Image of the silica cell wall of the diatom 'Didymosphenia geminata' from Rio Espolon, Futaleufu, Region X, Chile. The sample was collected in April 2010 from an extensive bloom on the river. The image has been processed to show the silica cell wall, removing the organic cell contents and the stalk material. (Image by Sarah A. Spaulding, US Geological Survey, FORT). Enlarged: here.
