September 2, 2016

Cranberry bog farm to coastal wetland

Tidmarsh Farms is the largest wetland restoration in the state of Massachusetts with over 200 acres in Plymouth, MA. Once a functioning cranberry bog farm, the Living Observatory is working to restore the area back to its original state as a coastal wetland. This is no small undertaking, and will require years of careful management. Studying the site at the beginning of the restoration effort (time zero) offers some huge advantages. Scientists like, Rob Vincent at MIT Sea Grant will be able use the site to study the entire restoration process from start to finish. The post-restoration multi-year study will focus on ecosystem response over time, providing resource managers with valuable information about the use of cranberry bog restoration for improving coastal resilience and healthy coastal ecosystems. This timeline of data will increase our understanding of the restoration process and strengthen the argument for future conservation. Some of the activities that MIT Sea Grant will be involved in during the restoration include:

Monitoring greenhouse gas emissions
Rob Vincent is working with the EPA to monitor greenhouse gas emissions on the site. They selected multiple transects across the site and closed plants and soil in air-tight chambers. A portable greenhouse gas analyzer sampled gas emissions from the changers when exposed to light (which included plant and soil respiration) and covered in darkness (removing plant respiration from the equation). Gases measured included methane, carbon dioxide, nitrous oxide, oxygen, and water vapor. This is a really exciting opportunity for MIT Sea Grant to include wetland restoration in the EPA’s model of greenhouse gas emissions in coastal habitats.

Measuring carbon storage in soil and plant species changes
Rob Vincent is taking cores throughout the wetland restoration site to measure carbon storage in the soil. When this area was an active cranberry bog farm, they spread sand over the entire bog every two years in order to aerate the soil and maximize cranberry plant productivity. You can see a record of the sand applications as banded layers in the sediment cores, with dark peat at the very bottom from when this area was a natural wetland prior to cranberry operations. Rob will be measuring differences in carbon storage and rates of accumulation over time between historic natural, actively farmed, and restored wetland habitats. This information will be combined with the greenhouse gas emissions data to provide resource managers with a comprehensive analysis of the ecosystem services provided by cranberry bog restoration in terms of carbon cycling in coastal habitats and offsets to climate impacts.

Tracking PIT Tag Telemetry
Rob Vincent has partnered with the MassBays National Estuaries Program, state, and federal agencies to assess the effects of cranberry bog restoration on river herring spawning habitat. Passive integrated transponder (PIT) tags will be used to track adult river herring movement in channels throughout the restored wetland. The information will provide insight into the effectiveness of habitat restoration designs, the effects of fish passage structures on river herring spawning behavior, and the timing of herring spawning runs. The addition of sonar mapping and characterization of habitats in spawning ponds, along with stable isotope analysis to assess food web structure will provide resource managers with information about specific river herring resource preferences and the role of river herring in support of commercial and recreational fisheries. This work is funded by the MassBays National Estuary Program, under EPA Grant No. CE96173901.