Q-mode factor analysis of 55 surface samples and 190 species from water depths beyond 1,500 m in the Gulf of Mexico defined an 8 assemblage model which accounted for 91% of the original information contained in the data matrix. Distributions of these 8 assemblages are related to variations in sediment terrestrial organic carbon content, calcium carbonate content, and water depth. No relationship could be defined for the 8 assemblages and overlying water temperature, salinity, dissolved O₂ concentration, or median grain diameter of the sediment.

Species counts on 58 samples at ~10 cm intervals from the USNS Kane core K-129 were completed in order to examine the response of benthic foraminiferal populations to glacial/interglacial episodes in the Gulf. The core is from a site at 3,108 m water depth in the southwestern Gulf (20°56.7^primeN, 95°05.7^primeW). It was chosen because it had been previously zoned on the basis of planktonic foraminifers and it spans a relatively long interval of time (~165,000 years).

A 4 factor model of the core, produced by direct factor analysis, accounted for 93% of the original information of the 58 sample by 118 species matrix. An Eponides turgidus assemblage was found to dominate high calcium carbonate dissolution intervals through core K-129, whereas an Epistominella decorata assemblage dominates intervals of low carbonate dissolution. A Bulimina translucens assemblage shows highest factor loadings when surface water temperatures were elevated and continental glacial volumes were reduced. A Cibicidoides wuellerstorfi assemblage, which shows highest factor loadings during glacials, demonstrates a highly significant inverse relationship to the development of the Bulimina translucens assemblage.

The results of this study suggest that the deep-water benthic foraminifers of the Gulf of Mexico have responded to climatic events of global and regional significance through the late Quaternary. Global climatic effects may be inferred from demonstrated relationships between the foraminiferal assemblages and the planktonic oxygen isotope record, and dissolution history of core K-129. A regional effect is suggested by the relationship defined for the Cibicidoides wuellerstorfi assemblage and the distribution of terrestrial organic carbon of the Gulf through time.

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