本：南加州的暖温带海峡群岛和华盛顿的冷温带圣胡安群岛，形成一个纬度梯度，将对底栖生物群落、沉积物基底及其局部反馈效应进行量化。PI将通过与生物监测机构合作，为当地学校制定课程计划，在加州大学古生物学博物馆担任志愿者，并指导本科生进行研究，进一步增加旧金山弗朗西斯科湾区的科学参与。在本项目期间将进行三项总体调查：（1）与沉积速率、水温和生物扰动强度有关的死壳组合的发展、持续性和时间尺度;（2）死壳组合与活底栖生物群落之间的保真度及其与死壳持续性的关系;（3）将这些生态和埋藏动态联系起来的反馈效应。第一次调查将使用通过放射性碳测年确定的死后年龄，以量化时间平均的持续时间，并确定每个油田区域内和之间的贝壳损失参数（解体、封存和埋葬）。第二项调查将评估抽样社区和死壳组合之间的单变量生态指标和多变量组成的相关性。第三次调查将结合联合收割机这些物理和生物的结果，以模拟它们的相互作用，并确定埋藏反馈，对这些栖息地的作用。这项研究将查明底栖生境形成无脊椎动物群落演替的机制，并确定其本身形成无脊椎动物群落演替的机制，从而弥合物理海洋学和生物海洋学之间的重要差距。这些见解将改善（1）从化石记录的古生态学解释和（2）在不断变化的海洋条件下管理沿海生物多样性的保护战略。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The aim of this project is to assess the coevolution of benthic invertebrate communities and shell gravel habitats along a latitudinal gradient. Benthic communities directly modify their physical habitat as the skeletal debris (shells, bones, sclerites, etc.) of dead organisms over many generations accumulate in the sediment, creating patches of coarse substrates upon which epibenthic (surface-living) organisms can colonize. Despite being rare on modern continental shelfs, shell gravel habitats are hotspots for biodiversity and perhaps the best modern analogs of early fossil assemblages from before the onset of pervasive soft-sediment infaunal communities ( 65 million years ago). Further, while the evolutionary origins and ecological consequences of the global latitudinal gradient have been rigorously assessed to explain both modern and deep-time biodiversity, we still know little about latitudinal variation in the processes that determine the production, persistence, and preservation of fossil assemblages. The PI will collect and assess sediment samples from various substrate conditions (gravel vs mud, shallow vs deep) from two notable shell gravel environments along the Eastern Pacific coast of North America: The warm-temperate Channel Islands of Southern California and the cold-temperate San Juan Islands of Washington, forming a latitudinal gradient across which benthic communities, sediment substrates, and their local feedback effects will be quantified. The PI will further increase scientific engagement in the San Francisco Bay area by collaborating with biomonitoring agencies, creating lesson plans for local schools, volunteering with the University of California Museum of Paleontology, and mentoring undergraduates in research. Three overarching investigations will be conducted during this project: (1) the development, persistence, and temporal scale of dead-shell assemblages with respect to sedimentation rates, water temperature, and bioturbation intensity, (2) the fidelity between dead-shell assemblages and living benthic communities, and its relationship with dead-shell persistence, and (3) feedback effects that link these ecological and taphonomic dynamics. The first investigation will use postmortem ages determined via radiocarbon dating to quantify the duration of time averaging and determine shell loss parameters (disintegration, sequestration, and burial) within and between each field area. The second investigation will assess correlations in both univariate ecological metrics and multivariate composition among sampled communities and dead-shell assemblages. The third investigation will combine these physical and biological results to model their interactions and identify taphonomic feedbacks that act on these habitats. This research will bridge important gaps between physical and biological oceanography by identifying mechanisms by which benthic habitats shape – and are themselves shaped by – the succession of invertebrate communities. These insights will improve both (1) paleoecological interpretations from the fossil record and (2) conservation strategies for managing coastal biodiversity in a world of changing ocean conditions.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.