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Topographic profile of
representative Indian River Lagoon habitats: 1) mangrove/salt
marsh; 2) submerged habitats within the Indian River Lagoon; 3)
mangrove fringe; 4) oak forest/maritime hammock; 5) oak scrub;
6) saw palmetto scrub; 7) sea oats foredune; 8)
beach.
What is an ecosystem?
Ecosystems may be defined as communities of
plants, animals and microorganisms found within a particular area, interacting
with each other, and with the environment. Hence, the term
"ecosystem" encompasses both the biotic and abiotic components of a
particular environment. Ecosystems are complex and
dynamic entities that use energy, produce wastes and recycle nutrients. All
ecosystems, be they marine or terrestrial, are interconnected; what occurs
in one ecosystem affects the dynamics of another. Collectively, all
ecosystems make up the biosphere, or zone of life, which occurs in the thin
outer layer of the Earth's surface.
In most
ecosystems, energy from the sun is the initial energy source that powers growth
in plants and algae. Plants are autotrophic, meaning they are self feeding. The
mechanism of photosynthesis allows plants to take in light energy from the sun
and convert it into the chemical energy stored in sugars and other carbohydrates
produced by plants. Because production by plants forms the base of all food webs
in an ecosystem, and provides food for all other organisms, it is also called
primary production. Thus, plants are the producers in ecosystems. Consumers in
ecosystems cannot produce their own food, so must rely on ingesting other
organisms in order to obtain their energy. Consumers that eat only plants are
called herbivores; those that eat only other animals are called carnivores; and
those that eat both plants and animals are called omnivores. Decomposers in
ecosystems, such as bacteria and fungi, assist in recycling nutrients by
breaking down the complex organic molecules in dead plant and animal tissues
into simpler substances that can be made available for reuse.
Each time one organism consumes another, some of the energy from the ingested
organism is then taken up by the consumer. This transfer of food energy from one
organism to another is commonly referred to as the food chain. Rarely, however,
is this energy transfer a simple, direct process. Rather, it can be highly
dynamic and complex since most organisms eat more than one type of food and are
therefore involved in more than one food chain. The term food web more
accurately describes the complexity of food energy transfers between organisms,
and the process of nutrient recycling within ecosystems.
What is a habitat?
A habitat can be defined in general terms as the specific place in an
environment where an organism lives. Terrestrial and marine environments each
have distinct characteristics that determine whether a specific organism will be
found there. A close look at any area along the Florida coast reveals a number
of different habitats. In deep, offshore waters, a unique Oculina reef,
found no where else in the world, runs from Ft. Pierce to Daytona. Nearshore
reefs composed of coquina rock and sabellarid wormrock are quite common in some
coastal areas. Along the barrier island system in east central Florida, sand
dunes along the shoreline abound, and can be further subdivided into foredunes,
dune crests, swales, and secondary dunes. Inland of the dune system lie the
scrub zones and maritime hammocks that have been built upon stable backdunes.
Beyond hammocks, the land begins to fall toward the Indian River Lagoon where
the mangrove fringe is located. Mangrove areas border both the east and west
margins of the lagoon along most of its length. Within the lagoon itself are
various submerged aquatic habitats such as seagrass beds and oyster reefs, as
well as the many spoil islands which arose as the result of dredging in the
lagoon. Beyond the mangrove fringe are the fresh water swamps, hardwood
hammocks, and upland forests that characterize interior Florida.
The Indian River Lagoon stretches approximately 156 miles along the east
central Florida coast. Biodiversity in the Indian River Lagoon is so vast due to
both its vast diversity of habitats, and because of its unique geographical
position. East central Florida is fortuitously located in the transition area
between the temperate Carolinean Province to the north, and the subtropical
Caribbean Province to the south. Temperate species of plants and animals exist
in the Indian River Lagoon at the southernmost extent of their ranges, while
subtropical and tropical species exist at their northernmost extents. Generally,
the area around Cape Canaveral in northern Brevard County is where vegetation
patterns begin to shift from primarily warm-temperate shrubs and trees, to more
subtropical and tropical varieties.
We will discuss the various habitats of the Indian River Lagoon, Florida in
the following pages. To learn more about the plants and animals associated with
the various habitats of the Indian River Lagoon, or to find out how biological, geological and
physical processes might differ among various habitats, click on a habitat below
that you would like to explore:
Barrier Island Habitats
Beaches
Dunes
Scrub
Maritime hammocks
Mangrove fringes
Submerged Habitats
Seagrass beds
Oyster reefs
Salt Marshes
Mosquito Control Impoundments
Spoil Islands
Report by: K. Hill, Smithsonian Marine Station
Submit additional information, photos or comments to:
irl_webmaster@si.edu
Page last updated: October 9, 2002
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