Stratification of microorganisms and nutrients in the surface microlayer of small freshwater ponds

Using two different surface microlayer sampling devices (the Harvey and Burzell glass plate and the Garrett screen), two microlayer fractions could be distinguished. The first was from 0 to 50 mu m and the second was from 51 to 320 mu m. Significantly different (p < 0.05) concentrations of dissolved nutrients between the two microlayer fractions strongly suggests stratification within the surface microlayer. This apparent stratification is also examined for phototrophs, bacteria and other material found within the surface microlayer.