The Great Bay estuary is located in Southeastern New Hampshire. Seven different rivers empty into the estuary, which eventually runs into the Gulf of Maine. The University of New Hampshire's Jackson Estuarine Laboratory is located on Adams Point (JEL on Map below) and the Coastal Marine Laboratory (CML) is in Newcastle, NH (CML on Map). UNH, along with Cornell University, also runs the Shoals Marine Laboratory, which is located 7 miles offshore on Appledore Island.
The estuarine habitat provides some very interesting challenges for the resident species, such as lobsters, crabs, striped bass, eelgrass and variouls bivalves. During the spring, and severe storms, freshwater runoff reduces the salinity dramatically, and these events are also associated with changes in water temperature and turbidity. Thus, estuarine organisms must be uniquely adapted to meet these environmental challenges.
The temperature in the Great Bay estuary is typically warmer than in nearby coastal waters. This is especially evident in the summer, when areas of the estuary are >10 degrees warmer. This can have a tremendous impact on the metabolism and growth of estuarine species. Interestingly, in the fall, the estuary cools more rapidly than the coastal water. This might trigger the migration of mobile species.
Freshwater runoff and snow melting contribute a great deal of freshwater to the estuary each spring. Typically, the salinity in the estuary drops to approximately 12 ppt each spring. However, the degree of runoff varies considerably from year to year and some years the salinity can drop close to zero. This will also happen during severe storms, such as hurricanes, at other time of year. While most estuarine species can tolerate moderate fluctuations in salinity, these large reductions can be lethal for many animals. Some species have adapted to this environment by migrating down the estuary to deeper, more saline areas during these events. We documented this type of behavior in lobsters during Hurricane Bob, in 1991 (Jury et al., 1995).