Gschwend%20thesis.pdf

CHAPTER 3. TEMPORAL VARIATIONS OF VOLATILE ORGANIC COMPOUNDS AT A
COASTAL STATION
INTRODUCTION
In the past, oceanographers have observed the relationship of' dissolved
or.ganic carbon (DOC) to --primary. produc ti vi ty. . For example, Duursma
(196l) carried out a time series study in the Baltic region and observed
that DOC increased during the spring phytoplankton bloom. Other workers
have monitored specific organic compounds such as amino acids (Riley and
Segar, 1970) and hydrocarbons and fatty acids (Schultz and Quinn, 1977)
in coastal regions and also noted the coincidence of specific compound
level increases with phytoplankton blooms. Consequently, it would be
expected that certain volatiles would increase in concentration during
local spring (and fall) algal blooms (Fish, 19l1; Lillick, 1937; Yentsch
and Ryther, 1959).
In the coastal region studied, seasonal cycles in abundance and
physiology occur for the various benthic marine algae (Con9ver, 1958;
Sears and Wilce, 1975; Ragan and Jensen, 1978) and for the seagrasses
(Sand-Jensen, 1975). The intensive primary productivity of these plants
. 2
(which may be as high as i to IO gmC/m /day (Kanwisher, 1966; Sand-
Jensen, 1975; Phillips, 1978) may also control the levels of specific
volatiles. It has recently been shown that various volatile unsaturated
hydrocarbons are chemical messengers for benthic marine algae (MUller,
1977). These signals may demonstrate seasonal variation, and their
study may discern bóth the periods and intensity at which they occur.
The region of Cape Cod also shows a seasonal influx of residents and
tourists. Thus, one may reasonably expect to see changes in anthropo-
genic volatile introduction to the coastal zone on a seasonal basis.
-74-
¡