Robert B Dunbar
Datos Biográficos
| ID | 5598752 |
|---|---|
| NOMBRE | Robert B Dunbar |
| NOMBRES | Robert B |
| APELLIDO | Dunbar |
| FIRMA | DUNBAR R B |
| AFILIACIONES | Stanford University |
| ORCID | 0000-0002-9728-5609 |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 10 |
| TOTAL DE CITAS | 25 |
| TOTAL COMO AUTOR | 10 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 2000 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2021 |
| ÍNDICE H | 3 |
Towards an ocean-based large ocean states country classification
International development country classifications are important for achieving development goals by directing differential support to a group of countries facing common development constraints. The small island developing States (SIDS) classification is a widely used country classification supporting developing island nations. Some nations are now self-identifying as “large ocean states” (LOS), citing the central role of the ocean for their develo…
Macro-nutrient concentrations in Antarctic pack ice
Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro-nutrient data (hereafter termed nutrients) in Antarctic pack ice (306 ice-cores collected from 19 research cruises). Dissolved inorganic nitrogen and silicic acid concentrations change with time, as expected from a seasonally productive ecosystem. In…
Accretion rates in coastal wetlands of the southeastern Gulf of California and their relationship with sea-level rise
Sea-level rise (SLR) is one of the most conspicuous examples of the environmental impact of recent climate change. Since SLR rates are not uniform around the planet, local and regional data are needed for proper adaptation plans. 210 Pb-dated sediment cores were analyzed to determine the trends of sediment accretion rates (SARs) at three tropical saltmarshes in the Estero de Urias lagoon (Gulf of California, Mexico), in order to estimate the SLR …
Compound-Specific 14 C Dating of Iodp Expedition 318 Core U1357A Obtained Off the Wilkes Land Coast, Antarctica
This study applied compound-specific radiocarbon analysis (CSRA) to a 186-m-long sediment core (U1357A) taken from Adélie Basin located on the continental shelf off Wilkes Land, East Antarctica. The CSRA targeted C 16 fatty acid as well as C 16 ., fatty acid and cyclopheophorbide- a -enol isolated from the sediment. Due to their high degradation rate, these compounds are expected to occur in low abundances in relict organic matter deposited at th…
Seasonally laminated diatom-rich sediments from Dumont d’Urville Trough, East Antarctic Margin
Laminated sediments are unique archives of palaeoenvironmental and palaeoceanographic conditions, recording changes on seasonal and interannual timescales. Diatom-rich laminated marine sediments are examined from Dumont d’Urville Trough, East Antarctic Margin, to determine changes in environmental conditions on the continental shelf from 1136 to 3122 cal. yr BP. Scanning electron microscope backscattered electron imagery (BSEI) and secondary elec…
Pre-Bomb Radiocarbon Variability Inferred from a Kenyan Coral Record
We report results from AMS radiocarbon measurements (δ 14 C) in corals recovered off the coast of Kenya. Bimonthly samples which span the pre-bomb era average −51 (±3.7; n=43), when age and Suess effect are corrected, and over the time of interest (1946–1954) do not exhibit any discernible seasonality. Relative to regional pre-bomb δ 14 C values in the western Indian Ocean, our results indicate 14 C enrichment off the coast of Kenya. Furthermore,…
Late Quaternary Climate and Hydrology of Tropical South America Inferred from an Isotopic and Chemical Model of Lake Titicaca, Bolivia and Peru
A simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5°C colder than today, based on previous modeling. Our simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. The latest Pleistocene Lake Titicaca was deep, fresh, and overflowing…
The History of South American Tropical Precipitation for the Past 25,000 Years
Long sediment cores recovered from the deep portions of Lake Titicaca are used to reconstruct the precipitation history of tropical South America for the past 25,000 years. Lake Titicaca was a deep, fresh, and continuously overflowing lake during the last glacial stage, from before 25,000 to 15,000 calibrated years before the present (cal yr B.P.), signifying that during the last glacial maximum (LGM), the Altiplano of Bolivia and Peru and much o…
Chronology of the Palmer Deep site, Antarctic Peninsula
Palmer Deep sediment cores are used to produce the first high-resolution, continuous late Pleistocene to Holocene time-series from the Antarctic marine system. The sedimentary record is dated using accelerator mass spectrometer radiocarbon methods on acid insoluble organic matter and foraminiferal calcite. Fifty-four radiocarbon analyses are utilized in the dating which provides a calibrated timescale back to 13 ka BP. Reliability of resultant ag…
A new estimate of the Holocene lowstand level of Lake Titicaca, central Andes, and implications for tropical palaeohydrology
New evidence from piston cores and high-resolution seismic reflection data shows that water levels in Lake Titicaca were as much as 100 m below the present level during the early to mid-Holocene (between .6 and 3.8 14 C kyr BP). Climatological and modelling studies indicate that Lake Titicaca rainfall depends on convective activity in upwind Amazonia; the lake-level data therefore suggest a drier Amazon Basin during this time. This view is bolste…
A new estimate of the Holocene lowstand level of Lake Titicaca, central Andes, and implications for tropical palaeohydrology
New evidence from piston cores and high-resolution seismic reflection data shows that water levels in Lake Titicaca were as much as 100 m below the present level during the early to mid-Holocene (between .6 and 3.8 14 C kyr BP). Climatological and modelling studies indicate that Lake Titicaca rainfall depends on convective activity in upwind Amazonia; the lake-level data therefore suggest a drier Amazon Basin during this time. This view is bolste…
Chronology of the Palmer Deep site, Antarctic Peninsula
Palmer Deep sediment cores are used to produce the first high-resolution, continuous late Pleistocene to Holocene time-series from the Antarctic marine system. The sedimentary record is dated using accelerator mass spectrometer radiocarbon methods on acid insoluble organic matter and foraminiferal calcite. Fifty-four radiocarbon analyses are utilized in the dating which provides a calibrated timescale back to 13 ka BP. Reliability of resultant ag…
Compound-Specific 14 C Dating of Iodp Expedition 318 Core U1357A Obtained Off the Wilkes Land Coast, Antarctica
This study applied compound-specific radiocarbon analysis (CSRA) to a 186-m-long sediment core (U1357A) taken from Adélie Basin located on the continental shelf off Wilkes Land, East Antarctica. The CSRA targeted C 16 fatty acid as well as C 16 ., fatty acid and cyclopheophorbide- a -enol isolated from the sediment. Due to their high degradation rate, these compounds are expected to occur in low abundances in relict organic matter deposited at th…
Accretion rates in coastal wetlands of the southeastern Gulf of California and their relationship with sea-level rise
Sea-level rise (SLR) is one of the most conspicuous examples of the environmental impact of recent climate change. Since SLR rates are not uniform around the planet, local and regional data are needed for proper adaptation plans. 210 Pb-dated sediment cores were analyzed to determine the trends of sediment accretion rates (SARs) at three tropical saltmarshes in the Estero de Urias lagoon (Gulf of California, Mexico), in order to estimate the SLR …
Pre-Bomb Radiocarbon Variability Inferred from a Kenyan Coral Record
We report results from AMS radiocarbon measurements (δ 14 C) in corals recovered off the coast of Kenya. Bimonthly samples which span the pre-bomb era average −51 (±3.7; n=43), when age and Suess effect are corrected, and over the time of interest (1946–1954) do not exhibit any discernible seasonality. Relative to regional pre-bomb δ 14 C values in the western Indian Ocean, our results indicate 14 C enrichment off the coast of Kenya. Furthermore,…
A new estimate of the Holocene lowstand level of Lake Titicaca, central Andes, and implications for tropical palaeohydrology
New evidence from piston cores and high-resolution seismic reflection data shows that water levels in Lake Titicaca were as much as 100 m below the present level during the early to mid-Holocene (between .6 and 3.8 14 C kyr BP). Climatological and modelling studies indicate that Lake Titicaca rainfall depends on convective activity in upwind Amazonia; the lake-level data therefore suggest a drier Amazon Basin during this time. This view is bolste…
Late Quaternary Climate and Hydrology of Tropical South America Inferred from an Isotopic and Chemical Model of Lake Titicaca, Bolivia and Peru
A simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5°C colder than today, based on previous modeling. Our simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. The latest Pleistocene Lake Titicaca was deep, fresh, and overflowing…
The History of South American Tropical Precipitation for the Past 25,000 Years
Long sediment cores recovered from the deep portions of Lake Titicaca are used to reconstruct the precipitation history of tropical South America for the past 25,000 years. Lake Titicaca was a deep, fresh, and continuously overflowing lake during the last glacial stage, from before 25,000 to 15,000 calibrated years before the present (cal yr B.P.), signifying that during the last glacial maximum (LGM), the Altiplano of Bolivia and Peru and much o…
Chronology of the Palmer Deep site, Antarctic Peninsula
Palmer Deep sediment cores are used to produce the first high-resolution, continuous late Pleistocene to Holocene time-series from the Antarctic marine system. The sedimentary record is dated using accelerator mass spectrometer radiocarbon methods on acid insoluble organic matter and foraminiferal calcite. Fifty-four radiocarbon analyses are utilized in the dating which provides a calibrated timescale back to 13 ka BP. Reliability of resultant ag…
Pre-Bomb Radiocarbon Variability Inferred from a Kenyan Coral Record
We report results from AMS radiocarbon measurements (δ 14 C) in corals recovered off the coast of Kenya. Bimonthly samples which span the pre-bomb era average −51 (±3.7; n=43), when age and Suess effect are corrected, and over the time of interest (1946–1954) do not exhibit any discernible seasonality. Relative to regional pre-bomb δ 14 C values in the western Indian Ocean, our results indicate 14 C enrichment off the coast of Kenya. Furthermore,…
Seasonally laminated diatom-rich sediments from Dumont d’Urville Trough, East Antarctic Margin
Laminated sediments are unique archives of palaeoenvironmental and palaeoceanographic conditions, recording changes on seasonal and interannual timescales. Diatom-rich laminated marine sediments are examined from Dumont d’Urville Trough, East Antarctic Margin, to determine changes in environmental conditions on the continental shelf from 1136 to 3122 cal. yr BP. Scanning electron microscope backscattered electron imagery (BSEI) and secondary elec…
Compound-Specific 14 C Dating of Iodp Expedition 318 Core U1357A Obtained Off the Wilkes Land Coast, Antarctica
This study applied compound-specific radiocarbon analysis (CSRA) to a 186-m-long sediment core (U1357A) taken from Adélie Basin located on the continental shelf off Wilkes Land, East Antarctica. The CSRA targeted C 16 fatty acid as well as C 16 ., fatty acid and cyclopheophorbide- a -enol isolated from the sediment. Due to their high degradation rate, these compounds are expected to occur in low abundances in relict organic matter deposited at th…
Accretion rates in coastal wetlands of the southeastern Gulf of California and their relationship with sea-level rise
Sea-level rise (SLR) is one of the most conspicuous examples of the environmental impact of recent climate change. Since SLR rates are not uniform around the planet, local and regional data are needed for proper adaptation plans. 210 Pb-dated sediment cores were analyzed to determine the trends of sediment accretion rates (SARs) at three tropical saltmarshes in the Estero de Urias lagoon (Gulf of California, Mexico), in order to estimate the SLR …
Macro-nutrient concentrations in Antarctic pack ice
Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro-nutrient data (hereafter termed nutrients) in Antarctic pack ice (306 ice-cores collected from 19 research cruises). Dissolved inorganic nitrogen and silicic acid concentrations change with time, as expected from a seasonally productive ecosystem. In…
Towards an ocean-based large ocean states country classification
International development country classifications are important for achieving development goals by directing differential support to a group of countries facing common development constraints. The small island developing States (SIDS) classification is a widely used country classification supporting developing island nations. Some nations are now self-identifying as “large ocean states” (LOS), citing the central role of the ocean for their develo…
Geology and Paleoclimatology Research (8 obras) · Oceanography (8 obras) · Geology (7 obras) · Geography (6 obras) · Holocene (6 obras) · Isotope Analysis in Ecology (6 obras) · Paleontology (6 obras) · Climate change (4 obras) · Ecology (4 obras) · Physical geography (4 obras)