cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/cbe3-tg26
title: NOAA/WDS Paleoclimatology - Western Makassar Strait Radiocarbon, d13C and d18O Data since the Last Glacial Termination

description: There is a growing database of radiocarbon (14C) reconstructions from biogenic carbonate taken from marine sediment cores being used to investigate changing ocean circulation and carbon cycling at the end of the last great ice age. Reported here are 14C results from a marine core taken in the Makassar Straits of the western equatorial Pacific that was intended to test whether there was evidence of geologic carbon release to the ocean during the glacial termination. A thorough investigation of planktic and benthic 14C ages with stable isotopes and CT-scans revealed extensive burrowing in the upper 2 m of the core that displaced younger sediments downward by more than half a meter into the glacial section of the core. The vertical displacement is evident in both planktic and benthic fossils. However, the extent of displacement and the stratigraphic disturbance became evident only after multiple measurements of different species and genera. A CT-scan prior to sampling would be an effective screening tool to avoid sampling problem cores such as this.
DOI: 10.25921/c5za-hh03
title: NOAA/WDS Paleoclimatology - Vanoni - Amden - PCAB - ITRDB SWIT390

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: Reference: 
# Vanoni M. 2012. Klimatische Einflusse auf die Wachstumsvariabilitat von Weisstanne und Fichte entlang des Weisstannen-Ausbreitungsgradienten. Master thesis. ETH Zurich, Zurich. NOAA Template Raw Measurements file added 2021-05-03.
DOI: 10.25921/cgmm-2052
title: NOAA/WDS Paleoclimatology - Southern Ocean Geochemistry Data going back into the Last Ice Age

description: Records of past climate and ocean circulation derived from marine sediments. Parameter keywords describe what was measured in this data set.  Additional summary information can be found in the abstracts of papers listed in the data set citations.
description: The NBP9802-06PC XRF sediment composition data has not been previously released, but other data from NBP9802-06PC was published in Chase et al.(2003), doi:10.1016/S0967-0645(02)00595-7 and Anderson et al.(2009), doi:10.1126/science.1167441. Data has undated samples older than the listed oldest date for the study.
      Provided Keywords: Southern Ocean, bottom water oxygen, radiocarbon ages, sediment composition
DOI: 10.25921/cdrj-ds97
title: NOAA/WDS Paleoclimatology - Bengal Fan Miocene to Present Plant-Wax Biomarker and Isotope Data

description: Modern tropical and subtropical C4 grasslands and savannas were established during the late-Miocene and Pliocene, over 20 Myr after evolutionary originations of the C4 photosynthetic pathway.  This lag suggests environmental factors first limited and then favored C4 plants.  Here, we examine the timing and drivers for the establishment of C4 grasslands on the Indian Subcontinent using carbon and hydrogen isotope signatures of plant-wax n-alkanes recovered from turbidites in the Bengal Fan.  Like prior studies, we find C4 ecosystems in the Ganges-Brahmaputra catchment first emerged at 7.4 Ma and subsequently expanded between 6.9 to ~6.0 Ma. Hydrogen isotope values varied from 10.2 to 7.4 Ma and then increased after 7.4, which suggests intermittent drying began before the establishment of C4 grasslands with further drying at the onset of C4 expansion.  Synthesis of published plant fossil data from the Siwalik Group of the Himalayan foreland basin documents an ecosystem trajectory from evergreen tropical forests, to seasonally deciduous forests, and then expansive C4 grasslands.  This trajectory coincided with a seasonally uneven drying trend due to both increased evaporation of plant leaf and soil waters and reduced rainfall, as identified in soil carbonate and tooth enamel datasets.  Collectively the fossil, biomarker, and isotopic evidence reveal the development of modern C4 ecosystems on the Indian Subcontinent followed a series of ecosystem transformations driven by drying and fire feedbacks, and possibly declining atmospheric pCO2, beginning at 10.2 Ma and strengthening through the late Miocene.
description: Biomarkers and isotope data from sediments of the Bengal Fan collected in ODP cores 717 and 718 for 17-0 million years BP
       Provided Keywords: International Ocean Discovery Program, Expedition 116, Site 717, Site 718, biomarkers, terrestrial vegetation, India, Nepal, hydrogen isotopes, carbon isotopes
DOI: 10.25921/c4gb-sz82
title: NOAA/WDS Paleoclimatology - Larson - Matawaumkeag - TSCA - ITRDB ME047

description: The International Tree-Ring Data Bank (ITRDB) provides public access to over 3000 tree-ring data sets collected over the past century, yet 809 of these sites have end dates between AD 1950 and 1980. These data cannot be calibrated with at least the past 30-40 years of instrumental data when used in climate reconstructions. We developed new tree-ring data sets at five sites in Maine, USA, to update earlier collections. Four of the five collections were successfully updated, with environmental changes at the fifth site limiting our success. Our results highlight the limits to tree longevity in a dynamic world and the need to increase and formalize efforts toward updating chronologies. We initiate a discussion to set forth explicit guidelines that help create consistent efforts to updating chronologies and provide a guide to beginning dendrochronologists who are particularly well suited to contribute to this area of work. The research was carried out through an introductory dendrochronology course taught at the University of Wisconsin-Platteville and offers a model to help direct the increasing availability of human resources to the rapidly growing field of dendrochronology.
description: NOAA Template Raw Measurements file added 2021-08-05.
DOI: 10.25921/c91r-zn22
title: NOAA/WDS Paleoclimatology - Kyok-Tash Cave, West Siberia Early Holocene Stable Isotope and Mg/Ca Data

description: Rapid permafrost degradation and peatland expansion occurred in Eurasia during the Early Holocene and may be analogous to the region’s response to anthropogenic warming. Here we present a 230Th-dated, multiproxy speleothem record with subdecadal sampling resolution from Kyok-Tash Cave, at the modern permafrost margin in the northern Altai Mountains, southwestern Siberia. Stalagmite K4, covering the period 11,400 to 8,900 years before present, indicates an absence of stable permafrost within three centuries of the Younger Dryas termination. Between 11,400 and 10,400 years ago, speleothem δ18O is antiphased between the Altai and Ural ranges, suggesting a reorganization of the westerly wind systems that led to warmer and wetter winters over West Siberia and Altai, relative to the zonally adjacent regions of Northern Eurasia. At the same time, there is evidence of peak permafrost degradation and peatland expansion in West Siberia, consistent with the interpreted climate anomaly. Based on these findings, we suggest that modern permafrost in Eurasia is sensitive to feedbacks in the ocean-cryosphere system, which are projected to alter circulation regimes over the continent.
description: Stable isotope (d18O, d13C) and Mg/Ca data from Stalagmite K4 collected in Kyok-Tash Cave, Altai Mountains, western Siberia, for the early Holocene (11-9 ka)
DOI: 10.25921/cz9a-mx60
title: NOAA/WDS Paleoclimatology - Maxwell - Warren Woods - FAGR - ITRDB MI033

description: Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 CE in the United States) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale network reconstructions in the US are modeled by few tree-ring chronologies. Further, many of the chronologies currently publicly available on the International Tree-Ring Data Bank (ITRDB) were collected in the 1980s and 1990s, and thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date and therefore the calibration period influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the spatial variability of instrumentally recorded droughts and, to a lesser extent, pluvials. By extending the calibration period to 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the spatial variability of past droughts and pluvials. Further, chronologies on the ITRDB need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.
description: Density of tree-ring network influence on drought reconstruction NOAA Template Raw Measurements file added 2021-12-29.
DOI: 10.15468/dl.qfh367
title: Occurrence Download

description: A dataset containing 18 species occurrences available in GBIF matching the query:
{
 "and" : [
 "TaxonKey is one of (Erythrina bidwillii)",
 "HasCoordinate is true",
 "HasGeospatialIssue is false"
 ]
}

 The dataset includes 18 records from 10 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0006214-251009101135966/datasets/export for details.
 
Data from some individual datasets included in this download may be licensed under less restrictive terms.
DOI: 10.25921/c4a7-ep34
title: NOAA/WDS Paleoclimatology - Maxwell - Davey Woods - LITU - ITRDB OH009

description: Tulip poplar is an important component of the eastern deciduous forest and one of the few diffuse-porous tree species with indeterminate apical growth in North America for which there are substantial dendroecological data. This dendroecological study evaluated correlations between radial growth of tulip poplar and monthly, seasonal, and annual climate variables and how these correlations varied across time and spatial climate gradients. The strongest and most spatially consistent correlations were with climate variables related to site water balance, especially precipitation. Growth was positively correlated with climate variables related to site water balance during the months of May through July of the year the annual ring forms and during the previous year growing season and autumn. Growth was negatively correlated with prior year growing season maximum temperature, but positively correlated with prior winter minimum temperature. There was some evidence of temporal variation in growth-climate associations between 1900 and 2016, but the climate variables with the strongest associations were consistent across different time periods. Correlations with climate variables related to water stress increased from east to west as precipitation decreased, but there was no spatial trend in correlations with growing season temperature from north to south as temperature increases. Strength of positive correlations with winter temperature increased from north to south. Growth of tulip poplar will likely be adversely affected if drought frequency or severity increases during the twenty-first century. Increased winter temperature would likely have a positive influence on growth during the subsequent growing season in some parts of the species range. Radial growth of tulip poplar is most affected by climate conditions during a narrow time period early in the growing season, similar to results obtained for multiple oak species and a few other diffuse-porous species in eastern North America. Simulation modelers might consider the phenology of these correlations to formulate more biologically realistic tree climate response functions.
description: Climate response of tulip poplar NOAA Template Raw Measurements file added 2021-12-29.
DOI: 10.25921/c0qh-rt59
title: NOAA/WDS Paleoclimatology - Maxwell - Goll Woods - QUMA - ITRDB OH012

description: Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 CE in the United States) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale network reconstructions in the US are modeled by few tree-ring chronologies. Further, many of the chronologies currently publicly available on the International Tree-Ring Data Bank (ITRDB) were collected in the 1980s and 1990s, and thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date and therefore the calibration period influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the spatial variability of instrumentally recorded droughts and, to a lesser extent, pluvials. By extending the calibration period to 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the spatial variability of past droughts and pluvials. Further, chronologies on the ITRDB need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.
description: Density of tree-ring network influence on drought reconstruction NOAA Template Raw Measurements file added 2021-12-29.
DOI: 10.25921/cnwj-xt85
title: NOAA/WDS Paleoclimatology - Global Ocean Glacial Termination Radiocarbon Modeling Results

description: Seafloor pockmarks of varying size occur over an area of 50,000 km2 on the Chatham Rise, Canterbury Shelf and Inner Bounty Trough, New Zealand. The pockmarks are concentrated above the flat-subducted Hikurangi Plateau. Echosounder data identify recurrent episodes of pockmark formation at ~100,000-year frequency coinciding with Pleistocene glacial terminations. Here we show that there are structural conduits beneath the larger pockmarks through which fluids flowed upward toward the seafloor. Large negative D14C excursions are documented in marine sediments deposited next to these subseafloor conduits and pockmarks at the last glacial termination. Modern pore waters contain no methane, and there is no negative d13C excursion at the glacial termination that would be indicative of methane or mantle-derived carbon at the time the D14C excursion and pockmarks were produced. An ocean general circulation model equipped with isotope tracers is unable to simulate these large D14C excursions on the Chatham Rise by transport of hydrothermal carbon released from the East Pacific Rise as previous studies suggested. Here we attribute the D14C anomalies and pockmarks to release of 14C-dead CO2 and carbon-rich fluids from subsurface reservoirs, the most likely being dissociated Mesozoic carbonates that subducted beneath the Rise during the Late Cretaceous. Because of the large number of pockmarks and duration of the D14C anomaly, the pockmarks may collectively represent an important source of 14C-dead carbon to the ocean during glacial terminations.
description: Simulations with radiocarbon-dead DIC injected into a single grid box located on the Eastern Pacific Rise. Each simulation has different injection rates: 0.16, 0.32, 0.64, and 1.28 GtC for 10000 years. Deep ocean overturning circulation is also weakened at model year 0, through brine rejection. The oceanic D14C field is saved in the 3d netcdf files while the atmospheric D14C is saved in the 2d netcdf files.
DOI: 10.25921/cxcs-n826
title: NOAA/WDS Paleoclimatology - Percent Biogenic Silica Data from the Antarctic Zone of the Indian Ocean Sector of the Southern Ocean Spanning the Past 630,000 Years

description: A new orbital-scale record of bulk sediment biogenic silica (opal) content from Ocean Drilling Program (ODP) Site 745B spans the past 630 kyr (Marine Isotope Stages (MIS) 1–16). Together with the published portion of the record (MIS 16–31, Billups et al., 2018), we obtain a 1 million year orbital-scale record of paleoproductivity in the Antarctic Zone of the Indian Ocean sector of the Southern Ocean. A coherent age model is based on tuning variations in the opal content to the benthic foraminiferal δ18O stack of Lisiecki and Raymo (2005). Consistent with other sites from the Antarctic Zone of the Southern Ocean, we align opal maxima with interglacial and opal minima with glacial intervals. Opal variations are significant at all three primary periodicities (100, 40, and 23 kyr), coherent (>95%), and inphase with the tuning target on the scale of individual cycles as well as their amplitude modulation. This supports the assumption of global ice volume-related changes in Southern Ocean paleoproductivity in the derivation of the age model. Between MIS 11 and 4, however, the opal record lacks minima corresponding to the glacial extremes of MIS 10, 8, and 6. During this interval of time, opal fluctuates primarily with a 23 kyr precession signal. We suggest that the productivity response to precession reflects an ice-free sea surface that remains sensitive to wind-driven upwelling of nutrients. Results from Site 745B illustrate the potential importance of regional climate forcing factors on longer time scales and their interplay with global climate background conditions.
DOI: 10.15468/dl.hhsc36
title: Occurrence Download

description: A dataset containing 1 species occurrences available in GBIF matching the query:
{
 "and" : [
 "TaxonKey is Solen kempi",
 "HasCoordinate is true",
 "BasisOfRecord is one of (Observation, Machine Observation, Human Observation, Occurrence evidence)",
 {
 "not" : {
 "OccurrenceStatus" : [
 "is one of (Absent)"
 ]
 }
 }
 ]
}

 The dataset includes 1 records from 1 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0006215-251009101135966/datasets/export for details.
 
Data from some individual datasets included in this download may be licensed under less restrictive terms.
DOI: 10.25921/c17g-ff42
title: NOAA/WDS Paleoclimatology - Axelson - Southern Trysil area historical timber - PCAB - ITRDB NORW017

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: Total ring width collections built on samples from several historical log buildings in the southern part of Trysil kommune in Norway. NOAA Template Raw Measurements file added 2021-02-22.
DOI: 10.25921/c4rp-y867
title: NOAA/WDS Paleoclimatology - Treml - Krkonose Mountains treeline - PCAB - ITRDB CZEC006

description: Significant alterations of cambial activity might be expected due to climate warming, leading to growing season extension and higher growth rates especially in cold-limited forests. However, assessment of climate-change-driven trends in intra-annual wood formation suffers from the lack of direct observations with a timespan exceeding a few years. We used the Vaganov-Shashkin process-based model to: (i) simulate daily-resolved numbers of cambial and differentiating cells; and (ii) develop chronologies of the onset and termination of specific phases of cambial phenology during 1961-2017. We also determined the dominant climatic factor limiting cambial activity for each day. To asses intra-annual model validity, we used eight years of direct xylogenesis monitoring from the treeline region of the Krkonose Mts. (Czech Republic). The model exhibits high validity in case of spring phenological phases and a seasonal dynamics of tracheid production, but its precision declines for estimates of autumn phenological phases and growing season duration. The simulations reveal an increasing trend in the number of tracheids produced by cambium each year by 0.42 cells/year. Spring phenological phases (onset of cambial cell growth and tracheid enlargement) show significant shifts towards earlier occurrence in the year (for 0.28-0.34 days/year). In addition, there is a significant increase in simulated growth rates during entire growing season associated with the intra-annual redistribution of the dominant climatic controls over cambial activity. Results suggest that higher growth rates at treeline are driven by (i) temperature-stimulated intensification of spring cambial kinetics, and (ii) decoupling of summer growth rates from the limiting effect of low summer temperature due to higher frequency of climatically optimal days. Our results highlight that the cambial kinetics stimulation by increasing spring and summer temperatures and shifting spring phenology determine the recent growth trends of treeline ecosystems. Redistribution of individual climatic factors controlling cambial activity during the growing season questions the temporal stability of climatic signal of cold forest chronologies under ongoing climate change.
description: The data represent raw tree-ring width series from the treeline ecotone in the Krkonose Mts. (Giant Mts.) in the north of the Czech Republic. One core was extracted from each tree (Picea abies). Sampling was performed during 2019 growing season, so the 2019 tree-ring is incomplete. NOAA Template Raw Measurements file added 2021-02-22.