Initial Cruise Prospectus (dated 14 Nov 1994)

SANTA CLAµS will be a multi-disciplinary investigation of biological, chemical, optical and photochemical processes in coastal ecosystems of the Antarctic Peninsula. This relatively short cruise has several independent but related objectives, listed below. In addition to Project S-046 (Karl) scientists, Professors Ken Mopper (Washington State University) and Dave Kieber (SUNY at Syracuse) plus five other individuals representing Project S-002, Anthony Amos (University of Texas) and Dr. Langdon Quetin and Bruno Rowell representing Project S-028 will also be aboard. Collaboration among all four projects is anticipated.

The detailed sample collections and experiments will be discussed in the field when we are all together aboard the R/V Polar Duke. There is sufficient flexibility in our schedule that we can make changes as necessary to the following cruise prospectus. A daily schedule of events will be posted in the lab and group meetings will be conducted on a regular basis. The following events are in quasi chronological order.

1. Sediment Trap Recovery and Re-deployment

We currently have three sediment trap moorings deployed near Victor Hugo Island (2) and in Crystal Sound (1). All three moorings were deployed in Jan 1994. A major objective of SANTA CLAµS is to recover these moorings and their samples and to redeploy two of the three arrays (one will be redeployed near Hugo Island, one in Crystal Sound and the third will be used for the Paradise Harbour investigation).

2. Hugo Island AWS

As part of the Palmer LTER program, an automatic weather station (AWS) similar to the one deployed at Bonapart Point and on RACER Rocks, will be established in the Victor Hugo archipelago during SANTA CLAµS. Tony Amos is the resident expert and will oversee the installation of this station. For the most part, all materials are pre-fabricated but some assembly is necessary. Among other things, the station needs to be anchored in the rock and secured with cables. A shore party will deploy by zodiac and will spend most of the day on the island. This entire operation is weather dependent. Ideally the AWS installation will immediately follow the recovery of the two Victor Hugo sediment trap moorings.

3. LTER "600" Line Survey

We anticipate visiting at least several of the standard LTER hydrostations along the 600 line (especially the outermost station 600.200). This will provide an opportunity for Project S-002 participants to conduct experiments in oceanic waters and will provide Ricardo Letelier a "blue water" site for his optical work. It will also give the LTER investigators another time point for their long-term study of this region. Whenever we occupy a station, we will conduct a series of routine experiments and collect routine hydrographic, chemical and biological data. At most, I anticipate occupation of 5 stations on the 600 Line.

4. Crystal Sound

As mentioned in section 1, above, we have a sediment trap moored in Crystal Sound. We anticipate that the Sound will be ice-covered, especially considering the fact that this year was a "heavy ice" (i.e., extensive coverage) year. Consequently, it may be difficult to locate and recover the trap -- but we shall try! Project S-028 personnel will be prepared to enter the water to help locate the trap once it is acoustically released. Redeployment should not be limited by ice cover.

We plan to spend several days in the ice pack either in Crystal Sound or elsewhere. The objectives of this work are several-fold but include a thorough assessment of the ice associated microbial communities (the so-called "brown ice"). Again, Project S-028 personnel will be essential for obtaining under ice collections of water and carefully directed frazil and platelet ice collections for analysis. Our measurements will include all of those listed under the LTER 600 Line Survey and then some. However, we also expect to conduct selected experiments as listed in section II-8-B. I expect that everyone will be rather busy working together on these studies. Again, we will have daily meetings to plan our sampling strategy and the directions of our experiments. Our investigations to date point to these unusual ice communities as vital and unusually active components of the antarctic marine ecosystem.

5. Grandidier Channel Survey

Depending upon ice conditions, we may return to Palmer Station from Crystal Sound via the Grandidier Channel, the inside route. If so, we expect to take routine hydrographic stations and to collect water for various experiments. Langdon and Bruno (S-028) may also take a series of net tows in this region in support of the LTER program objectives. If the ice conditions are unfavorable, we may be forced to return on the "outside," in which case we should pray for calm weather!

6. Paradise Harbour (or alternate site)

This phase of SANTA CLAµS will focus on comprehensive ecosystem process studies among viruses, bacteria, algae, protozoans and their habitat. A bottom-moored sequencing sediment trap will be deployed at the beginning of this investigation and will remain in place for the duration of the study. CTD/hydrographic stations will be routinely conducted (probably on 8 or 12 hr intervals). Numerous experiments (section II-8-B) will be conducted against this backdrop. Depending upon ice and or chl a concentrations, we may decide to relocate this regional experiment to Andvord Fjord or Dallman Bay. We would ideally want to catch the bloom in its early to middle phase.... a chl a concentration of 5-10 µg l^-1 -- thank you. Work assignments will be somewhat flexible and may change depending upon the initial field results.

7. Bransfield-Deception Island

As of 11/14/94 I have not yet received the coordinates of the probable hydrothermal mounds that our Spanish colleagues have previously mapped using Seabeam. If they arrive before or during the cruise we may spend approximately 1 day searching for antarctic hotsprings. If not, we will go to Deception Island to re-occupy several hydrographic stations that we established in Nov 1992 and to end our cruise with a Christmas eve banquet in one of the most unusual places on earth.

8. Measurements and Experiments (S-046)

A. Measurements

At most stations and in support of many of the experiments described below, we will routinely collect and process samples for the following measurements:

CTD/O₂/fluorescence/beam transmission profiling -- Tony Amos and Lance Fujieki will lead this effort but others may be "invited" to lend a hand on the console. Many of us will also be involved by providing deck support.
inorganic nutrients (NO₃, NO₂, PO₄, Si, NH₄) -- collected by all, measured by Terry Houlihan on board
organic nutrients (DOC, DON, DOP) -- collected by all and returned to UH for analysis
oxygen -- collected by all, analyzed on board by some (especially Albert Colman), data oversight and standardization by Dale Hebel and Albert Colman
dissolved inorganic carbon and alkalinity -- collected by all and returned to UH for analysis; some alkalinity titrations and perhaps spectrophotometric pH measurements will be done in the field by Chris Carrillo
bacterial numbers by flow cytometry -- collected by all and returned to UH for analysis by Hector Nolla
bacterial biomass by particulate lipopolysaccharide -- collected by all and returned to UH for analysis by Georgia Tien
primary production using ¹⁴C and a light/temperature controlled deck incubator system
bacterial production using ³H leucine and a temperature controlled deck incubator; experiments will also be conducted to examine effects of light (see below)
virus enumeration by transmission electron microscopy -- samples will be taken and sent to Dave Bird for analysis
particulate ATP -- Karin Björkman will prepare extracts in the field for analysis at UH
hydrogen peroxide -- Dave Pence will make these measurements on board
particulate C and N -- collected by all and returned to UH for analysis
particulate biogenic Si -- collected by Renate Scharek and returned to UH for analysis
particulate chlorophyll a by fluorometry -- Albert Colman and Karin Björkman will make these measurements on board
ectoenzymatic activity -- Jim Christian will make these measurements on board

B. Experiments

We plan to conduct many experiments during SANTA CLAµS and the following is simply a list of areas that I know will be explored. I have not extensively reviewed the independent work planned by Jim Christian, Renate Scharek or Chris Carrillo or those of the other science groups. I expect everyone to get involved in one or more of these studies and have made reference to key individuals and reponsibilities where appropriate.

ocean color drifter experiments -- Ricardo Letelier will be performing the first ever drifter-based measurements of ocean color. One experiment is planned for the 600 line and the other for Paradise Harbour. Ricardo will also be bringing a tethered spectral radiometer buoy that will be used to map radiance signals in the region. Samples will be collected for HPLC pigment analyses.
photorespiration studies -- Why do the phytoplankton blooms cease before the cells run out of light or nutrients? One possible mechanism is photorespiration. Under conditions of high light, low carbon dioxide and high oxygen concentrations, plants oxidize reduced carbon rather than reduce oxidized carbon. This inadvertent loss is called photorespiration (light-stimulated plant respiration). All three environmental conditions that favor photorespiration are known to exist during coastal blooms in Antarctica, yet this process has not been systematically investigated. Last year preliminary experiments were conducted to demonstrate that photorespiration did occur and this year we will determine actual rates both in the field and in laboratory perturbation experiments.
Viral lysis -- For the past two years we have counted virus particles in the LTER region. Viruses are ubiquitous and abundant, mostly in ice cover regions. We don't know if these are phytophage or bacteriophage but given the chl vs. bacterial distributions in these coastal regions I suspect the former.
Shipboard cultures -- Natural assemblages of phytoplankton will be collected and incubated to produce a shipboard "bloom" in 8-l bottles incubated in our surface water (light and temperature) incubator. This will allow us to follow the dissolved (nutrients, gases) and particulate constituents during the development of the bloom for the purpose of gaining information on reaction stoichiometries, bulk elemental ratios and microbial dynamics. These "ecosystems in bottles" approach will help us to gain closure with our work on the natural populations.
Extrapolation factors -- Many of our measurements of biomass and metabolic activities are indirect measurements that rely upon empirically-determined extrapolation factors to derive more meaningful estimates of carbon and energy flow. We have already conducted some field calibrations but more are required. These will be done as time permits.
Archaea in Antarctica -- Professor Ed Delong (UCSB) has made an extremely interesting and potentially very important observation regarding the numerical dominance of archaea in surface waters of Arthur Harbor during a previous LTER cruise. This work needs to be repeated and extended to offshore waters and to ice communities. Water samples will be concentrated by vortex flow and the particulate materials will be collected and stored frozen for nucleic acid probing at UH and UCSB. This work will be continued by Craig Moyer on the LTER annual cruise.
Hydrogen peroxide dynamics -- We intend to complete our 2-year comprehensive investigation of H₂O₂ concentrations, sources and sinks by performing experiments to look primarily at dark decay processes and rates. We also plan to investigate the relationships between DOM molecular weight and H₂O₂ photoproduction and to investigate the coupling of the photoproducts to bacterial metabolism. To the extent possible, this work will be coordinated with the Mopper/Kieber team.

This list is not conclusive and it has been prepared by Karl over a holiday weekend in a relative vacuum and has included only project S-046 plans. I may have omitted some critical items but the bulk of the planned research activities are covered here. I'm looking forward to an exciting cruise.