MANATEE AND DOLPHIN DEATHS IN FLORIDA ARE WORRYING SCIENTISTS

 


There is part of a once pristine and beautiful part of the Florida Everglades that has become deadly to dolphins and manatees. 

The Indian River Lagoon was once one of the most beautiful features in the natural springs landscape of the greater Florida Everglades, an underground river system that in ancient times covered almost all of the Floridian peninsula.  That beauty however that does not stop it from becoming a death trap.  Unfortunately what is killing these mammals is still a mystery.  

So far the crystal waters of Indian River have killed hundreds of manatees, pelicans and dolphins. 

Jan Landsberg, a research scientist with Florida Fish and Wildlife says about the die off that: "we have to hope we can find the answer, because until we do, we don't know how we can help prevent it in the future."

The pattern of death is frightening and bizarre.  Some manatees are dying so quickly that some still have food in their mouths.  Dolphins and pelicans, instead, are withering of starvation.  

Scientists do not know if the cause of the deaths is a single one, or if there is just a coincidental concomitance of the events. 

 

The only thing that ties these animal deaths together is the incredible mangrove lagoon of the Indian river.  A 3.7 million protection initiative has been launched to try halting the imminent collapse of the lagoon's ecosystem.  But what has wreaked havoc on the ecobalance of the environment is still undetermined. 

The Lagoon stretches 156 miles.  It is very shallow in certain places.  It has one of the highest marine life varieties and densities in the world. 

What might be causing the problem however, is the decade old runoff from the overdevelopment of the surrounding areas, that use the river as a dumping ground for everything from septic tanks, polluted side streams, natural and artificial canals, and fertilizer runoff from rain.  

Since there are no tides to wash out the pollutants, the toxic waste accumulates at the bottom and stagnates. 



 


The River runs approximately from Jupiter, Florida, to Cape Canaveral.  And it is in the Banana River region, depicted above, that the die off occurs.  

Trouble seems to have started a few years ago, following a severe drought.  Scarce rainfall alone can greatly enhance the salinity and the concentration of pollutants in the Lagoon.  Then in 2010 a colder than normal winter seems to have upset the ecobalance again.  

The double whopper of unusual events killed the microalgae that live on the lagoon surface. When they died, they released the nutrients that were in their bodies providing food for a blue green algae superbloom that collapsed the once pristine ecosystem. 

For months, the ecosystem belched out waters that were vomit green.  When the summer hit, things got even worse.  More than 130,000 acres of the algae covered the lagoon.  The seagrass below, now in the darkened waters, starved of light and oxygen, which in turn also killed th efish. 

Almost 60% of the seagrass died during this period.  The seagrass, by the way, is the bellweather flora of the lagoon.  It is the yardstick by which the lagoon's health is measured.  

Without the seagrass, sediments that had descended to the floor would be encased in the tangle. Now they are free to float up and away, polluting the river in every reach.  

 

In the summer of last year, the lagoon turned a vile brown color, which presaged an even worse algal bloom.  Whatever recovery the seagrasses had made were all but wiped out. 

Back to the mammals die offs: of the carcasses that were necropsied, none of them showed a clear indication of the cause of death.  Whatever is causing their demise, it is quick and merciless. What is becoming apparent though is the fact that the animals went quickly into shock and drowned.  The agent that sends them into shock seems to act as a neurotoxin, collapsing their lungs due to their inability to resurface for air.  Their muscles become paralized or fatigued, condemning them to a quick death at the bottom. 

As far as the dolphins were concerned, the bottle nosed mammals that live in these waters are seemingly starving to death.  85% of the carcasses retrieved were in an emaciated state.  But the dolphins are dying at six times the normal rate.  This year alone 10% of their population has been wiped out. There are only 700 estimated bottle nosed dolphins in these waters.  At this rate they will be wiped in less than a decade.



The 3.7 million dollar program promises to bring relief to the lagoon, a much needed one.  The health of the lagoon is slowly improving and with close monitoring, most of its problems could be reversed.  

For the most part, a toxin is suspected to be responsible for the die off, but without identification of the agent that kills, scientists are powerless to help the mammals.  When the algal blooms are brought under control, and the seagrasses are restored, there could be a break in the die off too. That is the aim of the program after all, and the scientists involved are determined to find answers and solution to the problem.  After all, the entire region subsists and is part of the river.  Without it, both humans and animals will suffer.
 

Partial Source : Wired/ 7.11.13

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