Journey Through Intertidal Freshwater Marshes In The Merrymeeting Bay Area (Bowdoinham, Dresden, Richmond and Brunswick Maine)
Robert Zottoli
Professor Emeritus
Fitchburg University
Fitchburg Massachusetts
General:
Merrymeeting Bay is an extensive tidal freshwater ecosystem formed by the merger of five rivers. The Androscoggin and Kennebec rivers are the largest. Tidal seawater moves along the bottom into the bay with the incoming tide and mixes with seaward flowing freshwater. The salinity of bay water seldom exceeds 5 parts per thousand. Ocean seawater has a salinity of about 35 parts per thousand. Because of the low salinity Merrymeeting Bay is classified as a tidal freshwater ecosystem.
Beginning at the end of April, Merrymeeting Bay undergoes an amazing transformation. Varieties of plants emerge from the seemingly lifeless mud surface forming extensive marshes. In September, the marsh disappears. The above-ground parts of marsh plants die back and are partially digested by bacteria eventually reducing them to small pieces (detritus) that can be trapped on the mud surface or flushed out to sea providing food to organisms on the sea floor. In the late fall all that remains are plant stems protruding just above the sediment surface.
The emergent seasonal vegetation provides food for large populations of small herbivorous fishes such as the common mummichog, Fundulus heteroclitus and migrating waterfowl as well as habitat for a variety of invertebrates and small fish. Fundulus on the other hand is consumed by fish-eating waterfowl and larger fish such as the striped bass. Nutrients in the bay support large populations of phytoplankton and zooplankton eaten by certain plankton feeding juvenile and adult fish (Alewives, Blueback Herring and Shad). Sturgeon feed for the most part on invertebrates living on or in the sediment.
For the past several years I have documented the distribution of common plants in several freshwater tidal marshes in Merrymeeting Bay and at Baybridge Landing in Brunswick Maine. The WordPress program was created to provide a field experience for those unable to reach the shoreline or those who would like to check typical tidal freshwater marsh species before going into the field. Please let me know if the program meets your needs. It would also be helpful if you could make suggestions on how to improve the program. Send comments to me at: rzottoli@roadrunner.com.
Materials and Methods:
A transect line was established from the low tide line to the landward marsh edge in an area located west of the public boat launching area in Baybridge Park, Topsham Maine. to record the distribution of common marsh plants. Species that were found 0.5 meters on either side of the line were identified using references listed below. A series of seven distinct zones were found. Zone 1 encompasses the bare mud surface from the low tide line to the beginning of the marsh. Zone 2 extends from the beginning of the marsh landward and is characterized by Pickerel Weed, Soft-stemmed Bulrush and Bur Marigold. Zone 3 is dominated by Wild Rice, Marsh Pepper,Knotweed and Pennsylvania Smartweed while Zone 4 is characterized by Big-Leaved Arrowhead and Sweet Flag. American Bur-Reed and Water Parsnip are the most abundant plants in Zone 5 while Zone 6 can be recognized by the presence of the Common Three Square sedge, Water Plantain, Wild Mint and Water Horehound. Zone 7 is populated for the most part by essentially terrestrial species (Refer to that section).
Plant distributions are not necessarily the same from place to place so that the zones described here may not be identical to those at other sites.
The following Wordpress sites, authored by Zottoli, provide a glimpse of some of the microscopic forms commonly found in Freshwater Tidal Marshes:
1.FreshwaterTidal Marshes In Mid Coast Maine Series1: Guide to Common Protozoans in Mid to Upper Intertidal Sediments at two sites in Merrymeeting Bay and one site in the Lower Reaches of the Androscoggin River
It includes descriptions, photographs and movies of common protozoans and can be accessed at:
https://protozoansintertidal.wordpress.com/
2. Freshwater Tidal Marshes In Coastal Maine Series 2: Guide To Rotifers In: https://rotifersintertidal.wordpress.com/
The web program was created to provide a field experience for those unable to reach the shoreline or for those who would like to review typical tidal freshwater marsh species before going into the field. Please let me know if the program meets your needs. It would also be helpful if you could make uggestions on how to improve the program. Send comments to me at: rzottoli@roadrunner.com
Digital photographs accompany brief written descriptions of selected plants as well as a few of their culinary and medicinal uses. Finally, some of the adaptive features that help a select few of the species to survive or thrive in the marsh are briefly mentioned.
Digital images were taken at different times throughout the seasons by Robert Zottoli. Most of the photographs were snapped with Nikon digital cameras (D800, D300 or D70 SLR), all equipped with a 60 mm AF Micro Nikkor 1:2.8 D lens. The majority of images were enhanced and reduced in size within Adobe Photoshop CS6. The website was constructed using Dreamweaver CS6 and then transferred to the WordPress program. Digital images provided on this web site may be reproduced for non-commercial, personal, educational or scientific purposes only. Copying or redistribution in any way for personal or corporate gain is not allowed without written permission from Robert Zottoli (rzottoli@roadrunner.com). Use the following format to identify pictures and give credit to photographer Robert Zottoli: https://zottoli2.wordpress.com.
Journey Through Intertidal Freshwater Marshes In The Merrymeeting Bay Area (Bowdoinham, Dresden, Richmond and Brunswick Maine) 
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