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

在过去的三年里，俄勒冈州沿海的渔民们对数以千计的杆状、果冻状动物的突然出现感到困惑和震惊，这些动物被称为焦煤虫，它们弄脏了渔具，主宰了捕获物。海滩游人也对这些生物着迷，这些生物在被冲上海浪时可以覆盖沙子。这种温水物种在南加州北部很少遇到，直到最近三年，在俄勒冈州海岸外的北加州洋流(NCC)，甚至进入阿拉斯加湾，它们变得越来越丰富。最近的一项渔业调查在5分钟的拖网中捕获了1.8万只金枪鱼。这对当地海洋食物网的影响尚不清楚，但火体可能会与其他重要物种争夺食物，潜在地改变NCC的海洋食物网。很少有研究进行，因此对增加发火体发生的影响的理解有限。因此，迫切需要更多地了解该物种。该项目提供了对NCC中可能存在的焦糖的生态影响的洞察。这项研究还将使在阿拉斯加湾等其他地区工作的研究人员受益。更广泛的影响将通过外联活动得到加强。一名本科生将在整个暑假为该项目工作，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(俄勒冈州纽波特市)的游客中心合作，制作一个关于火焰体的展示。该项目的首席调查员还将与俄勒冈州立大学的媒体外展团队合作，制作一篇关于这项研究的高质量科普文章，通过包括在线、印刷和社交媒体在内的各种媒体传播。大西洋火龙虾(俗称火龙虾)是一种温暖的海洋物种，直到最近才在南加州北部出现。然而，在过去三年中，在俄勒冈州海岸外的北加州洋流(NCC)以及远至阿拉斯加湾的北部洋流中，燃烧体变得越来越丰富，对生态系统生产力和渔业产生了影响。调查人员收集的初步数据显示，俄勒冈州海岸外的火虫群落具有极高的捕食率，这表明火虫水华能够捕食大量浮游植物。事实上，在世界海洋的其他地方，火藻水华能够消除海洋顶部10米处一半以上的浮游植物。NCC的火焰体水华可能会超过其他浮游动物食草动物，如桡足类和真甲壳类，从而对依赖这些甲壳类作为猎物的较高营养水平产生负面影响。这对食物链的影响可能是巨大的。包括太平洋大比目鱼、岩鱼、剑鱼和太平洋三文鱼在内的一些鱼类的胃内容物中已经记录了火焰体，但它们的卡路里含量是这些鱼类的首选猎物磷虾的一半。随着火小体水华发生的频率越来越高，迫切需要评估它们对国家气候中心潜在的生态影响。对全球海洋中的火焰体的生态作用的科学认识严重有限，国家海洋委员会中史无前例的火焰体连续大规模爆发的影响也是未知的。这个项目是一项关于火焰体在海洋食物网和NCC生物地球化学循环中的作用的深入研究，以回答以下研究问题：(1)火焰体每天清除浮游植物常备种群的比例是多少？(2)火焰体在NCC优先捕食的浮游植物的大小比例？(3)在NCC中，火焰体对有机物质流向海底的贡献是什么？这一裁决反映了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，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.