Palmer LTER: PhotoadT tation in a coastal phytoplankton bloom and ...
collection at sea. This research was supported by National Science Foundation grant OPP 91-18439 to D. Karl. (This is SOEST contribution number 3633.)
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References Christian, J.R., and D.M. Karl. 1992. Exocellular enzyme activities in Gerlache Strait, Antarctica. Antarctic Journal of the U.S., 27(5), 170-171. Christian, J.R., and D.M. Karl. 1993. Palmer LTER: Bacterial exoprotease activity in the Antarctic Peninsula region during austral autumn 1993. Antarctic Journal of the U.S., 28(5), 221-222. Dore, LE., G. Tien, R. Letelier, G. Parrish, J. Szyper, J. Burgett, and D.M. Karl. 1992. RACER: Distribution of nitrogenous nutrients near receding pack ice in Marguerite Bay. Antarctic Journal of the U.S., 27(5),177-179. Hoppe, H.-G. 1983. Significance of exoenzymatic activities in the ecology of brackish water: Measurements by means of methylumbelliferyl substrates. Marine Ecology Progress Series, 11(3), 299-308. Karl, D.M., A. Amos, 0. Holm-Hansen, M.E. Huntley, and M. Vernet. 1992. RACER: The Marguerite Bay ice-edge reconnaissance. Antarctic Journal of the U.S., 27(5), 175-177. Somville, M., and G. Billen. 1983. A method for determining exoproteolytic activity in natural waters. Limnology and Oceanography, 28(l),190-193. Waters, K.J., and R.C. Smith. 1992. Palmer LTER: A sampling grid for the Palmer LTER program. Antarctic Journal of the U.S., 27(5), 236-239.
U) U)
0
I
I
I
I
I
0 0.2 0.4 0.6 0.8 1 1.2 1.4 BGase (nmol/L/d)
Figure 3. Ratio of -gIucosidase to leucine aminopeptidase (BGase/LAPase) vs. -gIucosidase (BGase) (in nanomoles per liter per day) in surface samples from all stations. excretion, lysis, and grazing, that are likely to be present only for a short time. These processes are likely to play an important role in the adaptation of marine bacteria to this seasonally variable environment, and the biochemical characteristics of the bacteria may change rapidly. We thank the captain and crew of the RIV Polar Duke, the Antarctic Support Associates staff for technical support, and Terrence Houlihan and Roxane Maranger for help in sample
Palmer LTER: PhotoadTtation in a coastal phytoplankton bloom and impact on radiation utilization efficiency for carbon fixation e
OSCAR SCHOFIELD, BARBARA PREZEUN, and MARK A. MOLINE
Department of Biology and Marine Science Institute, University of California, Santa Barbara, ' California 93106
'Present address: Southern Regional Research Center, New Orleans Louisiana 70179
he occurrence and demise of most phytoplankton blooms T show a strong coherence with sea-water density fields; increasing biomass concentrations are associated with shallow mixing depths. This relationship supports the view that phytoplankton require a stable light environment, which allows the phytoplankton sufficient time to photoacclimate and overcome light-limitation of growth (Mitchell et al. 1991). Characterizing photoacclimation within a planktonic population over time has been difficult to document, however. As part of the Long-Term Ecological Research (LTER) program, the temporal dynamics of a phytoplankton bloom were documented near Palmer Station (640 40'S 64003'W) during the austral summer months of 1991-1992. The ability to follow the formation of this bloom over time can provide insight into the photoadaptational capabilities of the phytoplankton and the corresponding impact on water column optical properties.
Water samples were collected from station B within the nearshore sampling grid of the LTER (Prézelin et al. 1992). Significant symbols are listed in the table. In situ light levels (Q) were measured (Biospherical QL-100 scalar irradiance meter), and discrete water samples were transported back to Palmer Station in blackened carboys. Attenuation coefficients [K, per meter (m- 1)] were calculated from in situ Qpar. Phytoplankton pigmentation was determined by high-performance liquid chromatography following the protocols described in Prézelin et al. (1992). Photosynthesis-irradiance (P-I) curves were determined using described procedures (Prézelin et al. 1992). In situ photosynthetic rates were calculated from the maximum photosynthetic rate [m' milligrams of carbon per cubic meter per hour (mg C m 3 h-')], light-limited slope of the P-I curve (a, mg C m 3 h-' per micromole photons per square meter per second)-[a, mg C m 3 h-' (tmol photons
ANTARCTIC JOURNAL - REVIEW 1994 214
blooms, confining algal populations to the upper 20 m of the water column. Dissipation of the bloom during the second week of January 1992 coincided with storm activity, and low biomass water was advected into the area of station B (Moline, Prézelin, and Schofield 1994). Temporal variation in r at station B is presented in figure 2. Values of c showed large fluctuations over the season, with values ranging from
0.0035 0.003 0.0025 U) 0 0.002 15 0.0015 0 0.001 co 0.0005 CO)
References Christian, J.R., and D.M. Karl. 1992. Exocellular enzyme activities in Gerlache Strait, Antarctica. Antarctic Journal of the U.S., 27(5), 170-171. Christian, J.R., and D.M. Karl. 1993. Palmer LTER: Bacterial exoprotease activity in the Antarctic Peninsula region during austral autumn 1993. Antarctic Journal of the U.S., 28(5), 221-222. Dore, LE., G. Tien, R. Letelier, G. Parrish, J. Szyper, J. Burgett, and D.M. Karl. 1992. RACER: Distribution of nitrogenous nutrients near receding pack ice in Marguerite Bay. Antarctic Journal of the U.S., 27(5),177-179. Hoppe, H.-G. 1983. Significance of exoenzymatic activities in the ecology of brackish water: Measurements by means of methylumbelliferyl substrates. Marine Ecology Progress Series, 11(3), 299-308. Karl, D.M., A. Amos, 0. Holm-Hansen, M.E. Huntley, and M. Vernet. 1992. RACER: The Marguerite Bay ice-edge reconnaissance. Antarctic Journal of the U.S., 27(5), 175-177. Somville, M., and G. Billen. 1983. A method for determining exoproteolytic activity in natural waters. Limnology and Oceanography, 28(l),190-193. Waters, K.J., and R.C. Smith. 1992. Palmer LTER: A sampling grid for the Palmer LTER program. Antarctic Journal of the U.S., 27(5), 236-239.
U) U)
0
I
I
I
I
I
0 0.2 0.4 0.6 0.8 1 1.2 1.4 BGase (nmol/L/d)
Figure 3. Ratio of -gIucosidase to leucine aminopeptidase (BGase/LAPase) vs. -gIucosidase (BGase) (in nanomoles per liter per day) in surface samples from all stations. excretion, lysis, and grazing, that are likely to be present only for a short time. These processes are likely to play an important role in the adaptation of marine bacteria to this seasonally variable environment, and the biochemical characteristics of the bacteria may change rapidly. We thank the captain and crew of the RIV Polar Duke, the Antarctic Support Associates staff for technical support, and Terrence Houlihan and Roxane Maranger for help in sample
Palmer LTER: PhotoadTtation in a coastal phytoplankton bloom and impact on radiation utilization efficiency for carbon fixation e
OSCAR SCHOFIELD, BARBARA PREZEUN, and MARK A. MOLINE
Department of Biology and Marine Science Institute, University of California, Santa Barbara, ' California 93106
'Present address: Southern Regional Research Center, New Orleans Louisiana 70179
he occurrence and demise of most phytoplankton blooms T show a strong coherence with sea-water density fields; increasing biomass concentrations are associated with shallow mixing depths. This relationship supports the view that phytoplankton require a stable light environment, which allows the phytoplankton sufficient time to photoacclimate and overcome light-limitation of growth (Mitchell et al. 1991). Characterizing photoacclimation within a planktonic population over time has been difficult to document, however. As part of the Long-Term Ecological Research (LTER) program, the temporal dynamics of a phytoplankton bloom were documented near Palmer Station (640 40'S 64003'W) during the austral summer months of 1991-1992. The ability to follow the formation of this bloom over time can provide insight into the photoadaptational capabilities of the phytoplankton and the corresponding impact on water column optical properties.
Water samples were collected from station B within the nearshore sampling grid of the LTER (Prézelin et al. 1992). Significant symbols are listed in the table. In situ light levels (Q) were measured (Biospherical QL-100 scalar irradiance meter), and discrete water samples were transported back to Palmer Station in blackened carboys. Attenuation coefficients [K, per meter (m- 1)] were calculated from in situ Qpar. Phytoplankton pigmentation was determined by high-performance liquid chromatography following the protocols described in Prézelin et al. (1992). Photosynthesis-irradiance (P-I) curves were determined using described procedures (Prézelin et al. 1992). In situ photosynthetic rates were calculated from the maximum photosynthetic rate [m' milligrams of carbon per cubic meter per hour (mg C m 3 h-')], light-limited slope of the P-I curve (a, mg C m 3 h-' per micromole photons per square meter per second)-[a, mg C m 3 h-' (tmol photons
ANTARCTIC JOURNAL - REVIEW 1994 214
blooms, confining algal populations to the upper 20 m of the water column. Dissipation of the bloom during the second week of January 1992 coincided with storm activity, and low biomass water was advected into the area of station B (Moline, Prézelin, and Schofield 1994). Temporal variation in r at station B is presented in figure 2. Values of c showed large fluctuations over the season, with values ranging from
