Storage of marine particulate samples for light-absorption measurements
Limnol. Oceanogr., 44(4), 1999, 1139-1141 | DOI: 10.4319/lo.19126.96.36.1999
ABSTRACT: Spectral absorption studies of marine particulates by spectrophotometry usually require the concentrating of material, and it is often desirable to store concentrated samples prior to analysis. The effects of various storage methods for particles collected on glass-fiber filters were examined using natural marine particles. Sensitivity to storage effects differed for particles collected from different environments, but results consistently indicated that refrigeration for more than a few hours and freezing at -10°C are inadequate for preserving absorption by phytoplankton pigments in the visible region of the spectrum. Storage at -80°C and at liquid-nitrogen temperatures was found to be satisfactory, with liquid nitrogen providing the most reliable results for the longest periods evaluated (up to 1 yr). Increases in absorption were observed at ultraviolet wavelengths under all storage conditions, which suggests that optical properties in this region of the spectrum cannot be reliably assessed unless samples are analyzed immediately after collection.