From: "Ray Smith" Subject: Initial Report NBP01-05 Palmer LTER Sea Ice Cruise Date: Sat, 8 Sep 2001 10:23:33 -0700 Cruise Plan - Palmer LTER Sea Ice Cruise - NBPalmer (NBP01-05) This is the initial report of the second LTER Sea Ice Cruise (information with respect to the Palmer LTER and our first sea ice cruise may be found on our web site http://www.icess.ucsb.edu/lter). Thanks to the professional and excellent help from Raytheon technical support and the ship's officers and crew our cruise preparation went smoothly and we departed Punta Arenas 1500 on 7 Sept under partly cloudy skies and light winds. Currently (0700 8 Sept) we are headed south off the coast of Tierra del Fuego with light winds and calm seas. We expect to clear Cape Horne and enter the Drake Passage about 0200 on 8 Sept. Cruise dates and general location: 7 Sept - 19 Oct 2001 Punta Arenas to Punta Arenas We will be working within the LTER grid to the west of the Antarctic Peninsula. Cruise Objectives: NBP01-05 will be a sea ice process cruise during winter/spring to investigate & understand sea ice retreat processes & the relationship of these processes to the biota during this sea ice retreat period. Observations at the ice edge & in the ice will be designed to address short-term mechanistic processes & hypothesis linking sea ice, micro algae, krill, penguin & export processes. We will also study processes associated with the deposition of persistent organic pollutants (POP)in Antarctic food webs. Sea ice is critical to the Antarctic marine ecosystem & it has been hypothesized that biological material is incorporated into sea ice during it's formation and this material grows & is subsequently utilized within the system during the following winter & spring. Sea ice conditions in spring & early summer are hypothesized to be characterized by the melting cycle where there is a return of particulate organic material(POC) back into the water column either as a seed for phytoplankton bloom or enhanced sedimentation. The retreating pack ice is expected to have primarily krill larvae under the ice, with progressively older stages of krill associated with the marginal ice zone (MIZ) &/or ice bloom. Investigations during NBP01-05 will include: 1. Revisiting the stations where sea ice buoys were deployed during the winter (SOGLOBEC) cruises and to investigate the sea ice and snow characteristics at the sea ice buoy locations and how these characteristics have evolved over time. 2. Recovering the sea ice buoys when work at these time series stations have been completed. 3. Continuing observations in collaboration with the SOGLOBEC research objectives begun during July/Aug including Martinson/Perovich/Smith snow/ice optics research, Ross/Quetin krill and Fraser sea bird research; 4. Making snow & sea ice observations consistent with, and complementary to, our june99 cruise. 5. Studying the degree of coupling between krill and ice and the associated physical characteristics for sea ice. 6. Studying linkages between processes associated with krill, ice algae, nutrients, gases, bacteria & particle flux. 7. Testing hypotheses & mechanisms by which anthropogenic compounds are introduced into, and affect the relatively pristine Antarctic environment. 8. Quantification of the relative contribution of ice-related production compared with production driven by non-ice processes. 9. Obtaining diet samples from tagged and satellite tracked Adelie penguins (with comparison to net tow samples) and studying the relationship of the distribution of Adelies during the sea ice retreat period as they approach their first critical period for breeding. Specific Objectives include: 1) Recovery of sea ice buoys placed during July/Aug SOGLOBEC cruises. Currently there are four ice buoys being tracked by satellite: 7413 located roughly 100km west of Adeliade I; 7949 near the mouth of Marguerite Bay; 7440 inside the mouth of Marguerite Bay; 7950 about 100km west of Alexander I. These locations provide a north/south gradient of sea ice development, evolution and decay. Dependent upon sea ice conditions, three of these buoy locations will selected for roughly 5-day sea ice processes stations. 2) Finding the location of tagged Adlies. Many of these penguins are currently feeding in the polynya off the south coast of Adelaide I. We will obtain diet samples from penguins on the pack ice near this area as well as carry out MOCNESS tows in the open water of the polynya to investigate winter feeding habits of these upper level predators. 3) Test the hypothesis that biological material incorporated during the frazil ice fall formation, as well as subsequent snow-ice formation, includes this biological material and investigate processes associated with it's increased concentration relative to the water column. We will also study the evolution of this biological material over time and evaluate the distribution and condition of this material. Processes associated with the deposition of persistent organic pollutants (POP) will be studied. 4) Carrying out studies across the light gradient - from above to below the Antarctic circle - to investigate the growth and development of algae with respect to the availability of light across this latitudinal gradient. Optical properties of snow & sea ice will also be determined across this north/south gradient of snow/ice formation, evolution and decay. 5) Sediment traps will be deployed beneath the ice at our multi day ice stations. 6) Diver sampling of the underside of the sea ice sill be carried out and this will be coordinated with above surface snow/ice transects & sampling. 7) Determine physical, optical, pigment and POP characteristics of snow and sea ice cover during all sea ice stages encountered during cruise. 8) Determine physical, optical, chemical and biological characteristics of the underlying water column. 9) Determine occurrence and deposition of POP's on sea ice and into the water column. Station Locations (sea ice & weather permitting): 1) CTD station first opportunity in 3000 meter water depth. 2) CTD stations at 600.040 & 600.080 3) Ice process station at location of 7413 - if sea ice conditions permit this buoy will left to operate until the end of the cruise. 4) Adelie penguin diet samples and MOCNESS tows in Adelaide I polynya. 5) Ice process station at location of 7949 - again, if ice conditions permit this buoy will remain until later in the cruise. 6) CTD stations along 200 line. 7) Ice process station at location of 7959 - recover buoy at end of station 8) Alexander I polynya - Adelie diet samples if satellite tracking shows their location. 9) Repeat ice process station at location of 7949 - recover buoy at end of station. 10) Return to Adelaide I polynya if time permits. 11) Repeat ice process station at location of 7413 - recover buoy at end of station 12) CTD stations at 600.040 & 600.080 (& others as time permits) Ray Smith, Chief Scientist