Diel Changes of Neuston Biomass as Measured by ATP and Cell Counts, Lake Louise, Georgia, U.S.A.

Abstract

Variations of neuston adenosine triphosphate (ATP) over a 24 hr period confirmed observations of nocturnal surface film formation. ATP concentrations ranged from a low of 0.4 pmol.cm⁻² at 1200 hrs to 7.4 pmol. cm⁻² at 2000 hrs. The ATP dynamics were only partially explained by phytoplankton accumulation. Peridinium, which accounted for most of the phytoplankton volume at 2000 hrs, was related to the formation of the film, but did not account for the duration of the film. The physical parameters, wind speed, solar radiation, and water surface temperature, were negatively correlated with ATP. A causal relationship between any one variable and neuston biomass as represented by ATP could not be demonstrated. The processes, diel convective mixing and phytoplankton migration, may both contribute to the formation of the surface film in Lake Louise.