Bacteria and fungi in air over the Gulf of Gdansk and Baltic sea

Mesophile, psychrophile bacteria and fungal colony-forming units (CFU) in a ir were investigated over the Gulf of Gdansk, Southern Baltic Sea and coast al locations from 1994 to 1998. The presence of viable mesophile and psychr ophile bacteria and fungi in marine aerosols over the open sea and coastal locations was documented. The number of viable microbes over the coastal lo cations was significantly higher than over the open sea. Distinctly more me sophile bacteria (pollution related), compared to psychrophile (environment related) species, was found in aerosols over the open Baltic Sea. Evidence that oxygen supersaturation in the surface water may contribute to enhance d bubble-mediated sea-to-air bacteria transport was documented, in particul ar during the presence of summer plankton waterbloom in the Gulf of Gdansk, where Vistula River and sea waters are mixed. Several coastal investigatio ns combined both field and laboratory experiments to estimate the enrichmen t factors of bacteria in sea-derived droplets. This part of the study was p erformed using an Air-Sea Exchange Simulator (A-SES) developed for this pur pose. The A-SES produces streams of bubbles in the water and related jet an d film droplets in the air. Laboratory experiments confirmed significant en richment of the sea-to-air mesophile bacteria transfer. The estimated enric hment factor for mesophile bacteria may exceed that obtained for psychrophi le bacteria ejected with droplets by a factor of 12. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.