An investigation on sonic-scattering layers: the R.R.S. ‘Discovery’ Sond Cruise, 1965

Abstract

This is preliminary to a series of papers resulting from SOND 1965 Cruise aboard R.R.S. ‘Discovery’. The cruise was designed as an ecological study of sonic scattering layers at a certain season in a restricted volume of ocean in the region of the Canary Islands. These papers will appear periodically in this journal.

The Vertical Distribution of the Siphonophores Collected During the SOND Cruise, 1965

“…Although this will obviously not apply to all siphonophore species the population of Chelophyes appendiculata, whose mean day level was somewhat above this isotherm, appeared to vary with it. It is interesting to note that at St. 5796 and 5808 (see Currie et al 1969) during the SOND cruise, the 15 °C isotherm lay at about 220 m, while the main daytime population of C. appendiculata was found below this at 250 m, where the temperature was 14-4-14-5 °C.…”

“…its temperature/salinity/depth interrelationships, and also the origins of the separate water layers which constitute the water column, will be important factors in determining not only its total species composition but also the numbers of individuals present and their depth distribution. The TSD profiles undertaken at Fuerteventura are described by Currie et al (1969), and these indicate the presence of deep, saline Mediterranean water below about 650 m, while the rest of the water column, apart from the surface layers, has characteristics corresponding to those for North Atlantic Central Water.…”

“…The cruise itself and the hydrology of the area is described by Currie, Boden & Kampa (1969), and details of the nets used in the biological sampling programme are given by Foxton (1969), who also discusses some of the advantages and disadvantages of such a programme.…”

SOND Cruise 1965 Biological sampling methods and procedures

“…Particulars of hauls made with the IKMT, N113 and NF70V are summarized in Tables 1-3; for full station data, reference should be made to Currie et al (1969). As noted previously (p. 607) the NF70V hauls are supplementary to the main sampling programme and require no further comment.…”

“…Nominal depths (m): 50-0,100-50,150-100,200-150,300-200,400-300, 500-400, 600-500, 700-600, 800-700, 900-800, 1000-900. Corrected depths for each series are given in the Station List (Currie et al 1969). …”