Gschwend%20thesis.pdf

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approaches to the study of organic matter in the sea have previously
suggested the importance of this phenomenom. Menzel (1975), in his
review of organic matter in the sea, has speculated that DOC is
rapidly decomposed after pulse inputs since only poor correlation with
measured primary productivity and DOC values could be found. Obser-
vations on specific organic metabolites such as amino acids (Lee and
Bada, 1975) have also led investigators to conclude that these
compounds are quickly removed af ter release in to seawater. Thus, it
appears that the concentrations of some biochemically labile materials
may be controlled in seawater by heterotrophic activity.
Volatile compounds, whose principal source is production in
surface seawater, have an additional sink from seawater in transport
into the atmosphere. The mixed layer of the open ocean is degassed
with a residence time of about i month (Broecker and Peng, 1974).
Therefore, unless sources in the mixed layer continually produce a
volatile organic compound, this atmospheric sink will rapidly deplete
the individual volatile organic compound concentrations to values in
equilibrium with the atmosphere.
The total volatile fraction found in the Sargasso Sea and the
Peru upwelling region samples comprises less than O. OL% of the DOC.
Specific Volatiles: ,Pentadecane
Pentadecane was the best-studied volatile compound. It was
ubiquitous in surface seawater samples at a concentration near its
calculated thermodynamic
solubility (Schwarzenbach et aL., 1978).
The lack of other homologues (e. g., tetradecane and hexadecane)
indicates that this compound was not derived from a fossil fuel
source. Land derived dust, for example, from the region of the