Cape Darnley Early-Autumn Phytoplankton Bloom, March 2012

Keywords: Occurrence
Temporal coverage: 2012/2012

These data relate to a large-scale early-autumn phytoplankton bloom that occurred off Cape Darnley, East Antarctica, in March 2012. The bloom was detected by Dr Jan Lieser (Antarctic Climate and Ecosystems Cooperative Research Centre, ACE-CRC) through MODIS satellite and was opportunistically sampled from RSV Aurora Australis using the uncontaminated seawater line. Samples were analysed for protist species and abundances using light and scanning electron microscopy, and pigment analyses were conducted using high performance liquid chromatography. Additional water samples were taken for dissolved nutrient analyses.  

Specific details of the files are:

Cape Darnley Protist Counts
Samples were preserved with 1 % vol:vol Lugols iodine and stored in glass bottles in the dark at 4 degrees C. Protists were identified and counted using phase and Nomarski interference optics using Olympus IX71 and IX81 inverted microscopes at 400X to 640X magnification. Bright field optics were also used to discriminate taxa that contained chloroplasts. Protistan taxa were counted in 20 randomly chosen fields of view, except for highly abundant taxa that were counted in a subset of the field of view defined by an ocular quadrant (Whipple grid). Cell biovolumes and carbon conversion statistics were used to calculate the cell biomass of protistan taxa/groups.

Cape Darnley Fluorometer Calibration
Fluorometer measurements from the ships underway system were calibrated using chlorophyll a readings determined through high performance liquid chromatography. A linear relationship was established between fluorometer v HPLC chlorophyll a measurements at the same sites. The linear equation was then used to convert all underway fluorometry data from the voyage.

Cape Darnley Bloom HPLC Pigments CHEMTAX summary
Major phytoplankton groups at each site determined through analysis of pigments using high performance liquid chromatography and CHEMTAX. Methods were according to that of Wright et al. (2010).

Cape Darnley Bloom Nutrients
Dissolved nutrient concentrations. Samples were analysed by the Department of Primary Industries, Parks, Water and Environment, 18 St. Johns Avenue, Newtown, Tasmania 7008.

Cape Darnley Underway Data VOYAGE_04_0_201112
Raw underway data from Aurora Australis in the bloom region

Cape Darnley Underway Data Maps
Maps of the underway data in the bloom region
Quality: 
                  We were only able to obtain samples through the uncontaminated seawater line, with the intake positioned at 4.8 m below the ship. However, we think the majority of the bloom was at the surface associated with ice. Our data therefore likely under-represents the true surface phenomenon.

2018-10-10
The original files was reformatted to fit OBIS/GBFI/IPT Biodiversity.AQ tracking standards, and a new datasheet "CapeDarnelyBloom_2012.csv" was created. The new dataset contains datasetID, occurrenceID, recordNumber, verbatimLatitude, verbatimLongitude, decimalLatitude, decimalLongitude, locationID, locality, eventRemark, eventDate, year, month, basisOfRecord, occurrenceStatus, organismQuantity, organismQuantityType, preparations, institutionCode, continent. The lowest taxonomical rank of the species identified that could be determined is provided, after matched in WoRMS (World Register of Marine Species).