158
J. E. ct. RAYMONT
1963), arms of high standing crop tend to have fairly high productivity
rates (cf. Holmes, 1958, 1962; Bogorov, 1958). High latitudes tend to
have very high plankton productivity for a short period of the year.
Boreal regions also usually have a higher standing crop and productivity; Bogorov (1958) states that in the Pacific, the boreal area is some
10 times richer than tropical waters (cf. Holmes, 1958). The earlier
work of Hentschel and Wattenberg (1930) also associates the distribution of phosphate in the southern Atlantic Ocean with the richness in
density of plankton organisms.
In relation to total production the standing crop under a square
metre of sea surface is of importance. Riley et al. (1949) suggest that in
the offshore waters of the north-western Atlantic the total crop of
phytoplankton beneath a square metre of surface at lower latitudes
may not be very much smaller than that at a higher latitude, such as
the Gulf of Maine, provided that the very short spring burst of phytoplankton in boreal waters, which may not be effectively utilized, is
omitted from the calculation. One of the chief factors in calculating the
crop beneath a unit of surface at different latitudes is the greater depth
of the photosynthetic zone in more tropical areas. Riley’s comparison
of the total annual crop in the Gulf of Maine area and in the continental
slope water to the south-east suggests that the difference in biomass is
not very great, largely owing to the greater depth of the euphotic zone
in the more southern waters. With Sargasso Sea waters, however, the
total population is probably lower even though the photosynthetic
zone is greater. Ryther and Yentsch (1958) have shown that although
offshore waters can occasionally show high rates of production which
are comparable to inshore areas, these are due to temporary enrichment and are not sustained; production over a whole year is greater st
inshore stations. Their suggestions for the annual production from the
nutrient rich Long Island Sound waters to the impoverished Sargasso
Sea are:
gC/m2/year
Long Island Sound = 380
Shelf waters = 160-100 (depending largely on distance
from coast)
Ryther (1963) has summarized regional differences in annual productivity:
(1) for tropical open oceans, production is 18-50 g C/m2, (e.g. Sargasso)
though where some mixing occurs as off Bermuda the annual value
may reach 70 g C/m2.
North Sargasso’Sea = 78.
J. E. ct. RAYMONT
1963), arms of high standing crop tend to have fairly high productivity
rates (cf. Holmes, 1958, 1962; Bogorov, 1958). High latitudes tend to
have very high plankton productivity for a short period of the year.
Boreal regions also usually have a higher standing crop and productivity; Bogorov (1958) states that in the Pacific, the boreal area is some
10 times richer than tropical waters (cf. Holmes, 1958). The earlier
work of Hentschel and Wattenberg (1930) also associates the distribution of phosphate in the southern Atlantic Ocean with the richness in
density of plankton organisms.
In relation to total production the standing crop under a square
metre of sea surface is of importance. Riley et al. (1949) suggest that in
the offshore waters of the north-western Atlantic the total crop of
phytoplankton beneath a square metre of surface at lower latitudes
may not be very much smaller than that at a higher latitude, such as
the Gulf of Maine, provided that the very short spring burst of phytoplankton in boreal waters, which may not be effectively utilized, is
omitted from the calculation. One of the chief factors in calculating the
crop beneath a unit of surface at different latitudes is the greater depth
of the photosynthetic zone in more tropical areas. Riley’s comparison
of the total annual crop in the Gulf of Maine area and in the continental
slope water to the south-east suggests that the difference in biomass is
not very great, largely owing to the greater depth of the euphotic zone
in the more southern waters. With Sargasso Sea waters, however, the
total population is probably lower even though the photosynthetic
zone is greater. Ryther and Yentsch (1958) have shown that although
offshore waters can occasionally show high rates of production which
are comparable to inshore areas, these are due to temporary enrichment and are not sustained; production over a whole year is greater st
inshore stations. Their suggestions for the annual production from the
nutrient rich Long Island Sound waters to the impoverished Sargasso
Sea are:
gC/m2/year
Long Island Sound = 380
Shelf waters = 160-100 (depending largely on distance
from coast)
Ryther (1963) has summarized regional differences in annual productivity:
(1) for tropical open oceans, production is 18-50 g C/m2, (e.g. Sargasso)
though where some mixing occurs as off Bermuda the annual value
may reach 70 g C/m2.
North Sargasso’Sea = 78.