The Amazing Salt Marsh
Here in the Lowcountry we are surrounded by the salt marsh. It is under every bridge, beside most roads, in the forefront of beautiful sunsets. We walk along its edges and boat (kayak!) on its creeks. But it is so much more than the beautiful place we go to recreate. It is a vital, productive ecosystem. It is amazing.
Creating and Enabling Life
Would you believe that the salt marsh ecosystem is just a productive as the Amazon Forrest? It is. The salt marsh is very efficient at transforming sunlight into plant and animal material.
Photosynthesis creates plant life which decomposes and feeds algae and fungi, which feed fish and crabs and other invertebrates, which feed larger fish and crabs, etc...... It all starts with energy from the sun. See this article for details Coastal Carolina research
Elements crucial to a healthy salt marsh include Tides, Grass, Mud, and Oysters. We will explore each of these below.
Tides bring salt water from the ocean into the creeks of the marshes. In with the oxygenated water are zooplankton and phytoplankton to charge up the start of the food chain. The marsh can support so much life because it receives this 'fresh' water twice a day.
Left is a spot of marsh at low tide. The picture to the right is the same spot of marsh, but at high tide. As the ocean rises and falls with the tides, water flows from the ocean into the marshes and back out again, twice a day.
Spartina is actually a very wimpy grass. It does not win any competitions with neighbors for food and resources. To survive, it has found a location where it has no neighbors. Very few land plants can live in a salt water environment, can survive their roots being inundated with salt water, endure the harshness of salt spray and heat that is the salt marsh. Spartina can. So alone, with no competition, it thrives in our salt marshes.
This adorable marsh wren lives in the salt marsh. It is a shy bird, you might see it scoot across a creek, but it hides well in the grass. Look for its nest in higher stands of spartina.
Ever loose a shoe in the pluff mud getting out of your kayak? Me too...... And I have had to throw myself onto my belly as I was sinking up to my hips in order to get out of that goo.
Pluff mud is the result of all that grass decomposing. Algae and fungi attack the dying stalks each winter and turn it into mud. And that mud is home to fiddler crabs, snails and worms. These small creatures feed the fish and blue crabs that are spending their youth in the small creeks of the marsh.
Researchers have found that 1 million fiddler crabs can live in each acre of healthy salt marsh! But never wander into the mud yourself - you will get stuck!
Holding it all together are the oysters. Without them and the grass roots, the mud would wash out with the tide and the grass would die. The oysters are the bones of the marsh.
Oysters need conditions to be just so in order to thrive. They require waters with just a bit of current to proliferate, they need water level change from tides to stay healthy, and they need good (to them, this means calcium based) hard surfaces to attach to.
Oysters suction water through their gills, which capture food and can also filter out excess nitrogen, which is harmful to the ecosystem. An oyster can filter 7 gallons of water per day.
Important to Preserve
In addition to being an energy producing machine, the salt marsh acts as nursery for fishes in the ocean, and buffers our coastline from ocean storms.
The marsh is strong when standing up to natural challenges, but fragile when its ecosystem is threatened.
Hiding in the grasses and small creeks of the salt marsh are larvae and young of most of the crustaceans and fishes that we eat. Over 75% of the commercially important fish and crustaceans use the salt marsh during their life cycles.
Threats to the Salt Marsh
As we live and play beside and in the salt marsh, we disrupt this ecosystem. Erosion, pollution, changes in salinity, invasive species and rigid edges all threaten the marsh. Development removes it altogether.
Our fisheries and coastal lands depend upon the abundance and health of our salt marshes.
As we live in close contact with them, lets act thoughtfully and carefully, so we don't lose it.
Developments like these (left) not only eliminate salt marsh habitat, but increase pollution of the water due to run-off from impermeable surfaces.
Walls such as that pictured to the right do not allow the marsh to migrate as sea level rises.