Learning About Salt Marshes


I have spent much of my life visiting a house on Cape Cod that is on a salt marsh. I never really looked into what a salt marsh is or its value as an ecosystem, but lately have been thinking about it. Today I am delving into a salt marsh, and we will start with what it is and why they are important.

What Is a Salt Marsh?

A salt marsh is a wetlands ecosystem that is flooded and drained by the ocean's tides. They are formed where rivers or creeks meet the ocean. They are composed of deep mud and peat. Peat is a spongy, root-filled material composed of decomposing plant material. They can be low on oxygen which allows certain bacteria to grow, and this bacteria can give off the smell of rotten eggs often associated with salt marshes. I found this interesting since I have early memories of coming to visit my grandparents at night and the awful smell of the marsh always made me hate arriving. Then in the morning the smell was usually gone. 

The marsh has creeks that run through it, but they can change over time depending on tides and more. The marsh also filters out pollutants and provides places for oyster reefs as well as mussels to live. The salt marsh can take the carbon dioxide and sunlight and create carbon and new life. It cleanse our world and provides essential places for fish, shellfish and birds to begin their lives and live. There are also salt-tolerant plants that grow in the marsh. There are two parts of salt marsh: low marsh and high marsh. The low marsh gets flooded every day whereas the high marsh only a couple of times during a month. 

Low Marsh

In the low marsh there is cordgrass or Spartina alterniflora. This grass grows in deep mud that has low oxygen levels. It has strong roots and is flooded and drained of salt water twice a day. The cordgrass does many things important to the ecosystem as well as the surrounding environment. It actually protects the mainland from storms. Yep!! That salt marsh actually helps protect our house. It also helps collect more sediment (from the ocean) and build more marsh. It is also food for some of the wildlife and provides habitats. 

In the summer the marsh is nice and green. However, cordgrass is a perennial and dies off in the fall and winter.

The low marsh is where the creek is and provides a home for crabs as well as a nursery for some fish. 

High Marsh

In the high marsh there is more diverse life. It is only flooded about twice a month. Saltmeadow cordgrass or Spartina patens (commonly called salt marsh hay) and salt grass or Distichlis spicata grow in the high marsh. Many of the plants can store the salt and help with the habitat. 

There is not as much about the high marsh available as it has more dry plants that can handle the salt but not as often as the low marsh plants. More plants can grow here.

Our marsh is surrounded by phragmites. Phragmites also called common reeds are an invasive species. Phragmites can grow up to 14 feet tall by summers end. They can grow thick and take over some of the marsh. I have also seen they can have positive effects on the marsh. There are actually laws about cutting them here. 

Our phragmites serve as a landing place for many of the birds and especially the red-winged blackbirds. 

When I was young my grandfather took me into the marsh. It is hard to walk in and you really need boots on as the mud is messy. Now we tend to stay out of it since it is a breeding ground for deer ticks and yes, there is Lyme disease out there. My parents and I have all been treated after finding ticks on us. In fact at one point my parents' doctors would put them on the antibiotics right away when they found a tick on them because Lyme disease was so prevalent. 

Climate Change and Threats to Salt Marshes

Salt marshes are found around the world. They are on every coast of the United States. There are threats to them due to climate change and how people have interfered with them in the past. In Massachusetts as well as elsewhere there are groups trying to protect these important ecosystems. People's desire for land, farming, and more is slowly destroying them. When my grandparents built this house, they were told they had to build it along the edge of the marsh. Today the town realizes that is a mistake and tries to protect the marsh more and would not permit the house to be built as close as it previously demanded. As we worry about the eroding coastline we worry about our closeness to the marsh. Our house is in a flood plan and had it been built farther back it would not be. But we love the views and watching the changing marsh. And of course we love the sunsets!

To learn more about marshes check out this video.

To learn more about the wildlife check out this video as well. And to learn about the high marsh you can check out this video


Books & Other Resources:

I found a few books about salt marshes at the library if you would like to go that route.

1) 24 Hours in a Salt Marsh by Christy Peterson shares about a day at a salt marsh on the Oregon Coast.

2) Marvels in the Muck: Life in the Salt Marshes by Doug Wechsler shares about the life found in northern salt marshes (New Jersey is mentioned). Some of the wildlife shared I do not see (or know about at least) at Cape Cod.

3) A Day in the Salt Marsh by Kevin Kurtz takes the reader hour by hour naming various wildlife found in a marsh. It has some activities and more information at the end including why salt marshes are important and information about spartina and its adaptations.

4) Salt Marsh by Paul Fleisher shares about a salt marsh in Chesapeake Bay. 

Activities, Crafts & Lessons

Teach your kids more about salt marshes with these lessons, activities and crafts.