accumulating without benefit of a grass cover. Older portions of the spit that have built 
up to sea level acquire a grass cover which stabilizes the mudbank. Results indicate 
that sediment comes to rest on the growing mudspit as organically-bound agglomerates. 
Undispersed samples are unimodal at 4.50, have a lower density than solid particles of 
that size, and therefore settle more slowly. Most previous size analysis of Florida Bay 
sediments were made on mechanically and/or chemically disaggregated samples; this 
may have obscured the observation that Ramshorn Spit sediment is deposited as 
aggregates of fine particles bound with organic matter.-Adapted from authors' 
abstract. 
1982 0 
Rich, J., D. Kuehn, and T. D. Davies (1982) The paleoecological significance of ovoidites. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.) Ovoidites is an ovoid zygospore 
or aplanospore of the Zygnemataceae which is found in sediments of the Cretaceous to 
Holocene age. Spores typically exhibit a prominent line of dehiscence that allows them 
to split in half lengthwise. The variety of sizes, shapes, and sculpturing suggests that 
several natural species may be included within Ovoidites. Studies of sediment cores 
from marine, brackish, and freshwater sequences beneath islands in Florida Bay and at 
the mouth of the Harney River in Everglades National Park demonstrate the close 
association which the spores have with freshwater peats and related pollen 
assemblages. Palynological study of freshwater peats from the Okefenokee Swamp in 
Georgia shows additionally that Ovoidites occurs preferentially with open-water marsh 
peat and pollen assemblages. The spores typically are not found in tree- or shrub- 
dominated areas, and, therefore, are not associated with tree and shrub peats. The 
apparently narrow range of habitat preferences which the algae display suggests that 
Ovoidites may be a valuable indicator of ancient freshwater coal deposits. 
1982 0 
Schomer, N. S., and R. D. Drew (1982) An ecological characterization of the Lower 
Everglades, Florida Bay and the Florida Keys. US Fish and Wildlife Service, Office of 
Biological Services, Washington, DC. FWS/OBS-82/58.1. 246 pp. 
A conceptual model of the study area identified four major ecological zones: (1) 
terrestrial and freshwater wetlands, (2) estuarine and saltwater wetlands, (3) Florida 
Bay and mangrove islands, and (4) the Florida Keys. These are geographically 
delineated from one another by a combination of elevation gradient and positioning 
relative to one another and to major outside influences such as upstream watersheds, 
the continental shelf and major ocean current systems. These zones are delineated by 
differences in basic physical-chemical background factors such as substrate, climate, 
hydrology and water chemistry which in turn promote characteristic ecological 
communities. Many of these communities are similar between zones but localized 
differences do exist, as do significant shifts in relative abundance of community types. 
The terrestrial and freshwater wetlands support pinelands, sawgrass marshes, wet 
prairies, sloughs and occasional tree islands on freshwater peat, marl, and limestone 
soils. The estuarine and saltwater wetlands support mangrove forests, salt marshes 
and oscillating salinity systems on mangrove peat, marine marl, sand or "liver mud" 
substrates. Florida Bay exhibits oscillating meso - to hypersaline waters over 
grassbeds on marine lime mud sediments. These mud banks form an anastomosing 
pattern surrounding deeper "lake" areas having only a thin veneer of sediment. The 
exposed tips of the mud banks frequently support mangrove and salt prairie vegetation. 
The Florida Keys support almost all of the above communities to some small degree but 
are more prominently characterized by extensive offshore coral reefs. The upper Keys 
are themselves a relict reef exposed by global lowering of sea level. The lower keys 
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