The St. Andrew Bay Ecosystem
What
is an ecosystem?*
The concept of the ecosystem is a fundamental
unit of the science of ecology because it is the study of all the
organisms (living things) in an ecosystem interacting with each other
and with the physical and chemical properties (non-living things) of the
environment to produce a self-sustaining unit. An ecosystem develops
under the influence of the climate and the geological history of an area
and is then acted upon by plants and animals. An ecologist’s definition
of an ecosystem is any area of nature in which the biotic (living) and
abiotic (non-living) components interact to form a clearly defined
trophic (flow of energy) structure based upon the fixation of light
energy, biodiversity, and biogeochemical cycles (see Odum, 1971). The
only source of energy needed by the ecosystem is sunlight. Both the
biotic and abiotic components of an ecosystem influence one another, and
both are necessary for life on the planet. Ecosystem management,
therefore, should be directed at maintaining and restoring the
biodiversity, trophic structure, and biogeochemical cycles of the
ecosystem in question.
*excerpt
from
Keppner, Edwin J. and Keppner, Lisa, A. 2001. The St. Andrew Bay
Ecosystem, Our Environment. A Revision of "A Look to the Future". St.
Andrew Bay Environmental Study Team Publication #0004R. Revised June
2008. viii + 122 pp. (.pdf file, 1.2 MB)
Why should I care about St. Andrew Bay?
by Mike Brim
They say you care about things you love. And you love things you
understand, marvel at, and appreciate. So what is there about St.
Andrew Bay that could generate enough love to cause caring? Maybe
we should start at the beginning.
Approximately 5,000 years ago sea level stopped rising, just as it flooded small
coastal valleys and stream beds. Along the northwest coast of Florida this sea
level inundation created St. Andrew Bay. It’s a small bay, just under 70,000
acres, with three major “arms”: East Bay, West Bay and North Bay. The bay’s
watershed is small too. About ten times the size of the bay.
The major source of
freshwater inflow is Econfina Creek, which has only about 5% of the flow of the
Apalachicola River. The creek is spring-fed and thus it has carried very little
silt into the bay over the last 50 centuries. Without the introduction of tons
of silt, the bay has remained deeper than most true estuaries – depths of over
40 feet in the lower bay are common.
With little fresh water flowing into the bay it has remained very salty, almost
an extension of the Gulf of Mexico. And the waters within the bay have always
been very clear – perfect conditions for the establishment of lush seagrass
beds.
Tides along our part of the Gulf are very small. Spring tides (occurring twice
each month) are conditions of the greatest vertical difference between high tide
and low. Our spring tides are just over 2 feet. Neap tides, when the vertical
distance between high tide and low is the least, are only about 0.2 feet.
These conditions (little freshwater inflow, clear waters, minimal tides, high
salinity, great depth) have resulted in a very fragile bay system, but one with
over 2,900 species of animals associated with it. Over 300 species of fishes
alone occur in St. Andrew Bay. Our bay is a fragile biological jewel of species
diversity. In that sense, it is truly of national significance. It is a very
special bay.
Our bay is the center of our coastal, outdoor quality of life. We swim in it,
boat upon it, snorkel within it, fish from it, and enjoy the multitude of
wildlife that inhabit it or fly over its clear blue waters. We are the stewards
of this tiny special estuary. If it survives, if its species of marine life
prosper, it will be because we – all of us – took good care of it.
And so, if you love St. Andrew Bay, if you learn about its marvelous species and
habitats, you’ll have reason to care about it. After all – it’s your bay. It’s
really up to you. |
