Ann P McNichol
Biographic Data
| ID | 5598622 |
|---|---|
| NAME | Ann P McNichol |
| GIVEN NAMES | Ann P |
| FAMILY NAME | McNichol |
| SIGNATURE | MCNICHOL A P |
| ORCID | 0000-0002-9895-3912 |
| VERIFIED | Yes |
| TOTAL WORKS | 19 |
| TOTAL CITATIONS | 86 |
| AUTHOR COUNT | 19 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1995 |
| LATEST PUBLICATION YEAR | 2022 |
| H-INDEX | 4 |
Radiocarbon in the Marine Environment
Understanding carbon cycling in the ocean is critical for understanding past ocean dynamics, local impacts of environmental changes, and predicting future changes due to climate change. Radiocarbon plays an important role in deciphering the carbon puzzle and, here, we highlight some of the contributions this isotope has made to oceanography. The field is enormous and distilling it to three short papers was a challenge; we chose to focus on three …
Global Ocean Radiocarbon Programs
The importance of studying the radiocarbon content of dissolved inorganic carbon (DI 14 C) in the oceans has been recognized for decades. Starting with the GEOSECS program in the 1970s, 14 C sampling has been a part of most global survey programs. Early results were used to study air-sea gas exchange while the more recent results are critical for helping calibrate ocean general circulation models used to study the effects of climate change. Here …
Marine Organic Carbon and Radiocarbon—present and Future Challenges
We discuss present and developing techniques for studying radiocarbon in marine organic carbon (C). Bulk DOC (dissolved organic C) Δ 14 C measurements reveal information about the cycling time and sources of DOC in the ocean, yet they are time consuming and need to be streamlined. To further elucidate the cycling of DOC, various fractions have been separated from bulk DOC, through solid phase extraction of DOC, and ultrafiltration of high and low…
Radiocarbon in Dissolved Organic Carbon by Uv Oxidation
This study describes a procedural blank assessment of the ultraviolet photochemical oxidation (UV oxidation) method that is used to measure carbon isotopes of dissolved organic carbon (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). A retrospective compilation of Fm and δ 13 C results for secondary standards (OX-II, glycine) between 2009 and 2018 indicated that a revised blank correction was required to bring …
Influence of Different Acid Treatments on the Radiocarbon Content Spectrum of Sedimentary Organic Matter Determined by RPO/Accelerator Mass Spectrometry
In practice, obtaining radiocarbon ( 14 C) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting 14 C content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on 14 C content of sedimentary OM, we examine the variability …
Dimensions of Radiocarbon Variability within Sedimentary Organic Matter
Organic carbon (OC) radiocarbon ( 14 C) signatures in marine surface sediments are highly variable and the causes of this heterogeneity remain ambiguous. Here, we present results from a detailed 14 C-based investigation of an Arabian Sea sediment, including measurements on organic matter (OM) in bulk sediment, specific grain size fractions, and OC decomposition products from ramped-pyrolysis-oxidation (RPO). Our results show that 14 C ages of OM …
Assessing the Blank Carbon Contribution, Isotope Mass Balance, and Kinetic Isotope Fractionation of the Ramped Pyrolysis/Oxidation Instrument at Nosams
We estimate the blank carbon mass over the course of a typical Ramped PyrOx (RPO) analysis (150–1000°C; 5°C×min –1 ) to be (3.7±0.6) μg C with an Fm value of 0.555±0.042 and a δ 13 C value of (–29.0±0.1) ‰ VPDB. Additionally, we provide equations for RPO Fm and δ 13 C blank corrections, including associated error propagation. By comparing RPO mass-weighted mean and independently measured bulk δ 13 C values for a compilation of environmental sampl…
Ultra-Small Graphitization Reactors for Ultra-Microscale 14 C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (Nosams) Facility
In response to the increasing demand for 14 C analysis of samples containing less than 25 μg C, ultra-small graphitization reactors with an internal volume of ∼0.8 mL were developed at NOSAMS. For samples containing 6 to 25 μg C, these reactors convert CO 2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. G…
Improved Precision of Radiocarbon Measurements for CH 4 and CO 2 Using GC and Continuous-Flow AMS Achieved by Summation of Repeated Injections
Compound specific radiocarbon measurements can be made instantaneously using a gas chromatograph (GC) combustion system coupled to a 14 C AMS system fitted with a gas ion source. Samples below 10 μg C can be analyzed but the precision is reduced to 5–10% because of lower source efficiency. We modified our GC for CH 4 and CO 2 analysis and injected samples multiple times to sum data and increase precision. We attained a maximum precision of 0.6% f…
The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean
We report and compare radiocarbon observations made on 2 meridional oceanographic sections along 150°W in the South Pacific in 1991 and 2005. The distributions reflect the progressive penetration of nuclear weapons-produced 14 C into the oceanic thermocline. The changes over the 14 yr between occupations are demonstrably large relative to any possible drift in our analytical standardization. The computed difference field based on the gridded data…
Fire History of a Giant African Baobab Evinced by Radiocarbon Dating
The article reports the first radiocarbon dating of a live African baobab ( Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15–20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are n…
A Continuous-Flow Gas Chromatography 14 C Accelerator Mass Spectrometry System
Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO 2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14 C AMS system fitted with a microwave ion sourc…
Age and Growth Rate Dynamics of an Old African Baobab Determined by Radiocarbon Dating
In 2008, a large African baobab ( Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14 C date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age…
Challenges in Radiocarbon Dating Organic Carbon in Opal-Rich Marine Sediments
We explored the reliability of radiocarbon ages obtained on organic carbon phases in opal-rich Southern Ocean sediments. Paired biogenic carbonate and total organic carbon (TOC) 14 C analyses for three Southern Ocean cores showed that the TOC ages were systematically younger than the carbonate ages. Carbonate ages were consistent with oxygen isotopic and bio-stratigraphy, indicating error in TOC ages that could be explained by 5–24% of modern car…
Reproducibility of Seawater, Inorganic and Organic Carbon 14 C Results at Nosams
The majority of samples processed at the National Ocean Sciences AMS Facility (NOSAMS) thus far were collected as part of the World Ocean Circulation Experiment (WOCE). Due to the long storage time (2–3 yr) required to analyze thousands of samples on the accelerator mass spectrometer (AMS), a test was designed and implemented to determine the effects, if any, of storage time on 14 C concentration. We find no systematic offsets in AMS measurements…
Target Preparation for Continuous Flow Accelerator Mass Spectrometry
For very small samples, it is difficult to prepare graphitic targets that will yield a useful and steady sputtered ion beam. Working with materials separated by preparative capillary gas chromatography, we have succeeded with amounts as small as 20 μg C. This seems to be a practical limit, as it involves 1) multiple chromatographic runs with trapping of effluent fractions, 2) recovery and combustion of the fractions, 3) graphitization and 4) comp…
Microscale AMS 14 C Measurement at Nosams
Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO 2 are reduced to graphite over cobalt catalyst at an optimal temperature of 605°. Measured 14 C…
C AMS Measurements of <100 μG Samples with a High-Current System
The NOSAMS facility at Woods Hole Oceanographic Institution has started to develop and apply techniques for measuring very small samples on a standard Tandetron accelerator mass spectrometry (AMS) system with high-current hemispherical Cs sputter ion sources. Over the past year, results on samples ranging from 7 to 160 μg C showed both the feasibility of such analyses and the present limitations on reducing the size of solid carbon samples. One o…
Report of the Carbon in Oceans Workshop, Sunday 14 August 1994
This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries
Microscale AMS 14 C Measurement at Nosams
Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO 2 are reduced to graphite over cobalt catalyst at an optimal temperature of 605°. Measured 14 C…
Ultra-Small Graphitization Reactors for Ultra-Microscale 14 C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (Nosams) Facility
In response to the increasing demand for 14 C analysis of samples containing less than 25 μg C, ultra-small graphitization reactors with an internal volume of ∼0.8 mL were developed at NOSAMS. For samples containing 6 to 25 μg C, these reactors convert CO 2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. G…
Assessing the Blank Carbon Contribution, Isotope Mass Balance, and Kinetic Isotope Fractionation of the Ramped Pyrolysis/Oxidation Instrument at Nosams
We estimate the blank carbon mass over the course of a typical Ramped PyrOx (RPO) analysis (150–1000°C; 5°C×min –1 ) to be (3.7±0.6) μg C with an Fm value of 0.555±0.042 and a δ 13 C value of (–29.0±0.1) ‰ VPDB. Additionally, we provide equations for RPO Fm and δ 13 C blank corrections, including associated error propagation. By comparing RPO mass-weighted mean and independently measured bulk δ 13 C values for a compilation of environmental sampl…
Dimensions of Radiocarbon Variability within Sedimentary Organic Matter
Organic carbon (OC) radiocarbon ( 14 C) signatures in marine surface sediments are highly variable and the causes of this heterogeneity remain ambiguous. Here, we present results from a detailed 14 C-based investigation of an Arabian Sea sediment, including measurements on organic matter (OM) in bulk sediment, specific grain size fractions, and OC decomposition products from ramped-pyrolysis-oxidation (RPO). Our results show that 14 C ages of OM …
The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean
We report and compare radiocarbon observations made on 2 meridional oceanographic sections along 150°W in the South Pacific in 1991 and 2005. The distributions reflect the progressive penetration of nuclear weapons-produced 14 C into the oceanic thermocline. The changes over the 14 yr between occupations are demonstrably large relative to any possible drift in our analytical standardization. The computed difference field based on the gridded data…
Age and Growth Rate Dynamics of an Old African Baobab Determined by Radiocarbon Dating
In 2008, a large African baobab ( Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14 C date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age…
Global Ocean Radiocarbon Programs
The importance of studying the radiocarbon content of dissolved inorganic carbon (DI 14 C) in the oceans has been recognized for decades. Starting with the GEOSECS program in the 1970s, 14 C sampling has been a part of most global survey programs. Early results were used to study air-sea gas exchange while the more recent results are critical for helping calibrate ocean general circulation models used to study the effects of climate change. Here …
Radiocarbon in Dissolved Organic Carbon by Uv Oxidation
This study describes a procedural blank assessment of the ultraviolet photochemical oxidation (UV oxidation) method that is used to measure carbon isotopes of dissolved organic carbon (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). A retrospective compilation of Fm and δ 13 C results for secondary standards (OX-II, glycine) between 2009 and 2018 indicated that a revised blank correction was required to bring …
Fire History of a Giant African Baobab Evinced by Radiocarbon Dating
The article reports the first radiocarbon dating of a live African baobab ( Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15–20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are n…
C AMS Measurements of <100 μG Samples with a High-Current System
The NOSAMS facility at Woods Hole Oceanographic Institution has started to develop and apply techniques for measuring very small samples on a standard Tandetron accelerator mass spectrometry (AMS) system with high-current hemispherical Cs sputter ion sources. Over the past year, results on samples ranging from 7 to 160 μg C showed both the feasibility of such analyses and the present limitations on reducing the size of solid carbon samples. One o…
Influence of Different Acid Treatments on the Radiocarbon Content Spectrum of Sedimentary Organic Matter Determined by RPO/Accelerator Mass Spectrometry
In practice, obtaining radiocarbon ( 14 C) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting 14 C content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on 14 C content of sedimentary OM, we examine the variability …
Challenges in Radiocarbon Dating Organic Carbon in Opal-Rich Marine Sediments
We explored the reliability of radiocarbon ages obtained on organic carbon phases in opal-rich Southern Ocean sediments. Paired biogenic carbonate and total organic carbon (TOC) 14 C analyses for three Southern Ocean cores showed that the TOC ages were systematically younger than the carbonate ages. Carbonate ages were consistent with oxygen isotopic and bio-stratigraphy, indicating error in TOC ages that could be explained by 5–24% of modern car…
Radiocarbon in the Marine Environment
Understanding carbon cycling in the ocean is critical for understanding past ocean dynamics, local impacts of environmental changes, and predicting future changes due to climate change. Radiocarbon plays an important role in deciphering the carbon puzzle and, here, we highlight some of the contributions this isotope has made to oceanography. The field is enormous and distilling it to three short papers was a challenge; we chose to focus on three …
Improved Precision of Radiocarbon Measurements for CH 4 and CO 2 Using GC and Continuous-Flow AMS Achieved by Summation of Repeated Injections
Compound specific radiocarbon measurements can be made instantaneously using a gas chromatograph (GC) combustion system coupled to a 14 C AMS system fitted with a gas ion source. Samples below 10 μg C can be analyzed but the precision is reduced to 5–10% because of lower source efficiency. We modified our GC for CH 4 and CO 2 analysis and injected samples multiple times to sum data and increase precision. We attained a maximum precision of 0.6% f…
A Continuous-Flow Gas Chromatography 14 C Accelerator Mass Spectrometry System
Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO 2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14 C AMS system fitted with a microwave ion sourc…
Reproducibility of Seawater, Inorganic and Organic Carbon 14 C Results at Nosams
The majority of samples processed at the National Ocean Sciences AMS Facility (NOSAMS) thus far were collected as part of the World Ocean Circulation Experiment (WOCE). Due to the long storage time (2–3 yr) required to analyze thousands of samples on the accelerator mass spectrometer (AMS), a test was designed and implemented to determine the effects, if any, of storage time on 14 C concentration. We find no systematic offsets in AMS measurements…
Target Preparation for Continuous Flow Accelerator Mass Spectrometry
For very small samples, it is difficult to prepare graphitic targets that will yield a useful and steady sputtered ion beam. Working with materials separated by preparative capillary gas chromatography, we have succeeded with amounts as small as 20 μg C. This seems to be a practical limit, as it involves 1) multiple chromatographic runs with trapping of effluent fractions, 2) recovery and combustion of the fractions, 3) graphitization and 4) comp…
Report of the Carbon in Oceans Workshop, Sunday 14 August 1994
This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries
Reproducibility of Seawater, Inorganic and Organic Carbon 14 C Results at Nosams
The majority of samples processed at the National Ocean Sciences AMS Facility (NOSAMS) thus far were collected as part of the World Ocean Circulation Experiment (WOCE). Due to the long storage time (2–3 yr) required to analyze thousands of samples on the accelerator mass spectrometer (AMS), a test was designed and implemented to determine the effects, if any, of storage time on 14 C concentration. We find no systematic offsets in AMS measurements…
Target Preparation for Continuous Flow Accelerator Mass Spectrometry
For very small samples, it is difficult to prepare graphitic targets that will yield a useful and steady sputtered ion beam. Working with materials separated by preparative capillary gas chromatography, we have succeeded with amounts as small as 20 μg C. This seems to be a practical limit, as it involves 1) multiple chromatographic runs with trapping of effluent fractions, 2) recovery and combustion of the fractions, 3) graphitization and 4) comp…
Microscale AMS 14 C Measurement at Nosams
Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO 2 are reduced to graphite over cobalt catalyst at an optimal temperature of 605°. Measured 14 C…
C AMS Measurements of <100 μG Samples with a High-Current System
The NOSAMS facility at Woods Hole Oceanographic Institution has started to develop and apply techniques for measuring very small samples on a standard Tandetron accelerator mass spectrometry (AMS) system with high-current hemispherical Cs sputter ion sources. Over the past year, results on samples ranging from 7 to 160 μg C showed both the feasibility of such analyses and the present limitations on reducing the size of solid carbon samples. One o…
Challenges in Radiocarbon Dating Organic Carbon in Opal-Rich Marine Sediments
We explored the reliability of radiocarbon ages obtained on organic carbon phases in opal-rich Southern Ocean sediments. Paired biogenic carbonate and total organic carbon (TOC) 14 C analyses for three Southern Ocean cores showed that the TOC ages were systematically younger than the carbonate ages. Carbonate ages were consistent with oxygen isotopic and bio-stratigraphy, indicating error in TOC ages that could be explained by 5–24% of modern car…
The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean
We report and compare radiocarbon observations made on 2 meridional oceanographic sections along 150°W in the South Pacific in 1991 and 2005. The distributions reflect the progressive penetration of nuclear weapons-produced 14 C into the oceanic thermocline. The changes over the 14 yr between occupations are demonstrably large relative to any possible drift in our analytical standardization. The computed difference field based on the gridded data…
Fire History of a Giant African Baobab Evinced by Radiocarbon Dating
The article reports the first radiocarbon dating of a live African baobab ( Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15–20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are n…
A Continuous-Flow Gas Chromatography 14 C Accelerator Mass Spectrometry System
Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO 2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14 C AMS system fitted with a microwave ion sourc…
Age and Growth Rate Dynamics of an Old African Baobab Determined by Radiocarbon Dating
In 2008, a large African baobab ( Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14 C date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age…
Improved Precision of Radiocarbon Measurements for CH 4 and CO 2 Using GC and Continuous-Flow AMS Achieved by Summation of Repeated Injections
Compound specific radiocarbon measurements can be made instantaneously using a gas chromatograph (GC) combustion system coupled to a 14 C AMS system fitted with a gas ion source. Samples below 10 μg C can be analyzed but the precision is reduced to 5–10% because of lower source efficiency. We modified our GC for CH 4 and CO 2 analysis and injected samples multiple times to sum data and increase precision. We attained a maximum precision of 0.6% f…
Ultra-Small Graphitization Reactors for Ultra-Microscale 14 C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (Nosams) Facility
In response to the increasing demand for 14 C analysis of samples containing less than 25 μg C, ultra-small graphitization reactors with an internal volume of ∼0.8 mL were developed at NOSAMS. For samples containing 6 to 25 μg C, these reactors convert CO 2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. G…
Assessing the Blank Carbon Contribution, Isotope Mass Balance, and Kinetic Isotope Fractionation of the Ramped Pyrolysis/Oxidation Instrument at Nosams
We estimate the blank carbon mass over the course of a typical Ramped PyrOx (RPO) analysis (150–1000°C; 5°C×min –1 ) to be (3.7±0.6) μg C with an Fm value of 0.555±0.042 and a δ 13 C value of (–29.0±0.1) ‰ VPDB. Additionally, we provide equations for RPO Fm and δ 13 C blank corrections, including associated error propagation. By comparing RPO mass-weighted mean and independently measured bulk δ 13 C values for a compilation of environmental sampl…
Dimensions of Radiocarbon Variability within Sedimentary Organic Matter
Organic carbon (OC) radiocarbon ( 14 C) signatures in marine surface sediments are highly variable and the causes of this heterogeneity remain ambiguous. Here, we present results from a detailed 14 C-based investigation of an Arabian Sea sediment, including measurements on organic matter (OM) in bulk sediment, specific grain size fractions, and OC decomposition products from ramped-pyrolysis-oxidation (RPO). Our results show that 14 C ages of OM …
Influence of Different Acid Treatments on the Radiocarbon Content Spectrum of Sedimentary Organic Matter Determined by RPO/Accelerator Mass Spectrometry
In practice, obtaining radiocarbon ( 14 C) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting 14 C content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on 14 C content of sedimentary OM, we examine the variability …
Radiocarbon in Dissolved Organic Carbon by Uv Oxidation
This study describes a procedural blank assessment of the ultraviolet photochemical oxidation (UV oxidation) method that is used to measure carbon isotopes of dissolved organic carbon (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). A retrospective compilation of Fm and δ 13 C results for secondary standards (OX-II, glycine) between 2009 and 2018 indicated that a revised blank correction was required to bring …
Radiocarbon in the Marine Environment
Understanding carbon cycling in the ocean is critical for understanding past ocean dynamics, local impacts of environmental changes, and predicting future changes due to climate change. Radiocarbon plays an important role in deciphering the carbon puzzle and, here, we highlight some of the contributions this isotope has made to oceanography. The field is enormous and distilling it to three short papers was a challenge; we chose to focus on three …
Global Ocean Radiocarbon Programs
The importance of studying the radiocarbon content of dissolved inorganic carbon (DI 14 C) in the oceans has been recognized for decades. Starting with the GEOSECS program in the 1970s, 14 C sampling has been a part of most global survey programs. Early results were used to study air-sea gas exchange while the more recent results are critical for helping calibrate ocean general circulation models used to study the effects of climate change. Here …
Marine Organic Carbon and Radiocarbon—present and Future Challenges
We discuss present and developing techniques for studying radiocarbon in marine organic carbon (C). Bulk DOC (dissolved organic C) Δ 14 C measurements reveal information about the cycling time and sources of DOC in the ocean, yet they are time consuming and need to be streamlined. To further elucidate the cycling of DOC, various fractions have been separated from bulk DOC, through solid phase extraction of DOC, and ultrafiltration of high and low…
Chemistry (15 works) · Geology (14 works) · Accelerator mass spectrometry (13 works) · Isotope Analysis in Ecology (13 works) · Radiocarbon dating (12 works) · Chromatography (11 works) · Environmental Chemistry (10 works) · Geology and Paleoclimatology Research (10 works) · Mass spectrometry (9 works) · Carbon fibers (8 works)