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an improperly prepared or managed treatment cell . Whale rate- limiting factors are well known, their interactions with respect to determining rates of hydrocarbon biodegradation are not; therefore, it has been of significant value to those now doing this work to have been given the opportunity to have developed ' and implemented their own treatment protocols, for by proceeding thus they have been able to improve upon standard practice and develop methods which appear to have led to significant advances ' in the field of applied biodegradation technology. Much information has yet to be obtained, however, and efforts continue to acquire additional data regarding the following: PHYSICAL STATE OF THE (PETROLEUM) CONTAMINANT The surface area available for microbial "attack" has a marked influence on the fate of the petroleum contaminants . Such conditions may include a thin surface film ( slick) , a stable ' oil-water emulsion, entrainment within sediments , or association with suspended particles . Although dispersing the oil may increase its toxicity to higher organisms , it also makes the oil more susceptible to microbial attack. Hydrocarbon utilizing microorganisms typically position themselves at the hydrocarbon- water interface, a position that assures them maximum access to both the hydrocarbon substrate and water soluble mineral nutrients . Many such microbes also produce surface active agents that emulsify oil , thereby increasing surface area. This increased surface area provides additional area for microbial development and contaminant utilization. TEMPERATURE As with other microbial activities , the biodegradation of petroleum products as strongly temperature dependent. Whale thermophilic ( "heat-loving" ) hydrocarbon-degrading bacteria have been isolated, these microorganisms appear to play only a minor role- with mesophilic ( those thriving at moderate temperature) bacteria considered the more prolific degraders. OXYGEN Bacteria ' s initial attack on hydrocarbons, such as petroleum products , commonly involves oxygenase enzymes ( i .e. chemical ' compounds that catalyze the transfer of oxygen to the enzyme substrate ) . This transfer process requires the presence of oxygen and so the availability of oxygen must be considered as an important limiting factor for petroleum degradation. I II .