Collaborative Research: Toward an Improved Understanding of Blue Carbon: The Role of Seagrasses in Sequestering CO2

该项目将对控制海草草甸碳循环的因素进行定量了解，这将提高我们量化其作为蓝色（海洋）碳汇的潜力的能力，并预测其未来对气候变化的反应，包括海平面上升、海洋变暖和海洋酸化。这项研究将推动新一代生物光学地球化学模型和工具（echo）的发展，这些模型和工具有可能改变我们测量和预测浅水系统碳动态的能力。该奖项还将用于培养下一代年轻科学家，支持一名早期职业科学家、两名博士生、至少两名本科生和至少两名来自Ocean Lakes High School (Va. Beach) Math & Science Academy的实习生的研究，这些研究将在pi的联合监督下进行。所有学生将参与实验设计、实施和数据分析，并将在每年的主要国际科学会议上展示他们的研究成果，并在顶级同行评审期刊上发表他们的研究成果。PI Zimmerman与弗吉尼亚水族馆海洋科学中心保持着持续的合作，以促进该项目的教育解释和节目的发展，该项目将专门针对每年70万水族馆游客。水族馆的物理环境将被用作一个论坛，让游客与水族馆的工作人员和志愿者就更广泛的气候变化问题进行对话。齐默尔曼正在与弗吉尼亚水族馆合作，帮助设计和实施额外的教育计划、资源和展览，包括开发一个新的切萨皮克湾水箱，该水箱将容纳活海草。这个项目的成果将被纳入弗吉尼亚水族馆为期一年的青年科学家指导计划，并作为标准的教育材料，在水族馆的学校、童子军和普通观众的计划中使用。在整个项目的不同时间，pi和学生将参加弗吉尼亚水族馆的“科学演讲”系列讲座，这些讲座免费向公众开放，以帮助我们的研究与当地社区联系起来。该研究将利用最先进的方法来评估氧和碳交换（欧拉和涡动相关技术），结合生物量、沉积和水柱测量来开发和测试数值模型，这些模型可以扩大规模，量化西大西洋大陆边缘温带和热带环境中海草草甸的碳循环和封存动态，这些环境包括硅屑和碳酸盐沉积物。跨纬度和地球化学梯度的对比分析将解决不同物种和地球化学过程的相对贡献，从而更好地约束海草固碳对全球生物地球化学循环的作用。具体而言，该研究将量化：(i)具有不同生活史和结构复杂性的不同物种的C储量与直立生物量之间的关系，（ii）地上和地下代谢对碳交换的影响，以及（iii）沉积物类型（硅塑性与碳酸盐）对蓝碳储量的影响。将测量海草生物量、生长率、碳含量和同位素组成（地上和地下）、有机碳沉积和输出。为了建立一个生物光学地球化学模型，预测海草代谢对控制浅水碳循环的沉积物地球化学过程的影响，将测定PIC、POC和硫化铁沉淀物的沉积速率和同位素组成，以及溶解硫化物、二氧化碳、碱度和盐度的孔隙水浓度。模型预测将通过海草草甸DIC和O2交换的直接测量进行验证，使研究人员能够扩大密度依赖过程，以预测海草分布和密度对整个海底景观中碳循环和封存的影响。

This project will develop a quantitative understanding of the factors controlling carbon cycling in seagrass meadows that will improve our ability to quantify their potential as blue (ocean) carbon sinks and predict their future response to climate change, including sea level rise, ocean warming and ocean acidification. The research will advance a new generation of bio-optical-geochemical models and tools (ECHOES) that have the potential to be transform our ability to measure and predict carbon dynamics in shallow water systems. The award will also be used to train the next generation of young scientists by supporting the research of an early career scientist, two Ph.D. students, at least 2 undergraduate students, and at least two interns from the Ocean Lakes High School (Va. Beach) Math & Science Academy, under the combined supervision of the PIs. All students will participate in experimental design, implementation and data analysis and will present the findings of their research at major international scientific meetings each year as well as publishing their results in top-ranked peer reviewed journals. PI Zimmerman maintains an ongoing outreach collaboration with the Virginia Aquarium & Marine Science Center to facilitate the development of educational interpretation and programming from this project that will be specifically targeted to the 700,000 Aquarium visitors annually. The physical setting of the Aquarium will be used as a forum to engage the visitors in dialogue about the broader issue of climate change with Aquarium staff and volunteers. Zimmerman is collaborating with the Virginia Aquarium to help design and implement additional educational programs, resources, and exhibits including the development a new Chesapeake Bay tank that will house living seagrasses. The results from this project will be incorporated into Virginia Aquarium's year-long Mentoring Young Scientists program and as standards-based educational materials for use at the Aquarium in programs for schools, scouts and general audiences. At various times throughout project, the PIs and students will participate in the Virginia Aquarium's Speaking of Science lecture series, which are free to general public to help connect our research with the local community.The study will utilize cutting-edge methods for evaluating oxygen and carbon exchange (Eulerian and eddy covariance techniques) combined with biomass, sedimentary, and water column measurements to develop and test numerical models that can be scaled up to quantify the dynamics of carbon cycling and sequestration in seagrass meadows in temperate and tropical environments of the West Atlantic continental margin that encompass both siliciclastic and carbonate sediments. The comparative analysis across latitudinal and geochemical gradients will address the relative contributions of different species and geochemical processes to better constrain the role of seagrass carbon sequestration to global biogeochemical cycles. Specifically the research will quantify: (i) the relationship between C stocks and standing biomass for different species with different life histories and structural complexity, (ii) the influence of above- and below-ground metabolism on carbon exchange, and (iii) the influence of sediment type (siliciclastic vs. carbonate) on Blue Carbon storage. Seagrass biomass, growth rates, carbon content and isotope composition (above- and below-ground), organic carbon deposition and export will be measured. Sedimentation rates and isotopic composition of PIC, POC, and iron sulfide precipitates, as well as porewater concentrations of dissolved sulfide, CO2, alkalinity and salinity will be determined in order to develop a bio-optical-geochemical model that will predict the impact of seagrass metabolism on sediment geochemical processes that control carbon cycling in shallow waters. Model predictions will be validated against direct measurements of DIC and O2 exchange in seagrass meadows, enabling the investigators to scale-up the density-dependent processes to predict the impacts of seagrass distribution and density on carbon cycling and sequestration across the submarine landscape.