Distribution and ecology of recent benthonic foraminifera of the adelie george v continental shelf and slope antarctica
Milam, R.W.; Anderson, J.B.
Marine Micropaleontology 6(3): 297-326
Benthonic foraminifera from 46 surface samples collected on the George V-Adelie continental shelf and slope, east Antarctica, were analyzed to determine faunal distribution patterns. Bottom temperature and salinity, bathymetry, surface sediment texture and bottom current velocities interact to form distinct ecologic niches in the area. Distinct faunal assemblages (7) are recognized from the 75 genera and 110 spp. identified. Most samples taken from the continental shelf contain either dominantly calcareous or dominantly arenaceous assemblages. As in the Ross Sea and Weddell Sea, instability of calcium carbonate at shallow depths appears to be a prime factor in limiting faunal assemblage distribution. Above .apprx. 200 m a diverse calcareous assemblage is associated with relatively fresh shelf waters. Below 200 m faunal distributions show little affinity to bottom water temperature or salinity, and the depth range of calcareous and arenaceous assemblages overlap by approximately 250 m. Calcareous faunas are mainly associated with sandy substrates which reflect moderate to intense bottom current activity. Arenaceous faunas are associated with organic-rich, siliceous muds and oozes. These finer sediments apparently provide unsuitable habitats for calcareous foraminifera and/or are unsuitable media for the preservation of calcareous tests. Benthonic foraminifera on the George V-Adelie continental slope do not contain any of those species which are known to be associated with Antarctic Bottom Water on the Weddell Sea continental slope.