Scarborough Marsh EarthCache
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This geocache is part of the Gulf of Maine Council Geotour across Nova Scotia, New Brunswick, Maine, New Hampshire and Massachusetts. You can earn a limited edition geocoin for accumulating 100 points in the tour. Details for the geotour can be found at the GOMC website. To play, download the full geotour passport.
This EarthCache will take you on a visit to the Scarborough Marsh. At a size of 3,000 acres, and comprising 15% of the state's total salt marsh area, it is the largest tidal marsh in the state of Maine. While an undeniable attraction for visitors to this valuable eco-system is the varied and abundant wildlife, for the purposes of this earth science lesson this EarthCache will focus on the formation of salt marshes. The cache coordinates will take you to the parking lot at the Scarborough Marsh Audubon Center on Pine Point Road in Scarborough. No access to the buildings is required to fulfill the logging requirements for this cache. Parking is also permitted along the side of the road but please be careful as this can be a very busy area.
How a Tidal Marsh was formed:
Scarborough Marsh was formed over a long period of time. Because this low-lying area is sheltered to a great extent by the land masses at Pine Point and Prout's Neck, the waves, tides and currents haven't had the influence over the landscape that they have at other points along the coast. As tides have covered the protected land, sediments have been deposited and, over time, the sediments have created the ideal environment for marsh plant communities to be established. In turn, this vegetation has further retained tidal sediment, gradually increasing the marsh elevation and allowing for expansion of the tidal marsh.
TYPES of Marshes:
There are three basic types of tidal marshes in Maine: coastal/back barrier marshes, finger marshes, and fringe marshes.
- Coastal/back barrier marshes are formed behind a protective barrier such as a beach.
- Finger marshes are usually found at the head of bays
- Fringe marshes are found along protected shorelines in estuarine reaches of large rivers (coves, indentations, small tributaries, meanders) or at the toe of an eroding bluff.
By looking at a map, it can be determined which type of marsh is in question.
FEATURES of a Tidal Marsh:
(Information copied from a 1999 report by the Maine Audubon Society.)
The topography of a tidal marsh demonstrates 4 different types of surface configuration, all of which provide a variety of habitats for various species of plants and animals.
- Low marsh is flooded twice daily by tidal action. It typically occurs as a sloping fringe between the high marsh and a tidal creek or mudflat.
- High marsh is flooded irregularly by above-average tides. It is usually level and occurs between the low marsh and uplands.
- Pannes are shallow "ponds" that form within high marsh. Flooded periodically by spring tides (the monthly above-average tides associated with full moon and new moon), pannes provide an abundance of food for waterfowl and migrating shorebirds.
- Tidal creeks, open water, and tidal flats are also important components of the marsh ecosystem. Open water can be defined as a permanently flooded (i.e., below mean low water) water body greater than 100 meters (330 feet) wide. Tidal creeks are narrower, and may or may not have water at low tide. Tidal flats are nearly level to gently sloping unvegetated areas located within the intertidal zone.
In order to log this EarthCache you must first email me the responses to two questions:
- 1 - From the informational sign located behind the Audubon Center (N 43 33.949 W 70 22.463), and based on the description of the three marsh TYPES above, what type of tidal marsh (coastal back barrier, finger or fringe marsh) is Scarborough Marsh?
- 2 - What typical marsh feature (low marsh, high marsh, pannes, tidal creeks, open water or tidal flats) do you see when you cross the road directly from the Audubon Center? (N 43 33.935 W 70 22.495)
We hope you've enjoyed your visit to this interesting natural feature!
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