Can seaweed farming be a solution to eutrophication?

By Emily Cyr

Humans use lots of fertilizers in order to stimulate agricultural growth, but a lot of these fertilizers make their way into rivers, streams, and eventually to the ocean, where they pollute the environment with excess nitrogen. This problem is called eutrophication, and it can lead to harmful consequences such as fish kills.

Although marine organisms need some nitrogen to survive, too much of it can be harmful. When there is too much nitrogen in the ocean, it causes tons of growth in small microorganisms that take up all the oxygen, leaving none for bigger critters like fish or seals! Much like how if your parents give your siblings a pile of candy, but you aren’t home, your siblings will likely eat all of the candy before you get a chance, leaving you deprived of your essential candy. Marine scientists have been looking for ways to solve this problem, and have found that seaweed farming of sugar kelp could be a possible solution.

The aquariums that we are running our experiments in! We have taken nitrogen samples from both the water and the sugar kelp tissue. Photo credit: Emily Cyr

Sugar kelp, with the latin name of S. latissima, is a species of seaweed that is really common in the Gulf of Maine! Like other types of seaweed, sugar kelp is quite skilled at taking nitrogen from its environment and using it for growth. Many sugar kelp organisms are quite large and can uptake large amounts of nitrogen. Just like a large tree is able to photosynthesize more than a tiny sapling, a larger sugar kelp organism can uptake more nitrogen than a smaller one. It’s ability to uptake large amounts of nitrogen makes sugar kelp a great candidate for seaweed farming, and helps decrease eutrophication creating a healthier ecosystem!

This semester, I am working with Senior Research Scientist Nichole Price, who works with local seaweed farmers. We are running multiple experiments regarding nitrogen uptake rates of sugar kelp tissue types to figure out how sugar kelp and seaweed farming could be a possible solution for eutrophication.

Doing image analysis in ImageJ to determine important biological relationships in sugar kelp. Photo credit: Zaie Nursey

Emily Cyr is a Colby College student in the 2020 Sea Change Semester Program at Bigelow Laboratory. This intensive experience provides an immersion in ocean research with an emphasis on hands-on, state-of-the-art methods and technologies.

Can seaweed farming be a solution to eutrophication?