SOND Cruise 1965: Further factor analyses of the plankton data

Abstract

Factor analyses have been carried out on the total data for 134 planktonic forms sampled during the 1965 SOND cruise by R.R.S. ‘Discovery’. Species assemblages are largely consistent with the intragroup analyses carried out previously (Angel & Fasham, 1973). Factor score plots for the separate day and night series confirm the rather limited number of categories of vertical distribution patterns that occur despite the occurrence of vertical migration. The analysis of the combined day and night data confirms the rather limited number of patterns of vertical migratory behaviour. Size spectra of euphausiids in some of the assemblages associated with each category suggest that there may be resource partitioning. The trophic relationships within the assemblages appear to be structured and are discussed in the light of the limited knowledge of the feeding behaviour of many of the species involved. Diurnal vertical migration behaviour in planktonic species appears to be limited to the top 700 m.

Diet and feeding of Euphausia hanseni and Nematoscelis megalops (Euphausiacea) in the northern Benguela Current: ecological significance of vertical space partitioning

“…The results obtained suggest that the 2 species are vertically segregated, and their differential migratory habits are reflected in their cyclic feeding behaviour and food preference. Barange (1990) showed that vertical segregation was extended to the whole euphausiid community, suggesting that the 2 species considered are examples of sub-communities of the whole community (sensu Angel & Fasham 1974). With diffuse competition (Lane et al 1978) by other species (Barange 1990) not to be dismissed, the results presented are evidence for a strong structure of the shelf break zooplankton con~munity dunng the study.…”

“…Thus, analysis of feeding and selectivity of vertically segregated species may provide some insight into the extent of partitioning of food 220-resources and the ecological benefits of vertical space partitioning (Angel & Fasham 1974, Roger 1975, Mullin & Evans 1976). …”

Bathymetric Distribution of Planktonic Ostracods (Ostracoda; Crustacea) in the Gulf of Oman (Northwest Indian Ocean) in relation to the Oxygen Minimum Zone

“…The sampling procedures adopted in the Gulf of Oman were identical to those used for the Atlantic surveys (Angel, 1969(Angel, , 1979Angel and Fasham, 1973, 1974Angel et al 2007; Fasham and Angel, 1975), so direct comparisons can be made between the profiles observed. The environment conditions in the Gulf of Oman are markedly different from those in the North Atlantic.…”