Why Salt Marshes are Falling Apart

http://www.redorbit.com/news/video/science_2/1112714950/why-are-our-salt-marshes-falling-apart/


Summary

This video discusses a long-term ecological study at Plum Island Estuary, Massachusetts. Over a nine year period, Linda Deegan (Senior Scientist) and her colleagues added nutrients (nitrogen and phosphorus) to the tidal water of a natural salt marsh. The nutrients were increased to levels comparable to what densely populated coastal areas typically receive from septic and sewage systems and fertilizer run-off. They found that increased nutrients are a significant driver of salt-marsh disintegration and loss.

Scientists had some understanding that salt marshes have the ability to absorb nutrients without end; they would simply grow more grass. But there is a limit to the amount of nutrients that marshes can absorb. When Linda Deegan and her team of scientists added the nutrients, they found out that the plants respond: the grass gets taller and greener. Due to the over abundance of nutrients, the plants have less roots. Since the function of roots is to absorb nutrients, the plants in this experiment did not need them anymore. Because of the lac of roots, the plants are getting taller and fall over into the water current, where they are pulled and tugged on and break up the creek bank causing fissures and fractures in the edge of the creek. To prevent salt marsh loss you could maintain your lawn with less nitrogen abundant fertilizers. As a society, we need to install sewage systems that do not use nitrogen.


Relevance to Class

In the very first unit that we studied, we learned about ecology and biomes. One of the terms we learned about was an estuary. An estuary is where streams and rivers merge with ocean water. Estuaries serve as breeding grounds for many invertebrate and fish species, and as nesting and feeding areas for a great diversity of birds. One of the major ecosystems found in estuaries are salt marshes. Grasses that can grow in salty water and algae are major photosynthetic organisms in salt marshes. These producers support a variety of animals, including crabs, oysters, clams, and small fish. If we, as a society, do not control our nitrogen supply, these important ecosystems will be destroyed.

Video Information

URL: http://www.redorbit.com/news/video/science_2/1112714950/why-are-our-salt-marshes-falling-apart/
Date of Publication: October 17, 2012
Made by: Linda Deegan
Credit: The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts USA