@article{govindankutty menon_davis_nuernberg_nomaki_salonen_schmiedl_glock_2023, title={A deep-learning automated image recognition method for measuring pore patterns in closely related bolivinids and calibration for quantitative nitrate paleo-reconstructions}, volume={13}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-023-46605-y}, abstractNote={Abstract}, number={1}, journal={SCIENTIFIC REPORTS}, author={Govindankutty Menon, Anjaly and Davis, Catherine V. and Nuernberg, Dirk and Nomaki, Hidetaka and Salonen, Iines and Schmiedl, Gerhard and Glock, Nicolaas}, year={2023}, month={Nov} }
 @article{davis_sibert_jacobs_burls_hull_2023, title={Intermediate water circulation drives distribution of Pliocene Oxygen Minimum Zones}, volume={14}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/s41467-022-35083-x}, DOI={10.1038/s41467-022-35083-x}, abstractNote={Abstract}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Davis, Catherine V. and Sibert, Elizabeth C. and Jacobs, Peter H. and Burls, Natalie and Hull, Pincelli M.}, year={2023}, month={Jan} }
 @article{winkelbauer_hoogakker_chance_davis_anthony_bischoff_carpenter_chenery_hamilton_holdship_et al._2023, title={Planktic foraminifera iodine/calcium ratios from plankton tows}, volume={10}, ISSN={2296-7745}, url={http://dx.doi.org/10.3389/fmars.2023.1095570}, DOI={10.3389/fmars.2023.1095570}, abstractNote={Planktic foraminifera test iodine to calcium ratios represent an emerging proxy method to assess subsurface seawater oxygenation states. Several core-top studies show lower planktic foraminifera I/Ca in locations with oxygen depleted subsurface waters compared to well oxygenated environments. The reasoning behind this trend is that only the oxidized species of iodine, iodate, is incorporated in foraminiferal calcite. The I/Ca of foraminiferal calcite is thought to reflect iodate contents in seawater. To test this hypothesis, we compare planktic foraminifera I/Ca ratios, obtained from plankton tows, with published and new seawater iodate concentrations from 1) the Eastern North Pacific with extensive oxygen depletion, 2) the Benguela Current System with moderately depleted oxygen concentrations, and 3) the well oxygenated North and South Atlantic. We find the lowest I/Ca ratios (0.07 µmol/mol) in planktic foraminifera retrieved from the Eastern North Pacific, and higher values for samples (up to 0.72 µmol/mol) obtained from the Benguela Current System and North and South Atlantic. The I/Ca ratios of plankton tow foraminifera from environments with well oxygenated subsurface waters, however, are an order of magnitude lower compared to core-tops from similarly well-oxygenated regions. This would suggest that planktic foraminifera gain iodine post-mortem, either when sinking through the water column, or during burial.}, journal={Frontiers in Marine Science}, publisher={Frontiers Media SA}, author={Winkelbauer, Helge A. and Hoogakker, Babette A. A. and Chance, Rosie J. and Davis, Catherine V. and Anthony, Christopher J. and Bischoff, Juliane and Carpenter, Lucy J. and Chenery, Simon R. N. and Hamilton, Elliott M. and Holdship, Philip and et al.}, year={2023}, month={Feb} }
 @article{chaabane_garidel-thoron_giraud_schiebel_beaugrand_brummer_casajus_greco_grigoratou_howa_et al._2023, title={The FORCIS database: A global census of planktonic Foraminifera from ocean waters}, volume={10}, ISSN={["2052-4463"]}, DOI={10.1038/s41597-023-02264-2}, abstractNote={Abstract}, number={1}, journal={SCIENTIFIC DATA}, author={Chaabane, Sonia and Garidel-Thoron, Thibault and Giraud, Xavier and Schiebel, Ralf and Beaugrand, Gregory and Brummer, Geert-Jan and Casajus, Nicolas and Greco, Mattia and Grigoratou, Maria and Howa, Helene and et al.}, year={2023}, month={Jun} }
 @article{davis_doherty_fehrenbacher_wishner_2023, title={Trace element composition of modern planktic foraminifera from an oxygen minimum zone: Potential proxies for an enigmatic environment}, volume={10}, ISSN={["2296-7745"]}, url={http://dx.doi.org/10.3389/fmars.2023.1145756}, DOI={10.3389/fmars.2023.1145756}, abstractNote={Oxygen limited marine environments, such as oxygen minimum zones, are of profound importance for global nutrient cycling and vertical habitat availability. While it is understood that the extent and intensity of oxygen minimum zones are responsive to climate, the limited suite of viable proxies for low oxygen pelagic environments continues to pose a real barrier for paleoclimate interpretations. Here we investigate the proxy potential of an array of trace element (Mg, Mn, Zn, and Sr) to Ca ratios from the shells of Globorotaloides hexagonus, a planktic foraminifer endemic to tropical through temperate oxygen minimum zones. A species-specific relationship between Mg/Ca and temperature is proposed for quantitative reconstruction of oxygen minimum zone paleotemperatures. Both Mn/Ca and Zn/Ca ratios vary with oxygen concentration and could be useful for reconstructing G. hexagonus habitat where the primary signal can be d\istinguished from diagenetic overprinting. Finally, a robust correlation between Sr/Ca ratios and dissolved oxygen demonstrates a role for Sr as an indicator of oxygen minimum zone intensity, potentially via foraminiferal growth rate. The analysis of these relatively conventional trace element ratios in the shells of an oxygen minimum zone species has tremendous potential to facilitate multiproxy reconstructions from this enigmatic environment.}, journal={FRONTIERS IN MARINE SCIENCE}, publisher={Frontiers Media SA}, author={Davis, Catherine V. and Doherty, Shannon and Fehrenbacher, Jennifer and Wishner, Karen}, year={2023}, month={Mar} }
 @article{richey_fehrenbacher_reynolds_davis_spero_2022, title={Barium enrichment in the non-spinose planktic foraminifer, Globorotalia truncatulinoides}, volume={333}, ISSN={0016-7037}, url={http://dx.doi.org/10.1016/j.gca.2022.07.006}, DOI={10.1016/j.gca.2022.07.006}, abstractNote={Observations of elevated barium-to-calcium ratios (Ba/Ca) in Globorotalia truncatulinoides have been attributed to contaminant phases, deep calcification depth and diagenetic processes. Here we investigate intra- and inter-test Ba/Ca variability in the non-spinose planktic foraminifer, G. truncatulinoides, from a sediment trap time series in the northern Gulf of Mexico to gain insights into the environmental influences on barium enrichment in this and other non-spinose species. We use laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to differentiate between the elemental composition of the crust and lamellar calcite in non-encrusted (<150 m calcification depth) and encrusted (>150 m calcification depth) specimens of G. truncatulinoides. We find that the Ba/Ca ratio in lamellar calcite is between two and three orders of magnitude higher (10–280 μmol/mol) than that of the crust (0–3 μmol/mol). We include seasonal water column profiles of the Ba/Ca ratio in the northern Gulf of Mexico and determine that the vertical gradient in seawater barium concentration cannot account for the intra-test Ba/Ca variations in G. truncatulinoides. We find the Ba/Ca ratio of the crust to be within the range observed in co-occurring spinose species of foraminifera (pink and white chromotypes of Globigerinoides ruber, and Orbulina universa) while the range of Ba/Ca in lamellar calcite is consistent with co-occurring non-spinose foraminifera (Pulleniatina obliquiloculata, Globorotalia menardii, G. tumida, and Neogloboquadrina dutertrei). Our data are consistent with the hypothesis that G. truncatulinoides calcifies in a marine snow aggregate microenvironment that is enriched in barium relative to ambient seawater. We suggest that G. truncatulinoides crust is formed after the rhizopodia retract and the foraminifer detaches from its marine snow substrate.}, journal={Geochimica et Cosmochimica Acta}, publisher={Elsevier BV}, author={Richey, Julie N. and Fehrenbacher, Jennifer S. and Reynolds, Caitlin E. and Davis, Catherine V. and Spero, Howard J.}, year={2022}, month={Sep}, pages={184–199} }
 @article{davis_2022, title={Deglacial restructuring of the Eastern equatorial Pacific oxygen minimum zone}, volume={3}, ISSN={2662-4435}, url={http://dx.doi.org/10.1038/s43247-022-00477-8}, DOI={10.1038/s43247-022-00477-8}, abstractNote={Abstract}, number={1}, journal={Communications Earth & Environment}, publisher={Springer Science and Business Media LLC}, author={Davis, Catherine V.}, year={2022}, month={Jun} }
 @article{davis_shaw_d’haenens_thomas_hull_2022, title={Photosymbiont associations persisted in planktic foraminifera during early Eocene hyperthermals at Shatsky Rise (Pacific Ocean)}, volume={17}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0267636}, DOI={10.1371/journal.pone.0267636}, abstractNote={Understanding the sensitivity of species-level responses to long-term warming will become increasingly important as we look towards a warmer future. Here, we examine photosymbiont associations in planktic foraminifera at Shatsky Rise (ODP Site 1209, Pacific Ocean) across periods of global warming of differing magnitude and duration. We compare published data from the Paleocene-Eocene Thermal Maximum (PETM; ~55.9 Ma) with data from the less intense Eocene Thermal Maximum 2 (ETM2; ~54.0 Ma), and H2 events (~53.9 Ma). We use a positive relationship between test size and carbon isotope value (size-δ13C) in foraminifera shells as a proxy for photosymbiosis in Morozovella subbotinae and Acarinina soldadoensis, and find no change in photosymbiont associations during the less intense warming events, in contrast with PETM records indicating a shift in symbiosis in A. soldadoensis (but not M. subbotinae). Declines in abundance and differing preservation potential of the asymbiotic species Subbotina roesnaesensis along with sediment mixing likely account for diminished differences in δ13C between symbiotic and asymbiotic species from the PETM and ETM2. We therefore conclude that photosymbiont associations were maintained in both A. soldadoensis and M. subbotinae across ETM2 and H2. Our findings support one or both of the hypotheses that 1) changing symbiotic associations in response to warming during the PETM allowed A. soldadoensis and perhaps other acarininids to thrive through subsequent hyperthermals or 2) some critical environmental threshold value was not reached in these less intense hyperthermals.}, number={9}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Davis, Catherine V. and Shaw, Jack O. and D’haenens, Simon and Thomas, Ellen and Hull, Pincelli M.}, editor={Incarbona, AlessandroEditor}, year={2022}, month={Sep}, pages={e0267636} }
 @article{oakes_davis_sessa_2021, title={Using the Stable Isotopic Composition of Heliconoides inflatus Pteropod Shells to Determine Calcification Depth in the Cariaco Basin}, volume={7}, url={http://dx.doi.org/10.3389/fmars.2020.553104}, DOI={10.3389/fmars.2020.553104}, abstractNote={Pteropods have been hailed as the “canary in the coal mine” for ocean acidification, however, questions remain about their life history, habitat, and the environmental parameters that the isotopic composition of their shells reflect. In order to use pteropods as recorders of ocean chemistry, it is first necessary to understand where they calcify and how this may change through the year, whether this signal is affected by dissolution, and if shells are retained in the subfossil, and eventually fossil, record. Here we create the first annual record of the stable isotopic composition of shells of the pteropodHeliconoides inflatusin the Cariaco Basin, Venezuela utilizing samples and data from the CARIACO time series. Sixty-fourH. inflatusspecimens from 17 sediment trap samples between November 1996 and April 1998, and 22 specimens from the late Holocene-aged CAR2000-MC-2 core were analyzed for shell condition (an assessment of the amount of dissolution that a shell has experienced), size, and carbon and oxygen isotopic composition. Carbon isotopic measurements of juveniles (< 1mm) were more variable than those in adults (>1 mm), suggesting juvenile pteropods likely have a higher growth rate, and therefore different metabolic vital effects, and a more varied diet than adult pteropods.H. inflatuswas found to have an apparent calcification depth of 51.2 ± 34.0 m, suggesting they calcify at the shallowest part of their diurnal migration in the mixed layer (10–35 m in the Cariaco Basin).H. inflatusshell calcification will therefore only be impacted by changes in water chemistry at mixed layer depths. The shell condition did not impact the stable isotopic composition of the shells in either the sediment trap or core sample, suggesting the potential for using the isotopic composition of pteropod shells as oceanographic proxies when they are preserved. Comparisons between sediment trap and core sample show a 0.5°C warming that is marginally significant and a significant 0.45‰ decrease in δ13C between the late Holocene and the late 1990's. These measurements reflect changes in oceanic conditions linked to anthropogenic fossil fuel emissions known as the Suess effect, and lay the groundwork for establishing pteropods as paleoceanographic proxies in the future.}, journal={Frontiers in Marine Science}, publisher={Frontiers Media SA}, author={Oakes, Rosie L. and Davis, Catherine V. and Sessa, Jocelyn A.}, year={2021}, month={Jan} }
 @article{davis_wishner_renema_hull_2021, title={Vertical distribution of planktic foraminifera through an oxygen minimum zone: how assemblages and test morphology reflect oxygen concentrations}, volume={18}, ISSN={1726-4189}, url={http://dx.doi.org/10.5194/bg-18-977-2021}, DOI={10.5194/bg-18-977-2021}, abstractNote={Abstract. Oxygen-depleted regions of the global ocean are rapidly expanding, with
important implications for global biogeochemical cycles. However, our
ability to make projections about the future of oxygen in the ocean is
limited by a lack of empirical data with which to test and constrain the
behavior of global climatic and oceanographic models. We use
depth-stratified plankton tows to demonstrate that some species of planktic
foraminifera are adapted to life in the heart of the pelagic oxygen minimum
zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the
eastern tropical North Pacific OMZ. The tests of the former are preserved in
marine sediments and could be used to trace the extent and intensity of
low-oxygen pelagic habitats in the fossil record. Additional morphometric
analyses of G. hexagonus show that tests found in the lowest oxygen environments are
larger, more porous, less dense, and have more chambers in the final whorl.
The association of this species with the OMZ and the apparent plasticity of
its test in response to ambient oxygenation invites the use of G. hexagonus tests in
sediment cores as potential proxies for both the presence and intensity of
overlying OMZs.
                    }, number={3}, journal={Biogeosciences}, publisher={Copernicus GmbH}, author={Davis, Catherine V. and Wishner, Karen and Renema, Willem and Hull, Pincelli M.}, year={2021}, month={Feb}, pages={977–992} }
 @article{davis_benitez-nelson_2020, title={Evidence for rapid trace element alteration of planktic foraminiferal shells from the Panama Basin: Manganese adsorption during vertical transport}, volume={157}, ISSN={0377-8398}, url={http://dx.doi.org/10.1016/j.marmicro.2020.101872}, DOI={10.1016/j.marmicro.2020.101872}, abstractNote={The trace elemental composition of planktic foraminifera shells serves as a proxy for understanding the physical environment in which foraminifera lived, but may also reflect chemical alterations that occur after death. Understanding how foraminiferal geochemistry varies across time, species, and after death is therefore essential for deconvolving ecological from diagenetic information and decoding the environmental signals contained within foraminiferal shells. We analyzed the trace elemental composition (Mg/Ca, Sr/Ca, Ba/Ca, Mn/Ca, and U/Ca) of four species of planktic foraminifera (Globigerina ruber, Neogloboquadrina dutertrei, Globorotalia menardii, and Globorotaloides hexagonus) from moored sediment traps (890, 2590, and 3560 m deep) in the Panama Basin collected over one calendar year (1979–1980). Shells recovered from the shallowest trap demonstrate moderate variability in trace elemental composition, both throughout the time series and between species. Most elemental ratios are not significantly influenced by depth, with the exception of Mn/Ca. Ratios of Mn/Ca are substantially higher in the 3560 m trap versus the 890 m trap, with increases with depth greater in the thin walled species G. ruber and G. hexagonus. Elevated Mn/Ca ratios are frequently noted in fossil foraminifera shells as the result of diagenesis within the sediment. Our results demonstrate the potential for Mn-enrichment of foraminiferal calcite, via Mn adsorption onto the surface of foraminiferal shells, within the water column during sinking and prior to deposition in the sediment.}, journal={Marine Micropaleontology}, publisher={Elsevier BV}, author={Davis, Catherine V. and Benitez-Nelson, Claudia R.}, year={2020}, month={May}, pages={101872} }
 @article{davis_livsey_palmer_hull_thomas_hill_benitez-nelson_2020, title={Extensive morphological variability in asexually produced planktic foraminifera}, volume={6}, ISSN={2375-2548}, url={http://dx.doi.org/10.1126/sciadv.abb8930}, DOI={10.1126/sciadv.abb8930}, abstractNote={Planktic foraminifera reproduce sexually and asexually, overturning assumptions of heritability and dispersal.}, number={28}, journal={Science Advances}, publisher={American Association for the Advancement of Science (AAAS)}, author={Davis, Catherine V. and Livsey, Caitlin M. and Palmer, Hannah M. and Hull, Pincelli M. and Thomas, Ellen and Hill, Tessa M. and Benitez-Nelson, Claudia R.}, year={2020}, month={Jul}, pages={eabb8930} }
 @article{davis_myhre_deutsch_caissie_praetorius_borreggine_thunell_2020, title={Sea surface temperature across the Subarctic North Pacific and marginal seas through the past 20,000 years: A paleoceanographic synthesis}, volume={246}, ISSN={0277-3791}, url={http://dx.doi.org/10.1016/j.quascirev.2020.106519}, DOI={10.1016/j.quascirev.2020.106519}, abstractNote={Deglacial sea surface conditions in the subarctic North Pacific and marginal seas are the subject of increasing interest in paleoceanography. However, a cohesive picture of near-surface oceanography from which to compare inter and intra-regional variability through the last deglaciation is lacking. We present a synthesis of sea surface temperature covering the open North Pacific and its marginal seas, spanning the past 20 ka using proxy records from foraminiferal calcite (δ18O and Mg/Ca) and coccolithophore alkenones (Uk’37). Sea surface temperature proxies tend to be in agreement through the Holocene, though Uk’37 records are often interpreted as warmer than adjacent δ18O or Mg/Ca records during the Last Glacial Maximum and early deglaciation. In the Sea of Okhotsk, Holocene discrepancies between δ18O and Uk’37 may be the result of changes in near-surface stratification. We find that sea-surface warming occurred prior to the onset of the Bølling-Allerød (14.7 ka) and coincident with the onset of the Holocene (11.7 ka) in much of the North Pacific and Bering Sea. Proxy records also show a cold reversal roughly synchronous with the Younger Dryas (12.9–11.7 ka). After the onset of the Holocene, the influence of an intensified warm Kuroshio Current is evident at higher latitudes in the Western Pacific, and an east-west seesaw in sea surface temperature, likely driven by changes in the strength of the North Pacific Gyre, characterizes the open interglacial North Pacific.}, journal={Quaternary Science Reviews}, publisher={Elsevier BV}, author={Davis, Catherine V. and Myhre, Sarah E. and Deutsch, Curtis and Caissie, Beth and Praetorius, Summer and Borreggine, Marisa and Thunell, Robert}, year={2020}, month={Oct}, pages={106519} }
 @article{sarno_benitez‐nelson_ziolkowski_hendy_davis_tappa_thunell_2020, title={The Impacts of Flood, Drought, and Turbidites on Organic Carbon Burial Over the Past 2,000 years in the Santa Barbara Basin, California}, volume={35}, ISSN={2572-4517 2572-4525}, url={http://dx.doi.org/10.1029/2020PA003849}, DOI={10.1029/2020pa003849}, abstractNote={Abstract}, number={7}, journal={Paleoceanography and Paleoclimatology}, publisher={American Geophysical Union (AGU)}, author={Sarno, Caitlyn T. and Benitez‐Nelson, Claudia R. and Ziolkowski, Lori A. and Hendy, Ingrid L. and Davis, Catherine V. and Tappa, Eric J. and Thunell, Robert C.}, year={2020}, month={Jul} }
 @article{davis_fehrenbacher_benitez-nelson_thunell_2020, title={Trace Element Heterogeneity Across Individual Planktic Foraminifera from the Modern Cariaco Basin}, volume={50}, url={http://dx.doi.org/10.2113/gsjfr.50.2.204}, DOI={10.2113/gsjfr.50.2.204}, abstractNote={ABSTRACT}, number={2}, journal={Journal of Foraminiferal Research}, publisher={GeoScienceWorld}, author={Davis, Catherine V. and Fehrenbacher, Jennifer S. and Benitez-Nelson, Claudia and Thunell, Robert C.}, year={2020}, month={Apr}, pages={204–218} }
 @article{davis_wishner_renema_hull_2020, title={Vertical distribution of planktic foraminifera through an Oxygen Minimum Zone:how assemblages and shell morphology reflect oxygen concentrations}, volume={8}, DOI={10.5194/bg-2020-280}, abstractNote={Abstract. Oxygen-depleted regions of the global ocean are rapidly expanding, with important implications for global biogeochemical cycles. However, our ability to make projections of a future deoxygenated ocean is limited by a lack of empirical data with which to test and constrain the behavior of global climatic and oceanographic models. We use depth-stratified plankton tows to demonstrate that some species of planktic foraminifera are adapted to life in the heart of the pelagic Oxygen Minimum Zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the Eastern Tropical North Pacific OMZ. The shells of the former are preserved in marine sediments and could be used to trace the extent and intensity of low-oxygen pelagic habitats in the fossil record. Additional morphometric analyses of G. hexagonus show that shells found in the lowest oxygen environments are larger, more porous, less dense, and have more chambers in the final whorl. The association of this species with the OMZ and the apparent plasticity of its shell in response to ambient oxygenation invites the use of G. hexagonus shells in sediment cores as potential proxies for both the presence and intensity of overlying OMZs.
                        }, publisher={Copernicus GmbH}, author={Davis, Catherine V. and Wishner, Karen and Renema, Willem and Hull, Pincelli M.}, year={2020}, month={Aug} }
 @article{hsiang_brombacher_rillo_mleneck‐vautravers_conn_lordsmith_jentzen_henehan_metcalfe_fenton_et al._2019, title={Endless Forams: >34,000 Modern Planktonic Foraminiferal Images for Taxonomic Training and Automated Species Recognition Using Convolutional Neural Networks}, volume={34}, ISSN={2572-4517 2572-4525}, url={http://dx.doi.org/10.1029/2019PA003612}, DOI={10.1029/2019pa003612}, abstractNote={ABSTRACT}, number={7}, journal={Paleoceanography and Paleoclimatology}, publisher={American Geophysical Union (AGU)}, author={Hsiang, Allison Y. and Brombacher, Anieke and Rillo, Marina C. and Mleneck‐Vautravers, Maryline J. and Conn, Stephen and Lordsmith, Sian and Jentzen, Anna and Henehan, Michael J. and Metcalfe, Brett and Fenton, Isabel S. and et al.}, year={2019}, month={Jul}, pages={1157–1177} }
 @article{davis_ontiveros‐cuadras_benitez‐nelson_schmittner_tappa_osborne_thunell_2019, title={Ongoing Increase in Eastern Tropical North Pacific Denitrification as Interpreted Through the Santa Barbara Basin Sedimentary δ
            <sup>15
            N Record}, volume={34}, ISSN={2572-4517 2572-4525}, url={http://dx.doi.org/10.1029/2019PA003578}, DOI={10.1029/2019pa003578}, abstractNote={Abstract}, number={9}, journal={Paleoceanography and Paleoclimatology}, publisher={American Geophysical Union (AGU)}, author={Davis, C. V. and Ontiveros‐Cuadras, J. F. and Benitez‐Nelson, C. and Schmittner, A. and Tappa, E. J. and Osborne, E. and Thunell, R. C.}, year={2019}, month={Sep}, pages={1554–1567} }
 @article{davis_davis_thunell_osborne_black_benitez‐nelson_2019, title={Reconstructing 800 Years of Carbonate Ion Concentration in the Cariaco Basin Using the Area Density of Planktonic Foraminifera Shells}, volume={34}, ISSN={2572-4517 2572-4525}, url={http://dx.doi.org/10.1029/2019PA003698}, DOI={10.1029/2019pa003698}, abstractNote={Abstract}, number={12}, journal={Paleoceanography and Paleoclimatology}, publisher={American Geophysical Union (AGU)}, author={Davis, A. N. and Davis, C. V. and Thunell, R. C. and Osborne, E. B. and Black, D. E. and Benitez‐Nelson, C. R.}, year={2019}, month={Dec}, pages={2129–2140} }
 @article{davis_fuqua_pride_thunell_2019, title={Seasonal and interannual changes in planktic foraminiferal fluxes and species composition in Guaymas Basin, Gulf of California}, volume={149}, ISSN={0377-8398}, url={http://dx.doi.org/10.1016/j.marmicro.2019.05.001}, DOI={10.1016/j.marmicro.2019.05.001}, abstractNote={Paleoclimate records based on planktic foraminifera shells are reliant upon an understanding of how populations respond to annual and interannual changes in surface hydrography. In particular, annual and interannual flux variability would be expected to impact the interpretation of geochemical proxies from foraminifera shells. A seven-year time series from Guaymas Basin, Gulf of California reveals a seasonal progression of foraminiferal species flux, with faunal assemblages characteristic of winter, summer, and fall conditions. Observations of flux along with remotely sensed sea surface temperatures and previously published oxygen isotope data are used here to assess the range of environmental conditions each species would be expected to represent in the fossil record. We find that both species abundances and phenology are altered during negative El Niño Southern Oscillation (ENSO) phases, as occurred over the course of the study period. This observation is used in conjunction with published δ18O data to subsample fluxes in simulation of assemblages collected and analyzed by standard paleontological methods. This approach indicates that during periods more influenced by El Niño conditions, Globigerina bulloides would record warmer conditions, while Neogloboquadrina dutertrei would reflect cooler conditions.}, journal={Marine Micropaleontology}, publisher={Elsevier BV}, author={Davis, Catherine V. and Fuqua, Lauren and Pride, Carol and Thunell, Robert}, year={2019}, month={May}, pages={75–88} }
 @article{bird_darling_russell_fehrenbacher_davis_free_ngwenya_2018, title={16S rRNA gene metabarcoding and TEM reveals different ecological strategies within the genus Neogloboquadrina (planktonic foraminifer)}, volume={13}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0191653}, DOI={10.1371/journal.pone.0191653}, abstractNote={Uncovering the complexities of trophic and metabolic interactions among microorganisms is essential for the understanding of marine biogeochemical cycling and modelling climate-driven ecosystem shifts. High-throughput DNA sequencing methods provide valuable tools for examining these complex interactions, although this remains challenging, as many microorganisms are difficult to isolate, identify and culture. We use two species of planktonic foraminifera from the climatically susceptible, palaeoceanographically important genus Neogloboquadrina, as ideal test microorganisms for the application of 16S rRNA gene metabarcoding. Neogloboquadrina dutertrei and Neogloboquadrina incompta were collected from the California Current and subjected to either 16S rRNA gene metabarcoding, fluorescence microscopy, or transmission electron microscopy (TEM) to investigate their species-specific trophic interactions and potential symbiotic associations. 53–99% of 16S rRNA gene sequences recovered from two specimens of N. dutertrei were assigned to a single operational taxonomic unit (OTU) from a chloroplast of the phylum Stramenopile. TEM observations confirmed the presence of numerous intact coccoid algae within the host cell, consistent with algal symbionts. Based on sequence data and observed ultrastructure, we taxonomically assign the putative algal symbionts to Pelagophyceae and not Chrysophyceae, as previously reported in this species. In addition, our data shows that N. dutertrei feeds on protists within particulate organic matter (POM), but not on bacteria as a major food source. In total contrast, of OTUs recovered from three N. incompta specimens, 83–95% were assigned to bacterial classes Alteromonadales and Vibrionales of the order Gammaproteobacteria. TEM demonstrates that these bacteria are a food source, not putative symbionts. Contrary to the current view that non-spinose foraminifera are predominantly herbivorous, neither N. dutertrei nor N. incompta contained significant numbers of phytoplankton OTUs. We present an alternative view of their trophic interactions and discuss these results within the context of modelling global planktonic foraminiferal abundances in response to high-latitude climate change.}, number={1}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Bird, Clare and Darling, Kate F. and Russell, Ann D. and Fehrenbacher, Jennifer S. and Davis, Catherine V. and Free, Andrew and Ngwenya, Bryne T.}, editor={Frontalini, FabrizioEditor}, year={2018}, month={Jan}, pages={e0191653} }
 @article{fehrenbacher_russell_davis_spero_chu_hönisch_2018, title={Ba/Ca ratios in the non-spinose planktic foraminifer Neogloboquadrina dutertrei: Evidence for an organic aggregate microhabitat}, volume={236}, ISSN={0016-7037}, url={http://dx.doi.org/10.1016/j.gca.2018.03.008}, DOI={10.1016/j.gca.2018.03.008}, abstractNote={Ba/Ca ratios in many non-spinose planktic foraminifera are markedly higher than those observed in spinose planktic species, but the cause for these high Ba/Ca ratios is not understood. A better understanding of this geochemical anomaly could provide insights into the habitat and/or controls over Ba incorporation in these species and expand their utility in paleoclimate research. In spinose species, shell Ba/Ca depends only on the Ba/Ca ratio of seawater. Proposed explanations for high non-spinose Ba/Ca include (1) the empirical partition coefficient, DBa, differs from the spinose species, (2) shell Ba varies with seawater temperature and pH, or (3) non-spinose foraminifers have a preference for prey that has elevated Ba. We performed laboratory culture experiments to determine DBa for the thermocline-dwelling non-spinose planktic foraminifer Neogloboquadrina dutertrei. We find that the Ba/Ca ratio of foraminiferal calcite secreted in the laboratory varies linearly with the Ba/Ca ratio of the seawater. The DBa for this species, 0.11 ± 0.008 (2SE; 95% CL), is similar to the DBa for spinose species (0.13 ± 0.004, 2SE; 95% CL). As in spinose species, the Ba/Ca ratio of cultured specimens of N. dutertrei is not influenced by culture temperature (12–22 °C) or seawater pHNBS (range 7.8–8.3). However, the Ba/Ca ratio of individual plankton-tow N. dutertrei specimens that completed their lifecycle in the ocean exceeds the Ba/Ca ratio of cultured specimens by up to three orders of magnitude. It is unlikely this difference between cultured specimens and ocean-grown specimens is due to seawater [Ba] variability, since seawater Ba/Ca ratios calculated using our DBa are much higher than exist in the ocean. Rather, we suggest that elevated shell Ba/Ca in plankton tow and fossil N. dutertrei is due to calcification in the microenvironment of marine organic aggregates such as marine snow, where [Ba] is elevated as a result of Ba release from biogenic particulates.}, journal={Geochimica et Cosmochimica Acta}, publisher={Elsevier BV}, author={Fehrenbacher, Jennifer S. and Russell, Ann D. and Davis, Catherine V. and Spero, Howard J. and Chu, Edward and Hönisch, Bärbel}, year={2018}, month={Sep}, pages={361–372} }
 @article{burke_renema_henehan_elder_davis_maas_foster_schiebel_hull_2018, title={Factors influencing test porosity in planktonic foraminifera}, volume={15}, ISSN={1726-4189}, url={http://dx.doi.org/10.5194/bg-15-6607-2018}, DOI={10.5194/bg-15-6607-2018}, abstractNote={Abstract. The clustering of mitochondria near pores in the test walls of foraminifera
suggests that these perforations play a critical role in metabolic gas
exchange. As such, pore measurements could provide a novel means of tracking
changes in metabolic rate in the fossil record. However, in planktonic
foraminifera, variation in average pore area, density, and porosity (the
total percentage of a test wall that is open pore space) have been variously
attributed to environmental, biological, and taxonomic drivers, complicating
such an interpretation. Here we examine the environmental, biological, and
evolutionary determinants of pore characteristics in 718 individuals,
representing 17 morphospecies of planktonic foraminifera from 6 core tops in
the North Atlantic. Using random forest models, we find that porosity is
primarily correlated to test surface area, test volume, and habitat
temperature, key factors in determining metabolic rates. In order to test if
this correlation arose spuriously through the association of cryptic species
with distinct biomes, we cultured Globigerinoides ruber in three
different temperature conditions, and found that porosity increased with
temperature. Crucially, these results show that porosity can be plastic:
changing in response to environmental drivers within the lifetime of an
individual foraminifer. This demonstrates the potential of porosity as a
proxy for foraminiferal metabolic rates, with significance for interpreting
geochemical data and the physiology of foraminifera in non-analog
environments. It also highlights the importance of phenotypic plasticity
(i.e., ecophenotypy) in accounting for some aspects of morphological
variation in the modern and fossil record.
                    }, number={21}, journal={Biogeosciences}, publisher={Copernicus GmbH}, author={Burke, Janet E. and Renema, Willem and Henehan, Michael J. and Elder, Leanne E. and Davis, Catherine V. and Maas, Amy E. and Foster, Gavin L. and Schiebel, Ralf and Hull, Pincelli M.}, year={2018}, month={Nov}, pages={6607–6619} }
 @article{davis_hewett_hill_largier_gaylord_jahncke_2018, title={Reconstructing Aragonite Saturation State Based on an Empirical Relationship for Northern California}, volume={41}, ISSN={1559-2723 1559-2731}, url={http://dx.doi.org/10.1007/s12237-018-0372-0}, DOI={10.1007/s12237-018-0372-0}, number={7}, journal={Estuaries and Coasts}, publisher={Springer Science and Business Media LLC}, author={Davis, Catherine V. and Hewett, Kathryn and Hill, Tessa M. and Largier, John L. and Gaylord, Brian and Jahncke, Jaime}, year={2018}, month={Apr}, pages={2056–2069} }
 @article{borreggine_myhre_mislan_deutsch_davis_2017, title={A database of paleoceanographic sediment cores from the North Pacific, 1951–2016}, volume={9}, ISSN={1866-3516}, url={http://dx.doi.org/10.5194/essd-9-739-2017}, DOI={10.5194/essd-9-739-2017}, abstractNote={Abstract. We assessed sediment coring, data acquisition, and publications from the North Pacific (north of 30° N) from 1951 to 2016. There are 2134 sediment cores collected by American, French, Japanese, Russian, and international research vessels across the North Pacific (including the Pacific subarctic gyre, Alaskan gyre, Japan margin, and California margin; 1391 cores), the Sea of Okhotsk (271 cores), the Bering Sea (123 cores), and the Sea of Japan (349 cores) reported here. All existing metadata associated with these sediment cores are documented here, including coring date, location, core number, cruise number, water depth, vessel metadata, and coring technology. North Pacific sediment core age models are built with isotope stratigraphy, radiocarbon dating, magnetostratigraphy, biostratigraphy, tephrochronology, % opal, color, and lithological proxies. Here, we evaluate the iterative generation of each published age model and provide comprehensive documentation of the dating techniques used, along with sedimentation rates and age ranges. We categorized cores according to the availability of a variety of proxy evidence, including biological (e.g., benthic and planktonic foraminifera assemblages), geochemical (e.g., major trace element concentrations), isotopic (e.g., bulk sediment nitrogen, oxygen, and carbon isotopes), and stratigraphic (e.g., preserved laminations) proxies. This database is a unique resource to the paleoceanographic and paleoclimate communities and provides cohesive accessibility to sedimentary sequences, age model development, and proxies. The data set is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.875998.
                    }, number={2}, journal={Earth System Science Data}, publisher={Copernicus GmbH}, author={Borreggine, Marisa and Myhre, Sarah E. and Mislan, K. Allison S. and Deutsch, Curtis and Davis, Catherine V.}, year={2017}, month={Sep}, pages={739–749} }
 @article{bird_darling_russell_davis_fehrenbacher_free_wyman_ngwenya_2017, title={Cyanobacterial endobionts within a major marine planktonic calcifier (<i>Globigerina bulloides</i>, Foraminifera) revealed by 16S rRNA metabarcoding}, volume={14}, ISSN={1726-4189}, url={http://dx.doi.org/10.5194/bg-14-901-2017}, DOI={10.5194/bg-14-901-2017}, abstractNote={Abstract. We investigated the possibility of bacterial symbiosis in Globigerina bulloides, a palaeoceanographically important, planktonic foraminifer. This marine protist is commonly used in micropalaeontological investigations of climatically sensitive subpolar and temperate water masses as well as wind-driven upwelling regions of the world's oceans. G. bulloides is unusual because it lacks the protist algal symbionts that are often found in other spinose species. In addition, it has a large offset in its stable carbon and oxygen isotopic compositions compared to other planktonic foraminifer species, and also that predicted from seawater equilibrium. This is suggestive of novel differences in ecology and life history of G. bulloides, making it a good candidate for investigating the potential for bacterial symbiosis as a contributory factor influencing shell calcification. Such information is essential to evaluate fully the potential response of G. bulloides to ocean acidification and climate change. To investigate possible ecological interactions between G. bulloides and marine bacteria, 18S rRNA gene sequencing, fluorescence microscopy, 16S rRNA gene metabarcoding and transmission electron microscopy (TEM) were performed on individual specimens of G. bulloides (type IId) collected from two locations in the California Current. Intracellular DNA extracted from five G. bulloides specimens was subjected to 16S rRNA gene metabarcoding and, remarkably, 37–87 % of all 16S rRNA gene sequences recovered were assigned to operational taxonomic units (OTUs) from the picocyanobacterium Synechococcus. This finding was supported by TEM observations of intact Synechococcus cells in both the cytoplasm and vacuoles of G. bulloides. Their concentrations were up to 4 orders of magnitude greater inside the foraminifera than those reported for the California Current water column and approximately 5 % of the intracellular Synechococcus cells observed were undergoing cell division. This suggests that Synechococcus is an endobiont of G. bulloides type IId, which is the first report of a bacterial endobiont in the planktonic foraminifera. We consider the potential roles of Synechococcus and G. bulloides within the relationship and the need to determine how widespread the association is within the widely distributed G. bulloides morphospecies. The possible influence of Synechococcus respiration on G. bulloides shell geochemistry is also explored.
                    }, number={4}, journal={Biogeosciences}, publisher={Copernicus GmbH}, author={Bird, Clare and Darling, Kate F. and Russell, Ann D. and Davis, Catherine V. and Fehrenbacher, Jennifer and Free, Andrew and Wyman, Michael and Ngwenya, Bryne T.}, year={2017}, month={Feb}, pages={901–920} }
 @article{fehrenbacher_russell_davis_gagnon_spero_cliff_zhu_martin_2017, title={Link between light-triggered Mg-banding and chamber formation in the planktic foraminifera Neogloboquadrina dutertrei}, volume={8}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/ncomms15441}, DOI={10.1038/ncomms15441}, abstractNote={Abstract}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Fehrenbacher, Jennifer S. and Russell, Ann D. and Davis, Catherine V. and Gagnon, Alexander C. and Spero, Howard J. and Cliff, John B. and Zhu, Zihua and Martin, Pamela}, year={2017}, month={May}, pages={15441} }
 @article{davis_rivest_hill_gaylord_russell_sanford_2017, title={Ocean acidification compromises a planktic calcifier with implications for global carbon cycling}, volume={7}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-017-01530-9}, DOI={10.1038/s41598-017-01530-9}, abstractNote={Abstract}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Davis, Catherine V. and Rivest, Emily B. and Hill, Tessa M. and Gaylord, Brian and Russell, Ann D. and Sanford, Eric}, year={2017}, month={May} }
 @article{davis_fehrenbacher_hill_russell_spero_2017, title={Relationships Between Temperature, pH, and Crusting on Mg/Ca Ratios in Laboratory-Grown<i>Neogloboquadrina</i>Foraminifera}, volume={32}, ISSN={0883-8305}, url={http://dx.doi.org/10.1002/2017pa003111}, DOI={10.1002/2017pa003111}, abstractNote={Abstract}, number={11}, journal={Paleoceanography}, publisher={American Geophysical Union (AGU)}, author={Davis, Catherine V. and Fehrenbacher, Jennifer S. and Hill, Tessa M. and Russell, Ann D. and Spero, Howard J.}, year={2017}, month={Nov}, pages={1137–1152} }
 @article{davis_myhre_hill_2016, title={Benthic foraminiferal shell weight: Deglacial species-specific responses from the Santa Barbara Basin}, volume={124}, ISSN={0377-8398}, url={http://dx.doi.org/10.1016/j.marmicro.2016.02.002}, DOI={10.1016/j.marmicro.2016.02.002}, abstractNote={Here we present a record of size-normalized shell weight for four species of benthic foraminifera through a period of rapid environmental change during the most recent deglaciation (Santa Barbara Basin, CA). A strong Oxygen Minimum Zone (OMZ), the product of high surface productivity and poor ventilation, characterizes the eastern Pacific; this subsurface zone is mechanistically coupled with high concentrations of dissolved inorganic carbon. The OMZ migrated vertically during warming of the last deglaciation, leading to rapid shifts in the oxygenation and inorganic carbon system of the benthos. The size-normalized weight (SNW) of benthic foraminifers Uvigerina peregrina, Bolivina interjuncta, and Bolivina tumida reflects only the broad trends of the vertical migration of the OMZ, and inorganic carbon system, overshadowed by clear species-specific trends. The relative importance of OMZ migrations versus other environmental variables and optimal growth conditions differs across species of benthic foraminifera. In U. peregrina, SNW primarily peaks with foraminiferal density and increased abundance of that species, while B. interjuncta and B. tumida increase in SNW with a shrinking of the OMZ (and carbon maximum) in the late Holocene. Bolivina argentea shows no long-term trends in SNW potentially due to its ability to migrate through the sediment. Our results suggest that, while inorganic carbon and dissolved oxygen may play a role in determining shell weight across species of benthic foraminifera, neither parameter alone is responsible for changes in benthic foraminiferal shell weight in the fossil record.}, journal={Marine Micropaleontology}, publisher={Elsevier BV}, author={Davis, Catherine V. and Myhre, Sarah E. and Hill, Tessa M.}, year={2016}, month={Apr}, pages={45–53} }
 @article{davis_hill_russell_gaylord_jahncke_2016, title={Seasonality in planktic foraminifera of the central California coastal
upwelling region}, volume={13}, ISSN={1726-4189}, url={http://dx.doi.org/10.5194/bg-13-5139-2016}, DOI={10.5194/bg-13-5139-2016}, abstractNote={Abstract. The close association between planktic foraminiferal assemblages and local hydrography make foraminifera invaluable proxies for environmental conditions. Modern foraminiferal seasonality is important for interpreting fossil distributions and shell geochemistry as paleoclimate proxies. Understanding this seasonality in an active upwelling area is also critical for anticipating which species may be vulnerable to future changes in upwelling intensity and ocean acidification. Two years (2012–2014) of plankton tows, along with conductivity–temperature–depth profiles and carbonate chemistry measurements taken along the north-central California shelf, offer new insights into the seasonal dynamics of planktic foraminifera in a seasonal coastal upwelling regime. This study finds an upwelling affinity for Neogloboquadrina pachyderma as well as a seasonal and upwelling associated alternation between dominance of N. pachyderma and Neogloboquadrina incompta, consistent with previous observations. Globigerina bulloides, however, shows a strong affinity for non-upwelled waters, in contrast to findings in Southern California where the species is often associated with upwelling. We also find an apparent lunar periodicity in the abundances of all species and document the presence of foraminifera even at very low saturation states of calcite.
                    }, number={18}, journal={Biogeosciences}, publisher={Copernicus GmbH}, author={Davis, Catherine V. and Hill, Tessa M. and Russell, Ann D. and Gaylord, Brian and Jahncke, Jaime}, year={2016}, month={Sep}, pages={5139–5150} }
 @article{moffitt_moffitt_sauthoff_davis_hewett_hill_2015, title={Paleoceanographic Insights on Recent Oxygen Minimum Zone Expansion: Lessons for Modern Oceanography}, volume={10}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0115246}, DOI={10.1371/journal.pone.0115246}, abstractNote={Climate-driven Oxygen Minimum Zone (OMZ) expansions in the geologic record provide an opportunity to characterize the spatial and temporal scales of OMZ change. Here we investigate OMZ expansion through the global-scale warming event of the most recent deglaciation (18-11 ka), an event with clear relevance to understanding modern anthropogenic climate change. Deglacial marine sediment records were compiled to quantify the vertical extent, intensity, surface area and volume impingements of hypoxic waters upon continental margins. By integrating sediment records (183-2,309 meters below sea level; mbsl) containing one or more geochemical, sedimentary or microfossil oxygenation proxies integrated with analyses of eustatic sea level rise, we reconstruct the timing, depth and intensity of seafloor hypoxia. The maximum vertical OMZ extent during the deglaciation was variable by region: Subarctic Pacific (~600-2,900 mbsl), California Current (~330-1,500 mbsl), Mexico Margin (~330-830 mbsl), and the Humboldt Current and Equatorial Pacific (~110-3,100 mbsl). The timing of OMZ expansion is regionally coherent but not globally synchronous. Subarctic Pacific and California Current continental margins exhibit tight correlation to the oscillations of Northern Hemisphere deglacial events (Termination IA, Bølling-Allerød, Younger Dryas and Termination IB). Southern regions (Mexico Margin and the Equatorial Pacific and Humboldt Current) exhibit hypoxia expansion prior to Termination IA (~14.7 ka), and no regional oxygenation oscillations. Our analyses provide new evidence for the geographically and vertically extensive expansion of OMZs, and the extreme compression of upper-ocean oxygenated ecosystems during the geologically recent deglaciation.}, number={1}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Moffitt, Sarah E. and Moffitt, Russell A. and Sauthoff, Wilson and Davis, Catherine V. and Hewett, Kathryn and Hill, Tessa M.}, editor={Hong, YiguoEditor}, year={2015}, month={Jan}, pages={e0115246} }
 @article{davis_badger_bown_schmidt_2013, title={The response of calcifying plankton to climate change in the Pliocene}, volume={10}, ISSN={1726-4189}, url={http://dx.doi.org/10.5194/bg-10-6131-2013}, DOI={10.5194/bg-10-6131-2013}, abstractNote={Abstract. As a result of anthropogenic pCO2 increases, future oceans are growing warmer and lower in pH and oxygen, conditions that are likely to impact planktic communities. Past intervals of elevated and changing pCO2 and temperatures can offer a glimpse into the response of marine calcifying plankton to changes in surface oceans under conditions similar to those projected for the future. Here we present new records of planktic foraminiferal and coccolith calcification (weight and size) from Deep Sea Drilling Project Site 607 (mid-North Atlantic) and Ocean Drilling Program Site 999 (Caribbean Sea) from the Pliocene, the last time that pCO2 was similar to today, and extending through a global cooling event into the intensification of Northern Hemisphere glaciation (3.3 to 2.6 million years ago). Test weights of both surface-dwelling Foraminifera Globigerina bulloides and thermocline-dwelling Foraminifera Globorotalia puncticulata vary with a potential link to regional temperature variation in the North Atlantic, whereas in the tropics Globigerinoides ruber test weight remains stable. In contrast, reticulofenestrid coccoliths show a narrowing size range and a decline in the largest lith diameters over this interval. Our results suggest no major changes in plankton calcite production during the high pCO2 Pliocene or during the transition into an icehouse world.
                    }, number={9}, journal={Biogeosciences}, publisher={Copernicus GmbH}, author={Davis, C. V. and Badger, M. P. S. and Bown, P. R. and Schmidt, D. N.}, year={2013}, month={Sep}, pages={6131–6139} }