Population counts were made from 36 bottom samples taken during the 1965 cruise of the USCG Northwind in the Kara sea. Attempts were made to compare the distribution of the species of Foraminifera to the ecologic parameters, depth, bottom temperature, bottom salinity, oxygen, phosphate, free and dissolved nitrogen, silica, pH, water content of the surface sediment, soluble carbonates, organic carbon, median chlorite-kaolinite ratio, and percentages of sand, silt, coarse clay, and fine materials less than 0.001 mm. The population counts were not made from living Foraminifera. The water chemistry data represent a single reading at each station, taken during the late summer.
The distribution is not a simple depth zonation, primarily because of the presence of the warmer, more saline Atlantic waters which touch the bottom at various depths, compounded by widespread manganese oxidation in the bottom sediments. Abundance of Foraminifera appears to be directly proportional to bottom temperature and pH, and inversely related to oxygen, free nitrogen, and organic carbon. The other parameters indicate a more complex, nonlinear, relation to abundance.
Fifteen genera and 19 species of Foraminifera are common in these waters. Arenaceous Foraminifera are dominant. Calcareous species are abundant only in the northernmost stations which are in direct contact with the open Arctic waters. Globigerina pachyderma is the only planktonic species found.