Distribution and population structure of pelagic Ostracoda near the sea−ice edge in the Scotia Sea and off the King George Island

• Main Authors: Andrzej Osowiecki, Instytut Oceanologii, Polska Akademia Nauk
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1988
• Subjects: Arctic; Antarctic; Austral; King George Island; Scotia Sea; Antarc*; ice pack; Phytoplankton; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.498.3853; http://www.polish.polar.pan.pl/ppr23/ppr23-135.pdf

ABSTRACT: Four Ostracoda species belonging to one family, Halocyprididae, were found in plankton material collected from the Scotia Sea and off the King George Island (the Ant− arctic) during the austral summer 1988/1989. Alacia belgicae, A. hettacra and Meta− conchoecia isocheira were dominant making up to nearly 99 % of all Ostracoda. The hori− zontal distribution was modified by variability of hydrological conditions. The higher con− centrations of chlorophyll a and phytoplankton, which were found in the mid − and eastern parts of the Scotia Sea, coincided with the highest densities of Ostracoda. The influence of ice pack presence in the Scotia Sea upon the higher abundance of Ostracoda in the period in− vestigated in comparison with the earlier studies was distinctive. A vertical distribution analysis confirmed that the three above−mentioned endemic species were most abundant in the mesopelagial. The population structures of A. belgicae, A. hettacra, and M. isocheira were analysed. The presence of the youngest stage of A. belgicae in the Scotia Sea con− firmed the beginning of reproduction of this species at that time. The vertical distribution patterns of A. hettacra and M. isocheira populations were similar, although their age struc− tures in comparison with A. belgicae differ significantly. This was consistent with their higher “mean population stage ” values. Key words: Antarctic, pelagic Ostracoda, vertical distribution, horizontal distribution, population structure.