Harvey J. Marchant

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Filter fractionated picophytoplankton from Antarctic coastal waters (summer 2001) represented only 7–33% of total phytoplankton, even though total stocks were low (average Chl a = 0.32 μg l−1, range = 0.13–1.03 μg l−1). Though all cells passed a 2 μm filter, electron microscopy revealed most cells were over 2 μm, principally Parmales, Phaeocystis sp., and(More)
The growth, biochemical composition and fatty acid profiles of six Antarctic microalgae cultured at different temperatures, ranging from 4, 6, 9, 14, 20 to 30 ∘C, were compared. The algae were isolated from seawater, freshwater, soil and snow samples collected during our recent expeditions to Casey, Antarctica, and are currently deposited in the University(More)
BACKGROUND The aim of this study was to investigate whether an increase in malignancy level is accompanied by significant modifications of the expression of galectin-1, galectin-3, and Thomsen-Friedenreich antigen (T antigen) as well as the expression of binding sites for these three markers in head and neck squamous cell carcinomas (HNSCCs). METHODS(More)
We irradiated captive juvenile Euphausia superba in the laboratory with lower than spring surface levels of ultraviolet-B, ultraviolet-A and photosynthetically active radiation, in order to examine their response in terms of mortality and generalised activity. Levels of photosynthetically active radiation 3–5 times below surface irradiance caused krill to(More)
The plankton of twelve freshwater and slightly saline lakes in the Vestfold Hills, Antarctica was sampled in February 1991. All of the lakes are oligotrophic. The chlorophyll a concentrations in the lakes ranged from 0.10–2.69 μg · 1−1. The majority of the phytoplankton were flagellates or picoplanktonic cyanobacteria with the species composition varying(More)
Concentrations of plankton, suspended particles 0.74–87 μm equivalent spherical diameter and dissolved organic carbon (DOC) were measured from May to February at an Antarctic coastal site. Bacteria-sized particles 0.74–1 μm diameter, and bacterial cells and heterotrophic protists all exhibited a seasonal minimum during winter and maxima in summer. Bacteria(More)
Most ectothermic organisms become immobile at a few degrees above zero. The unicellular planktonic algaeDunaliella sp., andChlamydomonas sp. from Antarctic hypersaline lakes remain motile at temperatures as low as −14 °C.Pyramimonas gelidicola from the same habitat stops swimming at −10 °C but its flagella continue to beat at −14 °C. Further, the(More)
The response of Antarctic, tropical and temperate microalgae of similar taxonomic grouping to ultraviolet radiation (UVR) stress was compared based on their growth and fatty acid profiles. Microalgae of similar taxa from the Antarctic (Chlamydomonas UMACC 229, Chlorella UMACC 237 and Navicula UMACC 231), tropical (Chlamydomonas augustae UMACC 246, Chlorella(More)
Changes in the concentrations of bacteria, phytoplankton, protozoa, dissolved organic carbon (DOC), particulate organic carbon (POC), particulate carbohydrate (PCHO) and particulate organic nitrogen (PON) were followed throughout the summer at an Antarctic coastal site. The colonial prymnesiophyte Phaeocystis pouchetii was the first major phytoplankton(More)