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> open file report > OFR-FL-69007
U.S. Department of the Interior Some Aspects Of The Effects Of The Quantity And Quality Of Water On Biological Communities In Everglades National ParkBy Milton C. Kolipinski and Aaron L. Higer ABSTRACT Hydrobiological investigations in Everglades National Park are summarized under four main topics: (1) vegetative changes, (2) population dynamics of animals, (3) repopulation of small aquatic animals after droughts, and (4) water-quality characteristics. Changes of vegetation in Shark River Slough from 1940 to 1964, as determined from analysis of aerial/photographs, showed a decrease in acreage of wet prairie communities and an increase in sawgrass marshes and woody vegetation. The apparent reasons for the changes are shortened wet periods, increase in fires, and loss of soil. A long-range program of quantitative sampling of small fishes and aquatic invertebrates in Shark River Slough began in 1965. Preliminary findings indicate that long wet periods result (1) in an abundance of small aquatic animals, and (2) the successful formation of wading bird rookeries. The recovery of aquatic populations after drought depends on duration and extent to which the aquatic habitats dry. Animals burrows were shown to serve as survival holes for small fishes during droughts of short duration. The chemical constituents of the surface waters in Everglades National Park compare favorably with other naturally occurring waters in the United States that support a mixed fish fauna. Dissolved oxygen during periods of low water in alligator holes decreases to below 2 mg/l (milligrams per liter) during most of each 24-hour period, causing a mortality of susceptible fishes, such as the centrachids. An average of 0.02 µg/l (micrograms per liter) of DDT+DDD+DDE was found in the surface waters of the park. Several aquatic plants and animals exhibited biological magnification of insecticides. For example, mosquitofish contained 700 µg/kg (micrograms per kilogram) of the DDT family which is 4 orders of magnitude greater than that found in the waters.
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U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 13 December, 2004 @ 12:33 PM (KP)