Lost in the Seaweeds
By: Alexandrya Robinson, UHM MOP Student
Sargassum in the water. Photo by: Ria Tan, Flickr.
Climate change has caused a multitude of ripple effects all across the globe. One large area that has been impacted is from West Africa to the Gulf of Mexico, where the great Atlantic Sargassum belt is located. This is a five thousand mile stretch made up of a concentrated area of Sargassum– a floating species of brown seaweed that clumps together in mass formations. Yearly Sargassum blooms have increased in size since 2011, reaching peaks during the months of June and July. It is hypothesized that this increase is due to the change in ocean currents and wind patterns that are a result of climate change, but this has yet to be concretely determined by scientists.
The development of the Amazon for farmland has also aggravated the Sargassum blooms by allowing for more nutrient runoff into the ocean. This acts as a concentrated nutrient source for the seaweed. Although Sargassum in the ocean does provide the benefit of acting as a natural breeding ground for turtles, large excesses of the plant material become detrimental to that breeding area while also trapping larger marine animals and fish. Sargassum blooms also have the ability to suffocate valuable reefs, which are natural oceanic biodiversity hotspots.
Problems don’t stop there; once the seaweed washes up onto shore, excess Sargassum makes it impossible for sea turtles to nest effectively. The negative effects extend outside just the biological realm as well. On the beach, the Sargassum decomposes and releases mass amounts of noxious hydrogen sulfide gas, effectively stinking up beaches and killing tourism for the area. The adverse effects to places where the economy is heavily reliant on tourism have caused more than just unsightly problems due to the decomposing plant matter.
Across the board, having the Sargassum population grow at a greater rate than ever before is causing ecological and economic problems. In response to the need to adapt to the effects of climate change on coastal communities, researchers from Exeter and Bath have developed a solution to remediate the problem. The process, hydrothermal liquefaction, involves splitting up the biomass into more manageable portions using heat and pressure. Although energy intensive due to the necessary conditions required to make hydrothermal liquefaction work, there are positive results from this development.
From Sargassum blooms that have previously wrought havoc on the beaches, new source materials can be created. Biofuel, metals from the Sargassum, carbon dioxide, fertilizer, and charcoal are all useful byproducts of hydrothermal liquefaction. More energy conservation efforts such as papermaking, livestock feed, and building material from Sargassum have also helped to cope with the bloom sizes. Although this is not the full solution to dealing with massive Sargassum blooms, innovations continue to form in response.