Date: Thu, 28 Jan 1999 00:26:50 GMT To: ALSUTHER@nsf.gov, KERB@nsf.gov, mo-sciweekly@asa.org From: rossro@lmg.polar.org (Robin Ross) Subject: LMG99-01 science weekly Jan 18-24 Cc: sanamowa@lmg.polar.org, asalmg@lmg.polar.org, shawca@lmg.polar.org, patterka@lmg.polar.org, duleype@lmg.polar.org, kozlowwe@lmg.polar.org, tupaslo@lmg.polar.org Dear Colleagues, During the week of Jan 18-24 research activities for the Palmer LTER on the LM Gould were more diverse than early in the cruise. We completed the 600.* line, one of the five core transect lines, which is 20 km south of Anvers I. and runs off shore for about 220 km. We occupied 11 stations on this line from the base line in LeMaire Channel to the outermost station in 3000 m of water. As with the previous two core lines, we collected alongtrack data between each pair of stations for our analysis of determinants of spatial patterns. Midway along the 600.* line the calm seas provided an opportunity to retrieve the Hugo Island sediment trap in record time, with seeming great ease and to the accompaniment of whistles and cheers. The best show in town! The Hugo Island trap had been in place since January 1998, and the containers showed distinct periods of low and high particle flux. During this time we also conducted two bathymetric surveys of a small area just outside the Outcast Islands near Palmer Station to find a relatively flat spot for placement of a second sediment trap. The Palmer sediment trap is close to one of the nearshore stations, but in deeper water and away from the common pathways for the vessels. The trap was deployed in the early morning hours of 23 Jan. We also occupied the Palmer LTER nearshore stations and acoustic transects to continue the seasonal sampling program conducted with zodiacs from Palmer Station in the spring and summer. Two days in a row poor visibility from fog (Jan 22) and a storm (Jan 23) prevented us from running the high density foraging grid. The HD grid is a fine resolution grid (2.5 km) set up to study the effect of marine resources, e.g. krill distribution and biomass, on the distribution and foraging duration of Adelie penguins rearing chicks. On 24 Jan we were able to run the grid, losing only a small portion of the bird observations to poor visibility. During this period we also collected krill from three locations within the foraging area but at different distances from the colony. The length measurements and catch composition will be compared to samples of the diet of the Adelie penguins taken by LTER researchers at Palmer Station. Fortunately the weather broke in time for us to complete the HD grid before the period of peak chick growth finished. For multiple reasons we made a 3.5 h call at Palmer Station in the early evening of 22Jan. First, the Caledonia Star was due to call at Palmer Station and leave a T-C duct for pickup by the LM Gould so we could operate the CTD in dual sensor mode for the remainder of the cruise. Second, early this week the performance of one of the primary laboratory instruments, a Lambda 6 spectrophotometer, degraded sufficiently to necessitate an exchange of instruments at Palmer Station. Many additional tasks were accomplished during the call. We put live krill collected a few days before in the aquarium for a BBC film crew to photograph later in the month, weighed chemicals and samples so analysis could proceed on board the vessel, and mended a large net with the sewing machine on station. Rich Iszard-Crowley, the ASA computer technician, also gave several large CTD files to Palmer Station personnel to ftp to the LTER PI analyzing the data. With his input and the installation of the T-C ducts we hope to improve the precision of the sensors to the extent that Marc Pomeroy, the MST, will no longer have to run 'salts'. Many thanks to the Palmer Station inhabitants for their helpfulness and to Randy Sliester, the MPC, for manning the sewing machine. The skies continue to be primarily overcast, with the only bright sun late in the afternoon of the day we docked at Palmer, after spending most of the day in dense fog. The CTD traces showed some spiking at the seaward end of the 600.* line, but the problem was solved by ASA personnel on board by the next morning. Revision of the schedule helped minimize the impact of the CTD downtime. The support of both the ASA personnel on board and Captain Warren and his crew has been unstinting. We are currently conducting station work on the 400.*line, about 220 km south of Palmer Station. Robin M. Ross, Chief Scientist LMG 99-01 (99Jan LTER)