New Zealand Journal of Marine and Freshwater Research abstracts

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Summer tide-crack phytoplankton at White Island, McMurdo Sound, Antarctica

DAVID J. RAWLENCE¹

PAUL H. ENSOR²

GEORGE A. KNOX³

^1.Department of Biology University of New Brunswick P. O. Box 5050, Saint John New Brunswick Canada E2L 4L5f

^2.department of Zoology University of Canterbury Private Bag, Christchurch New Zealand

Abstract The standing crop and succession of marine microalgae are described for blooms in the surface water of a tide crack in the permanent ice of the Ross Ice Shelf at White Island, McMurdo Sound, Antarctica. The dominant microalgae during late November were Chlorophyta (Pyramimonas sp.). Bacillariophyceae (diatoms) were dominant from early December until the end of the study in late January. Five species were most abundant: Nitzschia cylindrus, Nitzschia curta, Nitzschia obli-quecostata, Fragilaria sp., and Synedra tabulata. The concentration of chlorophyll a was at the highest level (30.0 ng /') when Pyramimonas sp. were most abundant. Incident light and the percentage transmission of light to a depth of 1 m in the tide crack were also at maximum levels at this time. The chlorophyll a concentration decreased to below the limits of detection after the thaw in mid-January when there was an abrupt increase in the temperature and a decrease in the salinity of the surface waters in the tide crack. The concentration of dissolved oxygen was at a maximum when the diatoms were most abundant.

Keywords Antarctica; phytoplankton; periodicity; diatoms; Chlorophyta

New Zealand Journal of Marine and Freshwater Research, 1987, Vol. 21: 91-97 0028-8330/87/2101-0091$2.50/0 © Crown copyright 1987 Received 27 February 1986; accepted 29 April 1986

PDF file of entire paper: medium quality (544K); (scanned from paper original: notes about this process)

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