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This document contains, for ease of download, a figure summarizing isotopic systems used in chemostratigraphy and a list of additional references.

Closely related taxa are, on average, more similar in terms of their physiology, morphology and ecology than distantly related ones. How this biological similarity affects geochemical signals, and their interpretations, has yet to be tested in an explicitly evolutionary framework. Here, we compile and analyze planktonic foraminiferal size-specific stable carbon and oxygen isotope values (δ13C and δ18O) spanning the last 107 million years. After controlling for dominant drivers of size-δ13C and δ18O trends, such as geological preservation, presence of algal photosymbionts and global environmental trends, we identify that shared evolutionary history has shaped the evolution of species-specific “vital effects” in δ13C, but not in δ18O. Our results lay the groundwork for using a phylogenetic approach to ‘correct’ species δ13C vital effects through time, thereby reducing systematic biases in interpretations of long-term δ13C records – a key measure of holistic organismal biology and of the global carbon cycle.

The tectonic and paleoceanographic setting of the Great Australian Bight (GAB) and the Mentelle Basin (MB; adjacent to Naturaliste Plateau) offered an outstanding opportunity to investigate Cretaceous and Cenozoic climate change and ocean dynamics during the last phase of breakup among remnant Gondwana continents. Sediment recovered from sites in both regions during International Ocean Discovery Program Expedition 369 will provide a new perspective on Earth's temperature variation at sub-polar latitudes (60°-62°S) across the extremes of the mid-Cretaceous hot greenhouse climate and the cooling that followed. The primar y goals of the expedition were to • Investigate the timing and causes for the rise and collapse of the Cretaceous hot greenhouse climate and how this climate mode affected the climate-ocean system and oceanic biota; • Determine the relative roles of productivity, ocean temperature, and ocean circulation at high southern latitudes during Cretaceous oceanic anoxic events (OAEs); • Identify the main source regions for deep-water and intermediate-water masses in the southeast Indian Ocean and how these changed during Gondwana breakup; • Characterize how oceanographic conditions at the MB changed during the Cenozoic opening of the Tasman Passage and restriction of the Indonesian Gateway; • Resolve questions on the volcanic and sedimentary origins of the Australo-Antarctic Gulf and Mentelle Basin and provide stratigraphic control on the age and nature of the prebreakup successions. Hole U1512A in the GAB recovered a 691 m thick sequence of black claystone ranging from the early Turonian to the early Campanian. Age control is primarily based on calcareous nannofossils, but the presence of other microfossil groups provided consistent but low-resolution control. Despite the lithologic uniformity, longand short-term variations in natural gamma ray and magnetic susceptibility intensities show cyclic alternations that suggest an orbital control of sediment deposition that will be useful for developing an astrochronology for the sequence. Sites U1513-U1516 were drilled between 850 and 3900 m water depth in the MB and penetrated 774, 517, 517, and 542 meters below seafloor (mbsf), respectively. Under a thin layer of Pleistocene-upper Miocene sediment, Site U1513 cored a succession of Cretaceous units from the Campanian to the Valanginian. Site U1514 sampled an expanded Pleistocene-Eocene sequence and terminated in the upper Albian. The Cenomanian-Turonian interval at Site U1514 recovered deformed sedimentary rocks that probably represent a detachment zone. Site U1515 is located on the west Australian margin at 850 m water depth and was the most challenging site to core because much of the upper 350 m was either chert or poorly consolidated sand. However, the prebreakup Jurassic(?) sediments interpreted from the seismic profiles were successfully recovered. Site U1516 cored an expanded Pleistocene, Neogene, and Paleogene section and recovered a complete Cenomanian/Turonian boundary interval containing five layers with high total organic carbon content. Recovery of well-preserved calcareous microfossil assemblages from different paleodepths will enable generation of paleotemperature and biotic records that span the rise and collapse of the Cretaceous hot greenhouse (including OAEs 1d and 2), providing insight to resultant changes in deep-water and surface water circulation that can be used to test predictions from earth system models. Paleotemperature proxies and other data will reveal the timing, magnitude, and duration of peak hothouse temperatures and any cold snaps that could have allowed growth of a polar ice sheet. The sites will also record the mid-Eocene-early Oligocene opening of the Tasman Gateway and the Miocene-Pliocene restriction of the Indonesian Gateway; both passages have important effects on global oceanography and climate. Understanding the paleoceanographic changes in a regional context provides a global test on models of Cenomanian-Turonian oceanographic and climatic evolution related both to extreme Turonian warmth and the evolution of OAE 2. The Early Cretaceous volcanic rocks and underlying Jurassic(?) sediments cored in different parts of the MB provide information on the timing of different stages of the Gondwana breakup. The recovered cores provide sufficient new age constraints to underpin a reevaluation of the basin-wide seismic stratigraphy and tectonic models for the region.

The recently published Atlas of Oligocene Planktonic Foraminifera provides a comprehensive reassessment of the taxonomy, evolutionary relationships, stratigraphic distributions, and paleoecology of planktonic foraminifera from the Oligocene Epoch. Our aim was to produce a clear and workable taxonomy that covers all described Oligocene planktonic foraminifera and their synonyms. Our work is founded on new scanning electron micrographs (SEMs) of most of the type specimens and extensive illustration material from all over the globe, including in particular, New Jersey, the Adriatic Sea, Syria, Trinidad, Tanzania and Java, as well as new study of material from the International Ocean Discovery Program (IODP) and its predecessors. We have also included important species of the late Eocene and early Miocene that either complete a lineage or are critical to our understanding of phylogenetic relationships. The higher taxonomy is based on the examination of wall textures, which provides the primary divisions into spinose, nonspinose and microperforate groups. New microstructural observations on the tests of microperforate and medioperforate planktonic foraminifera from the Oligocene have allowed two types and two subtypes of wall texture to be distinguished and described for the first time. Detailed range and phylogenetic charts of all the taxa are presented, and existing geochemical data are synthesized, with the addition of some new stable isotope data. A total of 128 species, of which 14 are new ; and 26 genera, of which 2 are new, are described in the Atlas. New SEM images of the type specimens of over 60 species and their synonyms are shown for the first time in the volume, providing new insight on the shell architecture and wall texture, particularly for species that have previously been poorly illustrated. The resulting plates demonstrate the range in morphologic variability permitted in our refined taxonomic concepts throughout their geographic range and in material with differing preservation styles, allowing us to establish, confirm or dispute synonymies. The Atlas contains over 140 plates, and more than 2000 SEM images and will be invaluable for biostratigraphers, paleontologists, and paleoclimatologists, both in academia and industry, and of importance to all those interested in the fossil record and evolution of life and climate. Future areas for research on Oligocene and early Miocene planktonic foraminifera are also identified.

The Middle Eocene Climatic Optimum (MECO) is an ~500 kyr interval of pronounced global warming from which the climate system recovered in

As living organisms, planktonic foraminifera are not passive tracers of the environment. Their test geochemistry – arguably the single most important resource for paleoceanographic research – reflects the combined signal of environmental, biological and preservational processes. For most species, comparisons of test stable isotopic composition within and among taxa provide the primary means for disentangling the relative influences of these different processes. Here we test the foundations of our paleoceanographic interpretations with the first quantitative comparison of the determinants of carbon and oxygen isotopic variation across multiple ocean basins, studies, and species by re-analyzing size-specific data collated from the literature. We find clear evidence of species-specific biological effects (i.e., vital effects), as the intercepts of size-specific carbon and oxygen isotopic compositions differs significantly amongst species. Trends in body size and isotopic composition, particularly in dinoflagellate bearing taxa, suggest that much of the size-dependent isotopic variation observed in death assemblages (i.e., core-tops and sediments) relates to factors influencing the maximum size obtained by adults rather than ontogeny. The presence and type of photosymbiont hosted (dinoflagellate, chrysophyte or none) was a major factor affecting species- and size-specific δ18O values. In contrast, size-related trends in δ13C values were driven more by depth habitat (mixed layer, thermocline, sub-thermocline) than symbiont ecology. On this broad geographic and oceanographic scale, ocean basin and biome had a significant effect on the isotopic composition of individuals. Our analysis and its model-averaged predictions provide a quantitative basis for interpreting size-specific isotopic variation in 22-species of modern macroperforate planktonic foraminifera. We conclude by highlighting existing data gaps and outstanding questions of the relative influence of environmental, preservational and biological processes on variation in the test geochemistry of planktonic foraminifera.

As living organisms, planktonic foraminifera are not passive tracers of the environment. Their test geochemistry—arguably the single most important resource for paleoceanographic research—reflects the combined signal of environmental, biological, and preservational processes. For most species, comparisons of test stable isotopic composition within and among taxa provide the primary means for disentangling the relative influences of these different processes. Here we test the foundations of our paleoceanographic interpretations with the first quantitative comparison of the determinants of carbon and oxygen isotopic variation across multiple ocean basins, studies, and species by re-analyzing size-specific data collated from the literature. We find clear evidence of species-specific biological effects (i.e., vital effects), as the intercepts of size-specific carbon and oxygen isotopic compositions differ significantly among species. Trends in body size and isotopic composition, particularly in dinoflagellate bearing taxa, suggest that much of the size-dependent isotopic variation observed in death assemblages (i.e., core tops and sediments) relates to factors influencing the maximum size obtained by adults rather than ontogeny. The presence and type of photosymbiont hosted (dinoflagellate, chrysophyte, or none) were a major factor affecting species- and size-specific ?18O values. In contrast, size-related trends in ?13C values were driven by depth habitat (mixed layer, thermocline, subthermocline), symbiont ecology and whether the assemblage was alive or dead when sampled. On this broad geographic and oceanographic scale, ocean basin and biome had a significant effect on ?18O and ?13C values . Our analysis and its model-averaged predictions provide a quantitative basis for interpreting size-specific isotopic variation in 22 species of modern macroperforate planktonic foraminifera. We conclude by highlighting existing data gaps and outstanding questions of the relative influence of environmental, preservational, and biological processes on variation in the test geochemistry of planktonic foraminifera.

Stable oxygen and carbon isotope (O-18 and C-13) values measured in foraminiferal calcite are one of the primary tools used in paleoceanography. Diagenetic recrystallization of foraminiferal calcite can act to reset primary isotopic values, but its effects are typically poorly quantified. Here we test the impact of early stage diagenesis on stable isotope records generated from a suite of drill sites in the equatorial Pacific Ocean recovered during Ocean Drilling Program Leg 199 and Integrated Ocean Drilling Program Expedition 320. Our selected sites form paleowater and burial depth transects, with excellent stratigraphic control allowing us to confidently correlate our records. We observe large intersite differences in the preservation state of benthic foraminiferal calcite, implying very different recrystallization histories, but negligible intersite offsets in benthic O-18 and C-13 values. We infer that diagenetic alteration of benthic foraminiferal calcite (in sedimentary oozes) must predominantly occur at shallow burial depths (

The Middle Eocene Climatic Optimum (MECO) was a gradual warming event and carbon cycle perturbation that occurred between 40.5 and 40.1 Ma. A number of characteristics, including greater-than-expected deep-sea carbonate dissolution, a lack of globally coherent negative δ13C excursion in marine carbonates, a duration longer than the characteristic timescale of carbon cycle recovery, and the absence of a clear trigger mechanism, challenge our current understanding of the Earth system and its regulatory feedbacks. This makes the MECO one of the most enigmatic events in the Cenozoic, dubbed a middle Eocene “carbon cycle conundrum.” Here we use boron isotopes in planktic foraminifera to better constrain pCO2 changes over the event. Over the MECO itself, we find that pCO2 rose by only 0.55–0.75 doublings, thus requiring a much more modest carbon injection than previously indicated by the alkenone δ13C-pCO2 proxy. In addition, this rise in pCO2 was focused around the peak of the 400 kyr warming trend. Before this, considerable global carbonate δ18O change was asynchronous with any coherent ocean pH (and hence pCO2) excursion. This finding suggests that middle Eocene climate (and perhaps a nascent cryosphere) was highly sensitive to small changes in radiative forcing.