period of two years. Water and sediment samples were collected from 13 stations in 
the Basin; additional sites were sampled in north central Florida Bay for comparative 
purposes. It was found through sonic depth profiles and sediment cores that the same 
microkarst features are under the basin as are exposed farther north on the mainland. 
Analysis of results indicate that sediments accumulating in the basin has a bimodal size 
distribution from Penicillus secretions and abraded bioclastic debris. Storm-driven 
currents are responsible for sediment distribution and composition. In general, the 
salinity and C0 2 of the water decrease as pH and turbidity increase; salinity changes 
are the result of dilution and circulation; C0 2 changes result from vegetation, light, and 
temperature; pH is affected by C0 2 production and circulation; and turbidity is due to 
depth, agitation, and availability of loose material. It was suggested that there is a 
topographical low area parallel to the present keys and extending north seemingly an 
extension with present-day drainage. 
1980 - 1985 
Harriss, R. C., D. I. Sebacher, K. B. Bartlett, D. S. Bartlett, and P. M. Crill (1988) Sources 
of atmospheric methane in the south Florida environment. Global Biogeochem. Cycles . 
2 (3): 2 31 -43. 
Direct measurement of methane (CH 4 ) flux from wetland ecosystems of South Florida 
demonstrates that freshwater wet prairies and inundated sawgrass marsh are the 
dominant sources of atmospheric CH 4 in the region. Fluctuations in soil moisture are an 
important environmental factor controlling both seasonal and interannual fluctuations in 
CH 4 emissions from undistrubed wetlands. Land use estimates from 1900 to 1973 were 
used to calculate regional CH 4 flux. Human settlement in South Florida has modified 
wetland sources of CH 4 , reducing the natural prairies and marsh sources by 37%. 
During the same period, impoundments and disturbed wetlands were created which 
produce CH 4 at rates approximately 50% higher than the natural wetlands they 
replaced. Preliminary estimates of urban and ruminant sources of CH 4 based on 
extrapolation from literature data indicate these sources may now contribute 
approximately 23% of the total regional source. We estimate that the integrated 
effects of urban and agricultural development in South Florida between 1900 and 1973 
resulted in a 26% enhancement in CH 4 flux to the troposphere. This citation reports the 
results of CH 4 flux studies conducted from 1980 to 1985. 
1981 0 
Aisner, J. A., and S. B. Upchurch (1981) Genesis of a skeletal mound, Arsenic Bank, Florida 
Bay. Geol. Soc. Amer. Abs. . 13(7):394. 
[ABSTRACT ONLY. DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Arsenic Bank is 
a series of Holocene carbonate mounds located in southwestern Florida Bay. Surficial 
sediment samples and fourteen cores were taken from a mound in the middle of the 
Arsenic Bank chain to determine bank history, modes of sedimentation and biotic 
composition. The depositional history of the mound is, in ascending order, deposition of: 
(1) a basal, polyhaline facies; (2) an upper, normal marine facies; and (3) a storm 
facies within the normal marine facies. These facies document the Flandrian 
transgression in southwestern Florida Bay. The basal, polyhaline facies consists of 
muddy sand which accumulated in bedrock depressions about 3,200 yrs ago. This 
sediment was colonized by Thalassia and contains a brackish-water tolerant fauna. The 
normal marine facies is composed of beds of coral, algal and molluscan sediment with 
subordinant plants, foraminifera and sponges. Growths of Thalassia, Porites and 
sponges allowed for baffling of waves and currents and formed a loose, interlocking 
framework in which sediments were trapped. They also provided a substrate for a 
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