ALBERT

Description: This dataset contains single-shell stable isotope data (d18O and d13C), shell weights, ages, and preservation states of Cibicidoides shells spanning MIS 1-2 from ODP Site 929, Ceara Rise (5.976°N, -43.740°E, 4357 m water depth). Sediment samples were processed following standard procedures. From each 〉63µm sediment sample, all specimens of the genera Cibicidoides and Uvigerina were picked from the 〉150 µm size fraction. Using a binocular microscope, each individual Cibicidoides and Uvigerina specimen was critically evaluated for preservation quality. Details of the Foraminiferal Preservation Index (FPI) can be found in the corresponding publication. In short, an initial score (IS) of 5 is applied to an ideal specimen with clearly defined whorls, sutures, pores, and other surface features. A shell with an IS score of 3 usually contains enlarged pores and "smoothed" looking surface features, including sutures and surface ornamentation. An IS score of 4 is assigned to specimens with more subtly smoothed features, and/or slightly enlarged pores. From the IS3-5 value for a given specimen, deductions of 1-2 points are applied to generate its final score (FS). A deduction of 1 point is applied for either a missing or fractured chamber, and/or evidence of slight dissolution. A deduction of 2 points is applied for extensive missing or fractured chambers, and/or evidence of extensive dissolution. For example, an assigned FS1 value for a specimen could be the result of highly smoothed surface features, with some combination of extensive dissolution pockmarks and/or one to several fractured/missing chambers (i.e. IS3 - 2 = FS1). The letter "A" assigned to the final score indicates that the appearance of the shell is glassy, "B" is assigned to pseudo-glassy shells, and "C" to frosty specimens. Specimens of varying preservation quality were purposely chosen for single-shell stable isotope analyses. Each specimen was weighed, and shells featuring narrow mass ranges were selected for individual analytical runs of d18O and d13C which allows for the optimization of instrument tuning. Single Cibicidoides shells were analyzed on a Thermo Delta V Kiel IV dual inlet mass spectrometer at the Lamont-Doherty Earth Observatory, and were corrected relative to the NBS-19 calcite standard. Average precision on these analyses was better than 0.08‰ for δ18O and better than 0.06‰ for δ13C. The age model is based on published stable isotope records (Bickert et al., 1997; Billups et al., 1998) tuned to the deep sea benthic d18O stack (Lisiecki and Raymo, 2005; Ahn et al., 2017).

Description: The oxygen isotopic composition of benthic foraminifera (d18Ob) is widely used to date and correlate marine sediment sequences. However, d18Ob has found comparatively little use in the Arctic Ocean due both to uncertainty in Arctic marine sediment chronology and the lack of resemblance between Arctic and open ocean d18Ob records. We address this issue by combining Arctic d18Ob records (Cronin et al., 2019) with benthic ostracode Mg/Ca-BWT reconstructions (Cronin et al., 2017) to create a composite record of the history of seawater d18O in the intermediate-to-deep Arctic Ocean over the last 600 kyr. Seawater d18O and its uncertainty was calculated using PSU Solver (Thirumalai et al., 2016).

Description: This dataset contains single-shell stable isotope data (d18O and d13C), shell weights, ages, and preservation states of Cibicidoides shells spanning MIS 9-10 from ODP Site 1089 north of Agulhas Ridge (-40.936°N, 9.894°E, 4620 m water depth). Sediment samples were processed following standard procedures. From each 〉63µm sediment sample, all specimens of the genera Cibicidoides and Uvigerina were picked from the 〉150 µm size fraction. Using a binocular microscope, each individual Cibicidoides and Uvigerina specimen was critically evaluated for preservation quality. Details of the Foraminiferal Preservation Index (FPI) can be found in the corresponding publication. In short, an initial score (IS) of 5 is applied to an ideal specimen with clearly defined whorls, sutures, pores, and other surface features. A shell with an IS score of 3 usually contains enlarged pores and “smoothed” looking surface features, including sutures and surface ornamentation. An IS score of 4 is assigned to specimens with more subtly smoothed features, and/or slightly enlarged pores. From the IS3-5 value for a given specimen, deductions of 1-2 points are applied to generate its final score (FS). A deduction of 1 point is applied for either a missing or fractured chamber, and/or evidence of slight dissolution. A deduction of 2 points is applied for extensive missing or fractured chambers, and/or evidence of extensive dissolution. For example, an assigned FS1 value for a specimen could be the result of highly smoothed surface features, with some combination of extensive dissolution pockmarks and/or one to several fractured/missing chambers (i.e. IS3 – 2 = FS1). The letter “A” assigned to the final score indicates that the appearance of the shell is glassy, “B” is assigned to pseudo-glassy shells, and “C” to frosty specimens. Specimens of varying preservation quality were purposely chosen for single-shell stable isotope analyses. Each specimen was weighed, and shells featuring narrow mass ranges were selected for individual analytical runs of d18O and d13C which allows for the optimization of instrument tuning. Single Cibicidoides shells were analyzed on a Thermo Delta V Kiel IV dual inlet mass spectrometer at the Lamont-Doherty Earth Observatory, and were corrected relative to the NBS-19 calcite standard. Average precision on these analyses was better than 0.08‰ for δ18O and better than 0.06‰ for δ13C. The age model is based on the published stable isotope record (Hodell et al. 2001) tuned to the deep sea benthic d18O stack (Lisiecki and Raymo, 2005; Ahn et al., 2017).

Description: This dataset contains single-shell stable isotope data (d18O and d13C), shell weights, ages, and preservation states of Cibicidoides shells spanning MIS 1-2 from ODP Site 846 south of the Galapagos Islands (-3.095°N, -90.818°E, 3296 m water depth). Sediment samples were processed following standard procedures. From each 〉63µm sediment sample, all specimens of the genera Cibicidoides and Uvigerina were picked from the 〉150 µm size fraction. Using a binocular microscope, each individual Cibicidoides and Uvigerina specimen was critically evaluated for preservation quality. Details of the Foraminiferal Preservation Index (FPI) can be found in the corresponding publication. In short, an initial score (IS) of 5 is applied to an ideal specimen with clearly defined whorls, sutures, pores, and other surface features. A shell with an IS score of 3 usually contains enlarged pores and “smoothed” looking surface features, including sutures and surface ornamentation. An IS score of 4 is assigned to specimens with more subtly smoothed features, and/or slightly enlarged pores. From the IS3-5 value for a given specimen, deductions of 1-2 points are applied to generate its final score (FS). A deduction of 1 point is applied for either a missing or fractured chamber, and/or evidence of slight dissolution. A deduction of 2 points is applied for extensive missing or fractured chambers, and/or evidence of extensive dissolution. For example, an assigned FS1 value for a specimen could be the result of highly smoothed surface features, with some combination of extensive dissolution pockmarks and/or one to several fractured/missing chambers (i.e. IS3 – 2 = FS1). The letter “A” assigned to the final score indicates that the appearance of the shell is glassy, “B” is assigned to pseudo-glassy shells, and “C” to frosty specimens. Specimens of varying preservation quality were purposely chosen for single-shell stable isotope analyses. Each specimen was weighed, and shells featuring narrow mass ranges were selected for individual analytical runs of d18O and d13C which allows for the optimization of instrument tuning. Single Cibicidoides shells were analyzed on a Thermo Delta V Kiel IV dual inlet mass spectrometer at the Lamont-Doherty Earth Observatory, and were corrected relative to the NBS-19 calcite standard. Average precision on these analyses was better than 0.08‰ for δ18O and better than 0.06‰ for δ13C. The age model is based on published stable isotope records (Mix et al. 1995; Shackleton et al., 1995) tuned to the deep sea benthic d18O stack (Lisiecki and Raymo, 2005; Ahn et al., 2017).

Description: This dataset contains single-shell stable isotope data (d18O and d13C), shell weights, ages, and preservation states of Uvigerina shells spanning MIS 9-10 from ODP Site 846 south of the Galapagos Islands (-3.095°N, -90.818°E, 3296 m water depth). Sediment samples were processed following standard procedures. From each 〉63µm sediment sample, all specimens of the genera Cibicidoides and Uvigerina were picked from the 〉150 µm size fraction. Using a binocular microscope, each individual Cibicidoides and Uvigerina specimen was critically evaluated for preservation quality. Details of the Foraminiferal Preservation Index (FPI) can be found in the corresponding publication. In short, an initial score (IS) of 5 is applied to an ideal specimen with clearly defined whorls, sutures, pores, and other surface features. A shell with an IS score of 3 usually contains enlarged pores and "smoothed" looking surface features, including sutures and surface ornamentation. An IS score of 4 is assigned to specimens with more subtly smoothed features, and/or slightly enlarged pores. From the IS3-5 value for a given specimen, deductions of 1-2 points are applied to generate its final score (FS). A deduction of 1 point is applied for either a missing or fractured chamber, and/or evidence of slight dissolution. A deduction of 2 points is applied for extensive missing or fractured chambers, and/or evidence of extensive dissolution. For example, an assigned FS1 value for a specimen could be the result of highly smoothed surface features, with some combination of extensive dissolution pockmarks and/or one to several fractured/missing chambers (i.e. IS3 - 2 = FS1). The letter "A" assigned to the final score indicates that the appearance of the shell is glassy, "B" is assigned to pseudo-glassy shells, and "C" to frosty specimens. Specimens of varying preservation quality were purposely chosen for single-shell stable isotope analyses. Each specimen was weighed, and shells featuring narrow mass ranges were selected for individual analytical runs of d18O and d13C which allows for the optimization of instrument tuning. Single Uvigerina shells were analyzed on an Isoprime 100 dual inlet mass spectrometer with carbonate multi-preparation system at Rensselaer Polytechnic Institute, and were corrected relative to the NBS-19 calcite standard. These analyses produced average precision better than 0.06‰ for δ18O and better than 0.03‰ for δ13C. The age model is based on published stable isotope records (Mix et al. 1995; Shackleton et al., 1995) tuned to the deep sea benthic d18O stack (Lisiecki and Raymo, 2005; Ahn et al., 2017).

Description: This dataset contains single-shell stable isotope data (d18O and d13C), shell weights, ages, and preservation states of Cibicidoides shells spanning MIS 9-10 from ODP Site 846 south of the Galapagos Islands (-3.095°N, -90.818°E, 3296 m water depth). Sediment samples were processed following standard procedures. From each 〉63µm sediment sample, all specimens of the genera Cibicidoides and Uvigerina were picked from the 〉150 µm size fraction. Using a binocular microscope, each individual Cibicidoides and Uvigerina specimen was critically evaluated for preservation quality. Details of the Foraminiferal Preservation Index (FPI) can be found in the corresponding publication. In short, an initial score (IS) of 5 is applied to an ideal specimen with clearly defined whorls, sutures, pores, and other surface features. A shell with an IS score of 3 usually contains enlarged pores and “smoothed” looking surface features, including sutures and surface ornamentation. An IS score of 4 is assigned to specimens with more subtly smoothed features, and/or slightly enlarged pores. From the IS3-5 value for a given specimen, deductions of 1-2 points are applied to generate its final score (FS). A deduction of 1 point is applied for either a missing or fractured chamber, and/or evidence of slight dissolution. A deduction of 2 points is applied for extensive missing or fractured chambers, and/or evidence of extensive dissolution. For example, an assigned FS1 value for a specimen could be the result of highly smoothed surface features, with some combination of extensive dissolution pockmarks and/or one to several fractured/missing chambers (i.e. IS3 – 2 = FS1). The letter “A” assigned to the final score indicates that the appearance of the shell is glassy, “B” is assigned to pseudo-glassy shells, and “C” to frosty specimens. Specimens of varying preservation quality were purposely chosen for single-shell stable isotope analyses. Each specimen was weighed, and shells featuring narrow mass ranges were selected for individual analytical runs of d18O and d13C which allows for the optimization of instrument tuning. Single Cibicidoides shells were analyzed on an Isoprime 100 dual inlet mass spectrometer with carbonate multi-preparation system at Rensselaer Polytechnic Institute, and were corrected relative to the NBS-19 calcite standard. These analyses produced average precision better than 0.06‰ for δ18O and better than 0.03‰ for δ13C. The age model is based on published stable isotope records (Mix et al. 1995; Shackleton et al., 1995) tuned to the deep sea benthic d18O stack (Lisiecki and Raymo, 2005; Ahn et al., 2017).

Description: Late Quaternary paleoceanographic changes at the Lomonosov Ridge, central Arctic Ocean, were reconstructed from a multicore and gravity core recovered during the 2014 SWERUS-C3 Expedition. Ostracode assemblages dated by accelerator mass spectrometry (AMS) indicate changing sea-ice conditions and warm Atlantic Water (AW) inflow to the Arctic Ocean from  ∼  50 ka to present. Key taxa used as environmental indicators include Acetabulastoma arcticum (perennial sea ice), Polycope spp. (variable sea-ice margins, high surface productivity), Krithe hunti (Arctic Ocean deep water), and Rabilimis mirabilis (water mass change/AW inflow). Results indicate periodic seasonally sea-ice-free conditions during Marine Isotope Stage (MIS) 3 ( ∼  57–29 ka), rapid deglacial changes in water mass conditions (15–11 ka), seasonally sea-ice-free conditions during the early Holocene ( ∼  10–7 ka) and perennial sea ice during the late Holocene. Comparisons with faunal records from other cores from the Mendeleev and Lomonosov ridges suggest generally similar patterns, although sea-ice cover during the Last Glacial Maximum may have been less extensive at the new Lomonosov Ridge core site ( ∼  85.15° N, 152° E) than farther north and towards Greenland. The new data provide evidence for abrupt, large-scale shifts in ostracode species depth and geographical distributions during rapid climatic transitions.

Description: Late Quaternary paleoceanographic changes in the central Arctic Ocean were reconstructed from a multicore and gravity core from the Lomonosov Ridge (Arctic Ocean) collected during the 2014 SWERUS-C3 Expedition. Ostracode assemblages dated by accelerator mass spectrometry (AMS) indicate changing sea-ice conditions and warm Atlantic Water (AW) inflow to the Arctic Ocean from ~ 50 ka to present. Key taxa used as environmental indicators include Acetabulastoma arcticum (perennial sea ice), Polycope spp. (productivity and sea ice), Krithe hunti (partially sea-ice free conditions, deep water inflow), and Rabilimis mirabilis (high nutrient, AW inflow). Results indicate seasonally sea-ice free conditions during Marine Isotope Stage (MIS) 3 (~ 57–29 ka), rapid deglacial changes in water mass conditions (15–11 ka), seasonally sea-ice free conditions during the early Holocene (~ 10–7 ka) and perennial sea ice during the late Holocene. Comparisons with faunal records from other cores from the Mendeleev and Lomonosov Ridges suggest generally similar patterns, although sea-ice cover during the last glacial maximum may have been less extensive at the southern Lomonosov Ridge at our core site (~ 85.15° N, 152° E) than farther north and towards Greenland. The new data also provide evidence for abrupt, large-scale shifts in ostracode species depth and geographical distributions during rapid climatic transitions.