Tj. Boyd et Af. Carlucci, RAPID MICROBIAL-DEGRADATION OF PHENOLIC MATERIALS IN CALIFORNIA (USA)COASTAL ENVIRONMENTS, Aquatic microbial ecology, 11(2), 1996, pp. 171-179
Phenolic materials are common in terrestrial and freshwater environmen
ts, yet their distribution is limited in marine systems. Since these c
ompounds are common pollutants as well as important structural compone
nts of terrestrial and riverine humic materials, we used a phenolic mo
del compound for the study of organic carbon dynamics in coastal envir
onments. Concentrations and microbial utilization rates of p-cresol we
re determined in various waters off the coast of California, USA. Leve
ls of p-cresol ranged from 9.26 ng l(-1) in Humboldt Bay in Northern C
alifornia to 303 ng l(-1) near the White's Point Outfall in Southern C
alifornia. Levels of 37.1 to 61.1 ng l(-1) were found at 3 other sampl
ing locations in San Diego Bay and San Francisco Bay. Microbial utiliz
ation rates of p-cresol were determined by measuring cellular incorpor
ation and respiration of H-3-p-cresol. Utilization rates ranged betwee
n 1.02 (Spanish Landing in San Diego Bay) and 35.5 ng l(-1) h(-1) (San
Francisco Bay). Residence times for added tracer ranged from 10 (San
Francisco Bay) to 28 h (at White's Point Outfall). Turnover times calc
ulated from biodegradation rate and ambient concentration of p-cresol
ranged from 1.7 h (San Francisco Bay) to 37 h (Spanish Landing in San
Diego Bay). These rapid turnover times indicate high anthropogenic inp
ut of p-cresol and possibly natural input as a component of humic type
materials. In areas where freshwater input is significant, utilizatio
n kinetics may suggest biodegradation of more complex, phenol-containi
ng humic materials. We conclude that accumulation of phenols is not ge
nerally observed in coastal waters a short distance from input sources
due to rapid microbial utilization.