dominated by four species of copepods: Calanus finmarchicus, C. hyperboreus, C.
glacialis, and Metridia longa. Calanus finmarchicus enters with incoming Atlantic
water and survives but does not reproduce in the Arctic Ocean proper. Patterns of
seasonal migration and life stages (see Fig. 11.20) are reviewed by Falk-Peterson et
al. (2009). Calanus hyperboreus is the largest arctic copepod and best adapted to short
and unpredictable growing seasons, with a 3–5-year life cycle and very large lipid
stores. In the central Arctic Ocean, mesozooplankton standing stocks are
approximately four-fold greater than phytoplankton standing stocks (Table 11.3).
Copepod grazing rates estimated from their rate of fecal pellet production were 3–
20% of expected food-saturated rates. Further, estimates of food-saturated carbon
demand exceeded measured primary production rates. Based on those observations,
Olli et al. (2007) suggested that arctic mesozooplankton are food-limited, and that the
abundant copepods prevent the accumulation of phytoplankton stocks in the central
Arctic.
Fig. 11.20 Generalized seasonal migration and stage development of Calanus
finmarchicus, Calanus glacialis, and Calanus hyperboreus. Upper and lower lines
bound the general depth distributions of the populations.
(After Falk-Peterson et al. 2009.)