MS Nella Dan Voyage V5 1984/85 (SIBEX2) Track and Underway Data

This dataset contains the underway data collected during the MS Nella Dan Voyage V5 1984/85 (SIBEX2).Voyage name : Second International BIOMASS Expedition Phase II Voyage leader: H J Marchant Underway (meteorological) data are available online via the Australian Antarctic Division Data Centre web page (or via the Related URL section).BIOMASS (Biological Investigation of Marine Antarctic Systems and Stocks) , an international collaborative research program, was established in 1976 to run for 10 years with the aim of gaining a deeper understanding of the structure and dynamic functioning of the Southern Ocean marine ecosystem to provide a basis for any future management of the living resources.FIBEX (the First International BIOMASS Experiment), conducted in 1981, focussed on determining the distribution and abundance of the Antarctic krill, Euphausia superba, in two areas of the Southern Ocean, the Scotia Sea and Prydz Bay. In the latter area Australia worked together with France, Japan and South Africa.In SIBEX I, the first phase of the Second International BIOMASS EXperiment, conducted in 1984, the main emphasis was on oceanography. Because of logistic problems, Australia was unable to devote as much time to this project as was planned and officially withdrew, renaming its short cruise ADBEX II.The participants agreed that the principal activities of SIBEX II, the second phase of the Second International BIOMASS Experiment, were to be investigations of the biological processes occurring in the Southern Ocean. The Chief Scientists from the nations involved in research in the Prydz Bay area (Australia, France, South Africa and to a very limited extent, Japan) met in Hobart in September 1984, at the time of the meeting of CCAMLR (The Convention for the Conservation of Antarctic Marine Living Resources) to plan and coordinate their activities.Within the study area, 60 S to the Antarctic Coast and 58 to 93 E, a series of North-South transects were sailed. At intervals of 1 degree of latitude and 5 degrees of longitude, hydrographic stations and net samples were taken.A number of integrated activities were undertaken on this cruise. The cruise track and the spacing of the stations were designed to provide data on the distribution and abundance of adult as well as the juvenile stages of krill. In addition, other grazing invertebrates as well as fish, particularly larval stages, were sampled with a rectangular mid-water trawl (RMT 1+8) having nets with effective mouth areas of 1 and 8 metres squared.At the hydrographic stations, taken in conjunction with the net trawls, a profile of temperature, salinity, oxygen concentration and light intensity was measured from the surface to 600 metres (or to the bottom on or near the continental shelf) with a Neil Brown Mark 3 CTD apparatus. During the latter part of the cruise, equipment failure prevented oxygen profiling and limited the recording depth to 600m. Samples were taken at standard depths (0, 10, 25, 50, 100, 200 and 500m) with 5L Niskin bottles on a rosette sampler attached to the CTD apparatus for nutrient analysis and to ascertain the species diversity, abundance and productivity of phytoplankton, the food of the grazers.Hull-mounted echosounders operating at 120kHz and 38kHz were operated south of 60 S providing data along about 4600n.miles of cruise track on the distribution and abundance of planktonic organisms, including krill.The birds in the vicinity of the ship were identified and counted hourly and all whale sightings recorded. Meteorological, sea-ice and iceberg observations were also made.As well as this survey and routine monitoring, a variety of experimental and other studies were carried out. These included investigations of the metabolic rate, feeding, fecundity and hatching, swarming behaviour and sound production of krill.Phytoplankton and various stages in the life-cycle of krill as well as tissue and organs were prepared for later electron microscopical examination.Three moored current meter arrays, each consisting of 3 current meters at different depths as well as a CSIRO drifting buoy, drogued at 50m, were deployed to provide long-term information on the dynamics of the circulation in Prydz Bay.Photography of the seabed with a Benthos camera and flash was attempted at 3 stations before the breakdown of the main hydrographic winch.Samples were taken while returning to Hobart to investigate changes in the distribution and abundance of certain groups of phytoplankton and their relation to the concentration of reduced sulphur compounds. At 50 S zooplankton were sampled with a net trawl at 1000m.