Premium
Tropical Pacific–Atlantic climate‐driven switching of thermocline nutrient content and export production
Author(s) -
Loubere Paul,
Fariduddin Mohammad
Publication year - 2008
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2007gb003117
Subject(s) - thermocline , new production , oceanography , nutrient , environmental science , north atlantic deep water , glacial period , thermohaline circulation , tropical atlantic , geology , sea surface temperature , ecology , biology , phytoplankton , paleontology
In the modern tropics, thermocline nutrients upwell on the eastern sides of ocean basins and are used with varying efficiency in the different oceans. This leads to nutrient build‐up as well as elevated CO 2 efflux in the Pacific, something not seen in the Atlantic. We present evidence that thermocline nutrient and export production during the last glacial were reduced in the Pacific but were higher in the Atlantic. The evidence indicates an increased ice age supply of nutrients to the tropical Atlantic thermocline, but a reduction in the Pacific; thus, supply to a more efficient biological pump in the Atlantic was raised while that to the inefficient Pacific was diminished. Transformation to modern conditions was a two step process through the deglacial. The results demonstrate large‐scale reorganization of nutrient flow in the Atlantic and Pacific basins. The observed changes had the potential for positive feedback on glacial–interglacial variation of atmospheric CO 2 concentrations.