Biology and the Carbon Cycle
in term of chlorophyll a equivalent (Chl a + pheopigments). The gut pig-
ment content ranged from 1 to 60 ng Chl a eq/individual, with maximum
values (> 10 ng Chl a eq/individual) in the Chukchi Sea and the Nansen
Basin. As with the biomass, those values are well described by a second-
order regression. A good relationship appears between the gut pigment
content and the primary production (for Calanus hyperboreus female, r2 =
0.69). But the high zooplankton biomass in the first 100 m cannot be sup-
ported by the chlorophyll a concentration (r2 = 0.7552). On the other hand
this uncoupling, confirmed by the low gut pigment content, might be
explained by the omnivorous character of the main copepods; they can
feed on either phytoplankton or microzooplankton.
All these data give us new information on the role of mesozooplankton
in the Arctic food web. In the Arctic Ocean the zooplankton biomass in late
summer was similar to values reported for other oceans (Reid 1962, Be et
al. 1971). Copepods represent 80% of the whole mesozooplanktonic popula-
tion of the Arctic Ocean. The contribution of the mesozooplankton in the
carbon cycle is important, accounting for approximately 40% of the total
particulate organic carbon in the upper 100 m of the water column. The
mesozooplankton also feed on phytoplankton but probably more on micro-
Bamstedt, U. (1986) Chemical composition and energy content.
In The Bio-
logical Chemistry of Marine Copepods (E.D.S. Corner and S.C.M. O'Hara, Ed.),
Oxford: Clarendon Press, p. 158.
Be, A.W .H., M. Forns and O.A. Roels (1971) Plankton abundance in the
North Atlantic ocean. In Fertility of the Sea, p. 1750.
Conover, R.J. and M. Huntley (1991) Copepods in ice-covered seas--Distri-
bution, adaptations to seasonally limited food, metabolism, growth patterns
and life cycle strategies in polar seas. J. Mar. Syst., 2: 141.
Reid, J.L., Jr. (1962) On circulation, phosphatephosphorus content, and
zooplankton volumes in the upper part of the Pacific ocean. Limnology and
Oceanography, 7: 287306.