bbhfa blog

New Study Shows Biscayne Bay Could Suffer From "Regime Change"

The National Oceanic and Atmospheric Administration (NOAA) recently released a study looking at 20 years worth of data on pollution which has found that Biscayne Bay may be facing a "regime change." This means that the bay is changing from a seagrass dominated ecosystem to an algae dominated one.


If you didn't already know, Biscayne Bay is a shallow estuary located adjacent to Miami that extends about 55 miles along Florida's coast. Biscayne Bay supports ecologically critical habitats such as coral reefs, mangroves, and seagrass meadows. In fact, all seven species of seagrass found in Florida can be found in Biscayne Bay. 

The NOAA study looked at water quality parameters throughout Biscayne Bay between 1995 and 2014. The data showed that parts of the bay have gradually been filling with chlorophyll and phosphorous. Why should that worry you? Well, chlorophyll tells us how much algae is living the Bay, and when it increases, it could mean that the Bay is facing persistent algae blooms and spreading seagrass die-offs. Algae blooms happen when there are too many "nutrients" like nitrogen and phosphorous that are basically fertilizers. This can fuel algae in the water to bloom and can lead to the reduction of water clarity, fish die-offs, human health risks, and the loss of biodiversity.

So what is a "regime change" anyway? A regime change means that conditions change such that one type of environment turns into another type-- and this can be difficult, if not impossible, to reverse. In Biscayne Bay, this might mean that the lush seagrass meadows and clear water of Biscayne Bay could change to nutrient-rich green water filled with algae. This could adversely impact our seagrass meadows, which provide numerous ecosystem services such as habitat and shelter for juvenile species of recreationally and commercially important fish. Many of these juvenile fish also grow to later colonize coral reefs. Seagrasses also enhance shoreline protection and prevent erosion by stabilizing sediments with their roots as well as attenuating wave energy from storms. 

Once the ecosystem changes, it is almost impossible to change it back. We have already seen some initial changes in the Bay including a loss of 21 square miles of seagrass. In some areas, 80-90% of the seagrass has already disappeared. NOAA believes that land based sources of pollution are a large contributor to this problem. Such sources include stormwater runoff which contains nutrients from sewage, septic tanks, fertilizer, and other contaminants or chemicals.

That's why we have been working with NOAA for years to try to reduce land-based pollution sources. 

In 2015, NOAA, through its Habitat Blueprint Program, designated Biscayne Bay as a Habitat Focus Area to try and mitigate the pollution problem. This area is specially designated by NOAA as "at-risk" for habitat decline and degradation in very high value regions.

Miami Waterkeeper is a proud partner of NOAA's Habitat Blueprint Program. We have worked on a number of projects including our Junior Ambassador program, stormwater enforcement efforts, and most recently the development of a sample fertilizer ordinance to regulate fertilizer use on land. Find out more about our work with NOAA here!

What's your opinion about this?

Sign in with your email

Sign in with your social account

    Please check your e-mail for a link to activate your account.