Marine Biology at Palmer Station, 1975 Austral Winter

Marine biology at Palmer Station, 1975 austral winter

WILLIAMJ. SHOWERS, JR., ROBERT A. DANIELS, and DAREN LAINE Department of Geology and Division of Wildlife and Fisheries Biology University of California, Davis Davis, California 95616

Investigations of the shallow-water marine benthos compare the seasonal variation and abundance of were continued for the fourth year by the University of diatoms and foraminifera in sea ice to the water col- California, Davis, at Palmer Station (64146S. umn. The plankton samples mark the end of 4 years of 64"03W.), Anvers Island. Subtidal marine com- sampling begun by W.M. Krebs in the 1972 austral munities were examined and collections were made by winter (Krebs, 1974). scuba diving in the Arthur Harbor vicinity. Additional In 1975, fast ice first formed in Arthur Harbor in collections were made during the 1975-1976 austral July. The fast ice was interrupted by long periods of summer from aboard R/V Hero at the Melchior brash ice whose density depended on prevailing wind Islands, Paradise Harbor, Port Lockroy, the Argen- directions. Water visibility before and during the tine Islands, Brabant Island, Neumayer Channel, and freeze was 36 meters. Platelet ice was observed forming the Gerlache Strait. to 33 meters. Rocks and algae from the intertidal zone Mr. Lame studied the fast-ice community in Arthur to 5 meters were observed to be coated with ice. No Harbor. The community was observed in situ, and ice large formations of anchor ice were observed, but samples were collected from May to October by divers large fronds of the algae Desmarestia mensiesii and D. scraping the under surface of the fast ice. Ice blocks anceps were observed buoyed up to the under surface were removed with a chain saw or an ax to collect of the ice by platelet ice frozen in the fronds (figure 1). epontic diatoms and meiofauna. Plankton tows were The relationships among the communities made in the same area, ice conditions permitting, to associated with the ice were investigated. Such relationships have been investigated in the Davis Sea off I

Figure 1. Desmarlstla anceps buoyed up to the underside Figure 2. The amphipod Nototropis sp. in the platelet ice of the fast ice. The frond is approximately 1 meter. Am. under the fast ice. Amphipods aggregated around cracks phipods can be seen in the upper right corner. and irregularities under the ice surface.

22 ANTARCTIC JOURNAL N corilceps neg/ecta H. b/spin/s cntccc/icus

FISH 24%

ALGAE 24% AMPHIPODA 22%

Figure 3. Stomach contents by percent point IS0P0DA 7% 2% OTHER 7% volume of N. corilceps EUPHAUSIACEA 4% neglects and H. bispinis ECHINOIDEA 1% NEMERTINEA 7% MOLLUSCA 2% POLYCHEATA 17% antarcticus from the Ant- POLYCHEATA 2% arctic Peninsula, 1975.

East Antarctica (Andriashev, 1968; Gruzov, in press), ticus and N. c. neglecta represent the two feeding and components of the communities at Palmer have types (figure 3). Both are ambush feeders and are been described (Lipps and Krebs, 1974; Meguro, relatively abundant in the rubble bottom areas of Ar- 1962). At Palmer, the amphipod Nototropis sp. was thur Harbor. N. c. neglecta has a generalized diet and found in the loose flocculent platelet ice that ac- is capable of switching its food seasonally. This cummulates under the fast ice (figure 2). Cydippid and beroid ctenophores, chaetognaths, and the fish STOMACH CONTENTS IN PERCENT DRY WEIGHT

Pleuragramma antarcticum, juvenile Tematomus b er- N. b/spins on/nC//cus N. coni/ceps negecto nacchii, and Pagetopsis macropterus were associated with the cryopelagic community. When the initial freeze broke up in August, dominican gulls were AMPHIPODA observed feeding on the exposed cryopelagic community when blocks of ice overturned. Most ice blocks ISOPODA formed brash ice and drifted out to sea. Brash ice continued to freeze and break up until late November. Mr. Daniels investigated the trophic relationships of EUPHAUSIACEA several species of fish to determine the degree of specialization in feeding. Two species of fish, POLYCHEATA Notothenia coriiceps neglecta and Harpagfer bispinis antarcticus, were collected monthly in Arthur Harbor. Otter and Issacs-Kidd trawls from Hero were used to MOL LU SC A collect representatives of 26 other species from 26 sites along the Antarctic Peninsula in February, March, ECHINOIDEA and December 1975. All specimens were preserved in 10-percent buffered formalin. Larger individuals also were injected with NEMERTI NEA the preservative. Later, the fishes were dissected and their stomach contents examined. Food items were FISH separated, counted, and either assigned a point volume, using the method discussed by Hynes (1950), ALGAE or dried and weighed. The stomach contents of about 100 individuals of H. b. antarcticus were measured by both point volume and dry weights for comparison. OTHER

Ten species of fish were sufficiently represented in Figure 4. Stomach contents by percent point volume of N. the samples to compare food-item dominance. Of corliceps neglects and H. bispinis antarcticus from Arthur these species, four had specialized diets. H. b. antarc- Harbor - June and December 1975.

March/June 1977 23 Cr/bosto,no/des jeffreys/

C/b/c/des ...... reulgens ......

Trocham/na ocl,rccao

Globocass/du/Ina cr0550 Greater than Figure 5. Feeding Rosa//na 50 % feeding tolerances of five species globular/s 1 at 0°C of foraminif era found abundantly In the Palmer area. R. globularls has the 0 8 Il 25 34 42 51 60 68 widest salinity range of SALINITY (%e) the species investigated. behavior was not observed in the specialized feeder H. of seawater, and feeding activity was observed. b. antarcticus (figure 4). Feeding tolerance limits were set when less than 50 Like many other bottom dwellers, H. b. antarcticus percent of the individuals did not feed in the culture prepares a nest and broods eggs. Mr. Daniels observed for 3 days. All individuals were actively feeding prior nesting behavior in marked nests in the field and in to the media dilution or concentration (figure 5). The nests in the laboratory. Unlike other species, the effect of elevated temperature on feeding was in- female performs most parental activities, and a com- vestigated using a thermal gradient temperature block plex social system exists between the nest fish and designed after Bradshaw (1961). The same criteria for other members of the population. tolerance limits of more than 50-percent feeding were Mr. Showers investigated the life history and ecology used for the temperature experiments. R. globularis of benthic foraminifera. Laboratory cultures were fed in normal seawater from 0° to 12°C, and maintained to determine growth rates, reproduction Globocassidulina crassa fed from 0 0 to 11°C (figure processes and periodicities, and physiological 6). tolerances to temperature and salinity. Samples of In Arthur Harbor and adjacent to the collecting mud and algae were taken monthly at specific under- sites, seawater chemistry was monitored for 12 water sites, allowing comparison between laboratory months. Salinity varied from 33.56 to 32.23 parts per data and field observations following the technique of thousand, and seawater temperature varied from Myers (1942). Reproductive cycles of Rosalina globularts in the laboratory produced an alternation of dimorphic generations; gamont prolocular diameter was 45 to 50 microns, while agamont prolocular diameter was approximately 25 microns. Growth rates were higher for both generations to the 10-chamber stage than in individuals that had more TEMP than 10 chambers. Gamonts grew faster than (°C) agamonts. Laboratory growth was sporadic in some individuals; inactive periods lasted up to 4 months. Reproduction occurred around the 20-chamber stage of R. globularis, but plastogamy was observed in individuals with as few as 16 chambers. Laboratory growth rates indicate reproductive periodicities of 90 to 120 days. Field populations appear to reproduce in 3-month cycles, but show no prolocular dimorphism in the winter months (March to October), indicating o 5 10 15 20 25 30 35 40 45 50 55 repeated asexual reproduction. SALINITY (%0) Feeding tolerances to salinity variation were deter- Figure 6. Feeding tolerances of G. crassa and R. mined for five species of foraminifera. Cultures of 20 globularis at elevated temperatures. The area under the to 50 individuals were placed in various concentrations curves represents feeding activity of 50 percent or greater.

24 ANTARCTIC JOURNAL 1.06 0 to -1.94°C in 1976. Atkinson (1969) found R. Oceanography, Santiago, Chile, 1966. Cambridge, Scott Polar globularis, living in Cardigan Bay, Wales, with salini- Research Institute, Scientific Committee on Antarctic Research. 147-155. ty fluctuations of 30.2 to 34.6 parts per thousand and Atkinson, K. 1969. The association of living foraminifera with algae temperatures ranging from 5.5 1 to 8.5°C. Murray from the littoral zone, South Cardigan Bay, Wales. Journal of (1973) documents the wide geographic distribution of Natural History, 3: 517-542. R. globularis, suggesting that it is a very tolerant Bradshaw, J.S. 1961. Laboratory experiments on the ecology of species. Geographic distribution reflects reproductive foraminfera: Contributions to the Cushman Foundation for Foraminifera Research, 12: 87-106. as well as feeding tolerances, but this investigation of Gruzov, E. N. In press. Seasonal alterations in coastal communities. an antarctic population of R. globularis indicates that In: Proceedings of the Third SCAR/JUBS Symposium on Antarc- it has greater tolerance ranges than the other species tic Biology, Washington, D.C., August 1974. investigated. This conclusion agrees with the general Hynes, H.B.N. 1950. The food of fresh-water sticklebacks (Gasterosteus aculeatus and Pygosteus pungitus) with a review of distribution data for the species. methods used in studies of the food of fishes. Journal of Animal This research was supported by National Science Ecology, 19: 36-58. Foundation grant DPP 74-12139. We appreciate the Krebs, W.N. 1974. Physical chemical oceanography of Arthur Har- bor, Anvers Island. AntarcticJournal of the U.S. IX(5): 219-221. help of Holmes and Narver, Inc., support crews at Lipps, J.H., and W.N. Krebs. 1974. Planktonic foraminifera Palmer Station and aboard Hero, particularly S. associated with antarctic sea ice. Journal of Foraminferal Williams, W. Lokey, and G. Bennett. We are grateful Research, 4(2): 80-85. to C. Denys, who gave valuable help during the Meguro, H. 1962. Planktonic ice in the antarctic ocean. Antarctic 1975-1976 austral summer collecting aboard Hero. Research Series, 14: 72-79. Murray, J.W. 1973. Distribution and Ecology of Living Bent honic References Foraminfera. New York, Crane Russak. 275 p. Myers, E.H. 1942. A quantitative study of the productivity of Andriashev, A.P. 1968. The problem of the life community foraminifera in the sea. Proceedings of the American associated with the antarctic fast ice. In: Symposium on Antarctic Philosophical Society, 85: 325-342.

Penguin census by aerial photographic analysis at Cape Crozier, Ross Island

R. G. BUTLER and D. M)LLER-SCHWARZE Department of Zoology College of Environmental Science and Forestry State University of New York Syracuse, New York 13210

Accurate estimates of world numbers of most Bauer (1967) on the Crozet and Kerguelen Islands. antarctic and subantarctic penguin species are The species studied were king penguins currently impossible due to scarce and unreliable (Aptenodytes patagonica) and macaroni penguins data on breeding populations. Although a large (Eudyptes chrysolophus). Such analysis has also number of rookeries have been located, research has been used for censuses of the Adélie penguin been conducted in only a small percentage of these. rookeries at Cape Bird, Beaufort, Franklin, and Each new survey reports previously unknown Inexpressible islands (Stonehouse, 1965, 1969). information regarding species composition and size Using this method, a more accurate census was of populations inhabiting individual rookeries (for obtained for a large rookery of Adëlie penguins example, see Miiller-Schwarze and Muller- (Pygoscelis adelzae) at Cape Crozier (77°31S. Schwarze, 1975). This is especially true of the 169°23E.) on Ross Island, Antarctica. pygoscelid penguins. The problem is compounded The U.S. Navy, in conjunction with the U.S. by the fact that even in extensively studied rookeries Geological Survey, has taken aerial photographs of the the resident populations have often not been Cape Crozier rookery every season since 1961 (figure). accurately assessed. This has resulted in difficulties Photos (9 x 9 inches) from the Crozier mission flown with the interpretation of data on predation on 16 November 1966 were selected for a direct count pressure, mortality, etc. We suggest that this of all penguins in the main rookery and in the smaller, problem may be rectified through the proper adjacent east rookery. Exposures 5, 6, 7, 24, 38, and application of aerial photographic analysis. Aerial 41 (TMA 2004), taken at an altitude of 2,250 feet, photography was first used for penguin censuses by were used in this study. Counts were conducted with a March/June 1977 25