During summer periods of 2003-2005, spatial and vertical distributions of suspended particulate matter and bacteria in stratified and homogeneous waters of the White Sea was studied. Results of the study of various quantitative characteristics of the suspended particulate matter (first of all, area of surface and volumetric and mass concentrations) and abundance of microorganisms in water are discussed. A direct correlation between the value of the surface area of the suspended particulate matter and the total number of bacteria in water is revealed. However, it was manifested only during the early summer period of observations and was not expressed at the end of summer. Enhanced surface area of the suspended particulate matter can indicate the higher biochemical activity of its particles. Influence of pelitic (<0.01 mm) size fraction on bacteria abundance in different parts of the sea during summer is estimated.

Measurements of <0.002 mm size fraction were carried out at the Alfred Wegener Institute for Polar and Marine Research (Bremerhaven), of <0.005 mm size fraction - at the Sankt-Petersburg State University