Date of Graduation

Spring 5-2011

Level of Access

Open Access

Degree Name

Bachelor of Arts

Department or Program

Geology

Abstract

Many of the marshes in New England currently have a network of small, hand-dug ditches (put into place by the first European settlers 300+ years ago). Ditches drain the marsh during the tidal cycle. In an effort to restore these ditched marshes and increase the pool habitat, U.S. Fish and Wildlife Service has plugged eleven ditches in the southern end of the marsh beginning in the early 2000s. Few studies have been done to monitor the changes after restoration. The purpose of this research is to study the biogeochemical cycling of ditchplug and natural pools in the Sprague River Marsh in Phippsburg, ME. In the summer of 2010 mummichogs (Fundulus heteroclitus), surface sediment, vegetation, biomass cores, and other marine organisms were collected for stable isotope analysis. General water quality parameters were also monitored along with the collection of nutrient data (NO3-, PO4, and NH4). Extraction of 2007 LIDAR data was used to observe changes in elevation across the marsh in hopes to show shifts in surface vegetation cover. Results suggested enrichment in13C in the muscle tissue from the mummichogs collected in the ditchplugged pools. These trends were likely due to differences in vegetation type between the natural and ditchplugged areas of the marsh. These vegetation differences were thought to be driven by differences in elevation, salinity, and hydroperiod between the two study areas. The POM in the ditchplug area was also enriched in 13C relative to the natural pools. This was thought to be from different carbon sources or increased rates of primary production in the ditchplug pools relative to the natural pools. Further work is needed to understand carbon sourcing in the two systems in order to gain a better understanding of the biogeochemical cycling.

Open Access

Available to all.

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