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Farooq Azam is a biologist studying the roles of marine bacteria in ecosystems and biogeochemical cycles. With Kay D. Bidle, he showed that marine bacterial assemblages accelerate dissolution of the silica shells of diatoms. Removing the organic covering through microbial activity helps expose the mineral to dissolution, connecting the breakdown of biological material to recycling of a mineral nutrient.^[ref]

The result makes microscopic decomposition relevant to the ocean's silicon cycle: the persistence of a diatom shell depends on its biological coating and associated bacteria, as well as the chemistry of silica itself.

Kay D. Bidle is a biologist investigating marine microbial processes. His 1999 study with Farooq Azam compared the dissolution of diatom silica in the presence of marine bacterial assemblages. Bacterial processing accelerated dissolution, linking organic-material degradation to the release of mineral nutrients.^[ref]

A dead diatom is consequently not just an inert mineral particle. Its organic coating provides material for bacteria, and degradation of that covering changes access to the underlying silica. This is a concrete mechanism connecting microbial ecology to a biogeochemical cycle.

The silicon cycle is the movement and transformation of silicon among rocks, dissolved compounds, living organisms and sediments. In the ocean, diatoms take up dissolved silicic acid to construct silica cell walls. After death, their material can sink, dissolve and return silicon to the dissolved pool, or be retained in sediments.^[ref]

Kay D. Bidle and Farooq Azam compared diatom-silica dissolution with marine bacterial processing. Faster dissolution associated with removal of the organic covering showed that recycling depends on the particle's biological coating as well as its mineral content. Microbial decomposition can thus change how rapidly a mineral nutrient becomes available again.^[ref]