Particle size spectra, laser optical plankton counter (LOPC) - data from the SIPEX II voyage of the Aurora Australis

• Other Authors: AADC (originator), AU/AADC > Australian Antarctic Data Centre, Australia (resourceProvider)
• Format: Dataset
• Language: unknown
• Published: Australian Ocean Data Network
• Subjects: biota; oceans; PLANKTON; EARTH SCIENCE; BIOSPHERE; AQUATIC ECOSYSTEMS; SIPEX II; LOPC-PMS > Laser Optical Particle Counter; R/V AA > R/V Aurora Australis; ACE/CRC; AMD/AU; AMD; CEOS; GEOGRAPHIC REGION > POLAR; OCEAN > SOUTHERN OCEAN; Southern Ocean; aurora australis; Sea ice; ice covered waters
• Online Access: https://researchdata.ands.org.au/particle-size-spectra-aurora-australis/954493; https://data.aad.gov.au/metadata/records/AAS_4140_SIPEX_II_LOPC; https://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4140_SIPEX_II_LOPC; https://data.aad.gov.au/eds/4476/download; https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=4140

The problems associated with the dataset were related to some difficulties in deployment. Ice particles and clumps in surface waters were sampled by the LOPC as it was lowered and these needed to be removed from the dataset during post-deployment analysis. The dataset contains only data from sites 3-8. Sites 1-2 were "pilot" sites only for testing the LOPC and making sure it was functioning correctly. This dataset contains vertical profiles of particles in the upper water column (60 m depth) at six sites. A laser optical plankton counter (LOPC) was deployed through a hole in the sea ice, or from the stern of the Aurora Australis, and lowered to 60 m, logging as it was lowered. The LOPC records particles in the size range 100 um to 20 mm, though the small aperture (7 cm x 7 cm) means that the largest particles are probably only sampled rarely. For each site, the data are presented as normalised biomass for a series of equivalent spherical diameters (ESD). ESD is based on measurements of length and width of animals likely to be sampled via the LOPC (i.e. animals that are sampled at the same time with a traditional plankton net). The data were collected on the SIPEX II voyage of the Aurora Australis, from 14/9/2012 to 16/11/2012. Sites were all located in first year pack ice; the ship would nudge up to a floe and then samples of ice, zooplankton, etc. were collected directly by working on the floe. The LOPC was either deployed through a large hole in the pack ice, or it was deployed off the stern of the AA. Method of deployment did not really have an impact on the data collected, it was more a logistical decision based on conditions. The data can be used to compare biomass size spectra within and between aquatic environments. It was deployed for the first time in ice-covered waters during this project. It provides a baseline against which we could assess changes to the Southern Ocean environment in the future.