Oxygen in the waters of the lagoons make the habitat alive. you can see on the google map the rust brown areas that have been cut of from water exchange have become dead zones.
A large concern about the road project is its becoming a dam for the water flow that literally keeps the lagoons alive.
The oxygen depletion (anoxia) allows sulfate reduction to take place. Consequently, hydrogen sulfide accumulates, provoking a large increase in the mortality of macrofaunal species that are the foundation for life in the Lagoon.
Look at the Google map again and notice the creek network between the blue alive lagoons and the rust brown color in the isolated ponds.