Environmental consequences of expanded recruitment of an ecosystem engineer on a hypoxia-influenced continental shelf

高产的美国西海岸渔业物种和海洋哺乳动物依赖于底栖无脊椎动物群落的食物。然而，这些社区正在发生变化。这个项目解决了一个新成员对这些底栖生物群落的潜在生态后果，鬼虾新锥虫。在河口，新锥虫通过它们的挖洞活动不断地改造沉积物。虾的高丰度和挖洞的影响相结合，减轻了可能加剧低氧条件的营养流失（自然和人为）的影响。然而，新锥虫也被认为是牡蛎产业的威胁，因为它们的沉积物挖掘活动。它们在河口以外的分布范围的扩大可能会对邓氏蟹渔业产生额外的不可预见的后果（该地区价值为33-74亿美元/年），因为新特雷尼亚既是幼蟹的竞争对手，也是大型邓氏蟹的猎物。因此，需要新的数据来确定新锥虫进入新栖息地是如何改变近海底栖生物群落的。这项研究比较了虾丰度高和低的群落，以了解它们对近海底栖生物群落的影响。虾对氧和碳循环的贡献是通过实地测量来估计的。底栖生物群落评估正在量化这些相对较大的虾的存在对海底食物资源造成的变化。俄勒冈-华盛顿大陆架沿岸水域具有商业价值，但它们也受到越来越多的与人类有关的影响。可持续管理需要优化采掘、文化和娱乐活动。这项研究的广泛影响包括为管理者、商业渔业利益相关者和牡蛎种植者提供关键数据，为有关海洋利用规划和穴虾管理的决策提供信息。本项目为3名研究生和2名暑期本科生提供科研培训。小学课程开发的重点是软体底栖生物生态学。西海岸的K-12学生通常对潮间带和海带森林系统更熟悉，他们通常不知道海洋砂质/泥泞的底栖动物。俄勒冈州和华盛顿海岸以及其他地方大陆架水域不断变化的环境条件包括越来越频繁和严重的缺氧事件、海洋酸化和变暖。这些变化影响了生物群落，改变了物种分布。在2015年海洋热浪之后，在大陆架水域中记录了大量的穴居鬼虾，Neotrypaea sp.。新锥虫是一种生态系统工程师，以前人们认为它们在潮间带河口泥滩中大量存在，而在开阔的海洋中却很少存在。在河口，新锥虫通过它们的挖洞活动不断地改造沉积物。由于地穴灌溉，对虾可以增加氧循环，减少低氧条件等养分负荷的影响。然而，与新锥虫床相关的底栖动物氧气消耗的增加可能会通过加强区域缺氧而对大陆架产生相反的影响。本研究利用生境适宜性建模方法描述了与新锥虫扩大分布相关的环境条件。模型预测正在通过箱形取心和视频着陆器观测进行广泛的现场抽样验证。此外，底栖动物样本记录了新锥虫床内底栖无脊椎动物群落的变化，以及这是如何潜在地影响生物相互作用的。通过对有和没有丰富虾类的陆架区水生涡旋相关方差和核心孵化的分析，可以估计虾类对底栖氧通量和有机碳循环的贡献。这些数据被用来量化虾和它们的洞穴对相对于参考区域的中陆架底栖动物整体生产力的影响。新锥虫如何改变海底结构和生物地球化学需要表征，以预测这些生态系统工程师对高营养水平和渔业的食物供应的影响。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。

Highly productive US West Coast fishery species and marine mammals rely on benthic invertebrate communities for food. However, these communities are changing. This project addresses the potential ecological consequences of a new member to these benthic communities, the ghost shrimp Neotrypaea. In estuaries, Neotrypaea continuously rework the sediment via their burrowing activities. The combination of high shrimp abundances and the effects of burrowing mitigate the impacts of nutrient run-off (natural and human-induced) that can exacerbate low oxygen conditions. However, Neotrypaea are also considered threats to the oyster industry because of their sediment-excavating activities. An expansion of their distribution beyond estuaries may have additional unforeseen consequences for the Dungeness crab fishery (regionally valued at $33-74M/y) as Neotrypaea are both competitors with juveniles and prey for larger Dungeness crab. Thus, new data are needed to determine how offshore benthic communities are being altered by the recruitment of Neotrypaea into new habitats. This study is comparing communities with high and low shrimp abundances to understand their impact on offshore benthic communities. The shrimp’s contributions to oxygen and carbon cycling are being estimated through field measurements. Benthic community assessments are quantifying changes to food resources on the seafloor caused by the presence of these relatively large shrimp. The coastal waters along the Oregon-Washington shelf are commercially valuable, yet they are also subject to growing human-related impacts. Sustainable management requires optimizing extractive, cultural, and recreational activities. The broader impacts of this research include key data for managers, commercial fisheries’ stakeholders and oyster growers that inform decisions regarding ocean-use planning and management of burrowing shrimp. This project is providing research training for three graduate students and two summer undergraduate students. Curriculum development for elementary school students is focused on the ecology of soft-bottom benthos. The ocean sandy/muddy benthos are often unknown to K-12 students on the West Coast who are usually more familiar with intertidal and kelp forest systems.Changing environmental conditions in shelf waters along the Oregon and Washington coasts and elsewhere have included increasingly frequent and severe hypoxia events, ocean acidification, and warming. These changes have affected biological communities and altered species distributions. An abundant mid-shelf population of the burrowing ghost shrimp, Neotrypaea sp. was documented in shelf waters following the Marine Heat Wave of 2015. Neotrypaea are ecosystem engineers that were previously known to be abundant in intertidal estuary mudflats with an insignificant presence in the open ocean. In estuaries Neotrypaea continuously rework the sediment via their burrowing activities. The shrimp can increase oxygen cycling due to burrow irrigation and reduce impacts of nutrient loading such as low-oxygen conditions. However, enhanced benthic oxygen consumption linked to Neotrypaea sp. beds could have the opposite effect on the shelf by intensifying regional hypoxia. This study is characterizing the environmental conditions associated with the expanded distribution of Neotrypaea using a habitat-suitability modeling approach. Model predictions are being validated through extensive field sampling via box coring and video lander observations. In addition, the benthic samples are documenting changes in the benthic invertebrate communities within the Neotrypaea beds and how this is potentially affecting biological interactions. Analyses of aquatic eddy covariance and of core incubations in shelf areas with and without abundant shrimp are providing estimates of the shrimp’s contribution to benthic oxygen fluxes and organic carbon cycling. These data are being used to quantify the shrimp’s and their burrows’ effects on the overall productivity of the mid-shelf benthos relative to reference areas. How Neotrypaea alter seafloor structure and biogeochemistry need to be characterized to predict the impact of these ecosystem engineers on the food supply for higher trophic levels and fisheries.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.