• Issue

    Paleoceanography and Paleoclimatology: Volume 36, Issue 5

    May 2021

Research Article

Free Access

Coupled Atmosphere–Ocean Reconstruction of the Last Millennium Using Online Data Assimilation

  • First Published: 18 March 2021
Key Points

  • A new online paleoclimate data assimilation method for atmosphere–ocean reconstruction over the last millennium provides dynamical proxy memory

  • Reconstructed ocean field validation against instrumental products is largely skillful despite a sparse proxy network

  • Online data assimilation improves the dynamics and low-frequency variability of reconstructed coupled fields relative to offline assimilation

Issue Information

Free Access

Issue Information

  • First Published: 27 April 2021

Research Article

Free Access

Climatic and Topographic Control of the Stable Isotope Values of Rivers on the South Island of New Zealand

  • First Published: 06 May 2021
Key Points

  • Survey of spatial river δ18O values on New Zealand's South Island shows strong correlations to winter temperature and continentality

  • Lowest river δ18O values are present in the most continental locations in the lee of the high Southern Alps

  • Data are useful for interpreting isotopic paleoclimate proxy records related to surface waters

Free Access

Size-Fraction-Specific Stable Isotope Variations as a Framework for Interpreting Early Eocene Bulk Sediment Carbon Isotope Records

  • First Published: 25 March 2021
Key Points

  • Co-evolution of different components within pelagic carbonate systems drive spatial variations within bulk carbonate stable isotope records

  • An increase in coarse fraction abundance caused by change in abundance of calcifying organims across the Paleocene Eocene Thermal Maximum (PETM) at Shatsky Rise affects its utility as a proxy for carbonate dissolution

  • Size-fraction-specific isotope variations can significantly alter the magnitude of carbon isotope excursions in bulk sediments

Open Access

Simulating Miocene Warmth: Insights From an Opportunistic Multi-Model Ensemble (MioMIP1)

  • First Published: 01 April 2021
Key Points

  • A synthesis of Miocene modeling efforts, and surface temperature reconstructions, is presented within a single analysis framework

  • Miocene global mean surface temperature estimates span ∼5.3°C–11.5°C higher than preindustrial, only ∼2°C is explained by non–CO2 boundary conditions in climate models

  • Some simulations overlap with reconstructed global mean surface temperature estimates but fail to capture the weak temperature gradient

Free Access

Evidence for Decreased Precipitation Variability in the Yucatán Peninsula During the Mid-Holocene

  • First Published: 06 May 2021
Key Points

  • Stable isotope data confirm a wetter, less variable mid-Holocene climate in the northern Yucatán Peninsula compared to the late Holocene

  • Speleothem Mg/Ca has potential for use as a precipitation proxy in the Yucatán Peninsula

Free Access

Anti-Phase Strengthening of the South and East Asian Summer Monsoons During the Early Pliocene Driven by Southern Hemisphere Ice Volume

  • First Published: 07 April 2021
Key Points

  • Asian summer monsoon variations display a three-stage evolution during the early Pliocene

  • The East and South Asian summer monsoon trends are 180° out of phase during the early Pliocene

  • Anti-phase strengthening of the South and East Asian summer monsoons seems a robust pattern over the past 6 million years

Open Access

Ice Age-Holocene Similarity of Foraminifera-Bound Nitrogen Isotope Ratios in the Eastern Equatorial Pacific

  • First Published: 22 April 2021
Key Points

  • Foraminifera-bound δ15N was similar during the last ice age and the Holocene in the eastern equatorial Pacific, unlike bulk sedimentary δ15N

  • Bulk sediment δ15N is likely biased to lower ice age values by foreign N inputs and weaker sedimentary diagenesis

  • The foraminifera-bound δ15N data may reflect that water column denitrification was not reduced during the last glacial period

Free Access

Quantifying Diagenesis, Contributing Factors, and Resulting Isotopic Bias in Benthic Foraminifera Using the Foraminiferal Preservation Index: Implications for Geochemical Proxy Records

  • First Published: 22 April 2021
Key Points

  • Establishes new method for evaluating preservation quality of benthic foraminifera commonly used to construct geochemical proxy records

  • Links Cibicidoides and Uvigerina assemblage preservation at various sites to changes in water mass corrosivity through time

  • Quantifies potential diagenetic bias in published stable isotope records and provides guidance on how to avoid such bias in future records

Free Access

Diversification of Iron-Biomineralizing Organisms During the Paleocene-Eocene Thermal Maximum: Evidence From Quantitative Unmixing of Magnetic Signatures of Conventional and Giant Magnetofossils

  • First Published: 23 April 2021
Key Points

  • Giant magnetofossils are produced by microorganisms in response to vertical mixing and increased iron supply during rapid warming

  • High morphological disparity and abundance of magnetofossils are linked to seasonal nutrient cycling

  • Principal component analysis of first-order reversal curves can distinguish between groups of low and high coercivity magnetofossils

Open Access

Role of the Tropical Atlantic for the Interhemispheric Heat Transport During the Last Deglaciation

  • First Published: 23 April 2021
Key Points

  • Brazil Current heat transport coupled to changes in strength of the Atlantic Meridional Overturning Circulation during the last deglacial

  • Antiphased heat transport by the Brazil and North Brazil Currents during Heinrich Event 1

  • Warming of western tropical South Atlantic sea surface based on foraminiferal Mg/Ca exceeds numerical model results for Heinrich Event 1

Free Access

Biomarker and Carbon Isotopic Evidence of Marine Incursions in the Himalayan Foreland Basin During Its Overfilled Stage

  • First Published: 03 May 2021
Key Points

  • Biomarkers, n-alkanes and its 13C/12C ratios were measured from the eastern part of the Himalayan foreland basin

  • Specific organic molecules and field evidence suggests marginal marine condition at times in late Miocene due to proximity to Bengal Basin

  • The eastern part of Himalayan foreland evolved distinctly compared to the western and central regions until early Pliocene

Free Access

Climatically Modulated Dust Inputs from New Zealand to the Southwest Pacific Sector of the Southern Ocean Over the Last 410 kyr

  • First Published: 17 March 2021
Key Points

  • We present an SW Pacific Ocean lithogenic flux record for the last 410 ka that covaries with the Antarctic and sub-Antarctic dust records

  • Westerly wind-transported material from New Zealand is the most likely dust source over glacial-interglacial cycles

  • Silt-sized sediment was well sorted by bottom currents, which were more energetic in interglacials than glacials

Free Access

Climate-Modulated Nutrient Conditions Along the Labrador Shelf: Evidence From Nitrogen Isotopes in a Six-Hundred-Year-Old Crustose Coralline Alga

  • First Published: 30 March 2021
Key Points

  • Nitrogen isotopes from a crustose coralline alga are argued to record ocean circulation and nutrient utilization along the Labrador Shelf

  • Past periods of increased polar inflow waters and nutrient utilization are linked to negative modes of the Atlantic multidecadal oscillation

  • An anomalously long phase of low nutrient input since ∼1870 is linked to the weakening of the Atlantic meridional overturning circulation