Future challenges in shelf seas - Introduction to the Physical and Biological Oceanography of Shelf Seas - page 351

11

Future challenges in shelf seas

In this final chapter we shall try to provide a perspective of the science of shelf
seas and an indication of some of the important challenges which remain. In
looking to the future of the subject, we shall highlight the need to move from
temperate latitude shelf seas, which have been the focus of most research to
date, into the shelf seas of the Arctic and the tropics. In both these areas, the
suite of physical processes controlling the shelf sea environment and its biogeo-
chemistry is substantially different from that operating in temperate latitudes. As
well as looking at the prospects for future research in these areas, we shall also
consider new ideas on the role of the shelf seas in the global ocean system and
their putative influence on climate change since the last ice age. But first, we
shall try to identify the big questions which remain in relation to the scientific
understanding of the mid latitude shelf seas.

11.1 Remaining puzzles in the temperate shelf seas

...................................................................................
As we have seen in previous chapters, the dominant physical processes controlling
the environment of the shelf seas in temperate regions have been identified. The
different shelf sea regimes have been defined in terms of the particular processes
which dominate them, and the interaction of these processes has, in several cases,
been simulated at least to first order in numerical models.
The level of physical understanding of the regimes is generally sufficient to provide
a sound basis for biogeochemical studies, and considerable progress has been made
particularly in the elucidation of the factors controlling primary production. The
roles of stratification and reductions in vertical turbulent mixing in controlling the
spring bloom of phytoplankton are well established. Our understanding of how
layers of phytoplankton grow within pycnoclines, driven by modification of the
vertical turbulent exchange in regions of strong vertical gradients in light and
nutrients, has developed over the past two decades. Sub surface primary production
can now be regarded as of equal importance to the spring bloom in terms of the
supply of organic material to the rest of the shelf sea ecosystem.