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

LTREB：实验盐沼地块的长期变化：慢性富营养化和海平面上升的影响。

• 批准号: 0516430
• 负责人: Ivan Valiela
• 金额: --
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0516430&HistoricalAwards=false
• 关键词: LTREB; Long; term; Changes; Experimental

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.

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大西佩维塞特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，我们一直在试验施肥 4 剂量氮肥的 10 m 半径范围内绘制植被和海拔图。初步数据显示，由于富营养化和海平面上升，形态、覆盖、生物量和空间分布持续发生长期变化。在我们的 33 年研究中，由于海平面上升 12-14 厘米，在未富集的地块中，低沼泽植被的扩张以高沼泽植被为代价。相比之下，在施肥的土地上，氮供应的增加刺激了高沼泽植物的生长，这些植物的厚茅草增加了有机物的积累，有利于从洪水中捕获沉积物颗粒，从而对抗淹没。我们假设，氮供应的增加和海平面的上升改变了不同沼泽植物物种之间竞争成功的方向，并迫使长期相互作用彻底重新调整盐沼植物和依赖动物群落的空间配置和组成。对这些地块的持续研究提供了无与伦比的机会，可以了解世界范围内河口长期氮富集和海平面上升的相互作用如何重建盐沼生态系统。我们还将上传和分析这些地块过去的大量数据记录，以发布长期影响，并与其他研究人员共享。