We demonstrated in laboratory experiments that temperature control of marine bacteria action on diatoms strongly influences the coupling of biogenic silica and organic carbon preservation. Low temperature intensified the selective regeneration of organic matter by marine bacteria as the silicon:carbon preservation ratio gradually increased from approximately 1 at 33 degrees C to approximately 6 at -1.8 degrees C. Temperature control of bacteria-mediated selective preservation of silicon versus carbon should help to interpret and model the variable coupling of silicon and carbon sinking fluxes and the spatial patterns of opal accumulation in oceanic systems with different temperature regimes.