The spatial distribution and population structure of two dominant ice-associated copepods, Drescheriella glacialis and Paralabidocera antarctica, were studied during winter at nine locations in east Antarctic fast ice. These species accounted for at least 90% of the total metazoan abundance at each location. Abundances were high, reaching 175 individuals 1-1 (190,000 m-2) for D. glacialis and 660 1-1 (901,000 m-2) for P. antarctica. These abundances were probably partly supported by the high biomass of ice-algae (Pearson correlation coefficient, r=0.75), as indicated by chlorophyll-α concentrations (1.7-10.1 μg 1-1). The population structures of each species suggested very different life-history strategies. All developmental stages of D. glacialis were isolated from the ice cores, including females with egg sacs, supporting the hypothesis that this species reproduces in the sea ice during winter. This strategy might assist D. glacialis in leading a continually colonising existence, whereby it responds opportunistically to the availability of favourable habitat patches. The populations of P. antarctica were composed primarily of nauplii (>99%), consistent with past observations of a synchronised life cycle for this species. The strong coupling of the developmental cycle of P. antarctica to the growth and decay of sea ice suggests that local extinctions might occur in areas where ice break-out is unpredictable.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Population Ecology
Objective Division:	Environment
Objective Group:	Flora, Fauna and Biodiversity
Objective Field:	Antarctic and Sub-Antarctic Flora, Fauna and Biodiversity
Author:	Swadling, KM (Dr Kerrie Swadling)
ID Code:	21990
Year Published:	2001
Web of Science® Times Cited:	12
Deposited By:	Zoology
Deposited On:	2001-08-01
Last Modified:	2011-08-03
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