ALBERT

Description: Here we performed pulse-chase experiments with 13C-enriched dissolved inorganic carbon, followed by TEM and quantitative NanoSIMS isotopic imaging to visualize photosynthetic C assimilation by individual symbiotic dinoflagellates and subsequent translocation to their Orbulina universa host. NanoSIMS image processing was carried out as described in LeKieffre et al. (2017) and Nomaki et al. (2018). Briefly, TEM images were aligned with corresponding NanoSIMS 12C14N- images (Online Resource 1) using the software Look@NanoSIMS (Polerecky et al. 2012), which allows a user to hand-draw regions of interest (ROIs) corresponding to different organelles (e.g., dinoflagellate starch grains, foraminiferal lipid droplets, and fibrillar bodies). For each type of organelle and each time point, the average 13C-enrichment and its standard deviation were calculated based on 3 replicate foraminifera (except for the 6 h and 30 h time points, where only 2 replicates were available). The ROIs drawn on TEM images were also used to assess the relative abundance (in %) of lipid droplets in the foraminiferal endoplasm and starch grains in the dinoflagellate cytoplasm, respectively. Lipid droplet abundance was determined as the number of pixels occupied by lipid droplets divided by the total number of pixels of foraminiferal endoplasm. Starch grain abundance was determined as the number of pixels of occupied by starch grains divided by the total number of pixels covering dinoflagellate cytoplasm.

Description: Dataset contains seawater and foraminiferal chemical composition from the paper referenced above. Paper abstract: 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.

Description: The dataset compiles trace element/calcium concentrations measured in individual shells of non-spinose planktic foraminifera Neogloboquadrina dutertrei and Pulleniatina obliquiloculata collected from Eastern Equatorial Pacific core ME0005A-43JC (7.86ºN, 83.6ºW, water depth 1368 m) interval 79-80 cm. Shells are subjected to cleaning and after each cleaning step trace elements are measurement with a laser ablation inductively coupled plasma mass spectrometer at Oregon State University's Keck Lab, which is reported here. The columns include cleaning step, species, shell number, statistic (mean and intra-shell standard deviation, 1σ), Ba/Ca (mmol/mol), Mn/Ca (mmol/mol), Zn/Ca (mmol/mol), Mg/Ca (mmol/mol), and Al/Ca (mmol/mol).

Description: We present a reconstruction of deep-water carbonate saturation state (Delta [CO3]2-) in the western equatorial Pacific for the Last Glacial Maximum (LGM) and deglaciation based on changes in the Mg/Ca ratio of planktic foraminifers with increased water depth. Our data suggest there have been changes in bottom waterDelta [CO3]2- over the past 25,000 years at water depths as shallow as 1.6 km. The Delta [CO3]2- reconstruction for the LGM suggests Delta [CO3]2- was similar or slightly higher than modern values between 1.6 and 2.0 km, shifting sharply to lower values (an average ~30 µmol/kg lower) below 2.5 km. The shift in chemistry between 2.0 and 2.5 km supports a hypothesis that Pacific overturning circulation occurred deeper during the LGM with a slightly more ventilated water mass above 2.0 km. The data are not consistent with enhanced preservation in this region of the deep Pacific at depths greater than 2.5 km, suggesting that the long-held view of better preservation throughout the glacial deep Pacific must be reevaluated. For the deglaciation, we have evidence of a Delta [CO3]2- maximum that suggests enhanced deglacial preservation between 1.6 and 4.0 km in comparison to the Holocene and the LGM. The deglacial Delta [CO3]2- was as much as 28 µmol/kg higher than modern between 1.6 and 4.0 km. Results suggest carbonate burial rates were 1.5 times greater during the deglacial than the over the past 5 kyr.

Description: Mg/Ca anlaysis of foraminiferal calcite shells. Foraminifera obtained from sediments (benthic, Uvigerina spp.; sediment from ODP Site 1015, California Margin) and from plankton tows (planktonic, Orbulina universa, plankton tow specimens were collected near Green Island, Taiwan in May 2019 using a 1 m plankton net Sea-Gear, 150 µm mesh, 0-50 m depth), were analyzed. Mg/Ca were obtained applying Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and wavelength-dispersive X-Ray Spectroscopy by electron probe microanalyzer (EPMA). The goal is to assess the use of EPMA as an alternative technique for Mg/Ca analyses of foraminiferal calcite shells.

Description: Mg/Ca anlaysis of foraminiferal calcite shells. Foraminifera obtained from sediments (benthic, Uvigerina spp.; sediment from ODP Site 1015, California Margin) and from plankton tows (planktonic, Orbulina universa, plankton tow specimens were collected near Green Island, Taiwan in May 2019 using a 1 m plankton net Sea-Gear, 150 µm mesh, 0-50 m depth), were analyzed. Mg/Ca were obtained applying Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and wavelength-dispersive X-Ray Spectroscopy by electron probe microanalyzer (EPMA). The goal is to assess the use of EPMA as an alternative technique for Mg/Ca analyses of foraminiferal calcite shells.