Paleontological reconstructions of plankton community structure during warm periods of the
Cenozoic (last 66 million years) reveal that deep-dwelling 'twilight zone'(200–1000 m)
plankton were less abundant and diverse, and lived much closer to the surface, than in
colder, more recent climates. We suggest that this is a consequence of temperature's role in
controlling the rate that sinking organic matter is broken down and metabolized by bacteria,
a process that occurs faster at warmer temperatures. In a warmer ocean, a smaller fraction of …

Paleontological reconstructions of plankton community structure during warm periods of the
Cenozoic (last 66 million years) reveal that deep-dwelling'twilight zone'(200-1000 m)
plankton were less abundant and diverse, and lived much closer to the surface, than in
colder, more recent climates. We suggest that this is a consequence of temperature's role in
controlling the rate that sinking organic matter is broken down and metabolized by bacteria,
a process that occurs faster at warmer temperatures. In a warmer ocean, a smaller fraction of …