Publication Date:
2020-06-30
Description:
The spatial and temporal distribution and abundance of planktonic foraminifera in ocean waters are influenced by the interaction of biological factors (algal symbionts, food supply, predation, interfaunal relationships, productivity) and physical-chemical factors (nutrients, light, temperature, salinity, water density, turbidity, etc.). Estimates of standing stock have generally been obtained from plankton tows and not from total volumes of sea water. Size fractions less than 200μ have been ignored in most calculations of standing stocks, which usually increase by several orders of magnitude in progressively smaller size fractions. The relative abundance and distribution patterns of 32 species in Indian Ocean waters and surface sediments have been determined from 154 plankton tows and 190 core-tops. Principal-components analysis groups the populations into nine life assemblages and five fossil assemblages. A quantitative comparison between the life and fossil assemblages is then possible by algebraically relating the factor assemblages: FsFp× C The matrix of coefficients, C, shows the degree to which the spatially and seasonally independent plankton assemblages, Fp, are linearly mixed during the process of sedimentation to form the sea-bed assemblages, Fs. A large fraction of the sea-bed assemblages above the CaCO3 compensation depth may be derived by simple mixing of the plankton assemblages. The model shows, for example, how proportions of four discrete tropical and subtropical life assemblages contribute in producing a single tropical-subtropical fossil assemblage. According to this model, differential productivity, selective solution, and biotic mixing do not mark the primary distribution patterns of the living species.
Type:
Article
,
PeerReviewed
Format:
text
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