PALMER STATION SCIENCE SITREP APRIL 1995 S-028 LONG-TERM ECOLOGICAL RESEARCH ON THE ANTARCTIC MARINE ECOSYSTEM: AN ICE-DOMINATED SYSTEM. Robin M. Ross and Langdon B. Quetin, University of California, Marine Science Institute, Santa Barbara, California 93106. Personnel on station: Karen Haberman, Tim Miller Feeding experiments by krill on lab grown and field collected phytoplankton continued throughout april. Samples were analyzed by fluorometry, HPLC, and cell counts. Further samples were collected for CHN, lipid, and protein analysis which will take place at UCSB. Cultures were prepared for winter maintenance by the Winter Assistant Supervisor Laboratory Operations. S-036 ADAPTATIONS TO COUNTER DIFFUSIONAL CONSTRAINTS IN MUSCLE OF CHANNICHTHYID ICEFISHES. Bruce D. Sidell, University of Maine. Personnel on-station: Raffaele Acierno, Deena Barry, Zoe Eppley, William Riemenschneider, Bruce Sidell On 19 April, Polar Duke arrived at Palmer Station from Punta Arenas carrying field team members Acierno, Barry and Eppley. During 21-23 April trawling operations were carried out aboard Polar Duke in Dallman Bay (vicinity of Astrolabe Needle) for capture of additional fish specimens. Approximately 18 trawls were conducted after brief delays because of inclement weather and sea-state. Fishing operations were conducted in cooperation with field team personnel from project S-037 (H.W. Detrich, P.I.). Specimens captured included: approximately 110 G. gibberifrons, 30 C. aceratus, 6 C. rastrospinosus, 2 P. georgianus, 1 D. mawsoni, 1 P. macropterus, 11 N. coriiceps and 2 Bathyraja spp.. Animals were transported to Palmer Station and transferred to the station's aquarium to be held for experimentation. On 25 April, Polar Duke left Palmer Station with a representative of S-036 (Sidell) and project S-037 (Detrich) to examine possible new areas for trawling and for additional animal collection. An extended area off the western shore of Renaud Island was identified on the basis of charted soundings that appeared promising for bottom gear. Initial sonar images of the bottom at a location approximately 60 nm southwest of Victor Hugo Island suggested flat and hospitable bottom and a small (4-5ft) "try-trawl" was deployed. Upon recovery, the net had been significantly damaged by bottom conditions. An alternative location with shallower water was tried with similar results. Subsequent soundings with the higher resolution EPC depth recorders from the aft laboratory showed a pronounced return from flat bottom, but no signal penetrance, indicating hard, rocky substrate in the area. At 0400 LT on 26 April, the vessel headed north to the vicinity of Elephant Island, arriving approximately 1800 LT on the 27th. Again, bottom was scanned and another old net deployed, but was recovered damaged. A shallower contour closer to the Island was located and fished with good yield of G. gibberifrons and C. gunnari. This location appears to be a promising new area for collection of these species but should be restricted to shipboard harvesting and freezing of samples because of the extended steaming time to Palmer Station which compromises the viability of specimens. At 0615 on the 28th of April, Polar Duke left this area on a course set for Low Island, a trawling site successfully exploited in past seasons. Fishing began at Low Island at 0300 LT on the 29th, but several tows yielded essentially no fish and large quantities of tunicates. At 0900 LT of the same day, Polar Duke departed Low Island, bound for Dallman Bay. At 1300 LT of the same day, fishing activities commenced at Dallman Bay and continued until 0215 LT on the 30th. Specimens captured included: approximately 120 G. gibberifrons, 6 C. rastrospinosus, 6 C. gunnari, 9 N. coriiceps, 35 C. aceratus. Fish were transported back to Palmer Station and offloaded to the aquarium at 1130 LT on 30 April. During the month of April, station-based laboratory science activities progressed on several fronts. Tissues from C. rastrospinosus, C. aceratus and G. gibberifrons were sampled and fixed for subsequent electron microscopal studies at our CONUS laboratory. Determinations of activities of key enzymes of energy metabolism were made with heart ventricle, oxidative and glycolytic skeletal muscles of these same species. Initial enzymatic estimates were made with the same tissues from specimens of G. gibberifrons of a wide range of body sizes to ascertain whether any body size-related trends in catalytic activity of these enzymes might be found that relate to locomotory ability of the animals. Our guest Italian colleague, Dr. Acierno, initiated his experiments to determine the mechanical performance of isolated, perfused hearts of icefish species that express the intracellular hemoprotein, myoglobin (C. rastrospinosus), or do not express this protein (C. aceratus). These experiments were greatly aided by a new experimental chamber that was skillfully fabricated by on-site ASA construction personnel. Nuclei from heart cells of C. rastrospinosus, C. gunnari and C. aceratus were prepared and stored frozen for subsequent nuclear "run-on" assays that will be conducted in our CONUS laboratory to ascertain extent of myoglobin gene transcription in each species. Genomic DNA was isolated from C. rastrospinosus, C. gunnari, C. aceratus and P. georgianus and prepared for polymerase chain reaction (PCR) amplification of the intact myoglobin gene using specific primers developed in our laboratory. Products will be returned to our home institution for sequence analyses at the University of Maine's automated DNA sequencer facility. In combination, results of our experiments should shed light upon the mechanisms used to maintain cellular function of oxidative muscle tissues at cold body temperature and to determine the physiological significance and control of gene expression for myoglobin which shows very large variance in its expression among the channichthyid icefishes. Sucess of our season to date has been greatly enhanced by excellent support from ASA personnel, crew and master of Polar Duke and the support personnel of Palmer Station. They are all gratefully acknowledged. S-037 ASSEMBLY AND STABILITY OF MICROTUBULES FROM ANTARCTIC FISH AT LOW TEMPERATURES. H. William Detrich, Northeastern University, Boston, MA. Personnel on-station: Ennio Cocca, Bill Detrich, Tony Frankfurter, Kirk Malloy, Sandra Parker, Angela Ramsey, Mikael Rutberg During the month of April we continued the Palmer-based research program that we initiated in March. Significant accomplishments include: 1) purification of two microtubule motor proteins, axonemal dynein from Notothenia coriiceps (Detrich, Parker) and brain kinesin from Gobionotothen gibberifrons and Chaenocephalus aceratus (Ramsey), to near homogeneity; 2) measurement of the intrinsic ATPase activity of brain kinesin (Ramsey); 3) development of a new, high-yield chromatographic protocol, using Arginine-Sepharose, for purification of brain, erythrocyte, and egg tubulins from Antarctic fish (Frankfurter, Cocca); 4) analysis of the posttranslational modifications of N. coriiceps brain, flagellar, and erythrocyte tubulins using antibodies specific for tyrosinated, deyrosinated, and polyglutamylated isoforms (Frankfurter); 5) immunofluorescence microscopic analysis of the microtubule cytoskeletons of cultured neural, epithelial, testicular, and blood cells from N. coriiceps and C. aceratus (Rutberg); 6) completion of the field phase of whole-animal and cell-culture studies of UV-mediated DNA damage and repair in C. aceratus (Malloy; S-037/SGER); 7) isolation of high molecular weight genomic DNAs from N. coriiceps, C. aceratus, Chionodraco rastrospinosus, and Trematomus newnesi (Parker, Cocca); 8) isolation of total RNAs from multiple tissues (e.g., brain, blood cells, head kidney, spleen, etc.) of N. coriiceps, T. newnesi, C. aceratus, and C. rastrospinosus (Parker, Cocca); and 9) sampling and freezing of additional Antarctic fish tissues to support our research activities in our CONUS laboratory. Final analysis of these studies will be performed at our CONUS institution, Northeastern University. Our results should contribute significantly to an understanding of mechanisms of molecular adaptation of the cytoskeleton and UV repair systems to low body temperatures. Also during April we conducted three fishing trips in conjunction with Project S-036 (Sidell). The details of these trips have been well summarized in the April S-036 SITREP and will not be repeated here. Of significance was our identification of a new fishing ground for Champsocephalus gunnari and G. gibberifrons in shallow water off the western coast of Elephant Island. On 6 April Project member K. Malloy redeployed to CONUS after completion of his S-037/SGER research program. Detrich, Parker, Ramsey, Frankfurter, Cocca, and Rutberg reamin on station to continue our work into May. Throughout our field season we have been greatly assisted in our work by the ASA personnel of Palmer Station and the captain, crew, and ASA personnel of R/V Polar Duke. We gratefully acknowledge all of their efforts. S-091 PALMER IRIS SEISMOLOGY. R. Butler/G. Holcomb, U.S. Geological Survey, Albuquerque, NM. No personnel were on station. The system has been operated by the station science technician. On 3 April, glass bell jars were installed on the E/W and N/S instruments. Mass positions on all three seismometers were adjusted, and vacuums applied. S-106 VERY LOW FREQUENCY (VLF) REMOTE SENSING OF THUNDERSTORM AND RADIATION BELT COUPLING TO THE IONOSPHERE. U. Inan, Stanford University. No personnel were on station. The system has been operated by the station science technician. On 13 April, the Ampex recorder tape lifter arms failed to function properly. Data was lost for one 24-hour period. The station science technician modified the Ampex, and recordings continued. Starting 19 April, the Exabyte recorder failed to record two nights of narrowband data. The tape was reinitialized, and recording began again. On 25 April, at the request of the P.I., the Beta tape recording schedule was modified to cover the hours of 0100-0400UT, 0400-0700UT, and 0700-1000UT. S-275 UM/DOE-EML REMOTE ATMOSPHERIC MEASUREMENTS PROGRAM. J. Prospero/T. Snowdon, University of Miami; C. Sanderson/N. Chui, EML/DOE N.Y. No personnel were on station. The system has been operated by the station science technician. One sample filter was exposed for the duration of each week, and a weekly schedule of calibration, background, and sample counts was maintained. On 2 April, background counting ceased for unknown reasons. The system was reset, and continued to operate normally. T-312 TERASCAN SATELLITE IMAGING SYSTEM. R. Whritner, Scripps Institute of Oceanography, La Jolla, CA. No personnel were on station. The system has been operated by the station science technician. The TeraScan system collected, archived, and processed DMSP and NOAA telemetry, maintaining a schedule of 15 passes per day. AWS data was collected from the Bonaparte Point and Hugo Island automatic weather stations in support of the LTER project. On 11 April, the Sun workstation needed rebooting twice due to software hangs. Data from two satellite passes were lost. On 24 April, data from the Bonaparte Point AWS station ceased to be received with other NOAA satellite DCS data. Based on the final telemetry, it appears that the AWS station batteries have failed. T-513 UV MONITORING EXPERIMENT. C. Booth, Biospherical Instruments, Inc. No personnel were on station. The system has been operated by the science technician. Throughout the month, raw irradiance data were collected daily and transmitted to BSI. Preliminary irradiance data and inferred ozone abundances were produced in support of Science. During the month of April, data scans at 1000Z, 1100Z, 2200Z, and 2300Z were removed from the scan schedule due to decreasing sun elevation. An absolute calibration of the UV monitor was performed on 26 April. 09173811.764 PLM641.MAY