12
GUSDON -4. RILEY
Mean particle counts in all samples were as follows : surface 11.32 x
103/litre ; 100-200 m, 9.20 ; 500-900 m, 7.51 ; 1 000 m +, 7-86. Measurements of the area of the aggregates and of particulate carbon gave a
similar picture of vertical distribution, with a decrease in the upper
layers and only slight and random variations in the water below about
500 or 800 m.
There was some seasonal variation in particle counts and areal
measurements, with largest values in winter and spring, more or less
corresponding with seasonal variations in phytoplankton in that area.
There was also a seasonal variation in deep water. Much of the discussion in the paper cited was devoted to an attempt to rationalize
these deep water seasonal dhanges and the fact that there is not a
systematic decrease in particulate matter with depth. Continuation
of these discussions is relegated to later sections of this paper.
Gordon (1970a) refined the earlier methods for microscopic investigation and expanded the regional coverage of the North Atlantic. He
developed methods for cleaning the filtering apparatus and making
blank determinations, because it became apparent that contaminants
could be involved which were indistinguishable from naturally occurring
organic particles. He also used histochemical stains, the mercuric
bromphenol blue method of Mazia et al. (1953) for proteins and the
Schiff reagent for carbohydrates. Gordon obtained significantly
higher counts with stained slides than with unstained material. The
flakes, in particular, are often so nearly transparent that they can be
missed in routine counts. Therefore his counts are probably more accurate than previous ones but are not directly comparable with those in
earlier work. Gordon’s sampling areas ranged widely from the Sargasso
Sea to the Irminger Sea. Mean particle numbers were of the general
order of 100/ml in near surface waters, and 12-27/ml in deep water.
The Nova Scotia and Newfoundland shelf and slope areas were somewhat richer than offshore waters, as might be expected, but regional
differences were not pronounced.
C. Particulate organic carbon
1. Regional variations and vertical gradients
Wangersky and Gordon (1965) obtained extensive data on particulate organic carbon in subtropical and tropical waters along two transects between the coast of Africa and a point several hundred miles
southeast of Bermuda. This was a cruise of the “ Trident ” in 1963,
during which the material for particle counts described by Riley et al.
(1.964) was also collected.
GUSDON -4. RILEY
Mean particle counts in all samples were as follows : surface 11.32 x
103/litre ; 100-200 m, 9.20 ; 500-900 m, 7.51 ; 1 000 m +, 7-86. Measurements of the area of the aggregates and of particulate carbon gave a
similar picture of vertical distribution, with a decrease in the upper
layers and only slight and random variations in the water below about
500 or 800 m.
There was some seasonal variation in particle counts and areal
measurements, with largest values in winter and spring, more or less
corresponding with seasonal variations in phytoplankton in that area.
There was also a seasonal variation in deep water. Much of the discussion in the paper cited was devoted to an attempt to rationalize
these deep water seasonal dhanges and the fact that there is not a
systematic decrease in particulate matter with depth. Continuation
of these discussions is relegated to later sections of this paper.
Gordon (1970a) refined the earlier methods for microscopic investigation and expanded the regional coverage of the North Atlantic. He
developed methods for cleaning the filtering apparatus and making
blank determinations, because it became apparent that contaminants
could be involved which were indistinguishable from naturally occurring
organic particles. He also used histochemical stains, the mercuric
bromphenol blue method of Mazia et al. (1953) for proteins and the
Schiff reagent for carbohydrates. Gordon obtained significantly
higher counts with stained slides than with unstained material. The
flakes, in particular, are often so nearly transparent that they can be
missed in routine counts. Therefore his counts are probably more accurate than previous ones but are not directly comparable with those in
earlier work. Gordon’s sampling areas ranged widely from the Sargasso
Sea to the Irminger Sea. Mean particle numbers were of the general
order of 100/ml in near surface waters, and 12-27/ml in deep water.
The Nova Scotia and Newfoundland shelf and slope areas were somewhat richer than offshore waters, as might be expected, but regional
differences were not pronounced.
C. Particulate organic carbon
1. Regional variations and vertical gradients
Wangersky and Gordon (1965) obtained extensive data on particulate organic carbon in subtropical and tropical waters along two transects between the coast of Africa and a point several hundred miles
southeast of Bermuda. This was a cruise of the “ Trident ” in 1963,
during which the material for particle counts described by Riley et al.
(1.964) was also collected.