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  • 1
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    Authigenic Formation of Clay Minerals in the Abyssal North Pacific (2022)
    Details
    Publication Date: 2023-07-19
    Description: Present estimates of the biogeochemical cycles of calcium, strontium, and potassium in the ocean reveal large imbalances between known input and output fluxes. Using pore fluid, incubation, and solid sediment data from North Pacific multi‐corer cores we show that, contrary to the common paradigm, the top centimeters of abyssal sediments can be an active site of authigenic precipitation of clay minerals. In this region, clay authigenesis is the dominant sink for potassium and strontium and consumes nearly all calcium released from benthic dissolution of calcium carbonates. These observations support the idea that clay authigenesis occurring over broad regions of the world ocean may be a major buffer for ocean chemistry on the time scale of the ocean overturning circulation, and key to the long‐term stability of Earth's climate.
    Description: Key Points: North Pacific red clay sediments are a sink for marine calcium, strontium, and potassium. Authigenic formation of clay minerals is prevalent in pelagic sediments throughout the North Pacific. The main mechanism for clay formation is recrystallization of aluminosilicates, neoformation can occur in biogenic silica rich sediments.
    Description: EC H2020 PRIORITY “Excellent science” H2020 European Research Council http://dx.doi.org/10.13039/100010663
    Description: Blavatnik Family Foundation http://dx.doi.org/10.13039/100011643
    Description: Isaac Newton Trust http://dx.doi.org/10.13039/501100004815
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: National Science Foundation http://dx.doi.org/10.13039/100000001
    Description: https://doi.pangaea.de/10.1594/PANGAEA.946881
    Keywords: ddc:549 ; reverse weathering ; clay authigenesis ; calcium ; potassium ; porewater ; strontium
    Language: English
    Type: doc-type:article
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    CITATION GEO-LEO
  • 2
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    Calibration and application of B/Ca, Cd/Ca, and δ11B in Neogloboquadrina pachyderma (sinistral) to constrain CO2 uptake in the subpolar North Atlantic during the last deglaciation (2013)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 28 (2013): 237–252, doi:10.1002/palo.20024.
    Description: The North Atlantic and Norwegian Sea are prominent sinks of atmospheric CO2 today, but their roles in the past remain poorly constrained. In this study, we attempt to use B/Ca and δ11B ratios in the planktonic foraminifera Neogloboquadrina pachyderma (sinistral variety) to reconstruct subsurface water pH and pCO2 changes in the polar North Atlantic during the last deglaciation. Comparison of core-top results with nearby hydrographic data shows that B/Ca in N. pachyderma (s) is mainly controlled by seawater B(OH)4−/HCO3− with a roughly constant partition coefficient of 1.48 ± 0.15 × 10−3 (2σ), and δ11B in this species is offset below δ11B of the borate in seawater by 3.38 ± 0.71‰ (2σ). These values represent our best estimates with the sparse available hydrographic data close to our core-tops. More culturing and sediment trap work is needed to improve our understanding of boron incorporation into N. pachyderma (s). Application of a constant KD of 1.48 × 10−3 to high resolution N. pachyderma (s) B/Ca records from two adjacent cores off Iceland shows that subsurface pCO2 at the habitat depth of N. pachyderma (s) (~50 m) generally followed the atmospheric CO2 trend but with negative offsets of ~10–50 ppmv during 19–10 ka. These B/Ca-based reconstructions are supported by independent estimates from low-resolution δ11B measurements in the same cores. We also calibrate and apply Cd/Ca in N. pachyderma (s) to reconstruct nutrient levels for the same down cores. Like today's North Atlantic, past subsurface pCO2 variability off Iceland was significantly correlated with nutrient changes that might be linked to surface nutrient utilization and mixing within the upper water column. Because surface pCO2 (at 0 m water depth) is always lower than at deeper depths and if the application of a constant KD is valid, our results suggest that the polar North Atlantic has remained a CO2 sink during the calcification seasons of N. pachyderma (s) over the last deglaciation.
    Description: This research is funded by Lamont-Doherty Postdoctoral Fellowship, Lawrence Livermore Fellowship and the Australian National University (J.Y.), by NERC RAPID grant NER/T/S/2002/00436 (N. M. and D. T.), and by a NERC PhD studentship (J.R.).
    Description: 2013-11-30
    Keywords: Neogloboquadrina pachyderma (s) ; B/Ca, Cd/Ca, d11B ; Subsurface pH and pCO2 and nutrients
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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    PAPER (OA)
  • 3
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    Shallow calcium carbonate cycling in the North Pacific Ocean (2022)
    American Geophysical Union
    Details
    Publication Date: 2022-11-06
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 36(5), (2022): e2022GB007388, https://doi.org/10.1029/2022gb007388.
    Description: The cycling of biologically produced calcium carbonate (CaCO3) in the ocean is a fundamental component of the global carbon cycle. Here, we present experimental determinations of in situ coccolith and foraminiferal calcite dissolution rates. We combine these rates with solid phase fluxes, dissolved tracers, and historical data to constrain the alkalinity cycle in the shallow North Pacific Ocean. The in situ dissolution rates of coccolithophores demonstrate a nonlinear dependence on saturation state. Dissolution rates of all three major calcifying groups (coccoliths, foraminifera, and aragonitic pteropods) are too slow to explain the patterns of both CaCO3 sinking flux and alkalinity regeneration in the North Pacific. Using a combination of dissolved and solid-phase tracers, we document a significant dissolution signal in seawater supersaturated for calcite. Driving CaCO3 dissolution with a combination of ambient saturation state and oxygen consumption simultaneously explains solid-phase CaCO3 flux profiles and patterns of alkalinity regeneration across the entire N. Pacific basin. We do not need to invoke the presence of carbonate phases with higher solubilities. Instead, biomineralization and metabolic processes intimately associate the acid (CO2) and the base (CaCO3) in the same particles, driving the coupled shallow remineralization of organic carbon and CaCO3. The linkage of these processes likely occurs through a combination of dissolution due to zooplankton grazing and microbial aerobic respiration within degrading particle aggregates. The coupling of these cycles acts as a major filter on the export of both organic and inorganic carbon to the deep ocean.
    Description: This work was funded by NSF OCE-1220301 to W.B., NSF OCE-1220600 to J.F.A., and startup funding for A.V.S.
    Description: 2022-11-06
    Keywords: Calcium carbonate ; Dissolution ; Carbon cycle
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    PAPER (OA)
  • 4
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    Distribution and ecology data of planktic Foraminifera in the North Pacific (2018)
    PANGAEA
    In:  Supplement to: Taylor, Ben J; Rae, James W B; Gray, William Robert; Darling, Kate F; Burke, Andrea; Gersonde, Rainer; Abelmann, Andrea; Maier, Edith; Esper, Oliver; Ziveri, Patrizia (2018): Distribution and ecology of planktic Foraminifera in the North Pacific: Implications for paleo-reconstructions. Quaternary Science Reviews, 191, 256-274, https://doi.org/10.1016/j.quascirev.2018.05.006
    Details
    Publication Date: 2023-03-06
    Description: Planktic foraminifera census data have been used to reconstruct past temperatures through transfer functions, as well as changes in ocean ecosystems, chemistry and circulation. Here we present new multinet, plankton net and core-top census data from 20 sites in the Subpolar North Pacific. We combine these with previous data to provide an up to date compilation of North Pacific planktic foraminifera assemblage data. Our compilation is used to define 6 faunal zones: the subpolar zone; transitional zone; upwelling zone; subtropical zone; east equatorial zone; west equatorial zone; based on the distribution of 10 major species of planktic foraminifera. Two species of planktic foraminifera Neogloboquadrina pachyderma and Globigerina bulloides provide the basis for many subpolar paleo-reconstructions. Through the analysis of new multinet and CTD data we find that G. bulloides and N. pachyderma are predominantly found within 0-50 m of the water column and coincide with high food availability. N. pachyderma also shows a strong temperature control and can thrive in food poor waters where temperatures are low. Both species bloom seasonally, particularly during the spring bloom of March to June, with G. bulloides exhibiting greater seasonal variation. We suggest that percentage abundance of N. pachyderma in paleo-assemblages can be used to assess relative changes in past temperature, with G. bulloides abundance more likely to reflect changes in food availability. By comparing our core-top and multinet data, we also find a dissolution bias of G. bulloides over N. pachyderma in the North Pacific, which may enrich assemblages in the latter species.
    Keywords: AWI
    Type: Dataset
    Format: application/zip, 6 datasets
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    DATA PANGAEA
  • 5
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    Physical oceanography and chlorophyll from selected CTD stations during SONNE cruise SO202/1 (2018)
    PANGAEA
    Details
    Publication Date: 2023-03-06
    Keywords: AWI; Bering Sea; Chlorophyll a; CTD/Rosette; CTD-RO; Date/Time of event; DEPTH, water; Elevation of event; Event label; INOPEX; Latitude of event; Longitude of event; North Pacific Ocean; Oxygen; Salinity; SO202/1; SO202/1_02-1; SO202/1_10-1; SO202/1_13-1; SO202/1_14-1; SO202/1_15-1; SO202/1_27-2; SO202/1_31-1; SO202/1_33-1; SO202/1_34-1; Sonne; Temperature, water
    Type: Dataset
    Format: text/tab-separated-values, 35893 data points
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    DATA PANGAEA
  • 6
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    Abundances of planktic foraminifera from multinet samples taken during the SONNE cruise SO202/1 (2018)
    PANGAEA
    Details
    Publication Date: 2023-03-06
    Keywords: AWI; Bering Sea; Date/Time of event; Depth, bottom/max; Depth, top/min; DEPTH, water; Elevation of event; Event label; Foraminifera, planktic; Globigerina bulloides; Globigerinella siphonifera; Globigerinita glutinata; Globigerinoides ruber; Globoconella inflata; Globorotalia scitula; Globorotaloides hexagonus; INOPEX; Latitude of event; Longitude of event; MSN; Multiple opening/closing net; Neogloboquadrina dutertrei; Neogloboquadrina incompta; Neogloboquadrina pachyderma sinistral; North Pacific Ocean; SO202/1; SO202/1_02-5; SO202/1_10-4; SO202/1_13-3; SO202/1_14-4; SO202/1_15-3; SO202/1_27-4; SO202/1_31-2; SO202/1_33-2; SO202/1_34-2; Sonne; Turborotalita quinqueloba
    Type: Dataset
    Format: text/tab-separated-values, 574 data points
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    DATA PANGAEA
  • 7
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    U-series ages from calcitic cold-water corals from the Amundsen Sea
    PANGAEA
    In:  Supplement to: Gutjahr, Marcus; Vance, Derek; Hoffmann, Dirk L; Hillenbrand, Claus-Dieter; Foster, Gavin L; Rae, James W B; Kuhn, Gerhard (2013): Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrast with robust coral radiocarbon and Mg/Ca systematics. Chemical Geology, 355, 69-87, https://doi.org/10.1016/j.chemgeo.2013.07.002
    Details
    Publication Date: 2023-05-12
    Description: Radiocarbon and uranium-thorium dating results are presented from a genus of calcitic Antarctic cold-water octocorals (family Coralliidae), which were collected from the Marie Byrd Seamounts in the Amundsen Sea (Pacific sector of the Southern Ocean) and which to date have not been investigated geochemically. The geochronological results are set in context with solution and laser ablation-based element/Ca ratios (Li, B, Mg, Mn, Sr, Ba, U, Th). Octocoral radiocarbon ages on living corals are in excellent agreement with modern ambient deep-water D14C, while multiple samples of individual fossil coral specimens yielded reproducible radiocarbon ages. Provided that local radiocarbon reservoir ages can be derived for a given time, fossil Amundsen Sea octocorals should be reliably dateable by means of radiocarbon. In contrast to the encouraging radiocarbon findings, the uranium-series data are more difficult to interpret. The uranium concentration of these calcitic octocorals is an order of magnitude lower than in the aragonitic hexacorals that are conventionally used for geochronological investigations. While modern and Late Holocene octocorals yield initial d234U in good agreement with modern seawater, our results reveal preferential inward diffusion of dissolved alpha-recoiled 234U and its impact on fossil coral d234U. Besides alpha-recoil related 234U diffusion, high-resolution sampling of two fossil octocorals further demonstrates that diagenetic uranium mobility has offset apparent coral U-series ages. Combined with the preferential alpha-recoil 234U diffusion, this process has prevented fossil octocorals from preserving a closed system U-series calendar age for longer than a few thousand years. Moreover, several corals investigated contain significant initial thorium, which cannot be adequately corrected for because of an apparently variable initial 232Th/230Th. Our results demonstrate that calcitic cold-water corals are unsuitable for reliable U-series dating. Mg/Ca ratios within single octocoral specimens are internally strikingly homogeneous, and appear promising in terms of their response to ambient temperature. Magnesium/lithium ratios are significantly higher than usually observed in other deep marine calcifiers and for many of our studied corals are remarkably close to seawater compositions. Although this family of octocorals is unsuitable for glacial deep-water D14C reconstructions, our findings highlight some important differences between hexacoral (aragonitic) and octocoral (calcitic) biomineralisation. Calcitic octocorals could still be useful for trace element and some isotopic studies, such as reconstruction of ambient deep water neodymium isotope composition or pH, via boron isotopic measurements.
    Keywords: AWI_Paleo; Paleoenvironmental Reconstructions from Marine Sediments @ AWI
    Type: Dataset
    Format: application/zip, 3 datasets
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    DATA PANGAEA
  • 8
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    Deep water formation in the North Pacific and deglacial CO2 rise (2014)
    PANGAEA
    In:  Supplement to: Rae, James W B; Sarnthein, Michael; Foster, Gavin L; Ridgwell, Andy; Grootes, Pieter Meiert; Elliott, Tim (2014): Deep water formation in the North Pacific and deglacial CO2 rise. Paleoceanography, 29(6), 645-667, https://doi.org/10.1002/2013PA002570
    Details
    Publication Date: 2023-01-13
    Description: Deep water formation in the North Atlantic and Southern Ocean is widely thought to influence deglacial CO2 rise and climate change; here we suggest that deep water formation in the North Pacific may also play an important role. We present paired radiocarbon and boron isotope data from foraminifera from sediment core MD02-2489 at 3640 m in the North East Pacific. These show a pronounced excursion during Heinrich Stadial 1, with benthic-planktic radiocarbon offsets dropping to ~350 years, accompanied by a decrease in benthic d11B. We suggest this is driven by the onset of deep convection in the North Pacific, which mixes young shallow waters to depth, old deep waters to the surface, and low-pH water from intermediate depths into the deep ocean. This deep water formation event was likely driven by an increase in surface salinity, due to subdued atmospheric/monsoonal freshwater flux during Heinrich Stadial 1. The ability of North Pacific Deep Water (NPDW) formation to explain the excursions seen in our data is demonstrated in a series of experiments with an intermediate complexity Earth system model. These experiments also show that breakdown of stratification in the North Pacific leads to a rapid ~30 ppm increase in atmospheric CO2, along with decreases in atmospheric d13C and D14C, consistent with observations of the early deglaciation. Our inference of deep water formation is based mainly on results from a single sediment core, and our boron isotope data are unavoidably sparse in the key HS1 interval, so this hypothesis merits further testing. However we note that there is independent support for breakdown of stratification in shallower waters during this period, including a minimum in d15N, younging in intermediate water 14C, and regional warming. We also re-evaluate deglacial changes in North Pacific productivity and carbonate preservation in light of our new data, and suggest that the regional pulse of export production observed during the Bølling-Allerød is promoted by relatively stratified conditions, with increased light availability and a shallow, potent nutricline. Overall, our work highlights the potential of NPDW formation to play a significant and hitherto unrealized role in deglacial climate change and CO2 rise.
    Type: Dataset
    Format: application/zip, 7 datasets
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    DATA PANGAEA
  • 9
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    High-resolution sulfur isotopic composition measurements of volcanic sulfate from Toba candidate eruptions preserved in EDML and EDC Antarctic ice cores (2021)
    PANGAEA
    Details
    Publication Date: 2023-06-27
    Description: Multiple peaks in sulfate concentration in ice cores have been identified as potential candidates for the ~74 ka Toba supereruption. The sulfur isotopic composition of sulfate preserved in two EPICA Antarctic ice cores, EDML and EDC, for 11 of the candidates has been analysed at high temporal resolution for mass-independent fractionation (MIF) using multi-collector inductively coupled plasma mass spectrometry. S-MIF signals preserved in volcanic sulfate are indicative of stratospheric eruptions due to sulfur aerosols being exposed to ultraviolet radiation when erupted into and above the ozone layer and subsequently undergoing photochemical reactions. Sulfur aerosols in the stratosphere will have longer residence times than those in the troposphere and will scatter incoming solar radiation. This data set includes the eruption, sample type, depths, ages (using the AICC2012 age model), sulfate concentration (determined by ion chromatography) and isotopic composition data (δ34S, δ33S, Δ33S) and their associated errors.
    Keywords: AGE; Antarctica; Calculated, in volcanic fraction; DEPTH, ice/snow; Dome C; Dome C, Antarctica; EDC; EDML; EDRILL; EPICA; EPICA-Campaigns; EPICA Dome C; EPICA drill; EPICA Dronning Maud Land, DML28C01_00; Eruption; European Project for Ice Coring in Antarctica; Event label; Ice core; ICEDRILL; Ice drill; Ion chromatography; Kohnen Station; Multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS); sulfate; Sulfate; Sulfur isotopes; Type; volcanic; Volcanic fraction; Volcanic fraction, standard deviation; Δ33S; Δ33S, standard deviation; δ33S; δ33S, standard deviation; δ34S; δ34S, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 1440 data points
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    DATA PANGAEA
  • 10
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    Core-top census data of planktic foraminifera taken during the SONNE cruise SO202/1 (2018)
    PANGAEA
    Details
    Publication Date: 2023-06-27
    Keywords: AWI; Bering Sea; Candeina nitida; Date/Time of event; DEPTH, sediment/rock; Elevation of event; Event label; Foraminifera, planktic; Globigerina bulloides; Globigerina falconensis; Globigerinella calida; Globigerinella siphonifera; Globigerinita glutinata; Globigerinoides ruber; Globigerinoides tenellus; Globoconella inflata; Globorotalia scitula; Globorotalia truncatulinoides; Globorotalia tumida; Globorotaloides hexagonus; Globoturborotalita rubescens; INOPEX; Latitude of event; Longitude of event; MUC; MultiCorer; Neogloboquadrina dutertrei; Neogloboquadrina incompta; Neogloboquadrina pachyderma sinistral; North Pacific Ocean; Orbulina universa; SO202/1; SO202/1_06-2; SO202/1_07-2; SO202/1_13-4; SO202/1_27-1; SO202/1_31-5; SO202/1_40-2; Sonne; Sphaeroidinella dehiscens; Tenuitella iota; Trilobatus sacculifer; Turborotalita humilis; Turborotalita quinqueloba
    Type: Dataset
    Format: text/tab-separated-values, 144 data points
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    DATA PANGAEA
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