Newspaper article The Florida Times Union

Water Worries; Algae, Bacteria among Main Health Concerns regarding St. Johns River

Newspaper article The Florida Times Union

Water Worries; Algae, Bacteria among Main Health Concerns regarding St. Johns River

Article excerpt

Byline: Clayton Freeman

If you've lived in Jacksonville for any time, you've likely heard plenty of discussion about the health of the St. Johns River.

But can microscopic organisms such as algae and bacteria really mean more than just a nuisance to those out on the water? It's possible.

Algal blooms - large algae-covered regions fueled by excessive fertilizer runoff, worn-out septic tanks and other causes - have reared their slimy heads several times within the last decade, turning Jacksonville's most important natural asset into an ugly and potentially unhealthy mess.

And river-borne strains of Vibrio vulnificus, often called flesh-eating bacteria, have also caused infection along the St. Johns. A 7-year-old girl was infected with the bacteria after swimming in the river in July.

So, should people be concerned when they're enjoying life on the river?

The answer: It depends.


First, let's start with the basics on algal blooms.

Algal blooms occur when nutrients, chiefly nitrogen and phosphorus, run off into fresh water and feed the exponential growth of the algae that naturally exist in the river.

"We get what is referred to as a bloom, a rapid reproduction of the algae that turns the river green," said Quinton White, executive director of the Marine Science Research Institute at Jacksonville University.

The most recent major algae outbreak occurred in 2013, although lesser buildups have flared on and off sporadically for years.

It's more than just a cosmetic problem.

White said the species found in the St. Johns River is related to the bacteria that tainted the municipal water system earlier this summer in Lake Erie. That outbreak shut down Toledo, Ohio's water supply for several days in August. Jacksonville's drinking water is drawn from the Floridan aquifer rather than the St. Johns, so algal blooms aren't a threat to the water supply here.

Algal blooms produce toxic chemicals called microcystins, which can harm humans and animals.

"When it produces this toxin, it can kill marine life and cause a lot of detrimental things," said Vandana Bhide, a doctor of internal medicine at Mayo Clinic. "If people consume the water, they can get sick and it can be very serious."

Fortunately, it's easy to see when an algal bloom is flaring up.

"It's relatively simple," White said. "If you see a green sheen, my recommendation is that you avoid the water and certainly avoid any ingestion of the water."


Vibrio vulnificus poses a different kind of threat.

Unlike algae, with its stark visual effects, these microscopic bacterial invaders can't be seen. The bacteria dwell in water with a higher salt content, so they cause problems in areas where the river meets the Atlantic Ocean rather than upstream regions such as Clay County or St. …

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