You’ve probably heard it said, “most of our seagrass is gone.” Maybe you’ve been on the water and seen the problem — bare sand or the bottom covered by a reddish algae, but not luxurious fields of waving green seagrass.
What does this mean? What caused it? What can be done?
Fields of seagrass used to be the foundation of the Indian River Lagoon’s ecosystem. It provided homes for the small fish, crabs and clams. It generated oxygen to keep the fish alive and provided food for the manatees and other creatures.
Its loss means real trouble for the IRL. The cover is missing for the small animals, the food is gone for the manatees and the oxygen is less stable for the fish. And, because algae forms the new ecosystem foundation, the lagoon is stuck in a destructive cycle.
Algae is a natural part of the IRL. Unfortunately, nutrients (nitrogen and phosphorous) have been added that fertilize algae growth for decades. Initially, wastewater plants dumped directly into the IRL. Now, nutrients are added from septic units, storm water and other sources.
Around 2011, it reached a tipping point. The nutrients during the past 50 years, temperature and other factors appear to have led to seagrass decline and algae blooms.
Now we face an algae bloom cycle. When seagrass or algae dies, it settles at the bottom, is digested by microorganisms, and releases its nutrients back into the water. That stimulates more algae growth, which dies, and the cycle continues. Of course, the algae also makes the water cloudy, cutting sun to the seagrass and causing more to die, decay and liberate nutrients.
Restoring the natural seagrass base in the lagoon is a challenge. The Save Our Indian River Lagoon half-cent trust fund was organized to tackle the problem with a primary emphasis on reducing the nutrients in the water. Doing this should slow algae growth, help clear the water and encourage seagrass growth.
Questions remain though.
For example, is there enough seagrass seed stock in the IRL to restore the fields even with improved water? Scientific teams are currently looking at this and other questions. We’ll keep you posted. VV
For more, check out HelpTheLagoon.org.