“Mohawk Guy” and his Band of NeogenePlanktic Foraminifer Friends

Ocean Circulation

• We have one big ocean, separated into a number of basins• One thing can affect another, even if it is in another region

Changes in Ocean Circulation

• Changes to ocean circulation patterns in the past have changed the temperature of ocean water

• Surface water, deep ocean circulation and the location of the thermocline may be affected

• Availability of nutrients may also be affected• ……This will result in a change to foram

structure and distribution throughout time

JOIDES ResolutionODP Leg 130, Hole 806 B

• 0 19.11’ N, 159 21.69’ E• February 18, 1990 – February

22, 1990• 230 samples examined (110

planktonic foraminifer species identified)

Events that Changed Circulation

Geologic Time Scale

Distribution of forams in a typical tropical ocean

Important Concepts – Biological/Environmental

• Changes in a population can be triggered by environmental causes– seasonal changes, dissolved oxygen, pH, temperature,

water clarity, salinity or depth• As one species becomes extinct, other species

may move into that niche and replace it.– EX: hunting wolves to extinction can lead to an

explosion in deer populations.• climactic changes can cause populations to move

into different regions