The Ecology of the Seagrasses of South Florida - USGS National ...

Key Went St Pstarobur~ Cedor Key Panaocola
J F M A M J J A $ O N D J F M ~ M J J A ~ ~ O N D J F M A M J J A S O N D J ~ . M A M J J A S ~ , N C
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Flgura? 3. Average monthly temperatures in Florida, 1965 (McNul ty et a1 . 1972).
turbulence and occasional ly reduced sa1 in- 1.3 GEOLOGIC ENVTRQMl4ENT
Ottes, all sf whlch stress the local shallaw
wader cmunities. Et is thought that The south Florida mainland is lowthe
rapid influx of this type of water lying 1 imestone rock known as Miami 1 ime-
Prom Florida Bay through the relatively stone. For descriptive purposes the region
open passages of the central Keys, when can be broken into four sections: the
puohsd by strong northwesterly winter south peninsular main1 and (including the
wlnds, is the majar factor in the reduced Everglades), the sedimentary barrier
abundance of coral reefs in the central islands, the Florfda Keys and reef tract,
kys (Warszalek et 81, 1977).
and Florida Bay.
Tides are typically about 0,75 m (2,s The sedfmentary barrier islands of
ft) at the MJarni harbor muth. Thfs range north Biscayne Bay, Mr'ami Beach, Virginia
is reduced to (I6, 5 m (1,6 ft) f n the embay- Key, and Key Biscayne are unique for the
ntents such as South Biscayne Bay and to area because they are composed largely of
O,3 m (I ft) in restricted mbaylents like quartz sand, The islands are the southern
Card Sound (Van de #reeke 1976). The mean terminus of the longshore transport of
range decreases to the south and js 0.4 m sand that moves down the east coast and
(1.3 ft) at Key Mest Harbor, Tidal hejghts ultimately out to sea south of Key Bisand
velocities are extrmely complex in cayne. All other sediments of the region
south Florida as the Allantl'c tides are are primarily biogenic carbonate.
aemidiurnal , the gulf tides tend to be diurnal,
and much of this regSon is between The Florida Keys are a narrow chain
these two regimes. Neither tidal regime of islands extending from tiny Soldier
is particularly strong, however, and winds Key, just south of Key Biscayne, in first
frequently overcome the predicted tides. a southerly and then westerly arc 260 km
These factors, coupled with the baffl Jng (563 mi) to Key Mest and ultimately to the
effects of mudbanks, channels, and keys, Marquesas and the Dry Tortugas some 110 km
create an exceedingly complex tidal cSrcu- (69 mi) further west, The upper keys,
1 ation. from Big Pine no~thward, are composed of
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