Seagrass Habitats in Danger in Key Biscayne Bay

Written By Sofia Perez

For many people, one of the most poignant feelings in the midst of the current climate crisis is the sense we, as a human race, are writing the eulogy for the very places in which we grew up. It is a different kind of sadness than we are used to. It is not like watching comfortably from your sofa as David Attenborough narrates a story of deforestation or melting ice caps in a distant rain forest or icy tundra. It is your world- a world so close that you could go outside and touch it- a world so close that not only are you attached geographically, but you are attached by your memories.

Biscayne Bay, which provides a vital ecosystem for an entire host of species apart from the humans who cherish it, is a central part of the Floridian culture I grew up around. For us Floridians, it’s a place for water sports, leisure, and tourism. For other animals. it’s a place to breed, grow, and hunt.

Part of what makes Biscayne Bay such a unique estuary ecosystem is its geographic position where freshwater from mainland Florida mixes with saltwater from the Atlantic Ocean. Historically, it has received freshwater through sheetflow (the downslope movement of water) from Kissimee that traveled through Lake Okeechobee into the Everglades and then filtered into the bay through tributaries.This has provided a key habitat and nursery ground for marine algae, sponges, hard and soft coral, and other benthic organisms.

Biscayne Bay National Park (From “Bird and Climate Change in Our National Parks”, courtesy Audubon( Photographer: Henryk Sadura. Source: Alamy)

But, as always, the environment is delicate, and recent changes in sheetflow have severely altered the conditions in the bay. With tributaries having been dredged and channelized to reduce flooding, nutrient-filled canal discharge now flows into the bay rather than freshwater. These excess nutrients promote the growth of harmful bacteria and destructive algal blooms, triggering an increase in salinity as well as massive fish die offs.

Seagrasses have been one of the hardest hit of the wide range of habitats found in Biscayne Bay, suffering deterioration due predominantly to human activities. The Miami-Dade Grand Jury Report Biscayne Bay has warned that “without corrective action, the declining quality of this body of water may become irreversible.”

But seagrass loss doesn’t just occur in Biscayne Bay; it’s everywhere. In fact, scientists estimate that worldwide, as much as 50% of the total area covered by seagrasses has been lost in the last few decades, and that since 1980, there has been a net loss of approximately 1 soccer field’s worth of seagrass every thirty minutes. Most seagrass meadows are found in shallow beds and estuaries which are especially susceptible to human activities, making them vulnerable to unwelcome change.

Scientists estimate that as much as 50% of the total area covered by seagrass has been lost in the last few decades. (From “Seagrass, Disturbance, and the Blue Carbon Cycle”, courtesy Florida Keys National Marine Sanctuary. Photographer: Heather Dine. Source: NOAA Photo Library via

While this is fairly pessimistic, currently the greatest threat to seagrass meadows is the ignorance of the public. It is believed in the scientific community that seagrass meadows are the 3rd most valuable ecosystems in the world, only preceded by estuaries and wetlands. With most conservation efforts aimed at coral reefs or rainforests, it seems almost a crime that such important habitats have escaped our attention. So what happened? After all, one hectare of seagrass(2 football fields’ worth) is worth $19,000 per year, can process a year’s worth of treated sewage from 780 people, absorb 7,500 miles’ worth of pollutants emitted by an automobile, and generate $35,000 per year in ecological services.

At first it may seem that we don’t care about them because they’re boring, but this, I can assure you, couldn’t be further from the truth. There are four groups of seagrass and roughly 72 species, all with intricate root systems and veins which constitute meadows you can see from space. Not only this, but seagrass meadows can absorb carbon dioxide in excess of their needs, transporting it to their roots and storing it for thousands of years. Yes, thousands of years. And fun fact: they are the only true flowering plant in the ocean.

Seagrass species come in many different shapes and sizes, as illustrated by this conceptual diagram of some common seagrass species. (From “Tropical Connections: South Florida’s marine environment” (pg. 260), courtesy of the Integration and Application Network (, University of Maryland Center for Environmental Science. )

If this doesn’t interest you and make seagrass meadows your new favorite habitats, I will try one last time to garner your support for these magnificent ecosystems: not only do these meadows intrigue us, but in coastal areas they also defend, provide for, and support us. In a time when climate change threatens staggering change and the sea absorbs larger amounts of carbon dioxide with every passing year, ecosystems like seagrass meadows deserve a lot of credit. Worldwide, it is vital that they gain more attention from the public and become the focus of more conservation efforts, especially in Biscayne Bay, where seagrass meadows are among the planet’s largest. Yes, it feels like we are writing the eulogy for the very places in which we grew up, but it doesn’t have to be this way. With increased public awareness and willingness to create change, perhaps we truly can save the habitats we hold so close to our hearts.


“Biscayne Bay Is In Danger Of A ‘Regime Shift,’ NOAA Study Finds.” 2019. WLRN. August 5, 2019.

“Biscayne National Park.” 2018. Audubon. March 15, 2018.

Flynn, Rebecca. 2015. “Seagrass, Disturbance, and the Blue Carbon Cycle.” Oceanbites. December 23, 2015.

Göltenboth, Friedhelm, and Peter Widmann. 2006. “Seagrass Bed – an Overview | ScienceDirect Topics.” Www.Sciencedirect.Com. 2006.

“Grand Jury Report Warns Health Of Biscayne Bay Is ‘At A Tipping Point.’” 2019. WLRN. August 8, 2019.

“Important Facts about Seagrasses.” 2013. Key Biscayne Citizen Scientist Project. July 30, 2013.

News, Brooke Harbaugh / Special to Islander. 2020. “Biscayne Bay Reaches Water Quality Crisis.” IslanderNews.Com. September 24, 2020.

Reynolds, Pamela L. 2018. “Seagrass and Seagrass Beds.” Smithsonian Ocean. December 18, 2018.

“Seagrass Bed.” n.d. Oceana.

“Seagrass Habitats throughout Biscayne Bay Are in Trouble.” 2019. Key Biscayne Citizen Scientist Project. September 26, 2019.

Staletovich, Jenny. 2018. “Seagrass Keeps Dying in Biscayne Bay. Is It Getting Too Sick to Recover?” Miamiherald. Miami Herald. 2018.

“The Importance of Seagrass (and How You Can Protect It) | Sea Fans.” 2019. Sea Fans. March 2019.

“The Seagrass Died. That May Have Triggered A Widespread Fish Kill In Biscayne Bay.” 2020. WLRN. August 14, 2020.

1 thought on “Seagrass Habitats in Danger in Key Biscayne Bay

  1. Carmenza Blauch March 16, 2021 — 11:46 pm

    Very well done. Food for thought. ♥️


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