This thesis was conducted under the auspices of the Southern Ocean Continuous Plankton Recorder (CPR) Survey. The research conducted had the dual aims of providing baseline data for this long-term monitoring program and providing the first detailed analysis of zooplankton communities and distribution patterns in the Southern Ocean south of Australia. Data were principally collected between October 2001 and March 2002, during five voyages. As a primary step I investigated the sampling characteristics of CPR, and assessed the utility of the CPR as a long-term monitoring apparatus in the Southern Ocean. Given the shallow sampling depth of the CPR (~10.5m), a major requirement of this calibration was quantification of the fine-scale vertical distributions zooplankton. This was done through direct comparison of CPR samples with depth integrated NORPAC net hauls. The CPR-NORPAC comparison identified the component of the zooplankton sampled by the CPR and provided a means for comparison between past and present data sets. As a final component of this calibration, it was demonstrated that the CPR was effective at identifying biogeographic boundaries. An essential requirement for the identification of long-term ecological change is baseline data on natural ecosystem variability, particularly seasonality. Therefore, after calibration of the CPR the two fundamental components of spatial and seasonal variability were investigated. Firstly, the fine-scale horizontal structure of zooplankton communities was quantified from a 1170 nautical mile transect, along the 140oE meridian, spanning all of the major oceanographic zones south of Australia. Applying multivariate analyses a unique community zonation was identified which was strongly related to the complex oceanographic environment, characterised by multiple branches of the major fronts. The seasonal component of temporal variability was investigated separately in two major and distinctly different regions, the Seasonal Ice Zone and the Sub-Antarctic / Polar Frontal Zone. Multivariate analyses were used to quantify seasonal changes in species composition, Bray-Curtis dissimilarity, species densities, and the proportional contribution of species to communities. The spatial and temporal variation of zooplankton community structure was discussed in the light of environmental controls, species' vertical distributions, population cycles, and ecosystem functioning. Finally,the application of these data to long-term monitoring was discussed, and recommendations made for future research. The fields in this dataset are: CPR Segment Number Time (GMT) Date Latitude Longitude Segment Length (nautical miles) Salinity Sea Surface Temperature Species Fish Larvae Fish Scales Egg Mass Volume Bongo CTD Depth

This dataset contains results from Continuous Plankton Recorder (CPR) surveys in the Southern Ocean. When the opportunity arises, zooplankton species, numbers and abundance data are recorded on a continuous basis as vessels steam through the area between Australia and Antarctica, including Heard and Macquarie Islands. Observations have been made since June 1990 and are ongoing. Obviously the observations are not continuous over the region with time. Many of the original SO-CPR logbooks from the various voyages have also been scanned, and are available via the Australian Antarctic Data Centre's Reports Register. Zooplankton have been identified to lowest possible taxon, usually species, and counted for each segment. For copepods, copepodites and for some species nauplii (e.g. Rhincalanus gigas) have been counted separately, and for euphausiids, naupliar, calyptopis and furcilia developmental stages are identified. The fields in this dataset are: Tow_number - the CPR tow number Ship_name - the name of the ship on which the tow was conducted Season - two-year Antarctic season based around the austral summer, e.g. '2000-01' runs from July 2000 to June 2001 Latitude - the decimal latitude of the segment sample Longitude - the decimal longitude of the segment sample Observation_date - UTC date and time of the segment sample in ISO8601 format (yyyy-mm-ddTHH:MMZ) Observation_date_year - the observation date year Observation_date_month - the observation date month Observation_date_day - the observation date day Observation_date_hour - the observation date hour Observation_date_minute - the observation date minute Observation_date_time_zone - the observation date time zone (0=UTC) Segment_number - the individual segment number within each tow Segment_length - the distance travelled by the CPR during this segment (nautical miles). This is the true segment length as used in the Geocoding program used to cut the silk, and to calculate positions and average environmental data for each segment. In theory, all segments are 5 nautical miles long. However, this wasn't always the case with early Aurora Australis tows, where it was assumed that each marked segment was 5 nautical miles whereas each tow had subtle variations in silk advancement, depending on the wear of the cassette or travel with or against a current. True segment length has since been recalculated. At other times, some silks have been incorrectly cut and the true length has again been recalculated. The last segment of each tow may be less than 5 nautical miles. This field can be used to standardise species counts to say 5 nautical miles or to a theoretical volume filtered by multiplying the distance travelled by aperture area (12.7 x 12.7 mm): Volume Filtered = Distance (n miles) x 1852 metres x 0.0127^2. A 5 nautical mile segment theoretically represents 1.49 m^3. Total_abundance - total count of all zooplankton in a segment Phytoplankton_colour_index - visual estimation of the green colour of the silk mesh. Values are 'No Colour', 'Very Pale Green', 'Pale Green', or 'Green'. This colouration is due to the green chlorophyll pigments derived from chloroplasts of intact and broken cells and small unarmoured flagellates. It may provide an indicator of phytoplankton standing stock, although in the Southern Ocean there are some diatoms that are quite common on the silks but as they have very low amounts of chlorophyll the colour doesn't register in the PCI analysis. Fluorescence - water fluoresence measured by the vessel, averaged for the segment (arbitrary units). See Quality notes for more information. Salinity - water salinity measured by the vessel, averaged for the segment (psu). See Quality notes for more information. Water_temperature - water temperature measured by the vessel (degrees Celsius). See Quality notes for more information. Photosynthetically_active_radiation - photosynthetically active radiation measured by the vessel (micro-Einsteins m-2 s-1). This is not available on some vessels but has been included as a useful parameter to help differentiate data from night and day. The remaining fields ('Abylidae' through to 'Vibilia_sp') are zooplankton taxon names. The entries in these columns are the counts of each taxon in the segment.