99Jan LMG99-01 Annual Cruise 08jan99-12feb99 Annual sampling for the seventh Palmer Long-Term Ecologica 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 1999 cruise aboard the Research Vessel L.M.Gould (LMG99-1), sampling occurred between 8 January and 12 February with 16 crew, 6 Antarctic Support Associates, and 20 LTER participants. In addition we retrieved and re-deployed the Hugo sediment trap, and deployed a new trap outside the Outcast Islands south of Anvers Island. 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 eighth deployment at the Hugo site. Cooperative studies with scientists at Rothera Station continued, with 16 British Antarctic Survey scientists joining the LM Gould on January 31. On 19 January one of four giant petrels nesting near Palmer Station and fitted with a satellite transmitter was spotted from the bridge. This sighting will provide an accurate test of the Argos positions for this project. Sampling was done aboard the Laurence M. Gould (LMG99-1). Robin Ross served as 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. Sampling West Coast Antarctic Peninsula including near Palmer and LTER grid. Grid lines 500, 300, 600, 400, 200 Inshore Stations: North and South Transect Outside, 600, Inside, 500 High Density Grid Sediment Trap Hugo Rothera Avian Island Sea ice was only encountered in the southern part of Grandidier Channel (inside North), the inner reaches of Crystal Sound (inside South), and Tickle Channel in Marguerite Bay. The skies were consistently overcast, and light levels low even at mid-day. Chlorophyll a and primary productivity values were low, close to baseline, with the exception of the stations in the Grandidier Channel and near Avian Island at the mouth of Marguerite Bay. However surface waters were undersaturated in CO2. For higher trophic levels, salps and krill co-occurred at many stations, with Antarctic krill abundances at average levels. 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) inside island station sampling 5) sediment trap turn-around the new sampling items included: *) spatial transects Inside, Outside, 500line, 600line *) Avian Island diet sampling *) BAS comparison sampling *) sea ice sampling in Crystal_sound *) drifter deployment A fourth objective for 99Jan LTER was to continue a study of spatial variance initiated in 97Jan LTER. Data on a subset of the core parameters were collected continuously both between stations on the 5 standard cardinal transect lines (~ 200 km each), and alongshore both on the outer slope and the inner shelf (~ 200 km each). The fifth objective was to repeat a subset of the initial regime on two of the cardinal transects, one at the north end of the LTER sampling region (600.*) and one at the south end (300.*) to determine if timing of the various processes is the same all over the grid or moves north to south in a temporal sequence. Three major objectives were accomplished on the joint sampling day with BAS: sampling the diet of Adelie penguins nesting on Avian Island; landing of a BAS team on Avian Island to complete global positioning system work; a full water column station, during which we compared data from the LTER and BAS CTDs to 200 m, and did a deep water bottle cast for biogenic N and S gases. 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/99jan/* Palmer LTER: Annual January Cruise for 1999 (LMG99-1); R.Ross and K.Baker, Antarctic Journal of the United States National Science Foundation, Division of Polar Programs 24Apr99 10May00 Karen S. Baker Robin Ross

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