Gschwend%20thesis.pdf

the CSI Supergrator II.
-138-
First, it can be seen that the total levels approximately doubled
during, and presumably in response to, the phytoplankton bloom. Also,
a second peak occurred in May. The nutrient data do not support the
contention that this second maximum could be remineralization of the
earlier produced phytoplankton organic matter. The chlorophyll ~ values
do not show that another bloom øccurred at this time. The individual
volatiles provide insight: to the source of this second increase.
The alkylated benzenes demonstrated a doubling in the early part of
the month. Based on previous discussion, this
may be attributed to
pollution associated with weekend recreational activities; this sample
was aequired on a Monday. Therefore, the value of 400 ng/kg total volatiles
may be enly a few-day transient level.
The alkanes and some of the naphthalenes show a concentration spike
at the end of the month. This was earlier ascribed to a pollution event
involving a heavy
petroleum fraction.
The total volatile organic carbon investigated in this study comprised
about 0.02 - 0.05% of the DOC (assumed i mg/kg) pool. This is much less
than the 1-IO ~g/kg total volatiles found by MacKinnon (pers. comm., 1978) who
utilized similar methods.
SUMMRY
The temporal variations in the concentrations of several groups of
volatile organic compounds i.n coastal seawater have been studied.
Correlations with other known processes were sought to provide insight
into the cycling of these compounds.
The C2- and c3-alkylated benzenes covaried. Large concentration
increases were observed in the sumer, immediately following weekends.