Ciliated protozoan colonization of substrates from Dauphin Island, Alabama

The colonization of substrates by ciliated protozoans and the environmental factors that influenced colonization were examined in the Mississippi Sound from June 1999 to October 2000. Glass slides were used to collect attached ciliates at three locations along the north shore of Dauphin Island. Protozoan samples were collected monthly along with the following data: water temperature, nitrate and phosphate levels, salinity, turbidity, dissolved oxygen, and pH. The dominant genera that colonized the substrates during one week of submersion were the suctorians Acineta and Ephelota, and the peritrichs Cothurnia, Vaginicola, Vorticella, and Zoothamnium. These six genera constituted 99% of the sessile ciliates observed for 50 out of the 51 collections during the study. Population numbers peaked at 6327 cells cm(-2) during the summer of 1999, declined to near zero by January 2000 as the water temperature dropped into the low teens (Celsius), and then slowly began to rise again in the spring with a corresponding rise in water temperature. Comparisons of population size with many environmental factors have shown positive correlations with temperature and turbidity.