conducive to overall biomass production.Exactly how copepod populations would be
affected by the interactions of temperature, flow, illumination, nutrient supply and
predators that control the spring-bloom food chain where the Oyashio flows over the
slope remains to be fully resolved.
General Points about Decadal Cycling
(^) The equation between ecosystem responses to decadal climate variations and the
likely responses to general, long-term climate warming has been made repeatedly
(e.g. Richardson 2008). For instance, the distribution and abundance shifts correlated
with NAO and PDO occur more rapidly than the latitudinal shifts occurring in the
terrestrial realm. Marine plankton shift hundreds of kilometers per year, while land
plants and insects move poleward at <10 km yr−1. Clearly the fluid habitat generates
advection not operating on land, i.e. advective reach that reverses often and
completely. Once the ocean warms overall, more and more of the extended species
distribution shifts in the sea are likely to become permanent. Conceivably, some
species will be squeezed poleward into rather refugial bands or pockets. Species (like
the cod of the North Sea) that do not move are likely to find changed timing of their
food resources, and will have to cope with that in the same area where they must
compete with invaders at their own trophic level from previously more temperate
climes. Accepting all that, the equation is imperfect; the best we can do is leave the
best possible time-series data for future generations to determine how ocean ecology
varies over time.
(^) Such data are in short supply. We need time-series from all over the oceans so as to
get a sense of the global health of marine pelagic ecosystems. There are signs that we
will start more such series for our grandchildren to study. The work of collecting,
analyzing, and making ongoing scientific sense of such surveys is substantial, and few
are willing to undertake it. The CPR program on lines extending in all directions from
Britain appears to be stably sustained by SAHFOS. Sonja Batten and SAHFOS (e.g.
Batten & Freeland 2007) have initiated a new CPR line from Alaska to the Strait of
Juan de Fuca and one from Canada to Japan, which should contribute time-series if
there is institutional will to keep them going. There are other short or young
zooplankton series here and there, and they recently have been examined (Batchelder
et al. 2011). The gradually developing Global Ocean Observing System (GOOS) does
not promise to include much biology, apart from nutrients, fluorescence, and possibly
spectral light absorbance, but it should improve our knowledge of water-column and
surface-weather variation at a few points. The ARGOS program, if it can be sustained,
will provide volumetric maps of hydrography and possibly variables related to
phytoplankton. Thus, there is hope that we will know in some detail what happens to
oceans as the climate changes.