A5029547508- Geology and Paleoclimatology Research
- Forest ecology and management
- Botany and Plant Ecology Studies
- Geological Studies and Exploration
- Remote Sensing and LiDAR Applications
- Geological and Geophysical Studies
- Geological formations and processes
- Hydrocarbon exploration and reservoir analysis
- Coral and Marine Ecosystems Studies
- Methane Hydrates and Related Phenomena
- Pleistocene-Era Hominins and Archaeology
- Isotope Analysis in Ecology
- Archaeology and ancient environmental studies
- Tree-ring climate responses
- Oceanographic and Atmospheric Processes
- Marine and fisheries research
- Aquaculture disease management and microbiota
- Climate variability and models
- Marine animal studies overview
- Cryospheric studies and observations
- Heavy metals in environment
- Climate change and permafrost
- Paleontology and Stratigraphy of Fossils
- Geomagnetism and Paleomagnetism Studies
- Maritime and Coastal Archaeology
Woods Hole Oceanographic Institution
2015-2024
University of Arizona
2004-2020
Institut de l'Information Scientifique et Technique
2004-2020
Centre de Géosciences
2016
GFZ Helmholtz Centre for Geosciences
2016
King Abdullah University of Science and Technology
2013
Woodwell Climate Research Center
2007
University of Colorado Boulder
1996-2004
Institute of Arctic and Alpine Research
1996-2004
University of California, Irvine
2004
The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available updated data sets from 14 C measurements on tree rings, plant macrofossils, speleothems, corals, foraminifera. were derived the using random walk model (RWM) used to generate Marine09, which has account for additional uncertainties error structures. new ratified at 21st International Radiocarbon conference in July 2012 are as Supplemental Material www.radiocarbon.org. database can be accessed...
ABSTRACT Radiocarbon ( 14 C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating fluctuations in atmospheric C concentration. Although curves are constructed from independently archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume international both Northern...
The focus of this paper is the conversion radiocarbon ages to calibrated (cal) for interval 24,000–0 cal BP (Before Present, 0 = AD 1950), based upon a sample set dendrochronologically dated tree rings, uranium-thorium corals, and varve-counted marine sediment. 14 C age–cal age information, produced by many laboratories, converted Δ profiles calibration curves, atmosphere as well oceans. We discuss offsets in measured l4 errors therein, regional differences, tree–coral comparisons time...
Titanium and iron concentration data from the anoxic Cariaco Basin, off Venezuelan coast, can be used to infer variations in hydrological cycle over northern South America during past 14,000 years with subdecadal resolution. Following a dry Younger Dryas, period of increased precipitation riverine discharge occurred Holocene "thermal maximum." Since approximately 5400 ago, trend toward drier conditions is evident data, high-amplitude fluctuations minima time interval 3800 2800 ago "Little...
ABSTRACT The concentration of radiocarbon ( 14 C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their C in the marine environment therefore need a marine-specific calibration curve cannot be calibrated directly against atmospheric-based IntCal20 curve. This paper presents Marine20, an update to internationally agreed age that provides non-polar global-average record 0–55 cal kBP serves as baseline for regional oceanic variation. Marine20 is...
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed internationally ratified to replace the terrestrial marine components of IntCal98. The new data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 = AD 1950), provide much higher resolution, greater precision, more detailed structure than For Marine04 curve, dendrochronologically-dated tree-ring samples, converted with a box diffusion model mixed-layer ages, cover period 0–10.5 BP. Beyond...
A compilation of paleoclimate records from lake sediments, trees, glaciers, and marine sediments provides a view circum-Arctic environmental variability over the last 400 years. From 1840 to mid-20th century, Arctic warmed highest temperatures in four centuries. This warming ended Little Ice Age has caused retreats melting permafrost sea ice, alteration terrestrial ecosystems. Although warming, particularly after 1920, was likely by increases atmospheric trace gases, initiation mid-19th...
In the anoxic Cariaco Basin of southern Caribbean, bulk titanium content undisturbed sediment reflects variations in riverine input and hydrological cycle over northern tropical South America. A seasonally resolved record shows that collapse Maya civilization Terminal Classic Period occurred during an extended regional dry period, punctuated by more intense multiyear droughts centered at approximately 810, 860, 910 A.D. These new data suggest a century-scale decline rainfall put general...
Sedimentary time series of color reflectance and major element chemistry from the anoxic Cariaco Basin off coast northern Venezuela record large abrupt shifts in hydrologic cycle tropical Atlantic during past 90,000 years. Marine productivity maxima increased precipitation riverine discharge South America are closely linked to interstadial (warm) climate events marine isotope stage 3, as recorded Greenland ice cores. Increased at this latitude interstadials suggests potential for greater...
Abstract The Greenland ice core from NorthGRIP (NGRIP) contains a proxy climate record across the Pleistocene–Holocene boundary of unprecedented clarity and resolution. Analysis an array physical chemical parameters within enables base Holocene, as reflected in first signs climatic warming at end Younger Dryas/Greenland Stadial 1 cold phase, to be located with high degree precision. This event is most clearly abrupt shift deuterium excess values, accompanied by more gradual changes δ 18 O,...
A series of 14C measurements in Ocean Drilling Program cores from the tropical Cariaco Basin, which have been correlated to annual-layer counted chronology for Greenland Ice Sheet Project 2 (GISP2) ice core, provides a high-resolution calibration radiocarbon time scale back 50,000 years before present. Independent radiometric dating events GISP2 suggests that is accurate. Reconstructed activities varied substantially during last glacial period, including sharp peaks synchronous with Laschamp...
A high-resolution western tropical Atlantic sea surface temperature (SST) record from the Cariaco Basin on northern Venezuelan shelf, based Mg/Ca values in surface-dwelling planktonic foraminifera, reveals that changes SST over last glacial termination are synchronous, within +/-30 to +/-90 years, with Greenland Ice Sheet Project 2 air proxy and atmospheric methane record. The most prominent deglacial event occurred during Younger Dryas time interval, when SSTs dropped by 3 degrees 4 C....
Abstract Rapid changes in ocean circulation and climate have been observed marine-sediment ice cores over the last glacial period deglaciation, highlighting non-linear character of system underlining possibility rapid shifts response to anthropogenic greenhouse gas forcing. To date, these are still not fully explained. One obstacle hindering progress our understanding interactions between past is difficulty accurately dating marine cores. Here, we present a set 92 sediment from Atlantic...
Radiocarbon data from the Cariaco Basin provide calibration of carbon-14 time scale across period deglaciation (15,000 to 10, 000 years ago) with resolution available previously only Holocene tree rings. Reconstructed changes in atmospheric are larger than thought, largest change occurring simultaneously sudden climatic cooling Younger Dryas event. Carbon-14 and published beryllium-10 together suggest that concurrent climate were predominantly result abrupt shifts deep ocean ventilation.
The mechanisms of Late Pleistocene megafauna extinctions remain fiercely contested, with human impact or climate change cited as principal drivers. We compared ancient DNA and radiocarbon data from 31 detailed time series regional megafaunal replacements over the past 56,000 years standard new combined records Northern Hemisphere in Pleistocene. Unexpectedly, rapid changes associated interstadial warming events are strongly replacement extinction major genetic clades species megafauna....
ABSTRACT Endozoicomonas bacteria were found highly associated with the coral Stylophora pistillata , and these are also ubiquitously diverse corals worldwide. Novel -specific probes revealed that abundant in endodermal tissues of S. appear to have an intimate relationship coral.
The Sr/Ca ratio of coral aragonite is used to reconstruct past sea surface temperature (SST). Twenty‐one laboratories took part in an interlaboratory study measurements. Results show bias can be significant, and the extreme case could result a range SST estimates 7°C. However, most data fall within narrower Porites reference material JCp‐1 now characterized well enough have certified value 8.838 mmol/mol with expanded uncertainty 0.089 following International Association Geoanalysts (IAG)...
Identifying leads and lags between high- low-latitude abrupt climate shifts is needed to understand where how such events were triggered. Vascular plant biomarkers preserved in Cariaco basin sediments reveal rapid vegetation changes northern South America during the last deglaciation, 15,000 10,000 years ago. Comparing biomarker records proxies from same sediment core provides a precise measure of relative timing different regions. Abrupt deglacial tropical high-latitude North Atlantic...
Aims: To determine the relationship between yellow band disease (YBD)‐associated pathogenic bacteria found in both Caribbean and Indo‐Pacific reefs, virulence of these pathogens. YBD is one most significant coral diseases tropics. Materials Results: The consortium four Vibrio species was isolated from tissue on corals: rotiferianus, harveyi, alginolyticus proteolyticus. This affects Symbiodinium (zooxanthellae) hospite causing symbiotic algal cell dysfunction disorganization thylakoid...
High-quality data from appropriate archives are needed for the continuing improvement of radiocarbon calibration curves. We discuss here basic assumptions behind 14 C dating that necessitate and relative strengths weaknesses which obtained. also highlight procedures, problems, uncertainties involved in determining atmospheric surface ocean C/ 12 these archives, including a discussion various methods used to derive an independent absolute timescale uncertainty. The types required current...
Reversing the field Do terrestrial geomagnetic reversals have an effect on Earth's climate? Cooper et al. created a precisely dated radiocarbon record around time of Laschamps reversal about 41,000 years ago from rings New Zealand swamp kauri trees. This reveals substantial increase in carbon-14 content atmosphere culminating during period weakening magnetic strength preceding polarity switch. The authors modeled consequences this event and concluded that minimum caused changes atmospheric...