Hurrah for the Dredge: the ocean floor
Richard Hamblyn, 3 November 2005
The largest migration of life on earth departs every night from the twilight zone, the kilometre-deep middle layer of open ocean in which the majority of living creatures can be found. As darkness falls, millions of tons of animals, ranging in size from the smallest arrow worms to the largest cetaceans, swim their way up to the photic zone to feed in relative safety, braving shallower waters...