Palmer Station Science SitRep
September 1999

Wade H. Jeffrey, SSL

Ken Doggett, Sr. Asst. Supervisor, Laboratory Operations

This month saw the arrival of cruise 99-8 of the R/V LAURENCE M. GOULD signaling the start of the Palmer Station 1999/2000-summer research season.  Ice that had been choking Arthur Harbor and Hero Inlet (over-ice excursions had been possible just a few days before ship arrival) broke up and blew out only three hours before the ship=92s docking.  Wade Jeffrey (BO-200-O) arrived with two field team members and quickly began work.  Newly arriving laboratory personnel began assuming summer responsibilities and preparing for next portcall and three more science groups coming in mid-October.

September started out cold with average daily temperatures in the minus teens (-23.4 was the low on the 8th), warmed up to a few toasty days above zero (a high of 5.1 C on the 21st ..... although it was accompanied by the peak wind speed for the month at 56 knots) and then cooled back down to single digit negative averages.  We had 27 days of precipitation this month resulting in 58.1 mm of melted accumulation and 60 cm of snow.

Banded brash ice has returned since ship departure on the 23rd and has hampered Zodiac operations at Palmer Station.  Operations and Laboratory personnel have been working on the construction of a shore-based sampling platform to allow scientists to obtain seawater samples from Station but efforts to secure the platform have been hampered by sea ice flow and tide.  Samples obtained from Palmer=92s seawater system are inadequate for baseline analysis due to depletion of nutrients and plankton by organisms living in the intake pipes.  Shore-based sampling is problematic in that samples contain too much flocculence and makes filtering more time consuming and inefficient.

Bird life abounds at Palmer although we did not see any penguins in September.  Giant Petrels, Snow Petrels, Antarctic Petrels, Cape Petrels, Black-backed gulls, Blue-eyed Shags, Antarctic Terns and Sheathbills have all been sighted at Station this month.  Two Weddel Seals hauled out of Hero Inlet at the end of the month and pupped.  Leopard Seals and Elephant Seals have made brief appearances at and around Station.

The following programs were involved in research at Palmer Station:


Personnel on Station: Wade H. Jeffrey, Jason P. Kase, and J. Dean Pakulski. 

We arrived at Palmer Station aboard R/V LAURENCE M. GOULD on September 18.  The first week was spent setting up and testing equipment and incubators and conducting preliminary assays.  After several slight modifications, our solar simulator is now fully functional.  One objective of our project is to monitor daily patterns of bacterial production and UVB induced DNA damage during the period of ozone depletion.  This requires a series of standard outside incubations for incorporation of radiolabeled growth substrates and large volumes of seawater incubated for DNA damage.  Another objective is to monitor diel patterns of inhibition of bacterial production and induction and repair of DNA damage.  As the season progresses, both solar irradiance intensity and duration will increase until the December solstice.  We have begun weekly diel experiments to monitor effects on both production and DNA damage to determine if the patterns change as solar irradiance increases.  We are also interested in the genes responsible for DNA damage repair in bacteria.  Although we have been examining recA expression for several years, this season we are attempting to identify other genes induced by UV.  Approximately every third day, seawater samples are collected and placed in the outside incubators for UV exposure and a dark control.  At regular intervals throughout the day, sub-samples are removed and filtered for later analysis of UV-induced gene expression.  We are monitoring UV sensitivity in bacterioplankton populations over the course of the season as solar radiation intensifies to determine whether the bacteria become less sensitive to UV as natural exposure increases.  To do this we will collect weekly samples from LTER stations A, B and E and incubate them with radiolabeled growth substrates during a standardized exposure to our solar simulator.  Samples are also filtered for later monitoring of changes in microbial community structure using 16S rRNA genes.  Ice conditions allowed several days of zodiac operations.  Initial water samples have been collected from LTER stations A, B, and E.   Finally, we have begun the first of a series of experiments where we will determine if solar radiation may change the microbial community structure and subsequent growth sensitivity to UVR.  Water was collected from LTER station A and diluted tenfold in filtered seawater and is being incubated under full solar irradiance, with UVB blocked, with both UVA and UVB blocked, and in the dark.  At three-day intervals, subsamples will be collected for community sensitivity to UV using the solar simulator and for community structure changes.  We would like to thank ASA station personnel for their prompt and efficient assistance in getting our operations started this season.

GO-052-P  GPS CONTINUOUS OPERATION REFERENCE STATION.  J. Mullins, Principal Investigator, U.S. Geological Survey.
The station science technician has monitored the system.  During the month, GPS transmissions were collected continuously, converted daily to a RInEx format, compressed, and transmitted to the US Geological Survey in Reston, VA. New firmware was installed in the Z-12rover, and its ability to provide single point differential positions using RTK correctors from the base station was checked.

GO-091-O  GLOBAL SEISMOGRAPH STATION AT PALMER STATION.  R. Butler, Principal Investigator, Incorporated Research Institutions for Seismology (IRIS).
The station science technician has operated the system.  Global seismic events were recorded throughout the month.  The vertical mass experienced a dramatic positive movement in the middle of the month, probably resulting from a rapid warming trend, and a visit to the vault was required.  The seismometer motors were used to center all three masses, and though the pressures in the bell jars appeared to be quite good, each was pumped down briefly to reassert as good a vacuum as possible. Late in the month the seismic station experienced an unexplained inability to write data to its online buffers, which was cured by stopping acquisition and resetting the DP computer.  While the computer was powered down, a hard drive bracket was installed to replace the temporary mounting arrangement that had been in place since the drive was installed approximately six months ago.

The station science technician has operated the system.  The Stanford receiver records very low frequency (VLF) radio waves for studying ionospheric and magnetospheric natural phenomena. The HAIL narrowband system recorded enhanced VLF activity every day this month, and plots showing the best sequences of these events were produced and transferred to the grantees on a daily basis.

OO-204-O  MEASUREMENTS OF ATMOSPHERIC O2 IN RELATION TO THE GLOBAL CARBON CYCLE.  Ralph Keeling, Principal Investigator, Scripps Institution of Oceanography.
The station physician collects air samples on a semi-weekly basis.  The samples are return-shipped to Scripps for analysis of O2 and CO2 content. The goal of the program is to resolve seasonal and inter-annual variations in atmospheric O2  (detected through changes in O2/N2 ratio) which can aid in the determination of rates of marine biological productivity and ocean mixing and aid in the separation of the global sink for anthropogenic CO2 into terrestrial and oceanic components.  The program involves air sampling at a network of sites in the Northern and Southern Hemispheres.  Palmer Station is especially well situated to resolve signals due to carbon cycling in the Southern Ocean.

OO-254-O  CHLORINE-AND BROMINE-CONTAINING TRACE GASES IN ANTARCTICA.  R.A. Rasmussen, Principal Investigator, Oregon Graduate Institute for Science and Technology
The station physician takes air samples on a weekly basis.  The samples are returned to the Institute for analysis of a number of trace components, especially chlorine- and bromine- containing gases. These elements have been implicated in the chemical processes that contribute to the austral-spring depletion of the ozone layer over Antarctica. This work will contribute to a better understanding of the buildup of trace constituents, particularly those of high-latitude marine origin.

OO-264-O  COLLECTION OF ATMOSPHERIC AIR FOR THE NOAA\CMDL WORLDWIDE FLASK SAMPLING NETWORK.  James T. Peterson, Principal Investigator, Environmental Research Laboratories, National Oceanic and Atmospheric Administration (NOAA). 
The station physician takes air samples on a weekly basis.  The NOAA Climate Monitoring and Diagnostics Laboratory team continues long-term measurements of trace atmospheric constituents that influence climate. The Palmer Station air samples are returned to the NOAA laboratory for analysis of trace constituents, including carbon dioxide. These measurements are part of NOAA's effort to determine and assess the long-term buildup of global pollutants in the atmosphere. This data will be used to determine how the rate of change of these parameters affects climate, particularly by including them in climate model studies.

OO-275-O  UM/DOE-EML REMOTE ATMOSPHERIC MEASUREMENTS PROGRAM.  C. Sanderson, Principal Investigator, Department of Energy, Environmental Measurements Laboratory. 
The station science technician has operated the system.  One sample filter was exposed for the duration of each week, and a weekly schedule of calibration, background, and sample counts was maintained.  The RAMP system is part of a global network seeking to characterize the quantity and distribution of radionuclide particles occurring both naturally and artificially in the atmosphere.

OO-283-P  ANTARCTIC AUTOMATED WEATHER STATIONS.  Charles Stearns, Principal Investigator, University of Wisconsin.
The station science technician has monitored the local sites.  Automated Weather Station (AWS) transmissions were monitored from Bonaparte Point and RACER Rock using the TeraScan system.

TO-312-O TERASCAN SATELLITE IMAGING SYSTEM.  R. Whritner, Principal Investigator, Scripps Institution of Oceanography. 
The station science technician has operated the system.  Throughout the month, the TeraScan system collected, archived, and processed DMSP and NOAA satellite pass telemetry, maintaining a schedule of 19-23 passes per day.  NOAA, DMSP and encrypted SeaWiFs telemetry were archived for BP-032-O when the LTER grid was clear of clouds.  The 85 GHz SSM/I ice concentration images were sent to BP-032-O on a weekly basis.  SeaWiFs pass capture for the "enlightened" summer season began on 01 September.  Passes were captured in an encrypted format, and could only be decrypted 2-4 weeks after capture.  A single pass was decrypted late in the month to verify that capture was being performed successfully.  By the end of the month, two or three passes were being captured each day.  The TeraScan's GPS failed early in the month, and when it was replaced by a spare that subsequently also failed.  Low temperatures were identified as the most likely culprit, as both units worked fine for a while after a period of warming up, and a few days after the initial failure, as outside temperatures rose, both were able to work continuously again.  When temperatures again dropped, the GPSs again failed.  Following consultation with SeaSpace Corp., the old receiver/antenna that had been replaced in July in order to ensure GPS week rollover compliance was reinstalled, and it functioned properly.  One of the malfunctioning units was returned to SeaSpace for evaluation.  Visible, infrared, and microwave ice images were produced and provided to the R/V LAURENCE M. GOULD prior to and during its transit to Palmer, as well as while at station preparing to go north.

TO-513-O  UV MONITORING NETWORK.  C. Booth, Biospherical Instruments (BSI), Inc.
The station science technician has operated the system. Throughout the month, raw irradiance data scans were collected daily and transmitted to BSI, and preliminary irradiances and spectral integrals were produced in support of Science.  Absolute calibration scans were performed as scheduled.  The system's control panel, PMT cooler power supply, and DMM were rack mounted.  The GPS reading time was adjusted again to move it away from the change of the UT day when it might interfere with the program's daily switching tasks.