For more than three decades, the impact of anthropogenic nutrient loading in coastal ecosystems has been a major concern of scientists, coastal managers, and the public. Nutrient enrichment leads to a variety of negative ecosystem consequences including increased intensity, duration, and frequency of phytoplankton blooms, hypoxic and anoxic events, increased macroalgae blooms, losses of fish and shellfish habitat, decreased benthic diversity, and loss of eelgrass beds. Remarkably, little work has been done in intertidal areas, and very few studies have addressed the effects of nutrient enrichment on the coastal landscape or how changes in biogeochemical cycles can modify the coastline by promoting erosion, accretion, and shoreline evolution. This research determines the impact of anthropogenic nutrient loading on tidal flats and salt marshes at the Plum Island LTER site, Massachusetts. State-of-the-art field and laboratory techniques work will be used. Quantitative measurements of a wide variety of field parameters will be incorporated into coupled numerical models that will be used as a tool for examining impacts to the landscape and ecosystem over longer-time scales and at different locations. Results of the work will be generalizable and widely applicable to shallow coastal landscapes anywhere in the world. Broader impacts of the work include providing important projections of coastal erosion and wetland assessments to land managers, integration of research and education, training of significant numbers of undergraduates and a postdoc, and support of an early career researcher.
This project addressed an urgent environmental issue – What are the effects of increased nutrients on coastal landscapes and how does this affect the ecosystem services they provide? The last decade has seen a growing appreciation for the enormous benefits that humans gain from coastal habitats, including buffering from hurricanes and storms and provision of fisheries. This project is the first to test the degree to which saltmarshes can buffer adjacent aquatic ecosystems from eutrophication by experimentally determining how much water borne nutrients salt marshes can process and how this changes over time. This work suggests that current nutrient loading rates to many coastal ecosystems have overwhelmed the capacity of marshes to remove nitrogen without deleterious effects. In a long-term, experimental nutrient enrichment experiment alterations in key ecosystem properties reduced geomorphic stability resulting in creek-bank collapse with significant areas of creek bank marsh converted to unvegetated mud. This pattern of marsh loss parallels observations for anthropogenically nutrient-enriched marshes worldwide, with creek and bay edge marsh evolving into mudflats and wider creeks. Drowning of high marsh due to sea-level rise and loss of creek channel edge marsh due to eutrophication, especially when exacerbated by upland development that limits the ability of marshes to move inland, may lead to a coastal landscape with a dramatically reduced capacity to provide important ecological and economic services. Normal 0 false false false EN-US X-NONE X-NONE
