The Plum Island Ecosystems (PIE) LTER (Long Term Ecological Research) site is developing a predictive understanding of the response of a linked watershed-marsh-estuarine system in northeastern Massachusetts to rapid environmental change. Over the last 30 years, surface sea water temperatures in the adjacent Gulf of Maine have risen at 3 times the global average, rates of sea-level rise have accelerated, and precipitation has increased. Coupled with these changes in climate and sea level are substantial changes within the rapidly urbanizing watersheds that influence water, sediment, and nutrient delivery to the marsh and estuary. In PIE IV the research focus is on: Dynamics of coastal ecosystems in a region of rapid climate change, sea-level rise, and human impacts. This work will advance our understanding of how the structure and function of coastal ecosystems will be altered over the next several decades and beyond. Because of their position at the land-sea interface, coastal ecosystems are particularly threatened by human activities in watersheds and to sea-level rise. PIE research will address both fundamental ecological questions as well as provide critical information on how to manage these systems. For example, it will help us understand how species changes in a complex interaction network result in changes to the abundance of key species, food web structure, and energy flow. PIE research will also improve our understanding of the importance of the coastal zone to regional and global carbon and nitrogen budgets and advance our ability to model biogeochemistry at the ecosystem scale in a spatially explicit framework. Finally, it will provide a greater mechanistic understanding of biogeomorphic feedbacks that will be essential in future conservation efforts. The investigators will continue their award winning Schoolyard program, "Salt Marsh Science", which serves over 1,000 students in grades 5-12 in ten schools each year. In collaboration with the Gulf of Maine Institute PIE LTER is developing a new initiative with local Middlesex Community College. By providing flexible paid internships with academic credit, PIE will be able to reach students from economically and ethnically diverse backgrounds who might not otherwise consider STEM careers. Outreach is important to PIE scientists. Activities include scientific collaborations outside PIE and with local, state and federal agencies, involvement in the Marine Biological Laboratory science journalism program, and partnership with Mass Coastal Zone Management in conducting marsh elevation surveys. PIE scientists currently serve on panels or advisory groups for US Environmental Protection Agency (EPA), National Oceanic and Atmospheric Administration (NOAA), United States Fish and Wildlife Service (USFWS), and many state and local agencies. All data collected by the PIE LTER are centralized and made available to the public through a web site http://pie-lter.ecosystems.mbl.edu/.
Researchers at PIE will test how internal feedbacks within the marsh-estuary ecosystem influence the response of geomorphology, biogeochemistry, and food webs to three major drivers: climate, sea-level rise, and human alteration of the watershed. They anticipate large changes in the geomorphology of the marsh and estuary over the next several decades. They hypothesize that major feedbacks are exerted through sediment dynamics, changes in hydrology, alterations of carbon and nitrogen cycles, species interactions, and species introduction or loss due to warming. Positive biogeomorphic feedbacks within the marsh ecosystem will likely contribute to marsh persistence while sea level rises, but they hypothesize that PIE is moving from a predominantly high-elevation marsh to a lower elevation marsh, with less overall wetland, more open water, and more marsh edge. These changes will greatly impact estuarine biogeochemistry, primary production, and community dynamics. PIE IV will address three questions: Q1) How will the geomorphic configuration of the marsh and estuary be altered by changes in the watershed, sea-level rise, climate change, and feedbacks internal to the coastal system?; Q2) How will changing climate, watershed inputs, and marsh geomorphology interact to alter marsh and estuarine primary production, organic matter storage, and nutrient cycling?; and Q3) How will key consumer dynamics and estuarine food webs be reshaped by changing environmental drivers, marsh-estuarine geomorphology and biogeochemistry? Cross-system comparisons with other LTERs along gradients of temperature, species composition, tidal range, and sediment supply will further our understanding of long-term change in coastal ecosystems.
