Microscopic algae and the nearly invisible animals that eat them do more than just drift along the ocean surface. Plankton, defined by their habitat, not their taxonomy, are the foundation of the marine food chain—without them, marine life would go hungry and food chains would collapse. They also remove carbon dioxide from the sea and provide Earth's atmosphere with oxygen.

Molecular geneticist Richard R. Kirby gives a close look at plankton diversity in Ocean Drifters: A Secret World Beneath the Waves (Firefly Books, September 2011). Along with 150 high-magnification photographs, Kirby's book explains how rising sea surface temperatures due to anthropogenic climate change will alter the sea's food web and the ecology of Earth.

» View a slide show