Marine Ecosystem Enclosed Experiments - International ...

V
VII
VIII
IX
Fig. 2. Aromatic hydrocarbons that have been studied in mesocosm experiments.
transformation of that compound in the water column, with biodegradation probably
being responsible for mineralization.
In an earlier series of three experiments beginning in December 1976 and running
with intervals in between through to July 1978 (Gearing et al. 1979), evidence
of biodegradation of naphthalenes (VII) was obtained. In the latter two experiments,
semiweekly oil additions were carried out for several months. The degradation
potential for the naphthalenes was found to be enhanced by the semiweekly
additions of oil. This finding was backed up by depletion of naphthalenes in the
water column, attributable to biodegradation, which correlated nicely with the biodegradation
potentials determined. No rates were calculated, but significant
changes, due to biodegradation, were observed in 3-4 d.
From March 1982 to. September 1983, a series of 10 radiotracer experiments
were conducted using the MERL system (Wakeham et al. 1986a). All but three of
the experiments involved aromatic hydrocarbons or halogenated aromatic hydro-
128