Ecological Transitions in the California Current Ecosystem: CCE-LTER Phase II

加州海流生态系统（CCE）LTER站点是由远程和本地物理强迫以及海洋水柱中的生物相互作用构成的多产沿海上升流生物群落。CCE网站建立在CalCOFI 60年来广泛的时间序列测量的基础上，旨在了解该生态系统不同状态之间的过渡机制，以及它们的必然结果：生态系统恢复力。在CCE资助的第一阶段，该站点的调查人员发现了北太平洋（NPGO）的一种新气候模式;发现离岸风应力旋度和经典的沿海边界上升流域之间的食物网结构存在显着差异;检测到凝胶状食草动物的长期变化。（远洋被囊动物）、光学特性、硝态氮深度、缺氧的普遍性、分层和其他生态系统特征;揭示了铁和铁-光共同限制初级生产的区域;开发了ROMS模型，并将其用于后报模式，以诊断生态系统转变的因果关系，并将其用于预测模式，以指导拉格朗日过程巡航;开发了食物网建模的异速生长方法;发现了物理和生物时间序列在非线性程度上的差异;展示了捕鱼的破坏性影响;开创了新的数据实践;等等。从这第一次的努力点的空间结构的CCE，特别是在中尺度的重要性的调查结果。 在这次更新中，LTER调查人员的目标是中尺度锋面和涡旋，这是CCE生态扰动制度的重要组成部分。CCE研究人员发现，这些特征在CCE地区的年际和十年尺度上有所不同，他们假设它们随时间的变化可能有助于生态系统的转变。该项目将继续在CCE LTER进行研究。在下一阶段的研究中提出的首要问题是：导致沿海中上层生态系统不同状态的机制是什么？变化中的海洋气候、群落结构和生态系统动态之间的相互作用是什么？为了解决这些问题，研究人员建议研究4种可能有助于生态系统转变的机制：异常沿岸平流;响应分层和营养供应的原位食物网变化;跨海岸运输的变化;以及改变捕食压力。他们还将测试与中尺度过程的作用有关的3个假设，特别是关于它们在改变营养通量和捕食者-被捕食者相互作用中的作用，CCE区域中尺度锋面和涡旋的综合地球化学效应以及这些特征与更大尺度气候变率的关系。拉格朗日过程巡航、实验工作、时间序列测量、建模、数据合成和人与自然系统耦合研究的结合将用于解决这些问题。更广泛的影响：在加州南部沿海海洋提供的生态系统服务中值得注意的是该地区？这对于许多具有重要商业价值的鱼类和海洋无脊椎动物的产卵和/或收获具有重要意义。这项研究将为了解与基于生态系统的渔业管理有关的特性的时间和空间变异性提供关键的科学基础。这一信息是必不可少的，因为管理者开始处理不断变化的海洋酸度，分层和缺氧的后果，资源种群和社区。ISSE（社会与环境综合科学）研究将与经济学家，研究生和科学家合作开发生物经济模型，以研究生态系统变异性和渔民之间的相互作用？决策和资源分配。此外，CCE调查员将进一步开发和增强DataZoo，这是我们信息管理和数据共享环境的核心信息系统。他们将实施新的网络访问工具，以促进数据可视化和向学生，各级教师，科学家，管理人员，政策制定者和更广泛的公众传达CCE结果。教育，推广和能力建设（EOCB）计划将包括一个积极的计划，数十名研究生参与现场科学和通信。一名研究生将担任EOCB协调员的研究联络员，帮助将CCE科学转化为K-12课程计划。CCE LTER将与多元化城市学区的当地教师合作，将CCE科学带入课堂，并将继续与非营利海洋研究所开展外联和沿海海洋时间序列活动。这个LTER网站将扩展他们成功的RET和海上教师计划，使教师能够直接向学生传达科学探究的过程。他们的REU计划将继续针对代表性不足的本科生，以扩大海洋科学的管道。

The California Current Ecosystem (CCE) LTER site is a productive coastal upwelling biome structured by remote and local physical forcing, as well as biotic interactions in the ocean water column. The CCE site, building upon 60 years of extensive time-series measurements by CalCOFI, seeks to understand the mechanisms underlying transitions between different states of this ecosystem, as well as their corollary: ecosystem resilience. In the first phase of CCE funding investigators at this site uncovered a new climate mode for the North Pacific (NPGO); found marked differences in food web structure between the offshore wind stress curl and the classical coastal boundary upwelling domains; detected long-term changes in gelatinous grazers (pelagic tunicates), optical properties, nitracline depths, prevalence of hypoxia, stratification, and other ecosystem characteristics; revealed zones of iron and iron-light co-limitation of primary production; developed a ROMS model and used it in hindcast mode to diagnose causality of ecosystem transitions and forecast mode to guide Lagrangian process cruises; developed an allometric approach to food web modeling; discovered differences between physical and biotic time series in degree of nonlinearities; demonstrated the destabilizing effects of fishing; initiated new data practices; and more. Findings from this first effort point to the importance of spatial structuring of the CCE, especially on the mesoscale. In this renewal the LTER investigators target mesoscale fronts and eddies, which constitute an important part of the CCE ecological disturbance regime. CCE Investigators have found that such features vary on interannual and decadal scales in the CCE region and they hypothesize that their variability over time may contribute to ecosystem transitions. This project will continue studies at the CCE LTER. The overarching questions posed in this next phase of the study are: What are the mechanisms leading to different states in a coastal pelagic ecosystem? What is the interplay between changing ocean climate, community structure and ecosystem dynamics? To address these questions, the investigators propose to examine 4 mechanisms that could contribute to ecosystem transitions: anomalous alongshore advection; in situ food web changes in response to stratification and nutrient supply; changes in cross-shore transport; and altered predation pressure. They will also test 3 hypotheses related to the role of mesoscale processes, specifically concerning their role in altering nutrient fluxes and predator-prey interactions, the integrated biogeochemical effects of mesoscale fronts and eddies over the CCE region and the relationship of such features to larger scale climate variability. A combination of Lagrangian process cruises, experimental work, time series measurements, modeling, data synthesis, and a coupled human-natural system study will be used to address these questions. The project will also continue to measure the 5 LTER core variables.Broader Impacts: Notable among the ecosystem services furnished by the coastal ocean off southern California is the region?s importance for spawning and/or harvesting of many commercially important fishes and marine invertebrates. This research will provide a key scientific foundation for understanding time and space variability of properties relevant to ecosystem-based fisheries management. This information is essential as managers begin to address the consequences of changing ocean acidity, stratification, and hypoxia for resource populations and communities. ISSE (Integrated Science for Society and the Environment) studies will partner an economist, graduate student, and scientists in the development of a bioeconomic model to examine the interplay between ecosystem variability and fishers? decision-making and resource allocation. In addition, the CCE Investigators will further develop and enhance DataZoo, the information system central to our Information Management and data sharing environment. They will implement new web-accessible tools to facilitate data visualization and communication of CCE results to students, teachers across all levels, scientists, managers, policy-makers, and the broader public. An Education, Outreach, and Capacity Building (EOCB) program will include a vigorous program of involvement of tens of graduate students in site science and communication. A graduate student will serve as a research liaison with the EOCB coordinator, to help translate CCE science into K-12 lesson plans. CCE LTER will work with local teachers in a diverse urban school district to bring CCE science into the classroom, and will continue outreach and coastal ocean time series activities with the nonprofit Ocean Institute. This LTER site will expand their successful RET and Teacher-at-Sea programs, to enable teachers to communicate the process of science inquiry directly to students. Their REU program will continue targeting under-represented undergraduates to expand the pipeline into the ocean sciences.