An Ecosystem at Risk

NYT:

Along 50 miles of northern estuary waters off Brevard County and the Kennedy space complex, about 280 manatees have died in the last 12 months, 109 of them in the same sudden manner as the Banana River victims. As the manatee deaths peaked this spring, hundreds of pelicans began dying along the same stretch of water, followed this summer by scores of bottlenose dolphins.

The cause continues to evade easy explanation. But a central question is whether the deaths are symptoms of something more ominous: the collapse of the natural balance that sustains the 156-mile estuary’s northern reaches.....

Mr. Rice’s fear, widely shared, is that an ecosystem that supports more than 4,300 species of wildlife — and commercial fisheries, tourism and other businesses generating nearly $4 billion annually — is buckling under the strain of decades of pollution generated by coastal Florida’s explosive development.

The evidence of decline is compelling. In 2011 and 2012, unprecedented blooms of algae blanketed the estuary’s northern reaches for months, killing vast fields of underwater sea grass that are the building blocks of the estuary ecosystem. The grasses are breeding grounds for fish, cover from predators, home to countless creatures at the bottom of the food chain and, not least of all, the favorite menu item of manatees.

The sea grass has largely been supplanted by macroalgae, fast-growing seaweeds that clump into huge mats that drift free in the waters. And the character of the estuary is changing: already, algae-eating fish like menhaden are significantly increasing, Mr. Rice said.

Leesa Souto, a conservation biologist who heads the Marine Resources Council, a nonprofit group devoted to protecting the estuary, quoted one expert as saying that the loss of grasses destroyed the habitat for 1.4 billion immature fish.

“We fear the fishery collapse may be forthcoming as these missing juveniles will never reach adulthood two or three years from now,” she wrote in an e-mail.

Scientists are blaming nitrogen loading.  Nitrogen and phosphorus are wreaking havoc in rivers, lakes and oceans, and these stories could be written almost anywhere.  One more thing on the list we're going to have to deal with if we don't want to end up like those manatees.