01Jan LMG01-01 Annual Cruise 10 jan 01 - 24 jan 01 Annual sampling for the nineth Palmer Long-Term Ecological Research (LTER) January cruise was completed. The LTER stations were held on the the Western Antarctic Peninsula LTER meoscale grid. Sampling was also conducted within the foraging area of Adelie penguins whose reproductive success and foraging ecology was being studied simultaneously by investigators at Palmer Station. During the 2001 cruise aboard the Research Vessel L.M.Gould (LMG01-01), sampling occurred between 10 January and 24 January with full crew, 6 Antarctic Support Associates, and 21 LTER participants. In addition we retrieved and re-deployed the station E and Hugo sediment traps. The moored sediment trap array near Hugo Island now includes an ice sonar that senses both the presence and thickness of sea ice. This is the eleventh deployment at the Hugo site. Cooperative studies with scientists at Rothera Station continued, with British Antarctic Survey scientists joining the LM Gould on January 22. Sampling was done aboard the Laurence M. Gould (LMG01-01). Robin M. Ross, Chief Scientist Each austral summer since 1993, the Palmer Long-Term Ecological Research (LTER) program has surveyed the continental shelf and slope west of the Antarctic Peninsula and between Anvers and Adelaide Islands. Standard measurements at stations 20 kilometers apart with CTD on cardinal transect lines (600 through 200) with XBT between stations (10 km grid). The relative distributions of the predator (Adelie penguins) and prey (Antarctic krill) were observed on a high density grid at 2.5 km spacing. Because of the shortened cruise, we had to modify the standard sampling plan, and decrease the spatial resolution on both the 500.* and 300.* cardinal lines. Sampling West Coast Antarctic Peninsula including near Palmer and LTER grid. Grid lines 600, 500, 400, 300, 200 (500 and 300 shortened) High Density Grid Sediment Trap Hugo Sediment Trap PalE Rothera Station Avian Island Preliminary analysis of selected samples from the 600.*, 500.* and 400.* transect lines has been completed. Chlorophyll and production analyses show the typical offshore gradient. For the top 30m, nearshore values range from three to seven mg/m^3, while offshore, the concentrations were < 0.8 mg/m^3. Measurements of oxygen concentration, phycoerythrin, ectoenzyme activity, net community oxygen production and respiration are currently being made on board. Initial analysis of the 600, 500 and 400 LTER grid lines show surface water oxygen concentrations range from 351 to 409 umols/liter with the highest concentrations found in the Palmer Basin area. Areas of high surface ocean oxygen concentrations correlate with high rates of net community oxygen production of 24 umols O2/liter/day suggesting an active phytoplankton bloom. The 600 line production is slightly above the 92-99 January average, with the diatom bloom at the inside stations driving production levels as high as 0.92 gC/m^2. The 500 and 400 lines, however, show a slightly lower than average production, with the lowest levels seen at the outside of the 400 line (0.07gC/m^2). HPLC pigment analysis is being done on all samples, and we have also collected fluorescence data using a Chelsea Instruments Fast Repetition Rate Fluorometer at least one station per day in conjunction with BP-032-O optics work. On the 600.* LTER grid line, Antarctic krill and salps (Salpa thompsoni) co-occurred at all stations, with highest numbers of salps at mid- and outer shelf stations, and highest numbers of krill at the mid-shelf stations. However, on both the 500.* and 400.* LTER grid lines salps were sparse, and Antarctic krill numbers were of the same order as on the 600.* line. Unlike most Januaries during this 9 year time series, spawning of Antarctic krill was intense on all three lines, with spawning frequencies ranging from 9 to 15% of mature females per day. Chinstrap penguins (Pygoscelis antarctica) have been observed along the 600 - 400 (LTER) grid lines in unprecedented numbers and were particularly abundant off the shelf break along the 600 grid line. Along the 600 and 500 grid lines, overall seabird abundance was highest off the shelf break. Species richness was also greatest off the shelf break along the 600 line. Although there was no observable trend in richness or abundance relation to the shelf break on the 400 line, there was a noticeable increase in seabird abundance over the continental shelf at stations 400.140 and 400.160. Two days of winds gusting over 30 kts at times slowed our progress somewhat, but we were still able to deploy most instruments. The optics package and the FRRF were not deployed on several occasions due to the seas. A central tenet of the PAL is that the annual advance & retreat of sea ice is a major physical determinant of spatial & temporal changes in the structure & function of the Antarctic marine ecosystem, from total annual primary production to breeding success in seabirds. Evaluation is ongoing of a number of testable hypotheses linking sea ice to 1)the timing & magnitude of seasonal primary production, 2)the dynamics of the microbial loop & particle sedimentation, 3)krill abundance, distribution, & recruitment, and 4)the breeding success & survival of apex predators. The PAL program includes spatial sampling during annual and seasonal cruises in portions of our regional grid in th Western Antarctic Peninsula region & temporal sampling from spring through fall (October through March) in the area adjacent to Palmer Station. The program is designed to sample at multiple spatial scales within one regional scale grid, permitting repeated sampling on both seasonal and annual time scales, thus addressing both short & longterm ecololgical phenomena, as well as provding a basis for specific mechanistic studies. Sampling is designed to (1) document spatial and interannual variation in core physical and biological variables along and offshore; (2) to investigate the linkage between marine resources and Adelie penguins during a time of peak food requirements for the chicks; and (3) to maintain seasonal sampling on the Palmer nearshore stations. The cruise specifically continued: 1) cardinal grid line sampling 2) high density grid sampling 3) repeated inshore Palmer grid station sampling 4) picket line sampling 5) sediment traps turn-around the new sampling items included: *) Avian Island diet sampling *) BAS comparison sampling *) drifter deployment Standard station measurements included: a PRR/PUV cast to measure downwelling and upwelling radiation in UV and visible wavelengths; a shallow CTD cast with a HydroScat to measure backscattering in 6 visible wavelengths; a core CTD cast with full bottle sampling to characterize the gases, nutrients and living microorganisms, including primary producers, in the water column; 2 net tows with simultaneous bioacoustic transects; and seabird observations. Experiments were conducted at selected stations with the microorganisms and Antarctic krill collected. Both measurements of backscattering and of the spectral absorption by total particulate, detrital and chromophoric dissolved organic matter were parameters added by graduate student research projects. Underway measurements between stations included: seabird distributions; bioacoustics (120 kHz); continuous surface temperature, salinity, fluorescence, carbon dioxide partial pressure (as measured with a carbon dioxide equilibrator system), dissolved oxygen, pH and nitrate; and discrete samples taken at hourly intervals for nutrients and chlorophyll a. Core measurements available two years after the cruise. Citation acknowledgement: "Data from the Palmer LTER data archive were supported by Office of Polar Programs, NSF (OPP-9011927)." antarctic, southern ocean, bio-optics, phytoplankton, krill, marginal ice zone ~lter/data/01jan/* National Science Foundation, Division of Polar Programs 24Jan04 Karen S. Baker Robin Ross