scholarly journals HESSEL DE VRIES: RADIOCARBON PIONEER FROM GRONINGEN

Radiocarbon ◽  
2021 ◽  
pp. 1-15
Author(s):  
Pieter M Grootes ◽  
Hans van der Plicht
Keyword(s):  
Detection Limit ◽  
Tree Rings ◽  
Time Scale ◽  
Global Carbon Cycle ◽  
Close Collaboration ◽  
Climate Fluctuations ◽  
Basic Assumptions ◽  
De Vries ◽  
Natural Variations ◽  
Global Carbon

ABSTRACT Hessel de Vries contributed to radiocarbon (14C) dating for only one short decade. Yet, his development of proportional CO2 counting greatly facilitated 14C measurements, improved their reproducibility, and lowered both the amount of carbon needed for a measurement and the 14C detection limit by at least a factor ten. Validating Libby’s 14C method by checking its basic assumptions with improved sensitivity, de Vries documented relatively minor violations. Natural variations in atmospheric 14C concentrations, found in tree rings, marked the start of 14C tree-ring calibration. Variable differences in 14C concentration between the atmosphere and aquatic reservoirs revealed reservoir ages, leading to further studies. De Vries applied analogue modeling to gain a better understanding of the influence of cosmogenic 14C production and the global carbon cycle, inclusive CO2 exchange across the air-water boundary, on atmospheric 14C concentrations. In close collaboration with colleagues in archaeology and geology, de Vries documented climate fluctuations and archaeological developments over the last 50,000+ years and placed them on a common 14C time scale.

scholarly journals Subtle 14C Signals: The Influence of Atmospheric Mixing, Growing Season and In-Situ Production

Radiocarbon ◽  
1992 ◽  
Vol 34 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Pieter M. Grootes
Keyword(s):  
Tree Rings ◽  
Organic Material ◽  
Dynamic Models ◽  
Growing Season ◽  
Global Carbon Cycle ◽  
Small Samples ◽  
Ams Dating ◽  
Global Carbon ◽  
In Situ Production

Atmospheric 14C concentrations vary with time and latitude. These variations, measured directly on atmospheric samples, or in independently-dated organic material such as tree rings, supply data essential for the calibration of dynamic models of the global carbon cycle. Short variations in the production rate of atmospheric 14C are strongly attenuated in the relatively large atmospheric CO2 reservoir. In-situ production of 14C should be negligible for ages up to 80 ka bp. Background problems in AMS dating are more likely attributable to contamination of very small samples.

Are response function representations of the global carbon cycle ever interpretable?

Tellus B ◽  
2009 ◽  
Vol 61 (2) ◽  
Author(s):  
Sile Li ◽  
Andrew J. Jarvis ◽  
David T. Leedal
Keyword(s):  
Carbon Cycle ◽  
Response Function ◽  
Global Carbon Cycle ◽  
Global Carbon

The morphology of experimentally produced charcoal distinguishes fuel types in the Arctic tundra

The Holocene ◽  
2020 ◽  
Vol 30 (7) ◽  
pp. 1091-1096 ◽  
Author(s):  
Eleanor MB Pereboom ◽  
Richard S Vachula ◽  
Yongsong Huang ◽  
James Russell
Keyword(s):  
Arctic Tundra ◽  
Global Carbon Cycle ◽  
Fire Frequency ◽  
The Arctic ◽  
Fuel Type ◽  
The Past ◽  
Primary Means ◽  
Forested Ecosystems ◽  
Global Carbon ◽  
Tundra Ecosystems

Wildfires in the Arctic tundra have become increasingly frequent in recent years and have important implications for tundra ecosystems and for the global carbon cycle. Lake sediment–based records are the primary means of understanding the climatic influences on tundra fires. Sedimentary charcoal has been used to infer climate-driven changes in tundra fire frequency but thus far cannot differentiate characteristics of the vegetation burnt during fire events. In forested ecosystems, charcoal morphologies have been used to distinguish changes in fuel type consumed by wildfires of the past; however, no such approach has been developed for tundra ecosystems. We show experimentally that charcoal morphologies can be used to differentiate graminoid (mean = 6.77; standard deviation (SD) = 0.23) and shrub (mean = 2.42; SD = 1.86) biomass burnt in tundra fire records. This study is a first step needed to construct more nuanced tundra wildfire histories and to understand how wildfire will impact the region as vegetation and fire change in the future.

EPR-derived structures of flavin radical and iron-sulfur clusters from Methylosinus sporium 5 reductase

2021 ◽  
Author(s):  
Han Sol Jeong ◽  
Sugyeong Hong ◽  
Hee Seon Yoo ◽  
Jin Kim ◽  
Yujeong Kim ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Crucial Role ◽  
Methane Monooxygenase ◽  
Global Carbon Cycle ◽  
Ambient Conditions ◽  
Iron Sulfur Clusters ◽  
Iron Sulfur ◽  
Greenhouse Effects ◽  
Global Carbon ◽  
Significant Attention

Methane monooxygenase (MMO) has attracted significant attention owing to its crucial role in the global carbon cycle; it impedes greenhouse effects by converting methane to methanol under ambient conditions. The...

scholarly journals Amazonian Fire Events Disturbed the Global Carbon Cycle: A Study from 2019 Amazon Wildfire Using Google Earth Engine

2020 ◽  
Vol 3 (1) ◽  
pp. 43
Author(s):  
Subhajit Bandopadhyay ◽  
Dany A. Cotrina Sánchez
Keyword(s):  
Carbon Cycle ◽  
Carbon Sink ◽  
Brazilian Amazon ◽  
Global Carbon Cycle ◽  
Forest Productivity ◽  
Google Earth ◽  
Comparative Approach ◽  
Burned Area ◽  
Google Earth Engine ◽  
Global Carbon

An unprecedented number of wildfire events during 2019 throughout the Brazilian Amazon caught global attention, due to their massive extent and the associated loss in the Amazonian forest—an ecosystem on which the whole world depends. Such devastating wildfires in the Amazon has strongly hampered the global carbon cycle and significantly reduced forest productivity. In this study, we have quantified such loss of forest productivity in terms of gross primary productivity (GPP), applying a comparative approach using Google Earth Engine. A total of 12 wildfire spots have been identified based on the fire’s extension over the Brazilian Amazon, and we quantified the loss in productivity between 2018 and 2019. The Moderate Resolution Imaging Spectroradiometer (MODIS) GPP and MODIS burned area satellite imageries, with a revisit time of 8 days and 30 days, respectively, have been used for this study. We have observed that compared to 2018, the number of wildfire events increased during 2019. But such wildfire events did not hamper the natural annual trend of GPP of the Amazonian ecosystem. However, a significant drop in forest productivity in terms of GPP has been observed. Among all 11 observational sites were recorded with GPP loss, ranging from −18.88 gC m−2 yr−1 to −120.11 gC m−2 yr−1, except site number 3. Such drastic loss in GPP indicates that during 2019 fire events, all of these sites acted as carbon sources rather than carbon sink sites, which may hamper the global carbon cycle and terrestrial CO2 fluxes. Therefore, it is assumed that these findings will also fit for the other Amazonian wildfire sites, as well as for the tropical forest ecosystem as a whole. We hope this study will provide a significant contribution to global carbon cycle research, terrestrial ecosystem studies, sustainable forest management, and climate change in contemporary environmental sciences.

Distribution of radiocarbon as a test of global carbon cycle models

1995 ◽  
Vol 9 (1) ◽  
pp. 153-166 ◽  
Author(s):  
Atul K. Jain ◽  
Haroon S. Kheshgi ◽  
Martin I. Hoffert ◽  
Donald J. Wuebbles
Keyword(s):  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Global Carbon

scholarly journals The changing global carbon cycle: linking plant-soil carbon dynamics to global consequences

2009 ◽  
Vol 97 (5) ◽  
pp. 840-850 ◽  
Author(s):  
F. Stuart Chapin III ◽  
Jack McFarland ◽  
A. David McGuire ◽  
Eugenie S. Euskirchen ◽  
Roger W. Ruess ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Soil Carbon ◽  
Carbon Dynamics ◽  
Global Carbon Cycle ◽  
Soil Carbon Dynamics ◽  
Plant Soil ◽  
Global Carbon
Sign in / Sign up

Export Citation Format

Share Document