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CTD > Conductivity, Temperature, Depth

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  • 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.

  • 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).

  • 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.

  • 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).

  • Size fractionated chlorophyll a data (total and less than 20 µm) analysed using high performance liquid chromatography (HPLC). Underway samples were taken using a seawater line in the oceanographic lab on RSV Aurora Australis (approx. depth 4 m). CTD samples were taken using Niskin bottles attached to a CTD rosette. Six depths were sampled per station, based on fluorescence profiles from the CTD. Two of the two of six samples always included both near-surface (approximately 10 m) and the depth of the chlorophyll maximum where applicable. HPLC analyses were conducted according to the method of Wright et al. (2010). Column chlorophylls (µg L-1) and integrated chlorophylls (mg m-2) are shown in two separate tabs within the Excel spreadsheet.

  • 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.

  • 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.

  • Metadata record for data from ASAC Project 2393 See the link below for public details on this project. ---- Public Summary from Project ---- This project seeks to monitor Holocene-Quaternary variability of Antarctic bottom water outflow at a known deep pathway (east flank of Kerguelen Plateau) into a major ocean basin. Specifically, we can address the question of how sea-ice, frontal dynamics and SST variability are related to bottom-water production. Taken from the 2003-2004 Progress Report Two researchers from the ACE CRC and IASOS, Dr. Will Howard and Honours student Joanne Naylor, participated in a cruise to the Southern Kerguelen Plateau region in January-February 2004. The objectives were to carry out swath bathymetric mapping, subbottom profiling (using a 3.5 kHz echosounder), and coring, aboard the Japanese research vessel Mirai. We were successful in carrying out acoustic profiling and mapping in previously unmapped regions of the Southeast Indian Ridge and in the Labuan Basin area of Southern Kerguelen Plateau. Acoustic data have already been provided to Geoscience Australia, where these data will be incorporated into existing databases of bathymetry and bottom character of this (potential) part of the Australian Marine Jurisdiction. In addition we recovered two piston cores, one each from the SE Indian Ridge area and Kerguelen Plateau, as well as multicores (recovery of sediment-water interface). Inclement weather prevented us from recovering cores from all the suitable coring sites we identified, but we now have acoustic survey data in unprecedented detail and resolution to support future sampling efforts. The cores we recovered consist of pelagic sediments as follows: Split surfaces of archive half sections were exposed and lithological and sedimentological features were described using printed visual core description (VCD) sheets On MR03-K04 Leg 6, ODP-style nomenclature for lithological description (e.g., Mazzullo et al., 1988) was adopted. Results from smear slides, coarse-fraction microfossil observations were combined to construct summarised lithologic columns. This information was also confirmed by the later inspection of soft X-radiographs. Smear-slide descriptions and sieve sample also provide preliminary biostratigraphic estimates of base ages for the piston cores. Results In general, the sediments at both sites are composed of homogenous fine-grained pelagic sediments with extensive, though varying, bioturbation throughout. The lithological and sedimentological features are summarised as graphic columns with short notes, including a legend of symbols and lithologic patterns (Figures D-2-1, D-2-2, D-2-3). Digitised versions of individual VCD sheets and scanned soft X-radiographs used for constructing graphic columns are archived in the Appendix to this report. Southeast Indian Ridge (41 degrees 33.07'S, 90 degrees24,39 E, water depth: 2,913 m) The sediments from MC-05 and PC-05 from the northern flank of Southeast Indian Ridge are dominated by foraminifer-bearing nannofossil ooze. Foraminifera and nannofossils are abundant and well-preserved throughout the core. A qualitative analysis of the planktonic foraminiferal faunas from sieve samples taken at the base of the piston core and the top of the multicore show a diverse assemblage typical of coretops in the Southern Indian Ocean near the modern position of the Subtropical Front Zone, with abundant Globorotalia inflata, Globigerina bulloides, Globigerinita glutinata, and dextral Neogloboquadrina pachyderma (e.g. Howard and Prell, 1992 and 1994). The diatom Hemidiscus karsteni appears to be present in the core base whereas the radiolarian Stylatractus universus appears to be absent. These suggest a base age for PC-05 older that late Marine Isotope Stage (MIS) 7 (approx. 194 ka BP) and younger than late MIS 12 (approx 423 ka BP)*. Flow-in is severe in Sections IX and X and the core catcher of PC-05 (i.e. approx. the bottom 1.5 meters of the core). Comparison with the multicore indicates that the top of the piston core is also moderately disturbed by the piston action. Kerguelen Plateau (53 degrees 48.15'S, 81 degrees 52.75'E, water depth: 2,557 m) The sediments from MC-06 and PC-06 from Labuan Basin, Kerguelen Plateau are dominated by radiolarian-bearing diatom ooze with dispersed foraminifera, detrital grains, and rare nannofossils. Dispersed sand-to-gravel sized rock fragments are present in the core, indicating intermittent ice-rafted debris deposition. The soft X-radiographs similarly show the alternation of almost pure biogenic ooze with more clay-rich oozes with dispersed detrital grains. Though the core is bioturbated to some extent throughout its length, 1-2 cmscale laminations occur in Sections 3-8. Foraminifera present through core in varying states of preservation; nannofossils intermittently present. The planktonic foraminiferal assemblages are typical of coretops in the Subantarctic and Polar Front Zones, dominated by sinistral Neogloboquadrina pachyderma, Globigerina quinqueloba , and G. bulloides, with lesser contributions from globorotalids like Globorotalia crassiformis and and G. inflata. H. karsteni appears to be present from Section 6 (500 cm bsf) down, and abundant in Section 8, from 86 cm down (from approx. 786 cm bsf). The planktonic foraminifer G. crassiformis is present in the base. S. universus appears to be absent throughout the core. This preliminary estimate of the biostratigraphy suggests a base age for PC-06 older that late MIS 9 and younger than MIS 12 (i.e. between approx. 423 and 300 ka BP). The top 176 cm of this core are severely disturbed, being 'washed' during core recovery by water trapped in the core barrel by the stuck piston. All cores were also logged for geophysical properties and optical reflectance (an index of sediment properties). Also see the JAMSTEC (Japan Agency for Marine-Earth Science and Technology) site for more information.

  • 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