During the Pliocene and early Pleistocene (5-2.5 Myr ago), Earth changed from a warmer-than-today climate to a setting of strong glacial-interglacial cycles. One of the big unknowns of oceanic conditions is how the biggest Oxygen Minimum Zone (OMZ) in the east Pacific responded. We are using geochemistry (trace metals and isotopes), abundance, and morphometry (using deep learning techniques) on planktic foraminifera to reconstruct changes in the OMZ.