Do fine-scale water column structure and particle aggregations favor gelatinous-dominated food webs in subtropical continental shelf environments?

这项研究在两个不同的地点使用新的海洋观测技术，将生物和环境条件的测量结合起来，以了解高生产力的海洋大陆架食物网。在海洋食物网中，各种小动物群落统称为浮游动物，是包括鱼类和海洋哺乳动物在内的大型动物的猎物。浮游动物也会影响较低的营养水平，例如海洋微生物，而海洋微生物反过来又会影响整个海洋的营养和气体循环。该项目还支持研究生和本科生，其中包括萨凡纳州立大学的几名学生。萨凡纳州立大学是一所历史悠久的黑人大学，设有海洋科学本科生和研究生课程。实地研究为K-12教育工作者提供了真实的海洋体验，他们将参加计划中的研究巡航，并为当地一所高中的大三和大四学生提供研究机会，该学校的STEM代表不足群体的入学率很高。该项目涉及海洋科学中的基本问题，即环境条件如何影响大陆架生态系统中浮游动物群落的结构和组成。具有生物生产力的大陆架生态系统可以在风和冷季节的垂直混合水域和温暖和平静条件下的垂直分层水域的两端之间振荡。温暖、平静的条件有利于浮游生物和颗粒物质形成致密的层或聚集体，产生生物活动的热点，这可能会使海洋生物以比水柱平均丰度所暗示的更高的速度觅食。尽管在几个陆架环境中已经描述了层形成的物理机制和与之相关的浮游生物群，但对层对浮游动物群落组成和营养转移的影响知之甚少。对于快速繁殖的浮游被毛类，如盐类、火龙体、附属物和杜氏藻，这些层或聚集体可以作为丰富的食物资源，使中上层被毛类形成密集的水华，然后最终作为胶状捕食者的食物。这一系列事件，从蛋层形成到中上层被衣藻的繁殖和水华的捕食，可能会在整个海洋食物网中产生大量的胶状生物。研究人员将通过原位成像测量胶状浮游动物的细微尺度丰度，使用分子肠道内容物分析测量胶状浮游动物饲料，以及在垂直混合和分层条件下使用化合物特有的稳定同位素来测试食物网特性，以检验这一假设。为了确定食物网相互作用是否适用于具有和不具有垂直结构的水柱，将在南大西洋海湾和墨西哥湾北部的大陆架生态系统中比较这些过程。两者都为云母水华提供了有利的条件，但垂直层化的驱动因素不同。该项目由地球科学局共同资助，以支持AI/ML在地球科学领域的进步。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Using new ocean observing technologies in two contrasting locations, this research is combining measurements of biological and environmental conditions to understand highly productive ocean shelf food webs. Within marine food webs, a diverse community of small animals, referred to collectively as zooplankton, serve as prey for larger animals including fishes and marine mammals. Zooplankton can also influence lower trophic levels, such as marine microbes that in turn, affect nutrient and gas cycling throughout the oceans. This project is also supporting graduate and undergraduate students, including several from Savannah State University, a Historically Black University with undergraduate and graduate programs in marine sciences. The field research is providing authentic oceanographic experiences for K-12 educators, who will participate in the planned research cruises, as well as research opportunities for juniors and seniors at a local high school with high enrollment of groups underrepresented STEM. Public outreach includes annual open house events at the University of Georgia’s Skidaway Institute of Oceanography.This project addresses fundamental questions in ocean sciences regarding how environmental conditions affect the structure and composition of zooplankton communities in continental shelf ecosystems. Biologically productive shelf ecosystems can oscillate between extremes of vertically mixed waters during windy and colder seasons and vertically stratified waters during warmer and calmer conditions. Warm, calm conditions favor the formation of dense layers or aggregations of plankton and particulate material, generating hot spots of biological activity that potentially allow marine organisms to feed at much higher rates than water-column-average abundances might suggest. Although physical mechanisms of layer formation and plankton groups associated with them have been described in several shelf environments, less is known about the influence of layers on zooplankton community composition and trophic transfer. For fast-reproducing pelagic tunicates such as salps, pyrosomes, appendicularians, and doliolids, these layers or aggregations may serve as rich food resources that prime pelagic tunicates to form dense blooms which then ultimately serve as food for gelatinous predators. This sequence of events, from layer formation to pelagic tunicate reproduction and predation on the bloom, may generate high abundances of gelatinous organisms throughout the marine food web. The investigators will test this hypothesis by measuring fine-scale abundances of gelatinous zooplankton with in-situ imaging, gelantinous zooplankton diets using molecular gut content analysis, and food web properties using compound-specific stable isotopes in both vertically mixed and stratified conditions. To determine if food web interactions are generalizable to water columns with and without vertical structure, these processes will be compared in the South Atlantic Bight and northern Gulf of Mexico shelf ecosystems. Both provide favorable conditions for doliolid blooms yet differ in drivers of vertical stratification. This project is co-funded by the Directorate for Geosciences to support AI/ML advancement in the geosciences.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.