Eureka!: Small Wonders

Ancient clues to impending extinctions

Photo: Charles E. Mitchell

By Charlotte Hsu

These are the fossilized remains of a colony of Paraorthograptus kimi (P. kimi), a long-gone species of deep-sea plankton. For UB geologist Charles E. Mitchell, large-scale studies of thousands of such fossils provide a window into what drives extinction. One recent project found that ancient plankton communities started losing their diversity as early as 400,000 years before massive die-offs ensued, wiping out P. kimi and many other species. The work suggests that subtle changes may precede dramatic population declines, and Mitchell cautions that we need to be on the lookout for warning signs today as oceans respond to climate change and other pressures.