In Sarasota, the natural world is a world of water-lakes, rivers, beaches and swamps-many worlds actually, many ecosystems, all depending on water for their existence.

To the west, across Sarasota Bay, lie the barrier islands, where giant sea turtles return to the summer beaches of their births to lay their eggs in the sugary sand. Inside the bay, where the wave energy is lower, mangroves line the shores. These strange trees are vital to the health of local fisheries. Their submerged roots are a haven for young game fish; and the leaves they shed underpin an entire food chain, sustaining an incredible array of micro-organisms, food for fish, birds and crustaceans.

Inland, not far to the east, runs the "Wild and Scenic" (an official designation) Myakka River; and here, too, is the spectacular park that bears its name. At 45 square miles, it's the largest state park in Florida. An assortment of watery habitats exists within its boundaries, including lakes, sinkholes, wet prairies, marshes and riverine swamps. Wildlife is abundant here, and habituated to man; long-legged wading birds wander among basking turtles and sunbathing alligators, and white tail deer browse the river's edge.

Throughout Sarasota County, among the rural communities, cattle ranches and citrus groves, lie hundreds of lakes, ponds and seasonal wetlands (or thousands-their number fluctuates with the duration and intensity of the rainy season), oases for migratory waterfowl like white pelicans, cormorants and ducks.

Closer to town, courtesy of the Sarasota Bay National Estuary Program, habitat restoration projects such as Quick Point Preserve and Coquina Baywalk at Leffis Key offer visitors a glimpse of Florida before Columbus. Nature trails wind through saltwater wetlands and sheltered lagoons, where white egrets stalk bait fish in meadows of seagrass.

On Siesta Key's Point of Rocks, fossilized slabs of an ancient beach lie in green, jumbled heaps, cloaked with shaggy mats of macro-algae, stippled with razor-sharp barnacles. On Lido Key, a canoe trail winds through crowded colonies of mangroves. The canopy closes overhead; little black mangrove crabs scuttle up oyster-coated prop roots; and sponges, caught in the shifting tide, roll like tumbleweed under the hull of your craft.

In Sarasota, the natural world is a world of water, informed by the tides, the rivers and the rain. Here are some postcards from the water's edge.