LTREB: Long-term Changes in Experimental Salt Marsh Plots: Effects of Chronic Eutrophication and Sea Level Rise.

氮富集和海平面上升是沿海生态系统包括盐沼生态变化的主要和加剧因素。我们建议在马萨诸塞州东部的大Sippewissett沼泽的实验区内定义慢性富营养化和海平面上升的长期影响和相互作用。自1970年以来，我们一直在绘制植被和海拔半径10米的地块实验施肥与4剂量的氮。初步数据显示，由于富营养化和海平面上升，在形态、覆盖、生物量和空间分布方面继续发生长期变化。在非富集地块低沼泽植被扩大的代价高沼泽植被响应12-14厘米的海平面上升，在我们的研究的33年。在施肥的地块，相反，增加氮供应刺激高沼泽植物的生长，其厚厚的茅草增加有机质的积累和有利于捕获的沉积物颗粒从洪水，从而对抗淹没。我们假设，增加氮供应和海平面上升改变不同种类的沼泽植物之间的竞争成功的方向，并迫使长期的相互作用，彻底重新洗牌的空间配置和组成的盐沼植物和依赖的动物群落。对这些地块的持续研究提供了一个无与伦比的机会，以了解世界各地河口的慢性氮富集和海平面上升的相互作用将如何重组盐沼生态系统。我们还将上传和分析这些地块过去的大量数据记录，以公布长期影响，并与其他研究人员分享。

Nitrogen enrichment and sea-level rise are major and intensifying agents of ecological change in coastal ecosystems, including salt marshes. We propose to define long-term effects and interactions of chronic eutrophication and sea-level rise within experimental plots in the Great Sippewissett marsh in Eastern Massachusetts. Since 1970, we have been mapping vegetation and elevation within 10 m radius plots experimentally fertilized with 4 dosages of nitrogen. Preliminary data show continuing long-term shifts in form, cover, biomass and spatial distribution due to both eutrophication and sea-level rise. In un-enriched plots low marsh vegetation expanded at the expense of high marsh vegetation in response to the 12-14 cm sea-level rise during the 33 years of our studies. In fertilized plots, in contrast, increased nitrogen supply stimulated growth of high marsh plants whose thick thatch increased organic matter accumulation and favored capture of sediment particles from flooding water, thus countering submergence. We hypothesize that increased nitrogen supply and rising sea-level alter direction of competitive success among different species of marsh plants, and force long-term interactions that thoroughly reshuffle spatial disposition and composition of swards of salt marsh plants, and dependent animal communities. Continuing study of these plots offers an unmatched opportunity to understand how the interaction of chronic nitrogen enrichment and increased sea-level rise that is occurring in estuaries world-wide will restructure salt marsh ecosystems. We will also upload and analyze the extensive past data record for these plots for publication of long-term impacts, and sharing with the other researchers.