RAPID: The ecological role of Pyrosoma atlanticum in the Northern California Current

在过去的三年里，俄勒冈州海岸附近突然出现了成千上万的杆状水母，它们污染了他们的渔具，占据了他们的渔获量，这让渔民们感到困惑和震惊。海滩游客也被这些生物迷住了，当它们被海浪冲走时，它们可以覆盖在沙滩上。这种温暖水域的物种很少在南加州北部出现，直到最近三年，它们在俄勒冈州海岸外的北加州洋流（NCC）中变得越来越多，甚至进入阿拉斯加湾。最近的一项渔业调查在5分钟的拖网中捕获了1.8万只火虫。对当地海洋食物网的影响尚不清楚，但火小体可能与其他重要物种竞争食物，可能改变NCC的海洋食物网。很少进行研究，因此对火体发生增加的影响的理解是有限的。因此，迫切需要更多地了解这个物种。该项目提供了对NCC中火小体可能的生态效应的深入了解。这项研究也将使在阿拉斯加湾等其他地区工作的研究人员受益。将通过外联加强更广泛的影响。一名本科生将在暑假期间参与该项目，获得宝贵的研究经验。研究小组将与哈特菲尔德海洋科学中心（Newport， OR）的游客中心合作，制作一个关于火体体的展览。该项目的首席研究员还将与俄勒冈州立大学的媒体拓展团队合作，撰写一篇关于该研究的高质量科普文章，并通过各种媒体流（包括在线、印刷和社交媒体）发布。大西洋火虫（俗称火虫）是一种温暖的远洋殖民地被囊动物，直到最近才出现在南加州北部。然而，在过去的三年里，火体虫在俄勒冈州海岸外的北加州洋流（NCC）中变得越来越丰富，并向北延伸到阿拉斯加湾，这对生态系统的生产力和渔业产生了影响。调查人员收集的初步数据表明，火体菌群在俄勒冈海岸附近有极高的放牧率，这表明火体菌的大量繁殖能够放牧大量的浮游植物。事实上，在世界其他地区的海洋中，火体藻华能够清除海洋顶部10米中一半以上的浮游植物。NCC的火体藻华可能会超过其他浮游动物食草动物，如桡足类和大腹虫，从而对依赖这些甲壳类动物作为猎物的高营养层产生负面影响。对食物链的影响可能是巨大的。在许多鱼类的胃内容物中已经发现了火小体，包括太平洋大比目鱼、岩鱼、黑脸鱼和太平洋鲑鱼，但它们的热量含量是这些鱼类首选猎物磷虾的一半。随着火体藻华发生频率的增加，迫切需要对其潜在的生态影响进行评估。对全球海洋中火体的生态作用的科学认识严重有限，并且在NCC中前所未有的持续大量火体的影响是未知的。本项目旨在深入研究火小体在中上层食物网中的作用和NCC的生物地球化学循环，以回答以下研究问题：(1)每天火小体大量繁殖去除的浮游植物现有资源的比例是多少？(2)在NCC中，热体优先吃的浮游植物的大小比例是多少？(3)高温体对NCC海底有机质通量的贡献是什么？该奖项反映了美国国家科学基金会的法定使命，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。

In the last three years, fishermen off the coast of Oregon have been baffled and alarmed by the sudden appearance of thousands of rod-shaped, jelly-like animals, called pysrosomes, fouling their gear and dominating their catches. Beach-goers, too, have been fascinated by these creatures that can blanket the sand when washed up in the surf. This warm water species was rarely encountered north of southern California until the last three years, when they have become increasingly abundant in the Northern California Current (NCC) off the coast of Oregon and even up into the Gulf of Alaska. A recent fisheries survey caught 18,000 pyrosomes in a 5-minute trawl. The effect on local marine food webs is not clear, but pyrosomes could compete with other important species for food, potentially changing the marine food web of the NCC. Few studies have been conducted so understanding of the implications of increased pyrosome occurrence is limited. There is thus an urgent need to learn more about the species. This project provides insight into the possible ecological effects of pyrosomes in the NCC. The study will also benefit researchers working in other regions, like the Gulf of Alaska. Broader impacts will be strengthened by outreach. An undergraduate student will work on the project over the summer, gaining valuable research experience. The research team will create a display about pyrosomes in collaboration with the Visitor Center at the Hatfield Marine Science Center (Newport, OR). The lead investigator on the project will also work with the media outreach team at Oregon State University to produce a high-quality popular science article about the research to be distributed via various media streams, including online, in print, and via social media.Pyrosoma atlanticum (commonly known as the pyrosome) is a warm water species of pelagic colonial tunicate that until recently had not occurred north of southern California. However, in the last three years, pyrosomes have become increasingly abundant in the Northern California Current (NCC) off the coast of Oregon, and as far north as the Gulf of Alaska, with implications for ecosystem productivity and fisheries. Preliminary data collected by the investigators show that pyrosome colonies off the Oregon Coast have extremely high grazing rates, suggesting that pyrosome blooms are capable of grazing significant amounts of phytoplankton standing stock. Indeed, in other parts of the world oceans, pyrosome blooms are capable of removing more than half of the phytoplankton standing stock in the top 10 m of the ocean. Pyrosome blooms in the NCC could outcompete other zooplankton grazers, such as copepods and euphausiids, thereby negatively affecting the higher trophic levels that rely on those crustaceans as prey. The effects on the food chain are likely to be significant. Pyrosomes have already been recorded in the stomach contents of a number of fish species, including Pacific halibut, rockfishes, sablefish, and Pacific salmon, yet their caloric content is half that of these fish species' preferred prey, krill. With increasing frequency of pyrosome blooms, there is an urgent need to assess their potential ecological implications in the NCC. Scientific understanding of the ecological role of pyrosomes in the global oceans is severely limited and the effects of the unprecedented continuous large blooms of pyrosomes in the NCC are unknown. This project is an intensive study on the role of pyrosomes in the pelagic food web and biogeochemical cycles of the NCC to answer the following research questions: (1) What proportion of the phytoplankton standing stock do pyrosome blooms remove daily? (2) What size fraction of the phytoplankton do pyrosomes preferentially graze upon in the NCC? (3) What is the contribution of pyrosomes to the flux of organic matter to the sea floor in the NCC?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.