Microbiological Parameters for Differentiating between Coastal and Open Waters in the Northern Baltic Proper and the Gulf of Finland

摘要

The abundance of selected types of micro‐organisms was compared between seven sites in inshore and offshore areas in the northern Baltic proper and at the entrance to the Gulf of Finland. The aim was to find out which of the microbiological parameters indicate terrestrial and littoral influences on the sites investigated and which of them indicate offshore conditions. During four cruises in 1977–78, samples were collected from 1‐0 m depth, within one or a few days, at five offshore and two inshore sites.Microbial numbers decreased consistently with increasing distance from the shore. The influence of terrestrial runoff, outflows from littoral areas and sediments was clear in the two Tvärminne inshore areas but not in the Ajax area situated about 10 km seaward of the outermost skerries of the Tvärminne archipelago. The influence of these factors was most distinctly indicated by viable bacteria at 18°C and polymyxin‐resistant bacteria, rods and bacterial spores. Offshore characteristics were indicated by vibrios and bacteria obviously in a starved state. Proteolytic bacteria and yeasts did not indicate either of these