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CTD > Conductivity, Temperature, Depth

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  • At each CTD station the Fast Repetition Rate Fluorometer (FRRF) was carried out onto the trawl deck and shackled (+ cable tie) to the winch cable. When the crew in the aft control room were ready the PAR (Photosynthetically Active Radiation) cap was removed and the FRRF activated with the magnet. It was deployed at a rate of 0.3m/sec to 10m, stopped for 30sec, then the descent was continued to 100m at same rate where it was stopped for another 30 sec. The FRRF was then brought back up at 0.3m/sec to deck. Once on deck the FRRF was turned off, it was hosed down with hot fresh water and the PAR cap replaced. Underway data were collected from the flow-through system in the lab on all South/North transects. West to East legs were not surveyed. The FRRF data were downloaded after every Vertical Drop and at the end of the Underway legs. The post-processing and analysis of data will be carried out after the voyage. The Final dataset is in the form of a Binary file for each drop and Underway leg. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).

  • We deployed CTD sensors on five of the SIPEX 2 ice stations for collecting temperature and salinity of the water column under the sea ice. This dataset contains the raw data as outputted from the CTD in Excel format, in English. The dates that the CTD were deployed are in the file names (i.e. 20121023 is October 23, 2012).

  • Metadata record for data from ASAC Project 1101 See the link below for public details on this project. ---- Public Summary from Project ---- Most of our knowledge of the Antarctic marine ecosystems comes from summer surveys. There are very few observations of this ecosystem in winter and there is a fundamental lack of knowledge of understanding of even basic questions such as 'what is there?' and 'what's it doing?'. The proposed visit to the sea ice zone in winter is a rare opportunity to conduct observations on phytoplankton, krill, birds, seals and whales, so that we can begin to understand the biological processes that go on in winter. Data for this project were intended to be collected on a 1998 winter voyage of the Aurora Australis, but a fire on board meant that the voyage had to return to port before work could be carried out. Data were then collected the following year during a 1999 winter voyage of the Aurora Australis (IDIOTS), which ran from July to September. Data attached to this metadata record, include zooplankton and CTD data collected from the Mertz Glacier region. The data have been compiled by Angela McGaffin, and can be found in the "processed" folder of the download file. Original datasets are also available in the "Original Datasets" folder.

  • Purpose of future metagenomic (DNA), metaproteomic (protein) and metatranscriptomic (RNA) analysis: For each sample, two drums (~200L each) of seawater were collected. Samples were taken from CTD sites, and surface samples (2m depth) taken at each of these sites. At most of these CTD sites, a deeper sample was taken according to the location of the DCM at that site. The 200L seawater is pumped through a 20 micron mesh to remove the largest particles, then the biomass is collected on three consecutive filters corresponding to decreasing pore size (3.0 microns, 0.8 microns, 0.1 microns). This is repeated for each sample using the second 200L of seawater to generate duplicates for each sample. The overall aim is to determine the identity of microbes present in the Southern Ocean, and what microbial metabolic processes are in operation. In other words: who is there, and what they are doing. Special emphasis was placed on the SR3 transect. Samples were collected as below. For each sample, a total of six filters were obtained (3x pore sizes, 2x replicates). Each filter is stored in a storage buffer in a 50mL tube, and placed at -80 degrees C for the remainder of the voyage.

  • As part of Australian Antarctic Science project # 4298 and Antarctica New Zealand project K131A, integrated biological and physical observations were conducted including these series of CTD measurements. The objective of these measurements is to quantify the oceanographic conditions at our field camp off Davis Station in November-December 2015. In situ CTD measurements at the thermistor and the ROV (Remotely Operated Vehicle) sites were deployed using a Seabird-37SMP-ODO MicroCat CTD. Logistics and environmental constraints permitted measurements for seven casts during our deployment at Davis in 2015. The location of the thermistor site is at (-68.57272 degrees N; 77.93273 degrees E), and the ROV site had its origin (x=0, y=0) at (-68.568904 degrees N,+77.945439 degrees E). The software used was the standard SeatermV2 2.4.1.

  • See the referenced paper for additional details. Sampling. Sampling was conducted on board the RSV Aurora Australis during cruise V3 from 20 January to 7 February 2012. This cruise occupied a latitudinal transect from waters north of Cape Poinsett, Antarctica (65_ S) to south of Cape Leeuwin, Australia (37_ S) within a longitudinal range of 113-115_ E. Sampling was performed as described in ref. 29, with sites and depths selected to provide coverage of all major SO water masses. At each surface station, E250-560 l of seawater was pumped from E1.5 to 2.5m depth. At some surface stations, an additional sample was taken from the Deep Chlorophyll Maximum (DCM), as determined by chlorophyll fluorescence measurements taken from a conductivity, temperature and depth probe (CTD) cast at each sampling station. Samples of mesopelagic and deeper waters (E120-240 l) were also collected at some stations using Niskin bottles attached to the CTD. Sampling depths were selected based on temperature, salinity and dissolved oxygen profiles to capture water from the targeted water masses. Profiles were generated on the CTD descent, and samples were collected on the ascent at the selected depths. Deep water masses were identified by the following criteria: CDW 1/4 oxygen minimum (Upper Circumpolar Deep) or salinity maximum (Lower Circumpolar Deep); AABW 1/4 deep potential temperature minimum; AAIW 1/4 salinity minimum 18. The major fronts of the SO, which coincide with strong horizontal gradients in temperature and salinity 19,30, separate regions with similar surface water properties. The AZ lies south of the Polar Front (which was at 51_ S during sampling), whereas the PFZ lies between the Polar Front and the Subantarctic Front. In total, 25 samples from the AZ, PFZ, SAMW, AAIW, CDW and AABW were collected for this study (Fig. 1, Supplementary Data 1). Seawater samples were prefiltered through a 20-mm plankton net, biomass captured on sequential 3.0-, 0.8- and 0.1-mm 293-mm polyethersulphone membrane filters and filters immediately stored at _80 _C31,32. DNA extraction and sequencing. DNA was extracted with a modified version of the phenol-chloroform method 31. Tag pyrosequencing was performed by Research and Testing Laboratory (Lubbock, USA) on a GS FLXb platform (Roche, Branford, USA) using a modification of the standard 926F/1392R primers targeting the V6-V8 hypervariable regions of bacterial and archaeal 16S rRNA genes (926wF: 50-AAA-CTY-AAA-KGA-ATT-GRC-GG-30 , 1,392 R: 50-ACG-GGCGGT-GTG-TRC-30). Denoising, chimera removal and trimming of poor quality read ends were performed by the sequencing facility.

  • 3 CTD casts were conducted during a limited marine science voyage by the Nella Dan to Prydz Bay during the 1985-1986 summer Antarctic season. The voyage leaser was Tom Maggs, and the deputy leader was Peter Heyward. The ship followed the schedule listed out below: Hobart 29-Dec-1985 04-Jan-1986 Edgeworth David 13-Jan-1986 17-Jan-1986 Shackleton Ice Shelf Davis 21-Jan-1986 21-Jan-1986 Marine Science 22-Jan-1986 23-Jan-1986 Marine Science Prydz Bay Davis 24-Jan-1986 26-Jan-1986 Marine Science 27-Jan-1986 27-Jan-1986 Marine Science Prydz Bay Mawson 29-Jan-1986 01-Feb-1986 Davis 03-Feb-1986 04-Feb-1986 Mawson 06-Feb-1986 06-Feb-1986 Davis 09-Feb-1986 09-Feb-1986 Edgeworth David 13-Feb-1986 13-Feb-1986 Shackleton Ice Shelf Casey 14-Feb-1986 14-Feb-1986 Hobart 22-Feb-1986 24-Feb-1986

  • Data were collected during the 1997-1998 austral summer on voyages by the Aurora Australis and Southern Surveyor. Taken from the abstract of the referenced paper: Oceanographic processes in the subantarctic region contribute crucially to the physical and biogeochemical aspects of the global climate system. To explore and quantify these contributions, the Antarctic Cooperative Research Centre (CRC) organised the SAZ Project, a multidisciplinary, multiship investigation carried out south of Australia in the austral summer of 1997-1998. Here we present a brief overview of the SAZ Project and some of its major results, as detailed in the 16 papers that follow in this special section. The Southern Ocean plays an important role in the global oceanic overturning circulation and its influence on the carbon dioxide contents of the atmosphere. Deep waters upwelled to the surface are rich in nutrients and carbon dioxide. Air-sea interaction modifies the upwelled deep waters to form bottom, intermediate, and mode waters, which transport freshwater, oxygen, and carbon dioxide into the ocean interior. The overall effect on atmospheric carbon dioxide is a balance between outgassing from upwelled deep waters and uptake via both dissolution in newly formed waters (sometimes referred to as the solubility pump) and the transport of photosynthetically formed organic carbon to depth in settling particles (referred to as the biological pump). Determining the variations in the overturning circulation and the associated carbon fluxes in the past and their response to increased anthropogenic emissions of carbon dioxide in the future is essential to a full understanding of the controls on global climate. At present the upwelled nutrients are incompletely used. Low light in deep wind-mixed surface layers, lack of the micronutrient iron, and other factors restrict phtyoplankton production so that Southern Ocean surface waters represent the largest high-nutrient, low chlorophyll (HNLC) region in the world.

  • 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.

  • 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.