Spatial distribution and temporal variability of heterotrophic bacteria in the sediments of Paranaguá and Antonina bays, Paraná, Brazil

RESUMO

The temporal and spatial varability of heterotrophic bacteria was analyzed in sandy, sandy-sit and silty sediments of Paranaguá and Antonina Bays (SE Brazil). Samples were taken from seven stations along a salinity gradient, from the Paranaguá Bay access to Corisco Island in Antonina Bay, between November 1985 and November 1986. The results were compared with deep-water salinity,pH temperature, dissolved oxygen and rainfall. ZoBell 2216E, at the salinities 0(0/00) and 32(0/00), was used as culture media. Principal component analysis showed that the concentration of heterotrophic bacteria was consistently lower in sandy sediments near the entrance of the Paranaguá Bay. Otherwise, the silty sedimants did not differ significantly from the other sediments. Highest halophilic levels were recorded at the mouth of Maciel tidal creek. These results suggest that the amount of bacteria, in the region, is not related to sediment grain size but to currents speed which may benefit or not the organic matter deposition. Non halophile and halotolerant bacteria can be limited by high salinity. Contrary to observations in the water column, high pluviosity did not influence the heterotrophic bacteria number in the sediment from the studied area.