(^) Small pelagic fish, especially anchovy and sardines, are abundant in EBCS.
Sardines tend to reside offshore and feed on phytoplankton and small zooplankton,
whereas anchovy are more abundant inshore and feed on larger plankton. Although
the four EBCS show only a two-fold range in primary production, fish production is
more than 10-fold greater in the Peru/Humboldt system than in the other three. Most
of this is due to the enormous stock of anchoveta (Engraulis ringens) off Peru. Bakun
and Weeks (2008) attribute that high fish productivity to the strength of nutrient input
by upwelling and the extended surface residence time of upwelled water to allow
phytoplankton growth. They also hypothesize that periodic El Niño perturbations may
prevent the establishment of populations of slow-growing, predatory fish.
(^) Jahnke (2010) compared sedimentary deposition rates for organic carbon in the four
EBCS (along with all other continental margins). Deposition rates (g C m−2 yr−1)
were similar for all four regions, but the total deposition ranged from 6 to 15 × 10^12 g
C yr−1 (Table 11.8) because of differences in the surface area of each margin (Canary
California > Peru/Humboldt > Benguela). This amount of deposition accounts for
1–2% of EBCS primary production. Overall, the EBCS comprise 16% of total
continental margin surface area and account for 22% of global organic carbon
deposition on continental margins.
The Indian Ocean
Indian Ocean – the Tropics and Subtropics
(^) The Indian Ocean is massively blocked on its northern side by the Asian continent, so
it has no northern temperate or arctic zones. Moreover, the two very large
embayments at the northern side are dramatically affected by continental influence,
but in different ways. The Arabian Sea, which is deep with moderately narrow