RUI: Changes in Baseline Conditions in Gulf of Maine Coastal Ecosystems Over the Last 4000 Years

预测海洋生态系统对自然和人为扰动的反应仍然是海洋学面临的最大挑战之一。为了评估这些系统当前变化的重要性，并预测未来可能发生的变化，海洋学家需要了解生态系统的生态历史。这项研究的目的是为西北大西洋边缘陆架盆地缅因湾（GoM）创建长期记录。目前对墨西哥湾生态系统恢复能力的认识主要基于过去70多年的研究。在这个项目中，研究人员将通过分析保存在现代和古代海洋生物组织中的稳定碳(C)、氮(N)和硫(S)同位素，来了解墨西哥湾延伸至4000年前的生态系统过程，以评估近岸初级生产、营养连通性和食物网动态的长期趋势。研究人员将采用现场、分析和建模技术相结合的方法：(1)确定海草、微藻和巨藻的有机物目前转移到沿海食物网的空间尺度；(2)确定过去4000年来墨西哥湾生物间近岸初级生产和营养连系变化的时间、幅度和空间范围。组织样本将从不同的沿海环境、博物馆收藏和墨西哥湾的三个沿海考古遗址中获得。主要生产者和消费者的大块有机组分将在贝茨学院和南丹麦大学进行C和N同位素分析和S同位素分析。将测量必需氨基酸（如苯丙氨酸）的C同位素组成，从而确定食物网底部的碳源。近岸食物网相互作用将通过使用C、N和S同位素数据和非稳态方程来建模，其中包括消费者猎物选择中依赖竞争的变化。该项目的更广泛影响包括：提供记录墨西哥湾沿岸系统弹性的长期数据集，这将有助于为墨西哥湾制定更好的资源管理战略，与丹麦同事开展国际合作，并为本科生提供支持。贝茨学院是一所本科文理学院，致力于支持学生的研究。除了论文项目外，学生还将协助建立和维护关系数据库和互动网站，以传播和管理从项目中产生的数据。

Predicting the responses of marine ecosystems to natural and anthropogenic perturbation remains one of the greatest challenges to oceanography. In order to assess the significance of current changes in these systems and to predict possible future changes, oceanographers need to understand the ecological history of the ecosystem. The aim of this study is to create long-term records for the Gulf of Maine (GoM), a marginal shelf basin in the northwest Atlantic. Current knowledge of the resilience of the GoM ecosystem is based largely on studies focused on the last 70+ years. In this project, investigators will develop an understanding of ecosystem processes in the GoM extending back 4000 years by analyzing stable carbon (C), nitrogen (N) and sulfur (S) isotopes preserved in tissues of modern and ancient marine organisms to assess long-term trends in nearshore primary production, trophic connectivity, and food web dynamics.The investigators will employ a combination of field, analytical, and modeling techniques to: (1) determine the spatial scale over which organic matter derived from seagrasses, microalgae, and macroalgae is currently transferred into coastal food webs, and (2) determine the timing, magnitude, and spatial extent of changes in nearshore primary production and trophic connectivity among organisms living in the GoM through the last 4000 years. Tissue samples will be obtained from different coastal settings, museum collections, and three coastal archaeological sites in the GoM. The bulk organic fractions of primary producers and consumers will be analyzed for C and N isotopes at Bates College and S isotopes at the University of Southern Denmark. The C isotope composition of essential amino acids (e.g., phenylalanine) will be measured, allowing for determination of the carbon source at the base of the food web. Nearshore food web interactions will be modeled by using the C, N and S isotope data and non-steady state equations that include competition-dependant changes in the consumers prey choice.The Broader Impacts of the project include: providing long-term datasets documenting the resiliency in the GoM coastal system which will enable development of better resource management strategies for the GoM, an international collaboration with Danish colleagues, and support for undergraduate students. Bates College is an undergraduate liberal arts institution with a strong commitment to supporting student research. In addition to thesis projects, students will assist with building and maintaining a relational database and interactive website to disseminate and manage the data generated from the project.