The Estero Bay Estuary is bordered on the west by a chain of barrier islands, which include: Estero Island, Long Key, Lovers Key, Black Island, Big Hickory Island, and Little Hickory Island, from north to south respectively. Within the estuary are hundreds of smaller islands, many with no upland area. Mangrove trees are by far the most dominant vegetation in the bay, although extensive seagrass beds are found within the shallow bays and sounds. The climate in the region is subtropical with most rainfall occurs from June to September. The estuary is supplied with freshwater by a number of small rivers and streams.
The Estero Bay estuary complex began to form approximately 5,000 years ago when a rise in sea level flooded the mouth of the Caloosahatchee River and the smaller rivers and creeks of the present Estero Bay area. This flooding caused sediments to be deposited at the mouth of the Caloosahatchee River and the lesser streams. The sediments from the Caloosahatchee River were carried by the longshore currents south to be deposited as barrier islands bounding the present Estero Bay. The sediments deposited from the smaller rivers and streams in Estero Bay filled in the bay to cause its present shallow depth.
There are several major archaeological and historic sites within Estero Bay and the adjacent upland areas. Most of the area has not been surveyed and it is anticipated that additional sites will be located. Known sites include both Native American and European encampments and villages, but most are prehistoric shell (kitchen) middens. Due to sea level rise, most coastal sites from the earliest occupation of the area lie drowned in the bay or farther out in the Gulf of Mexico.
Oyster bars form a unique substrate in areas where there are no other hard substrates. They serve to decrease turbidity by trapping sediment and stabilizing erosion processes. They provide a hard substrate and habitat for as many as 300 other species of organisms which in turn attract predators for those species.
The dominant community type in the Estero Bay Estuary is the mangrove forest. Four species of mangroves occur in the bay. Moving progressively inward, those species are the red mangrove (Rhizophora mangle), black mangrove (Avicennia germinans), white mangrove (Laguncularia racemosa), and buttonwood (Conocarpus erectus). The most common dispersion of mangroves within Estero Bay is as a fringe along the shorelines of the bays, lagoons, and other waterways. All four species can be found within this fringe. There are also significant overwash mangrove areas, where mostly red mangroves are standing in water with little or no associated uplands. There are a few more inland areas where mangrove species are more interspersed and where the individual mangroves are more stunted in growth.” Unless there is clear scientific evidence of “dwarf” or “scrub” varieties, I think it is much more likely that the smaller mangroves in such inland sites are a result of tougher growing conditions for them.
The seagrass beds are primarily comprised of three seagrasses: turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme), and Cuban shoal grass (Halodule wrightii). In areas of low salinity, such as near the mouth of freshwater rivers and creeks, widgeon grass (Ruppia maritima) can be found. The denser seagrass beds are usually found in shallow water with a fairly constant level of salinity and a reduced turbidity.
Tidal flats comprise diverse habitats that share the characteristic of having only sparse vegetation from the three previous habitat types if they have any vascular vegetation at all. They do however contain extensive algal beds and have important (although poorly understood) roles in the estuary. These areas consist of estuarine beaches, spoil areas, shoal areas, mud flats, and areas waterward of mangrove forests.
Gulf of Mexico
The Gulf of Mexico is the 9th largest water body in the world. At its deepest it is 14,383 ft (4,384 m) deep. But here off the coast of southwest Florida, the Gulf of Mexico shelf is much shallower. Artificial reefs, natural ledges, sink holes, and other formations are all between 18’ to 110’ feet depth out to 25 miles offshore.
Reference: Florida Department of Environmental Protection, Office of Coastal and Aquatic Managed Areas, Estero Bay office.