A salt marsh forms when incoming tides carry and deposit sediment across low-lying land resulting in wet mudflats. Saltwater tolerant plants take hold over time and spread, stabilizing the land somewhat through the growth of root systems. As plants decay more sediment is deposited which forms a habitat capable of supporting small organisms. Over hundreds of years, the tides create this unique place where the land meets the sea. The barrier island - Plum Island - protects this section of the marsh called The Newbury Marsh. The Merrimack, Parker and Ipswich rivers all feed into this marsh.
The Newbury Salt Marsh has four distinct zones
- the lower marsh is usually submerged under water
- the upper marsh is drier land supporting varied vegetation tolerant of salt
- the salt pans are depressions that trap and hold water during high tides and
- the highest or outer edges that are wet only during extremely high tides.
Coastal salt marshes appear to be seas of grasses or meadows, however, it is all water-logged and very unstable! The soil quickly becomes like a sponge holding water, unable to support any weight. Saltwater marshes are constantly changing landscapes. If you were to watch the deep water channels over a period of time you would see the twists and turns of the water patterns changing.
Twice a day the tides bring saltwater into the marsh. Salt-tolerant plants actually need this salt to survive as do the insects and others that live in this harsh environment. You can sometimes see white tailed deer from the nearby Parker River Wildlife Refuge licking the salt, that has crystallized on the vegetation, to supplement their dietary needs.
Invasive reeds are threatening the Newbury Marsh. These tall grasses, topped with wispy fronds, spread rapidly and choke out native plants. This impacts the entire marsh community adversely. Many species of insects, fish, shellfish, reptiles, amphibians, birds and mammals call the salt marsh home. Keeping the marsh healthy is critically important in protecting our coastline from storm damage. This fragile environment also supports our local fish and shellfish industry and provides a recreational paradise for kayaking, canoeing, hiking, boating and birding. The marsh is a globally important foraging and resting spot for migrating birds along the Atlantic flyway. The state of Massachusetts has designated this an Area Of Critical Concern (ACEC) because of its quality and uniqueness as well as the significance of the natural and cultural resources.
In order to claim this Earthcache you will need to email the answers to the following questions to the cache owner. All answers are posted at the coordinates so be specific, no internet finds please.
- Approximately how many acres does the Great Marsh cover?
- What percentage of all marine and shellfish depend on salt marshes during some part of their lives?
- Which salt marsh vegetation zone is only flooded sporadically?
- Name one thing that can destroy a salt marsh?
- Optional task: Include a photo of you and/or your GPS device taken at the coordinates with the marsh in the background. It is nice to see how the landscape changes by the season.
If you want to learn about a freshwater tidal marsh further up the Merrimack River please visit my Earthcache GC2CXME - "Merrimack Tidal Marsh".