mid-winter 1984. One station near the mouth and one station 11 km up the estuary were
sampled. Detailed physical descriptions of these coastal areas may be found in Imberger
et al. (1983), and Oertel and Dunstan (1981). Bacterial biomass was estimated by acridine
orange direct counts (AODC) and microscopic cell sizing (Hobbie et al. 1977; Newell and
Fallon, 1982). Bacterial growth rates were estimated using the 3H-thymidine incorporation technique (Fuhrman and Azam, 1980, 1982; Moriarty and Pollard, 1981 ;
Newell and Fallon, 1982). Changes in cell numbers were also used to estimate growth
rates in calibration experiments used to establish the factor for cells produced per mole of
thymidine incorporated. Tritiated thymidine (New England Nuclear, 50 Ci/ mmole) was
added to a final concentration of 20 nmolar. Protozoan biomass was estimated by the
direct count epifluorescence method of Sherr and Sherr (1983).
RESULTS AND DISCUSSION
Instantaneous growth rates of the nearshore planktonic bacteria based on tritiated
thymidine incorporation, // (thy), and temperature showed a moderately strong
correlation (Fig. 1). With all four cruises included, r 2 = 0.329, showing that temperature
(or perhaps an unknown covarying factor) accounted for about 1 / 3 of the variation in
//(thy) for all nearshore data. One may also note the tendency for growth rates to decrease
with increasing distance from shore. Also of interest is the difference in seasonal response
for station 1 and station 5. Station 1 shows a strong seasonal response, whereas station 5
shows little or no seasonal response. Stations between 1 and 5 show an intermediate
seasonal response.
Figure 1 : Temperature vs.µ (thy) for nearshore ocean studies. Stations 1,2,3,4, & 5 are 0.25,3,6,9, & 15 km is
offshore, respectively. A logarithmic growth model is assumed for µ values throughout this work.
138
sampled. Detailed physical descriptions of these coastal areas may be found in Imberger
et al. (1983), and Oertel and Dunstan (1981). Bacterial biomass was estimated by acridine
orange direct counts (AODC) and microscopic cell sizing (Hobbie et al. 1977; Newell and
Fallon, 1982). Bacterial growth rates were estimated using the 3H-thymidine incorporation technique (Fuhrman and Azam, 1980, 1982; Moriarty and Pollard, 1981 ;
Newell and Fallon, 1982). Changes in cell numbers were also used to estimate growth
rates in calibration experiments used to establish the factor for cells produced per mole of
thymidine incorporated. Tritiated thymidine (New England Nuclear, 50 Ci/ mmole) was
added to a final concentration of 20 nmolar. Protozoan biomass was estimated by the
direct count epifluorescence method of Sherr and Sherr (1983).
RESULTS AND DISCUSSION
Instantaneous growth rates of the nearshore planktonic bacteria based on tritiated
thymidine incorporation, // (thy), and temperature showed a moderately strong
correlation (Fig. 1). With all four cruises included, r 2 = 0.329, showing that temperature
(or perhaps an unknown covarying factor) accounted for about 1 / 3 of the variation in
//(thy) for all nearshore data. One may also note the tendency for growth rates to decrease
with increasing distance from shore. Also of interest is the difference in seasonal response
for station 1 and station 5. Station 1 shows a strong seasonal response, whereas station 5
shows little or no seasonal response. Stations between 1 and 5 show an intermediate
seasonal response.
Figure 1 : Temperature vs.µ (thy) for nearshore ocean studies. Stations 1,2,3,4, & 5 are 0.25,3,6,9, & 15 km is
offshore, respectively. A logarithmic growth model is assumed for µ values throughout this work.
138