168
R. I ( . DELL
mechanism supplying a possible route for some forms occasionally, and
never quite effective enough for other forms to achieve dispersal by this
means. Distances between shallow water areas, direction and strength
of ocean currents, and fluctuating temperature differentials would provide a series of variables to match the varying facilities for dispersal
FIQ. 17. Existing dispersal routes into Antarctica based upon ocean currente and the
islands of the Scotia Aro. The same mechanisms allow Antarctic species to reach
the Magellan region through the Scotia Arc, and then to be dispersed by the West
Wind Drift.
R. I ( . DELL
mechanism supplying a possible route for some forms occasionally, and
never quite effective enough for other forms to achieve dispersal by this
means. Distances between shallow water areas, direction and strength
of ocean currents, and fluctuating temperature differentials would provide a series of variables to match the varying facilities for dispersal
FIQ. 17. Existing dispersal routes into Antarctica based upon ocean currente and the
islands of the Scotia Aro. The same mechanisms allow Antarctic species to reach
the Magellan region through the Scotia Arc, and then to be dispersed by the West
Wind Drift.