PARENT SESSION
Oral Session #23: Aquatic Ecology: Salt marshes, estuaries, ephemeral wetlands.
Presiding: D. Childers
Monday, August 5. 1:00 PM to 3:45 PM. Palo Verde Room, Radisson.
Groundwater, location and water quality of New England salt marsh pools.
Bohlen, Curtis*,1, Blacken, Renee1, Breen, Brandon1, 1 Bates College, Lewiston, Maine
ABSTRACT- Shallow pools, often known as "pannes", are a characteristic microenvironment of New England Salt Marshes. They provide habitat for a variety of fishes and invertebrates, while providing feeding opportunities for birds, including waterfowl and waders. Over the last several decades, production and restoration of these pools has become a significant focus of salt marsh restoration throughout New England. Yet little is known about what drives the considerable variation in condition among these pools. We mapped all surface water features in the Sprague River Marsh, in Phippsburg, Maine and collected synoptic water quality information (pH, salinity, oxidation -reduction potential, temperature and dissolved oxygen) from most of the over 500 pools on the site at least once during the 2001 growing season. We collected more detailed water quality data on a subset of 40 of the pools. We also monitored selected groups of pools to examine temporal patterns of change in pool condition. Information on groundwater and surface water elevations taken at selected locations throughout the marsh provided hydrologic information to help interpret water quality results. Annual, monthly, diurnal, and spatial patterns in water quality were found. Annual, lunar, and diurnal changes in pool condition reflect patterns in solar radiation, tidal inundation, and groundwater hydrology. Pools with low dissolved oxygen and oxidation-reduction potentials (which often support characteristic sulfur bacteria) tend to be close to adjacent uplands. We suggest that the influence of groundwater on surface water habitats of New England Salt Marshes has been underappreciated.
KEY WORDS: salt marshes, hydrology, water quality, spatial patterns