Lange, M. A., S. F. Ackley, P. Wadhams, and G. S. Dieckmann. 1989. Journal of the U.S., this issue. Development of in the Weddell Sea. Annals of Glaciology, Muench, R. D., M. D. Morehead, and J. T. Gunn. 1992. Regional current 12:92-96. measurements in the western Weddell Sea. Journal of the U.S., McPhee, M. C., D. G. Martinson, J. H. Morison. 1992. Upper-ocean this issue. measurements of turbulent flux in the western Weddell Sea. Antarctic

Microbial production in the antarctic The history of microbial rate process studies in the pack ice is remarkably short. Most studies of microalgae from the ant- pack ice: Time-series studies at the pack ice have concentrated on single measurements of US.-Russian biomass and microscope identification of microalgae (Garrison et al. 1983; Clarke and Ackley 1984; Marra and Boardman 1984; Garrison and Buck 1985; Garrison et al. 1987). Unlike studies in land-fast ice, few studies of the pack have included photosyn- C. W. SULLIVAN, C. H. FRITSEN, AND C. W. MORDY thetic or bacterial growth rate measurements of ice-associated microorganisms, and none involved time-series studies of the Graduate Program in Ocean Sciences accumulation of biomass for days or longer. Hancock Inst it ute for Marine Studies Little is known about microalgal and bacterial production in pack ice even though pack ice accounts for the majority of the and antarctic sea ice habitat. Burkholder and Mandelli (1965) reported on the photosynthesis-irradiance relationships of those micro- algae living during summer within the areally limited saline Department of Biological Sciences, ponds caused by infiltration of sea water on the surface of ice University of Southern California floes. During three Antarctic Marine Ecosystem Research at the Los Angeles, California 90089-0371 Ice Edge Zone (AMERIEZ) cruises to the Weddell/ Sea pack-ice region members of our laboratory conducted seasonal investigations of the distribution of algal and bacterial biomass Computer simulation models of production and productivity along profiles of ice cores collected during must include productivity estimates from three major zones: the spring 1983, autumn 1986 and winter 1988 (Kottmeier and Sullivan open ocean, the ice edge, and the pack ice. Of these zones the 1987, 1990; Lizotte and Sullivan 1991, 1992). least studied is the pack-ice zone. Presumably this results from Microalgal and bacterial biomass were observed to be highly severe logistic constraints and the general paucity of radiometric concentrated in several microhabitats of pack ice compared with data from satellite-borne sensors, such as the Coastal Zone Color the surrounding sea water. We reported that the pack ice had a Scanner (CZCS) (Sullivan et al. 1988; Comiso et al. 1990). In the mean of 5 milligram chlorophyll a per square meter and a range absence of this information, productivity in the ice-covered re- of 2 to 9 milligram chlorophyll a per square meter (Dieckmann, gion is usually considered nil (Smith and Nelson 1986). Conse- Sullivan, and Garrison 1990). Such high concentrations in ice quently, investigations of microbial production of the sea-ice frequently equal standing crops observed in 10 to 50 meters of the zone are required to more fully understand pack-ice ecosystem integrated water column beneath the ice indicating the potential production. This is especially important since sea ice may cover importance of pack ice as a site of primary production. 20 million square kilometers of the ocean surface and associated Experiments at sea showed ice algal and bacterial cells were microbial communities may account seasonally for a substantial metabolically active when melted into filtered sea water at 0 C fraction of production not previously measured. With good revealing a considerable potential for autotrophic and het- estimates of production of sea ice microbial communities erotrophic production of particulate matter. These studies sug- (SIMCOs) more accurate models of southern ocean productivity gested that the microbial communities of pack ice may potentially can be constructed that approach those we have developed for play a substantial role in regional production. However, we did fast-ice regions (Arrigo et al. 1991, 1992). not establish whether their potential was realized in situ because The long-range goals of our work are to sufficiently under- we could not follow population growth over a sufficiently long stand the spatial and temporal variability of SIMCO biomass, period to be able to determine whether microbial biomass in- productivity and the factors that influence them in order to be creased with time. able to model primary productivity in the antarctic pack-ice zone We anticipated that time-series studies of SIMCOs in pack ice with sufficient accuracy to predict interannual production in a would improve our knowledge of the actual production of pack- changing environment. ice systems as was previously revealed in investigations of land- Two specific questions that were addressed experimentally at fast systems (Sullivan et al. 1985; Grossi et al. 1987; Kottmeier et Ice Station Weddell #1(ISW) were: al. 1987; Palmisano et al. 1987). They showed that previous • What are the in situ growth and turnover rates of pack-ice micro- studies underestimated sea-ice production 4- to 10-fold. organisms (algae and bacteria) from the western Weddell Sea? The establishment of the ISW-i in the western Weddell Sea as • What fraction of primary production in the pack-ice zone is part of the Antarctic zone (An Zone) project provided us with a contributed by microalgae associated with various pack-ice envi- unique opportunity to perform time-series investigations in or- ronments vs. the water column? der to assess primary and secondary microbial production in the

1992 REVIEW 113

Samples collected at Ice Station Weddell #1 and on N. B. Palmer SITE A SITE B for estimation of microbial biomass and production rates

Determination Number of samples 20U

ISW N. B. PALMER 135_

50 Chlorophyll a 390 210 Pigments (HLC) 131 50 70 Bacterial cells 285 135 90 POC/PON 161 30 Mititic index 83 16 102 Primary production 20 0 0 5 0 IS 2 25 Natural fluorescence/beam-c (water column profiles) 22 21 Total Pigments (ig/L) Total Piginents(agIL) Nutrients 261 53

SITE J

U interior of the pack-ice zone. Such studies have never been previously reported because this under sampled oceanic region, 30 perennially covered by pack ice, was accessible only by occa-

sional -based cruises. Such cruises permitted only 45 6 single sampling of individual ice floes without ecologists know- - ing the previous history of the ice and its associated microbial 0 20 40 60 60 100 120 community, or their subsequent fate. In addition, at ISW-1 we Total Pigments (ug/L) were able to conduct ecological studies within the context of a multidisciplinary research program that contributed substan- Profiles through ISW ice flow at three study sites (A,B, and tially to our understanding of biologically relevant features of the showing the vertical distribution of total pigments (chlorophyll a + physical environments of ice and the upper boundary layers of phaeopigments). the ocean. The major objective of the biological component of ISW was to test if a substantial fraction of southern ocean primary and grew to 88 byJD94 (ridging and rafting events prevented further secondary bacterial production is derived from microbial com- sampling past this time). Snow on the new lead accumulated to munities colonizing pack-ice and the underlying water column. only 3 to 5 centimeters in depth during the study. Our investiga- Three study sites (sites A, B, and J) characterized by different tions and sampling regime were closely coordinated with S. ice types were established on the ISW-1 floe. Each was represen- Ackleys ice physics program since one objective of his program tative of common ice types in the region. All three study sites were was to describe the physical properties, including microstr- systematically sampled for ice and snow thickness, chlorophyll a ucture, of the ice environment within which the SIMCOS grow and phaeopigment concentrations, HPLC determination of pig- and develop. ment composition, floristic determinations, bacterial abundance, Samples collected (table) at ISW have only recently been particulate organic carbon and nitrogen (POC/PON), light ab- returned to our laboratory at the University of Southern Califor- sorbing properties of particulate matter, nutrient (NO 3; NO2-1 nia for analysis; therefore, only preliminary information is avail- NH4 , PO4 3, Si(OH)4) concentrations and salinities. In situ incuba- able at this time. The figure shows the distribution of total pho- tions using 14C-bicarbonate also were conducted in order to tosynthetic pigment concentrations along profiles of the initial estimate ice-algal growth rates and water column profiles of ice cores collected at each of the three time series sites. At each site natural fluoresence/beam-c were made to estimate chlorophyll a distinctly different pattern can be recognized. At sites A and J and particulate concentrations, photosynthetic rates, and photo- the highest concentration of pigments were located near the synthetically active radiation (PAR) beneath ice and in leads (see bottom of the core at the ice-seawater interface; while at site B, the table). highest pigment concentration occurred as an interior band be- Study site A(sampled from JD 56 to 150) was located inan area tween 5 to 15 centimeters from the snow-ice interface. During the of the floe characterized by a hummocked surface indicating this course of ISW two to three cores were collected at each site at ice had experienced previous deformation. The ice morphology regular intervals. If microbial communities were growing in siu was typical of second- year ice in the Weddell sea (Lytle et al. and contributing to primary production in the pack ice, we expet 1990). Snow thickness ranged from 25 to 45 centimeters and ice to observe an accumulation of algal and bacterial biomass at these thickness between 1.2 to 1.8 meters. Study site B (sampled fromJD sites as a function of time, in part because the pack provides a 60 to 125) was located in a broad flat area of the floe with a more refuge for these microorganisms. uniform ice thickness ranging between 1.0 to 1.1 meters and We note that the attention of the international community relatively uniform snow cover ranging between 15 to 20 centime- of polar biological oceanographers recently has been focused on ters. The relatively undeformed morphology and thin snow the antarctic pack-ice zone by the Scientific Committee on Ant- cover suggests that this was first-year ice, which had survived the arctic Research (SCAR) Group of Specialists on Southern Ocean summer season. Study site J was established in a recently refrozen Ecology. In their workshop report #8, "Ecology of the Antarctic lead on JD 73, after the new ice had already reached a thickness Sea-Ice Zone," January 1992, they state, "The overall objective of of 30 centimeters. Sampling at site J was continued until the ice an integrated research program should be to determine the role

114 ANTARCTIC JOURNAL of the antarctic sea-ice zone on antarctic marine systems, and in Garrison, D. L., K. R. Buck, and G. A. Fryxell. 1987. Algal assemblages in the control of global biogeochemical and energy exchanges." It is antarctic pack ice and in ice-edge plankton. Journal of Phycology, anticipated that the results of the studies described here will 23:564-572. Grossi, S. M., S. T. Kottmeier, R. L. Moe, G. T. Taylor, and C. W. Sullivan. contribute to that goal. 1987. Sea ice microbial communities VI: Growth and production in We wish to acknowledge A. Gordon and V. Lukin for organi- bottom ice under graded snow cover. Marine Ecology Progress Series, zation and camp management; J. Ardai and D. Bell for logistics 35:153-164. support; I. Melnikov, R. Swayzer III, P. Sullivan, and ice physics Kottmeier, S. T. and C. W. Sullivan 1987. Late winter primary prod- group personnel for field assistance at 15W-1 and on board R/V uction and bacterial production in sea ice and seawater west of the Palmer. This research was supported by National Science Foun- Antarctic Peninsula. Marine Ecology Progress Series, 36:287-298. dation grant DPP 90-23669. Kottmeier, S. T. and C. W. Sullivan. 1990. Bacterial biomass and produc- tion in pack ice of antarctic marginal ice edge zones. Deep-Sea Res- earch, 37(8):1,311-1,330. References Lizotte, M. P. and C.W. Sullivan. 1991. Photosynthesis-irradiance rela- tionships in microalgae associated with antarctic pack ice: evidence Arrigo, K. R., C. W. Sullivan, and J. N. Kremer. 1991. A bio-optical model for in situ activity. Marine Ecology Progress Series, 71:175-184. of antarctic sea ice. Journal of Geophysical Research, 96:10,581-10,592. Lizotte, M. P. and C. W. Sullivan. 1992. Photosynthetic capacity in Arrigo, K. R., J. N. Kremer, and C. W. Sullivan. 1992. A simulated antarctic microalgae associated with antarctic pack ice. Polar Biology, in press. fast ice ecosystem. Journal of Geophysical Research, submitted. Lytle, V. I., K. C. Jezek, S. Gogineni, R. K. Moore, and S. F. Ackley. Brkholder, P. R., E. F. Mandelli. 1965. Productivity of microalgae in 1990. Radar backscatter measurements during the winter Weddell antarctic sea ice. Science. 149:872-874. Gyre study. Antarctic Journal of the U.S., 25(5):123-125. Clarke, D. B. and S. F. Ackley. 1984. Sea ice structure and biological Marra, J. and D. C. Boardman. 1984. Late winter chlorophyll a distribu- activity in the antarctic marginal ice zone. Journal of Geophysical tions in the Weddell Sea. Marine Ecology Progress Series, 19:197-205. Research, 89:2,087-2,095. Palmisano, A. C., SooHoo, J . Beeler, and C. W. Sullivan. 1987. Effects of Comiso,J. C., N. G. Maynard, W. 0. Smith, Jr., and C. W. Sullivan. 1990. four environmental variables on photosynthesis-irradiance relation- Satellite ocean color studies of antarctic ice edge in summer/autumn. ships in Antarctic sea-ice microalgae. Marine Biology, 94:299-306. Journal of Geophysical Research, 95(C6):9,481-9,496. Smith, W. 0., Jr. and D. M. Nelson. 1986. Importance of ice edge phy- Dieckmann, C. S., C. W., Sullivan, and D. Garrison. 1990. Seasonal toplankton production in the southern ocean. BioScience, 36:251-257. standing crop of ice algae in pack ice of the Weddell Sea, . Sullivan C. W., A. C. Palmisano, S. Kottmeier, S. M. Grossi, and R. Moe. EOS, AGU/ASLO Ocean Sciences Meeting, New Orleans, Louisiana, 1985. The influence of light on growth and development of the sea ice 12-16 February 1990. microbial community in McMurdo Sound. R. Siegfried, P. R. Condy, Garrison, D. L., C. W. Sullivan, and S. F. Ackley. 1986. Sea ice microbial and R. M. Laws (Eds.), Fourth SCAR Symposium on Antarctic Biology, communities in Antarctica. BioScience, 36(4):243-250. Nutrient Cycles and Food Webs, Berlin: Springer-Verlag, 78-83. Garrison, D. L. and K. R. Buck. 1985. Sea-ice algal communities in the Sullivan, C. W., C. R. McClain, J. C. Comiso, and W. 0. Smith, Jr. 1988. Weddell Sea: species composition in ice and species composition in ice Phytoplankton standing crops within an antarctic ice edge assessed and plankton assemblages. In J. S. Gray, and M. E. Christiansen(Eds.), by satellite remote sensing. Journal of Geophysical Research, 93(C10): Marine biology of polar regions and effects of stress on marine organisms, 12,487-12,498. New York: John Wiley and Sons, 103-121.

Atmospheric sciences on Ice Station Weddell

EDGAR L. ANDREAS AND KERAN J. CLAFFEY Em

U.S. Army Cold Regions Research and Engineering Laboratory Hanover, New Hampshire 03755-1290

1.0 . 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 Wind Dlec0on Magnetic) ALEKSANDR P. MAKSHTAS AND BORIS V. Iv&riov Figure 1. The neutral-stability, 10-meter drag coefficient obtained from wind speed profile measurements, as a function of wind Arctic and Antarctic Research Institute direction. The undisturbed sector around this profile mast was from , 199226 1500 to 3100 magnetic; thus, these are the only directions plotted.

The joint U.S.-Russian atmospheric sciences program on Ice ice-ocean interaction from measurements made on the air side of Station Weddell featured close coordination and mutually ben- the interface. We collected data that will let us determine the eficial collaboration. Our broad objective was to understand air- surface stress on the upper ice surface and all of the components

1992 REvww 115