Researchers in South Florida are warning that seagrass are dying off at a rapid rate. In some areas, more than half of the underwater plant has disappeared in the past 50 years. This has had a major impact on ecosystems, and the consequences will become even more severe if the underlying problems are not addressed.
What is happening?
Seagrass is "the only true plant that can live completely submerged under water," according to the Florida Keys National Marine Sanctuary. More than 60 species of seagrass can be found worldwide, with seven of those existing in the Florida waters. It is the base of the food chain for much marine life.
Because seagrass grows completely underwater and plants need sunlight to photosynthesize into oxygen, seagrass relies on water clarity for the light to reach it. However, ocean water is getting less clear due to pollution, resulting in the seagrass dying off.
"We're losing water clarity because, in Florida, we've largely been polluting our water with nutrients," James Fourqurean, a professor of Biological Sciences at Florida International University, explained to NBC Miami.
Nutrient pollution is when nutrients, mainly nitrogen and phosphorus, are added to bodies of water in large amounts and act like fertilizer. As plankton grow in the fertilized waters, they block the sunlight from seagrass.
Why is this cause for concern?
Many marine animals rely on seagrass to survive. Manatees, for example, which mainly eat seagrass, have experienced a mass die-off in recent years, mostly due to starvation, as the seagrass has become depleted.
Conch, lobster, group, shrimp, and other fish that humans eat also rely on seagrass — if those species begin to die off, it would have a major impact on Florida's fishing industry, and the price of seafood could skyrocket.
In addition, seagrass protects against erosion, meaning that without it, storm damage to coastal homes would intensify. "[Seagrass] hold down the sediment and the soil so that that doesn't move around and bury things during hurricanes," Fourqurean explained.
What is being done about it?
"We have to stop polluting our groundwater," Fourqurean told NBC Miami. "Probably the main thing we need to do in the Miami-Dade area and Fort Lauderdale is get rid of all our septic tanks."
Septic tanks pollute by both leaking into groundwater and through stormwater runoff, according to Miami Waterkeeper. The nutrient-rich pollution then causes algae blooms, which decrease water clarity, leading to depleted seagrass.
Miami-Dade County has begun replacing some septic tanks with sewer service, but according to experts like Fourqurean, the transition must happen faster and more decisively. "A city of our size — we should not be on septic tanks," he said.
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