Microbial Activity and Ultrastructure of Mineral-Based Marine Snow from Howe Sound, British Columbia

Abstract

Electron microscopy and biochemical measurements of heterotrophic and enzymatic activities were made on marine snow and underlying sediments collected from Howe Sound, British Columbia. SEM showed the marine snow to be accretions of comminuted phytoplankton, fecal pellets, cellular material, and mineral particles bonded by films and coatings of an amorphous material. The amount of amorphous substance decreased as Howe Sound became increasingly marine. Rod, cocoidal, and filamentous bacteria were cultured from the marine snow. Heterotrophic microbial activity increased seaward and was found to be higher in marine snow than in underlying sediments. Phosphatase, protease, laminarinase, and xylanase were also more active in marine snow whereas sulfatase activity was found to be higher in the sediments. β-Glucosidase activity was demonstrated in marine snow only at sampling stations isolated from outer Howe Sound and the Strait of Georgia by a submarine sill.