Identifications, enumerations, and surface area estimates were made from 216 unpreserved water samples collected from August 1965 through July 1966. Surface, middle, and bottom levelswere sampled monthly at six stations located 3, 5, 21, 22, and 42 (two stations) nautical miles (5.6, 9.3, 38.9, 40.7, and 77.8 km) from shore in the Gulf of Mexico between St. Petersburg and Ft. Myers, Florida. The abundance levels, cellular surface areas, and species composition of diatom populations at these stations were examined from the standpoints of seasonality, sampling depths, and salinity; 186 taxa were recorded. Stations located near shore produced the heaviest cell concentrations; those offshore the least. Diatoms (all depths combined) averaged 1.4 x 107 µ2/1 surface area offshore, 13.6 x 107 µ2/1 at intermediate locations, and 13.0 x 108 µ2/1 inshore. Average cell numbers per liter were 8,570, 69,600, and 1,096,600. The average numbers of taxa recorded were 22, 31, and 42. Species with the greatest total surface area per liter of sample were: Rhizosolenia alata, R. setigera, R.stolterfothii, Skeletonema costatum, Leptocylindrus danicu, Rhizosolenia fragilissima, Hemidiscus hardmanianus, Guinardia flaccida, Bellerochea malleus, and Cerataulina pelagica. |
