(Table S) Planktonic foraminifera I/Ca during the PETM

As yet no evidence has been presented for pervasive deoxygenation in the upper water column through expansion of Oxygen Minimum Zones (OMZs) during the PETM. We apply a novel proxy for paleo-redox conditions, the iodine to calcium ratio (I/Ca) in bulk coarse fraction sediment and planktonic foraminiferal tests from pelagic sites in different oceans, and compared our reconstruction with modeled oxygen levels. The reconstructed iodate gradients indicate that deoxygenation occurred in the upper water column in the Atlantic, Indian Oceans, and possibly the Pacific Ocean as well during the PETM, due to vertical and potentially lateral expansion of OMZs

ODP Site 208-1263 PETM, ETM2, ETM3: barite accumulation rates, benthic foraminiferal data

Data from Ocean Drilling Program Site 1263 on Walvis Ridge in SE Atlantic include barite accumulation rates, benthic foraminiferal data, and carbon and oxygen isotopes for Eocene hyperthermals: PETM, ETM2, ETM3. Changes in primary productivity, in export of organic carbon from the surface ocean, and in remineralization deeper in the water column in the so-called “twilight zone” may substantially alter the marine biological carbon pump, thus carbon storage in the oceans. We present different proxy records commonly used for reconstructing paleoproductivity, and re-evaluate their use for understanding dynamic change within and between different constituents of the marine biological pump during transient global warming episodes in the past. Marine pelagic barite records are a proxy for carbon export from the photic and/or mesopelagic zone, and are not positively correlated with benthic foraminiferal proxies for arrival of organic matter to the seafloor over three early Eocene periods of global warming (Ocean Drilling Program Site 1263, SE Atlantic). These two proxies reflect processes in different parts of the water column, thus different components of the biological pump

Simulated warm polar currents during the middle Permian

[1] During Permian stage 6 (Wordian, Kazanian) the Pangaean supercontinent was surrounded by a superocean: Panthalassa. An ocean general circulation model has been coupled to an atmospheric energy balance model to simulate the sensitivity of the Wordian climate (similar to265 million years ago) to changes in greenhouse gas concentrations, high-latitude geography, and Earth orbital configurations. The model simulates significantly different circulation features with different levels of greenhouse gas forcing, ranging from a strong meridional overturning circulation in the Southern Hemisphere at low CO2 concentration (present level) to more symmetric overturning circulation cells with deep water formation in polar latitudes of both hemispheres at high CO2 concentration (8 times present level). The simulated climate with 4 times present level CO2 concentration agrees generally well with climate-sensitive sediments and phytogeographic patterns. The model simulates strong subtropical gyres with similarities to the modern South Pacific circulation and moderate surface temperatures on the southern continent Gondwana, resulting from a strong poleward heat transport in the ocean. An even more moderate climate is generated if high- latitude land is removed from the southern continent so that ocean currents can penetrate into the polar regions of Gondwana