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SIPEX

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  • This dataset contains data resulting from the measurement of brine samples extracted from the sea-ice during the 2012 SIPEX 2 (Sea Ice Physics and Ecosystems Experiment) marine science voyage. The Brine was collected from partially drilled holes in the ice using suction. In some of these cases the brine analysed came from holes which correspond to permeability measurements. In these cases a core number is associated with the brine data which will correspond to the core number in the permeability data set found in the master core list Excel file. The purpose of this data set was to act as a first step to quantify the effect that extra cellular carbon may have on the physical properties of brine and sea ice. At least 1 litre of brine was collected from each partial hole for analysis. The total sample was split for the following analyses. Viscosity of the brine was measured before and after filtering out any biological components that may have been in solution or otherwise in order to assess whether or not extracellular carbon has an effect on fluid flow in sea ice. What was not used for viscosity measurements was used for chlorophyll, extra-cellular carbon and bacterial analysis to gain a sense of the level and type of biology and biological compounds in the brine to then be compared to the measured physical properties. The biological analysis will be carried out at the university of Tasmania by Sarah Ugalde. On many of these samples the complex permittivity of the brine was also measured and the data can be found in the Relative_Permitivity_of_Brine folder with each sample corresponding in core number. For info on the permittivity measurements please see the metadata in that folder.

  • We checked each site by taking ice cores and observing the algae biomass to determine the likelihood of krill living under the sea ice in each location. We also used a Remotely Operated Vehicle (ROV) with cameras attached to observe the abundance of krill under the sea ice. If krill were present we used on the sea ice floe a zooplankton pump, called MASMA, according to Meyer et al. 2009, whereas at the edge of the floe column a custom-built fish pump system was used to collect krill near the surface. The Aqualife Biostream BP40 fish pump was capable of pumping up to 1300 litres per minute without harming animals that pass through the pump. For much of the voyage it was operated from the ctd room and at this increased suction head it ran at about 500 litres per minute. Krill were caught at ice stations 2, 6, 7 and 8. The Krill Sample-Overview.xls file contains information regarding how many krill were caught at each ice stations, who was involved and related information. The SIPEX II Krill Voyage Report.docx contains information about the various issues that were encountered during the voyage. It also contains information from the Bottom Krill experiment, which has its own dataset and metadata record. It is duplicated in both datasets. The larvae were used for a growth experiment using the IGR method and after length measurements frozen for carbon, nitrogen, lipids, stomach and gut content analysis. The total and carapace length were determined of juveniles as well as their digestive gland size. Animals were than dissected and tissues frozen at -80C for further analysis (see above). These condition parameters will be discussed in relation to physical and biological environmental parameters of the ice floe (e.g. sea ice thickness, snow coverage, under ice topography and biomass). When this data is analysed, the dataset will be updated to include analysed versions of the data listed in the Krill Sample-Overview.xls file. Also included in the dataset are technical documents and manuals pertaining to the fish pump that was used. Meyer B et al. 2009. Limnol Oceanogr 54:1595-1614

  • DC Electrical: In order to relate the fluid permeability to the electrical properties of sea ice, we also took measurements of the vertical component of the DC electrical conductivity tensor of sea ice. Cores extending to the bottom of an ice floe were taken and laid out holder. With the exception of sites 7 and 8 where we encountered a slush layer below the hard ice and could not core down to the ocean. The core bottom was determined at sites 7 and 8 to be the ice slush interface. Immediately upon extraction, holes that fit our thermistor probes were drilled every ten centimetres and a temperature profile was taken. Subsequently, slightly larger holes were drilled which fit our electrical probes (stainless steel nails). An AEMC Earth Resistivity Meter was then used to measure the resistance over 10 cm sections of the core (usually offset by 5 cm so that the measured temperature was in the centre of the section where electrical resistance was measured). The cores used in resistance measurements were taken very close to where the crystallographic cores were taken. In almost all cases the cores extracted for electrical measurements were also used for crystallographic analysis, so that there was an exact match of electrical properties with crystal structure. In such cases the DC electrical cores were then moved to a -20 degree C cold room for further processing immediately after measurements in the field. A thin vertical section, approximately 3mm thick, was taken from each of the cores stored for analysis. These sections were placed between a pair of cross polarized plates and photographed. Each photo was labelled with the core and date it was taken, and was photographed with a meter stick alongside for scale. After the thin sections were photographed, the remaining samples were melted to measure salinity. Some of the melted sea ice was saved for later O18 analysis to distinguish samples containing snow ice from those containing marine granular ice. The temperature and salinities we are then used to calculate brine volume fractions along the 10 cm sections of the core. The DC conductivity data collected can be found in the Electrical tab of the Master_Core_List.xls Excel file. The raw data can be found in the scans of our field note books located in the folder named notebooks. In the spread sheet the measured resistances of the 10 cm sections, temperatures, salinities and corresponding brine volume fractions are listed per core. For each core the supporting crystallography core number can be found in the crystallography column of the spread sheet. The photos of the crystallography cores can be found in the crystallography folder, separated into subfolders labelled with the site and core number, Each photo also contains a tag indicating the core number , site taken , date, and what depth range this covers. Tags may not contain a depth range for cores less than 1 meter. Please see the meter stick in each photo for scale.

  • The intention of the Deep Krill Camera and Trap System was to monitor and capture krill found during deep CTD operations. Two traps were installed on the CTD in place of Niskin Bottles. At pre-determined depths an internal light was illuminated and the traps were opened. After a set period of time a second trigger signal was sent to the traps, closing the entry point, encapsulating any Krill that were inside. The Krill Camera system was installed onto the CTD rosette. It consisted of a high-definition video camera (a GoPro Hero 2) within a pressure housing, flanked by two LED light sources. The power for this system was supplied via a rechargeable battery pack also mounted to the CTD. The camera system was remotely controlled from the surface via the CTD communications link. At specific depths the lights and camera were activated, recording the water column and ocean floor by adjusting focus length for fixed durations in an attempt to document Krill at lower depths. An additional camera was introduced into the system, mounted to allow video capture of the Krill Trap Operation. This camera was set to record at the beginning of the operations and left running for the duration of the deployment. Video data from the Krill camera is in MTS format, which can be opened with VLC Media Player. Trap footage is recorded in MP4 format, which can be opened with Quicktime or VLC Media Player. Trap triggering and camera operation data was recorded manually by Rob King.

  • Multiple CTD (conductivity, temperature, depth) casts were deployed during the SIPEX II AAD Marine Science voyage in September-November 2012. The system uses a descending rosette capable of holding up to 24 CTD bottles. During this voyage the CTD rosette also housed two krill traps (using controllable lights) and two GoPro cameras contained in pressurised, waterproof containers that were used to monitor the krill traps and view objects both on the sea bed and in the water column. Some functions of the GoPro cameras could be controlled from within the ship using the same transmission cable used by the CTD system. These functions included being able to change the focus setting of the cameras or start/stop recording. More information about the krill traps and cameras is contained in the SIPEX II Bottom Krill dataset. When a bottle is 'fired' from the ship it briefly opens, draws in water samples and closes again. It is not reopened until it is brought on board the ship. Bottles are opened at different depths to obtain samples from these depths. The depths vary from cast to cast and so are recorded in the CTD Log sheets (contained in this dataset as PDF files). Only raw data is contained in this dataset. The raw data was used by a variety of experiments during the SIPEX II voyage to produce results applicable to each experiment. Thanks go to the P and O crew of the RV Aurora Australis for their assistance during CTD operations.

  • Gas Flux over Sea Ice ------------- We observed amount of gas exchange between sea ice and atmosphere. At the ice station, semi-automated chambers developed in Japan, were used for measurement of air-sea ice CO2 flux. These chambers could be used to examine spatial variability and also temporal variability of gas flux over sea ice. Samples were also taken from the snow and ice in order to measure CH4 and VOC, however these analyses will be conducted post-voyage. This metadata record will be updated in future to reflect the analysis. The chambers are designed to be placed over a snow and sea ice. When the lid is closed, CO2 concentration was measured. The opening and closing functions of the chambers are automated and were set to a 30 minutes interval. CO2 concentration (as voltage) were recorded in the data logger (CR10X, Campbell Scientific Inc.) and downloaded after the experiments. Raw data are contained in the excel files. During the CO2 flux measurement, we collected the snow, sea ice, brine/slush and under-ice water. Snow and sea ice samples were melted after sampling in PVDF film bags (like Tedlar bags in order to avoid gas exchange with ambient air) in 4C temperature and treated for analysis. A chemical analysis for carbonate systems and VOC (water), salinity, nutrient, pigment and oxygen isotopic ratio samples will take place in Japan after the voyage for analysis. During the cruise, to examine ice growth processes, we made sea ice thin-section to classify the ice cores into granular ice, columnar ice or mixed granular and columnar ice (Eicken and Lange, 1989). The CO2 data are contained in Excel spreadsheets. These use Japanese column headings. Calcium Carbonate (CACO3.6H20) as Ikaite in Sea Ice and Snow ----------- At each listed ice station we collected sea-ice cores using a Kovacs 9cm ice corer. Cores were sectioned into 10-20cm and melted at 4 degrees C, filtered and dried for later analysis of Calcium Carbonate in a home laboratory using an ICP, which produces text file outputs (included). Also included is a spreadsheet listing the cores, and the calcium carbonate measurements.

  • Zooplankton were collected during the winter-spring transition during two cruises of the Aurora Australis: SIPEX in 2007 and SIPEX II in 2012. The umbrella net was 2 metres long, 28 cm2 mouth area and mesh size of 100 um. The net was lowered through holes drilled through the pack ice and lowered to 100 m. It was pulled slowly by hand to the surface, closed and brought back through the ice hole. The contents were preserved in 5% buffered formaldehyde and examined under a Leica M12 in the laboratory. Species were identified to the lowest taxon possible.

  • We observed total thickness (snow thickness + ice thickness) of sea-ice floes along 100m transects using an electromagnetic (EM) sensor. The data were read from the EM and written by hand into a log book as we moved along the transect. They were then transferred into an Excel spreadsheet. The parameters included are: - distance along transect - conductivity (vertical) - conductivity (horizontal) - total thickness (derived from vertical and horizontal conductivities)

  • We set out to achieve floe-scale 3-D mapping of sea ice draft and bio-optical parameters using a Multibeam SONAR and Hyperspectral radiometer mounted to an Autonomous Underwater Vehicle (AUV). The AUV utilised was the 'JAGUAR' Seabed-class vehicle from the Deep Submergence Laboratory at the WoodsHole Oceanographic Institution. The AUV comes with a CTD and ADCP. However these are not deployed as scientific sensors and therefore are unsupported in terms of metadata. In particular the CTD was not calibrated before or during the voyage. The AUV used a LongBaseLine system formed by three transponders to navigate to and from the survey grid. Two were located on the ice and the third was deployed from the back of the ship with an acoustic communications modem. Once at the survey grid beneath the sea ice, the AUV used the DVL to navigate using bottom-tracking of the underside of the sea ice. We conducted 4 missions beneath sea-ice during the SIPEX-II voyage. The current status of the data is that is in un-processed and unavailable until final processing is completed in 2013. Persons interested in the data should contact Dr Guy Williams directly for further information and preliminary figures relating to the AUV missions. The files currently in the archive are in raw form. Some preliminary data is provided for stations 2, 3, 4 and 6 as: floe-2-20120926.mat floe-3-20121003.mat floe-4-20121006.mat floe-6-20121013.mat These can be accessed using the Seabed_plot routines (MATLAB) in this folder. There is a readme file provided called what-is-this.txt Also included is the video footage taken from the AUV using a GoPro HD Hero. Video Codec: avc1 Resolution: 1920x1080 pixels Frame Rate: 29.970030 f/s Audio Codec: mp4a Audio Bitrate: 1536 kb/s Finally, plots of the data for ice stations 2,3,4 and 6 are included in the preliminary figures folder. The file names indicate which ice station the plots are from.

  • CTD casts were taken through holes in the ice floe at various locations during ice stations 3, 4, 6 and 7. Two Seabird 37M microcats were used. One microcat did not log time, whereas the other did. An Idronaut Ocean Seven 304 CTD (manufactured in Italy) was used during ice stations 7 and 8. CSV files are provided. A single file represents a set of casts at a single location. The files are organised in columns as: Column 1: Temperature (C) Column 2: Conductivity Column 3: Pressure Column 4: Salinity (ppt) Column 5: Date (DD MMM YYYY), UTC Column 6: Time (HH:MM:SS), UTC For the Seabird 37M (2006 model) belonging to Dr Hutchings, time on the microcat is set to UTC, to the second. For the AWI Seabird 37M (1999 model), time is not output. This microcat dribbled data to a laptop at 1Hz. Ice Station 3: A microcat was placed at about 7m below the surface (5m below the ice) at Ridge site 1. Salinity sensor was iced up on this cast Ice Station 4: Cast 1: 100m cast through the ROV hole on Oct 6th 10:30 UTC. Cast 2: 10m cast at the trace gas site, on Oct 8th 06 UTC. Cast 3: 100m cast at the trace gas site, on Oct 8th 09:30 UTC. Ice Station 6: Cast 1: 100m at ridge site 1 , on Oct 13th 03 UTC. Cast 2: 10m casts at Trace Gas site, on Oct 13th 04:30 UTC. F Note that salinity sensor was iced on 10m cast at trace gas site. Cast 3: Deployment at 7m depth at ridge site 1, on Oct 13th 06UTC. Cast 4: 100m cast at ridge site 1, on Oct 14th 23 UTC. Note that microcat stopped recording at about 65m in downcast. Ice Station 7: - CTD casts with Seabird 37M microcat: Cast 1: 100m cast, Transducer Hole A, at active ridge. 20th Oct 03:00Z. Power failed 60m into downcast. Cast 2: 30m cast, Y-axis 50m core hole. 20th Oct 05:15Z Cast 3: 40m cast followed by 100m cast. Y-axis 100m ADCP hole. 21st Oct 00:00Z. Power failed at 60m. Cast 4: 15m casts. Y-axis 50m core hole. 21st Oct 05:15Z Cast 5: ROV Hole. With Polly's pinger. 21 Oct 09:30Z. Power failure at 86m. - CTD casts with Gerhard Dieckman's Seabird microcat. Note this microcat does not output time, but dribbles 1Hz data. Cast 6: Transponder Hole near new ridge. 23rd Oct 06:30Z. Cast 7: Trace Metal / Bio site. 23rd Oct 07:30Z. Cast 8: At ROV Hole Ice Station 8: Synoptic (3 hourly) CTD casts Roster of CTD casts is contained in file 'CTD_time.xls'. This table is pasted below. Please note that the names of excel files containing the raw data are presented in this table. Filenames: Ice Station 3: Filename: 20121004/20121004_IceStation3_microcat_all.dat. Ice Station 4: Cast 1: Filename: 20121006_IceStation4_microcat_cast1.dat Cast 2: Filename: 20121008_IceStation4_microcat_cast2_gerhard.dat Cast 3: Filename: 20121008_IceStation4_microcat_cast3_gerhard.dat Ice Station 6: Cast 1: Filename: 20121013_IceStation6_microcat_cast1_ridge.dat Cast 2: Filename: 20121013_IceStation6_microcat_cast2_gerhard.dat Cast 3: Filename: 20121013_IceStation6_gerhardCat_ridge_052700.dat Cast 4: Filename: 20121014_IceStation6_microcat_ridge.dat Ice Station 7: CTD casts with Seabird 37M microcat: Cast 1: Filename: 20121020_IceStation7_microcat_transponder_newRidge.dat Cast 2: Filename: 20121020_IceStation7_microcat_50m.dat Cast 3: Filename: 20121021_Station7_100m.dat Cast 4: Filename: 20121021_Station7_50m.dat Cast 5: Filename: 20121021_Station7_ROVhole_plusPolly2_tryagain.dat CTD casts with the AWI Seabird microcat: Cast 6: Filename: 20121023_gerhardCat.dat Cast 7: Filename: 20121023_gerhardCat_hole2.dat Cast 8: Filename: CTD_jenny_20121023.xls Ice Station 8: Synoptic (3 hourly) CTD casts: The data files are: CTD_jenny_20121023.xls CTD_jenny_20121028.xls CTD_jenny_20121030.xls CTD_jenny_20121031.xls CTD_jenny_20121101(1).xls CTD_jenny_20121101(2).xls CTD_jenny_20121102.xls CTD_jenny_20121103.xls CTD_jenny_20121104.xls