Climate Change and the European Water Dimension - Agri ...

productivity in the upper layers could, however, have a negative impact on part of the
ecosystem and contribute to the development of low-oxygen (hypoxia) sub-layers
with drastic perturbations within demersal and benthic organisms (Grantham et al.
2004).
Figure IV.C.7. Within-year averages of monthly estimates of along-shore wind stress
off different upwelling sites: A. California. B. Iberian Peninsula. C. Morocco. D and E
Peru. Short dashes indicate the long-term mean for each series. Longer dashes indicate the
linear trend fitted by the method of least squares. (Source: Bakun (1990) Reprinted from
Science, with permission).
IV.C. 6. Carbon biomass and productivity
The coastal system represents undoubtedly the largest reservoir of particulate
organic carbon resulting from both local high productivity rates and large inputs of
terrestrial organic material via river runoff. In addition, the coastal waters in general
represent also a large pool of inorganic carbon from continuous exchange with the
atmosphere, river runoff and upwelling of deep oceanic waters. A large part of the
coastal carbon is recycled within the water column, while another part becomes
buried and eventually recycled in the sediment, or exported into the sub-layers of the
open ocean, involving complex interactions between various processes which are
sensitive to environmental forcing, but often neglected in global ocean models, or in
terrestrial ecosystem models, and consequently poorly represented in global
scenarios of climate change.
Coastal carbon pool
The carbon cycle in marine coastal waters involves two major processes: i) an
inorganic long-term cycle driven by water alkalinity and the formation of calcium
carbonate and ii) an organic short-term cycle with the formation of organic material
through photosynthesis.
Chemical weathering of rock material on land provides dissolved inorganic carbon to
the water system, further transported into the ocean as alkalinity (mainly HCO3 - ,
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