Catherine Johnston ’12 (Bowdoin) – Ecological and Economic Recovery of the Kennebec and Androscoggin River, Estuary, and Nearshore Marine Environment

Merrymeeting Bay is a freshwater tidal ecosystem located in midcoast Maine that receives water from six Maine rivers. Merrymeeting Bay and the Lower Kennebec River support a diverse food web that is important from both an ecological and economic perspective. The ability of Merrymeeting Bay to support anadramous fish, migratory waterfowl, and many other species has been greatly jeopardized by human activities in the last two centuries. The ecosystem is recovering and our research this summer was aimed at developing an understanding of the current state of the ecosystem. We were interested in assessing what is going on with respect to important aspects of the ecosystem; we focused on populations of vegetation, macroinvertebrates, and fish present in the bay and Lower Kennebec.

Submerged aquatic vegetation is a key component of the Merrymeeting Bay ecosystem. Freshwater species such as Tape Grass (Vallisneria Americana) and Pondweed (Potamogeton perfoliatus) are found in the bay and Lower Kennebec while Eel Grass (Zostera marina) is a marine species found around the mouth of the Kennebec River. The presence of these plants promotes the health of the ecosystem in a number of ways – from providing habitat for juvenile fish and trapping fine sediment to increasing dissolved oxygen levels and decreasing water flow. This summer we surveyed submerged aquatic vegetation in Merrymeeting Bay and the Lower Kennebec and we used a number of tools to study both the freshwater and marine species present in the ecosystem. Underwater video cameras provided visuals of what is present below the surface and what organisms make use of vegetation as a habitat and food source. GPS units allowed us to locate and document beds of vegetation and we eventually created a map illustrating the distribution and density of vegetation beds found around Merrymeeting Bay. In time, we hope that vegetation in the ecosystem will increase, and the map of vegetation we generated this summer can help determine the extent of future plant growth.

The yellow polygons on the map indicate beds of Tape Grass and Pondweed. We used a Trimble XM GPS unit and the program ArcGIS to generate a map of vegetation found in a segment of the Lower Kennebec River from the Chops to Bath. Polygons representing beds of vegetation were created in the GPS unit by walking around the perimeter of a bed while the Trimble traced the edge.

Faculty Mentor: John Lichter

Funded by the Sustainability Solutions Partners



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