Tuesday, March 11, 2008

A Delicate Balance

The Florida Times-Union

March 11, 2008

Alterations could have an impact

The million or so residents of Northeast Florida who commute daily over or along the St. Johns River give little thought to what happens below the river's surface.

All most of us see is water and the occasional seagull. The proposal by Central Florida governments to remove water has made the First Coast pay attention as we never have before. Much will be made of the economic impact that will befall the Orlando area if water is withheld. Similar dire outcomes are predicted for the residents and industries in Northeast Florida if water is diverted.

Unfortunately, only a few people appreciate the complex biological machine that is already stressed. No one knows what ultimately will happen when the flow of fuel - fresh water - is altered. Anyone who has lived near the St. Johns River already knows that it has been severely impacted. We have deepened channels, added pollutants, built bulkheads along its banks, filled wetlands, dammed the river, etc. It's testament to the resiliency of nature that the river continues to function at all.

Old-timers know that the St. Johns has changed in ways that are not good, and that the fish, crabs and just about all life dependent on the river are not what they should be. Fresh and saltwater meet at the coast where the river empties into the ocean. Twice a day, high tide pushes saltwater upstream and twice daily low tide sends some of that water back into the ocean. Changes in water salinity are natural, and plants and animals living there have adapted to this change. Even the occasional drought or flood is part of the natural cycle.

Life in the St. Johns River has had thousands of years to adapt to natural variations. Most of these adaptations go unnoticed by those of us who use the river or fish along its banks. But each year, animals move in response to changes in water temperature and salinity to spawn at just the right time. Their young ride currents out in the ocean and find their way into the river's nursery areas at exactly the right time. It's difficult to say how these century-old patterns have been altered already by even the small changes we make in how much and what kind of water reaches the coast.

Just as we pay little attention to our cars until they break, we don't notice small changes in the river until it affects our lives or pocketbooks. A clogged air filter makes your car run a little rough. The St. Johns River has also been "running rough" for some time, too. We would repair our car, but have largely ignored the St. Johns until smelly algae covered its surface. What will happen to the St. Johns River engine that has sustained Northeast Florida for centuries when the proper mix of water and nutrients is altered?

COURTNEY T. HACKNEY, Director of Coastal Biology, University of North Florida, Jacksonville

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