LTREB Renewal: Long Term Studies of Salt Marsh Primary Production

盐沼是地球上最具生产力的环境之一，它们被高度重视，因为它们为许多具有商业重要性的物种提供食物和苗圃栖息地，它们改善水质，它们缓冲建筑物和其他基础设施免受沿海风暴的影响，它们为野生动物创造新的土地和栖息地。该项目建立在对南卡罗来纳州北湾河口盐沼绳草生产力的数十年研究的基础上，这些研究对沼泽生产力的调节和维持盐沼与海平面平衡的反馈产生了新的见解。 这项研究很重要，因为海平面正在加速上升，并有可能淹没这些生态系统。 该项目将采用实验和实地观察相结合的方法，以了解随着海平面上升，草根生长的增加如何影响沼泽表面的海拔。 肥料添加将用于增加根系生长，并测试这将使沼泽表面上升的假设。 这些模拟沼泽海拔变化的操作将提供一个相对海拔如何影响植物生长的直接测试。这项研究将进一步发展的一个重要的管理工具，沼泽平衡模型，为沿海资源managers.LTREB研究在北Inlet. LTREB包括每月测量永久地块的干计数和高度的沼泽线草（互花米草）自1984年以来，每月测量孔隙水化学，蜗牛密度和沼泽表面高程的补充。 这些数据的综合导致了沼泽平衡理论和沼泽平衡模型的发展，描述了植物、营养物质、潮汐洪水和沉积物之间的反馈如何使沼泽与海平面达到平衡。 在接下来的五年里，该项目将继续发展理论，继续收集原始数据，并进行实验操作，以测试植物根系和营养物质对沼泽海拔的重要性。 据推测，养分的添加将增加根系的生长，从而提高平衡沼泽海拔。 恢复氮和磷的治疗领域的阴谋，与之前和之后的沉积物芯的计算机断层扫描，再加上沼泽表面高程的测量，将测试的影响，营养物质的相对重要性，地下生产和沉积物截留垂直加积。 使用沼泽器官的生物测定实验将直接检验生产力-海拔假设，并将与实地观察平行进行。该项目通过向民间团体介绍海平面上升和沼泽地问题、与决策者进行讨论以及参加政策论坛，对公众产生了更广泛的影响。将支持研究生培训和访问学者使用北湾盐沼的长期施肥和普查地块。

Salt marshes are among the most productive environments on earth and they are highly valued because they provide food and nursery habitat for numerous species of commercial importance, they improve water quality, they buffer buildings and other infrastructure against coastal storms, and they create new land and habitat for wildlife. This project builds on decades of research in North Inlet estuary in South Carolina on the productivity of salt marsh cord grass that have led to new insights about the regulation of marsh productivity and the feedbacks that maintain salt marshes in equilibrium with sea level. This research is important because sea level is rising at an accelerating rate and threatens to drown these ecosystems. This project will employ a combination of experiments and field observations to understand how increasing cord grass root growth impacts the elevation of the marsh surface as sea level rises. Fertilizer additions will be used to increase root growth and test the hypothesis that this will allow the marsh surface to rise. These manipulations to simulate changing marsh elevations will provide a direct test of how relative elevation affects plant growth. This research will further development of an important management tool, the Marsh Equilibrium Model, for coastal resource managers.LTREB research at North Inlet has included monthly measurements on permanent plots of stem counts and heights of marsh cord grass (Spartina alterniflora) made since 1984 and supplemented by monthly measurements of porewater chemistry, snail density, and marsh surface elevation. A synthesis of these data has led to the development of a marsh equilibrium theory and the Marsh Equilibrium Model describing how feedbacks among plants, nutrients, tidal flooding, and sediments move a marsh toward an equilibrium with sea level. During the next five years this project will continue development of theory, continue collection of primary data, and conduct experimental manipulations to test the importance of plant roots and nutrients on marsh elevation. It is hypothesized that nutrient additions will increase the growth of roots and thereby raise the equilibrium marsh elevation. A resumption of nitrogen and phosphorus treatments in field plots, with before and after computed tomography scans of sediment cores, coupled with measurements of marsh surface elevation will test the effects of nutrients on the relative importance of belowground production and sediment trapping to vertical accretion. Bioassay experiments using marsh organs will directly test the productivity-elevation hypothesis and will be conducted in parallel with the field observations. The broader impacts of this project extend to the public through talks given about sea level rise and marshes to civic groups, discussions with policy makers, and participation in policy forums. Graduate student training and use of the long-term fertilization and census plots in the salt marsh at North Inlet by visiting scholars will be supported.