Gschwend%20thesis.pdf

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The winter peaks of heptadecane are of unknown origin. Possibly,
they reflect the return to the water from the sediments of previously
deposited material.
The increased concentrations of all the n-alkanes in late May, 1978
wi th "cpr" of 1. 4 indicate
a pollution event. However, only acenaphthalene
and 2-ethyl naphthalene covary with the n~,alkanes among the various naphtha-
lene isomers investigated. Possibly the source was of a higher boiling
or weathered petroleum fraction.
As was the case for naphthalene, the n-alkanes were also found in
abundance in the restrips (figure 3-16). The filtering experiments also
demonstrated that about half the concentrations of these compounds could
be retained by a glass fiber filter. One concludes that these compounds
occur in seawater either adsorhed to particles or associated with
microorganisms.
(The hexadecane peak in March and April was due to the occurrence
of another compound coeluting (figure 3-l6); this is supported by GCMS.)
Aldehydes. A group of straight chain aldehydes (C6-CIO) were recovered
throughout the year from the seawater at CD (figure 3-18). These
compounds represent a highly reactive, both biochemically and chemically 1
group of volatiles. The temporal variation of the aldehydes in restrips
is similar to that seen in the initial (figure 3-18) strips and would be
expec ted to be so from the known poor recoveries of these compounds.
The most important feature of the year-round patterns for these aldehydes
was the concentration maxima in the spring and fall corresponding to
periods of algal blooms (see discus.sion of nutrients and chlorophyll ~).
This was most pronounced in the spring when the phytoplankton bloom was
most intense (figure 3~19). These compounds may be the result of direct