Variability of the Earth’s climate - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 51

Figure 2.12. Range of values suggested by Pagani et al. (2010) for Earth system sensitivity.
ideal setting is in the low-latitude gyre systems, where a mixed layer of warm, low
density, seawater in contact with the atmosphere generally overlies colder deep
waters with little intermixing. Such environments support abundant planktonic
foraminifera (a group of microscopic protists) that secrete calcite (CaCO 3 ) shells.
The shells fall to the seafloor, from which a record of upper-ocean pH of many
millions of years can be obtained.''
Pearson and Palmer (2000) ''analysed the ( d 11 B) of monospecific sample splits
of surface mixed-layer dwelling foraminifera from 32 sediment samples from the