ABSTRACT
Variations in the thymidine incorporation rate, bacterial abundance, and mean cell volumes in the surface water (0.5 m) of the Baltic Sea in spring and summer were compared in studies with different spatial scales (570 nautical miles [nmi] [ca. 1056 km], 220 nmi [ca. 407 km], 24 nmi [ca. 44 km], 12 nmi [ca. 22 km], and 200 m). The objective of the comparison was to investigate whether a single sample taken at one sampling point is representative enough for researchers to make generalizations about a larger water area. Bacterioplankton variation was connected more to seasonal characteristics than to the spatial scale of sampling. Variation was greater and more random in spring than in summer. The state variables (bacterial abundance and mean cell volume) varied less than the rate variable (thymidine incorporation). The results suggest that the sampling design for bacterioplankton studies in northern temperate seas should be planned primarily according to the season and that more stress should be put on rate variable measurements than on those of state variables.
Subject(s)
Feces/microbiology , Water Microbiology , Water Supply , Agriculture , Humans , Rural Health , ZimbabweABSTRACT
In highly humic water, acridine orange precipitated with dissolved humic matter, resulting in such bright background fluorescence that no bacteria could be seen. With bisbenzimide staining, a similar precipitate was nonfluorescent but obscured many cells. An acriflavine staining method proved useful and reproducible both in clear and in humic waters. Fading of fluorescence was not a problem, and stained samples could be stored after preparation. The fluorescence of cells stained with acriflavine was weaker than that with acridine orange, making counting extremely small cells slightly more difficult with the former stain.