(Message inbox:138) Date: Wed, 24 Jan 2001 21:29:36 -0300 To: mo-sciweekly@polar.org, mpc@lmg.polar.org, verretro@lmg.polar.org, alsuther@nsf.gov, kerb@nsf.gov, ppenhale@nsf.gov cc: rossro@lmg.polar.org, kozlowwe@lmg.polar.org, Menzies Dave , Carrillo Christopher , Chapman Erik , iresonki@lmg.polar.org From: "Ross, Robin" Subject: LMG01-01 14 -20 Jan 2001 Palmer LTER cruise Return-Path: rossro@lmg.polar.org Delivery-Date: Thu Jan 25 06:48 PST 200 Mime-Version: 1.0 X-Sender: rossro@mail.lmg.polar.org Content-Length: 5002 LMG01-01 2001 January LTER cruise: 14 - 20 January synopsis During the week of January 14-20 of the annual Palmer LTER summer cruise, we continued to occupy stations on the cardinal lines, and collect data on multiple aspects of the ecosystem, from hydrography to seabirds. 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. There are 5 cardinal lines occupied in the LTER study region during summer, e.g. 200.*, 300.*, 400.*, 500.* and 600.* between the southern ends of Adelaide and Anvers Islands. We completed the revised schedule of stations on the 500.*, 400.* and 300.* transect lines, and the inner half of the 200.* line during this week. 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. D. Menzies is investigating the potential sources of the occasional spiking showing up during CTD casts. Support from both RPSC and Captain Verret and the ECO crew has been essential and helped us to maintain a very intense sampling schedule. Preliminary analysis of selected samples from the 600.*, 500.* and 400.* transect lines has been completed, and each team has summarized these shipboard analyses. Additional results will be done in the laboratories of the home institutions. The PI for each team is in parentheses after the science code. BP-032 (R. C. Smith) - Kirk Ireson and Sara Searson Chlorophyll 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. The shallowest 1% light level was at the 600.100 station (19m), while the deepest was at 85m (station 400.200). Daily optics casts with the AC9/Hydroscat package have been going well. On the eighteenth, we had very clear weather, so two optics casts were done with the hopes of getting a good comparison with satellite data. BP-046 (D. Karl) - Chris Carrillo, Lance Fujieki, Daniel Hover, Matt Church, and Jenn Brum. 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. BP-016 (M. Vernet) - Wendy Kozlowski, Karie Sines, Karen Pelletreau, Erin Macri, Silvia Rodriguez, Mike Thimgan Preliminary estimates of primary production along the 600, 500 and 400 LTER grid lines have shown similar trends as the chlorophyll, with clear onshore-offshore as well as North-South gradients. 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. BP-028 (L. Quetin and R. Ross) - Robin Ross, Stephanie Oakes, Christopher Holmes, Jordan Watson, Holly Rodrigues, Brian Fredin 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. BP-013 (W. Fraser) - Erik Chapman and Heidi Geisz 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. Regards, Robin Ross, Chris Carrillo, Wendy Kozlowski, Kirk Ireson, Erik Chapman, David Menzies