Project Title: Evaluating the Impact of Hydrologic Alterations on Salt Marsh Sustainability in a Changing Climate
Project Partners: Cape Cod Mosquito Control Project, Louisiana State University, National Park Service, United States Fish and Wildlife Service, Rachel Carson National Wildlife Refuge, United States Geologic Survey, Waquoit Bay National Estuarine Research Reserve, Woods Hole Oceanographic Institution
Coastal managers are faced with the challenge of managing marsh hydrology in a way that meets human health needs, optimizes ecosystem services, and supports sustainability. In New England this includes accounting for the effects of ditches that were dug decades ago in 90% of the region’s salt marshes.
Ditches increase marsh drainage and reduce the spatial extent of shallow pools that may represent physical loss of buried soil carbon. However, efficient drainage may reduce the long-term sustainability of marshes by altering below ground biogeochemical and physical processes in a way that results in subsidence and lowered marsh elevation. Managers, restoration practitioners, and scientists at the Waquoit Bay National Estuarine Research Reserve, Woods Hole Oceanographic Institution, U.S. Geological Survey, U.S. Fish and Wildlife Service, National Park Service, and the Cape Cod Mosquito Control Project have expressed a need to understand the tradeoffs of hydrologic management strategies (i.e., ditch remediation, density, maintenance) and identify actions that will achieve user-specified outcomes— such as drainage, maintaining elevation, and carbon burial.
This project is a collaboration between scientists and end users to develop decision-support tools for marsh hydrological management strategies that promote sustainability and delivery of valuable ecosystem services under future sea level scenarios.
PI: Chris Maio, UMASS-Boston, PhD Candidate.
Advisor: Allan Gontz, UMASS-Boston
Funding: UMASS-Boston, Geological Society of America Research Award, collaborative in-kind-WBNERR
My research looks at coastal changes that have occurred in response to sea-level rise and storminess during the past 4000 years. I use a variety of methods including sediment core analysis, ground penetrating radar, GIS, and radiocarbon dating. Learning about how the Waquoit estuarine system responded to past sea level-rise and storminess will provide needed context for understanding and anticipating future changes.
An ancient red cedar forest was first revealed after a series of storms in 2010 resulted in significant erosion along South Cape Beach revealing 111 subfossil stumps along the beach and into the water. Thirteen stumps were radiocarbon dated and ranged in age from ~413-1200 years old. We assume this age represents the time at which the ancient trees were drowned by marine waters. Shoreline change analysis showed that between 1846 and 2008, the shoreline fronting the paleoforest retreated landward by 70 m at a long-term rate of 0.43 m/yr.
Sediment cores were analyzed to determine storm and sea level history. Radiocarbon dates of bivalve microfossils indicate that Waquoit Bay was first inundated by marine waters approximately 3600 years ago. The ongoing research will help decipher the relationship between sea-level rise, storminess, and the inundation of terrestrial ecosystems and will help to illuminate what caused the drowning of the South Cape Beach paleoforest.