Biogeochemistry and the Carbon Reservoir

2009 ◽  
pp. 439-483 ◽  
Author(s):  
Meixun Zhao ◽  
Pinxian Wang ◽  
Jun Tian ◽  
Jianru Li
Keyword(s):  
Carbon Reservoir

scholarly journals Implications of changing from grazed or semi-natural vegetation to forestry for carbon stores and fluxes in upland organo-mineral soils in the UK

2007 ◽  
Vol 11 (1) ◽  
pp. 61-76 ◽  
Author(s):  
B. Reynolds
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Best Practice ◽  
Agricultural Soils ◽  
Relative Magnitude ◽  
International Studies ◽  
Best Practice Guidelines ◽  
Carbon Reservoir ◽  
Mineral Soils ◽  
The Uk

Abstract. In the UK, as organo-mineral soils are a significant store of soil organic carbon (SOC), they may become increasingly favoured for the expansion of upland forestry. It is important, therefore, to assess the likely impacts on SOC of this potentially major land use change. Currently, these assessments rely on modelling approaches which assume that afforestation of organo-mineral soils is "carbon neutral". This review evaluates this assumption in two ways. Firstly, UK information from the direct measurement of SOC change following afforestation is examined in the context of international studies. Secondly, UK data on the magnitude and direction of the major fluxes in the carbon cycle of semi-natural upland ecosystems are assessed to identify the likely responses of the fluxes to afforestation of organo-mineral soils. There are few directly relevant measurements of SOC change following afforestation of organo-mineral soils in the UK uplands but there are related studies on peat lands and agricultural soils. Overall, information on the magnitude and direction of change in SOC with afforestation is inconclusive. Data on the accumulation of litter beneath conifer stands have been identified but the extent to which the carbon held in this pool is incorporated into the stable soil carbon reservoir is uncertain. The effect of afforestation on most carbon fluxes is small because the fluxes are either relatively minor or of the same magnitude and direction irrespective of land use. Compared with undisturbed moorland, particulate organic carbon losses increase throughout the forest cycle but the data are exclusively from plantation conifer forests and in many cases pre-date current industry best practice guidelines which aim to reduce such losses. The biggest uncertainty in flux estimates is the relative magnitude of the sink for atmospheric carbon as trees grow and mature compared with that lost during site preparation and harvesting. Given the size of this flux relative to many of the others, this should be a focus for future carbon research on these systems.

Links between atmospheric carbon dioxide, the land carbon reservoir and climate over the past millennium

2015 ◽  
Vol 8 (5) ◽  
pp. 383-387 ◽  
Author(s):  
Thomas K. Bauska ◽  
Fortunat Joos ◽  
Alan C. Mix ◽  
Raphael Roth ◽  
Jinho Ahn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
The Past ◽  
Carbon Reservoir ◽  
Atmospheric Carbon ◽  
Past Millennium

scholarly journals Lena River Delta formation during the Holocene

2014 ◽  
Vol 11 (3) ◽  
pp. 4085-4122 ◽  
Author(s):  
D. Bolshiyanov ◽  
A. Makarov ◽  
L. Savelieva
Keyword(s):  
Sea Water ◽  
River Delta ◽  
The Arctic ◽  
Laptev Sea ◽  
Lena River ◽  
Sea Levels ◽  
Marine Terraces ◽  
Delta Formation ◽  
Carbon Reservoir ◽  
Lena River Delta

Abstract. The Lena River Delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of Delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging, but accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River Delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8–6 Ka, 4.5–4 Ka, 2.5–1.5 Ka, 0.4–0.2 Ka) and decreasing (5 Ka, 3 Ka, 0.5 Ka) Laptev Sea levels to be distinguished in the Lena Delta area.

scholarly journals Carbon Stock Variation along altitudinal gradient of Wacho Forest in Hawa Galan District, Kellem Wollega Zone, Oromia Region, Ethiopia

2020 ◽  
Author(s):  
Gezahegn Gashu ◽  
Gebre Gidey ◽  
Sime Deressa ◽  
Zame Fekansa ◽  
Halid Awoke
Keyword(s):  
Forest Ecosystem ◽  
Carbon Stock ◽  
Terrestrial Ecosystem ◽  
The Third ◽  
Natural Break ◽  
Below Ground ◽  
Carbon Reservoir ◽  
Potential Strategy ◽  
Atmospheric Concentrations ◽  
Global Carbon

Abstract Background Forest ecosystem plays a crucial role in the global carbon cycle; as such, mitigating high atmospheric concentrations of carbon dioxide and other greenhouse gases by naturally taking carbon from the atmosphere through photosynthesis. Verification and accounting of carbon stock in forest ecosystem have been renowned as a potential strategy to reduce and stabilize atmospheric concentrations of greenhouse gas. Forest sequesters and store more carbon than any other terrestrial ecosystem and it is an important natural break on climate change. It acts as a carbon reservoir by storing large amount of carbon in trees, undergrowth vegetation, forest floor and soil. Result The mean carbon stock of each carbon pool was changed along altitudinal class of the study area. The largest mean above and below ground carbon stock was found in the second altitudinal class(1560.01-1643m) followed by first altitudinal class(1435-1560m) and the third altitudinal class (1643.01-1704m) of the study area. The largest mean dead tree and dead wood carbon stock was also stored in the first altitudinal class followed by the third and the second altitudinal class of the study area. The largest mean litter carbon stock was found in the first altitudinal class followed by the second and the third altitudinal class of the study area. The largest mean soil organic carbon was found in the third altitudinal class followed by the second and the first altitudinal class of the study area. Conclusions The carbon stock variation along altitudinal gradients indicated that, altitude had no a statistically significant effect on any of the carbon pools except litter carbon of the study area at 95% of confidence interval.

scholarly journals Spatial distribution and sources of organic carbon in the surface sediment of the Bosten Lake, China

2015 ◽  
Vol 12 (16) ◽  
pp. 13793-13817 ◽  
Author(s):  
Z. T. Yu ◽  
X. J. Wang ◽  
E. L. Zhang ◽  
C. Y. Zhao ◽  
H. Y. Lan
Keyword(s):  
Spatial Distribution ◽  
Organic Carbon ◽  
Energy Levels ◽  
Carbon Isotopic Composition ◽  
Bosten Lake ◽  
Carbon Isotopic ◽  
Complex Processes ◽  
High Kinetic Energy ◽  
Carbon Reservoir ◽  
Kaidu River

Abstract. Lake sediment is an important carbon reservoir. However, little is known on the dynamics and sources of sediment organic carbon in the Bosten Lake. We collected 13 surface (0–2 cm) sediment samples in the Bosten Lake and analyzed total organic carbon (TOC), total nitrogen (TN), stable carbon isotopic composition in TOC (δ13Corg) and grain size. We found a large spatial variability in TOC content (1.8–4.4 %) and δ13Corg value (−26.77 to −23.98 ‰). Using a three end member mixing model with measured TOC : TN ratio and δ13Corg, we estimated that 54–90 % of TOC was from autochthonous sources. Higher TOC content (> 3.7 %) was found in the east and central-north sections and near the mouth of the Kaidu River, which was attributable to allochthonous, autochthonous plus allochthonous, and autochthonous sources, respectively. The lowest TOC content was found in the mid-west section, which might be a result of high kinetic energy levels. Our study indicated that the spatial distribution of sediment TOC in the Bosten Lake was influenced by multiple and complex processes.

scholarly journals Glacial – interglacial atmospheric CO<sub>2</sub> change: a simple "hypsometric effect" on deep-ocean carbon sequestration?

2006 ◽  
Vol 2 (5) ◽  
pp. 711-743 ◽  
Author(s):  
L. C. Skinner
Keyword(s):  
Carbon Sequestration ◽  
Carbon Storage ◽  
Ocean Circulation ◽  
Deep Water ◽  
Deep Sea ◽  
Storage Capacity ◽  
Deep Ocean ◽  
Contributing Factors ◽  
Carbon Reservoir ◽  
Ocean Carbon

Abstract. Given the magnitude and dynamism of the deep marine carbon reservoir, it is almost certain that past glacial – interglacial fluctuations in atmospheric CO2 have relied at least in part on changes in the carbon storage capacity of the deep sea. To date, physical ocean circulation mechanisms that have been proposed as viable explanations for glacial – interglacial CO2 change have focussed almost exclusively on dynamical or kinetic processes. Here, a simple mechanism is proposed for increasing the carbon storage capacity of the deep sea that operates via changes in the volume of southern-sourced deep-water filling the ocean basins, as dictated by the hypsometry of the ocean floor. It is proposed that a water-mass that occupies more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. Hence by filling this interval with southern-sourced deep-water (enriched in dissolved CO2 due to its particular mode of formation) the amount of carbon sequestered in the deep sea may be greatly increased. A simple box-model is used to test this hypothesis, and to investigate its implications. It is suggested that up to 70% of the observed glacial – interglacial CO2 change might be explained by the replacement of northern-sourced deep-water below 2.5 km water depth by its southern counterpart. Most importantly, it is found that an increase in the volume of southern-sourced deep-water allows glacial CO2 levels to be simulated easily with only modest changes in Southern Ocean biological export or overturning. If incorporated into the list of contributing factors to marine carbon sequestration, this mechanism may help to significantly reduce the "deficit" of explained glacial – interglacial CO2 change.

scholarly journals Paleocene/Eocene carbon feedbacks triggered by volcanic activity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sev Kender ◽  
Kara Bogus ◽  
Gunver K. Pedersen ◽  
Karen Dybkjær ◽  
Tamsin A. Mather ◽  
...  
Keyword(s):  
North Atlantic ◽  
Proxy Records ◽  
The North ◽  
The Earth ◽  
Thermal Maximum ◽  
Igneous Province ◽  
Carbon Release ◽  
Carbon Reservoir ◽  
Earth’S Climate ◽  
North Atlantic Igneous Province

AbstractThe Paleocene–Eocene Thermal Maximum (PETM) was a period of geologically-rapid carbon release and global warming ~56 million years ago. Although modelling, outcrop and proxy records suggest volcanic carbon release occurred, it has not yet been possible to identify the PETM trigger, or if multiple reservoirs of carbon were involved. Here we report elevated levels of mercury relative to organic carbon—a proxy for volcanism—directly preceding and within the early PETM from two North Sea sedimentary cores, signifying pulsed volcanism from the North Atlantic Igneous Province likely provided the trigger and subsequently sustained elevated CO2. However, the PETM onset coincides with a mercury low, suggesting at least one other carbon reservoir released significant greenhouse gases in response to initial warming. Our results support the existence of ‘tipping points’ in the Earth system, which can trigger release of additional carbon reservoirs and drive Earth’s climate into a hotter state.

scholarly journals Ecosystem-Wide Impacts of Deforestation in Mangroves: The Urabá Gulf (Colombian Caribbean) Case Study

ISRN Ecology ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
J. F. Blanco ◽  
E. A. Estrada ◽  
L. F. Ortiz ◽  
L. E. Urrego
Keyword(s):  
Interdisciplinary Approach ◽  
Benthic Fauna ◽  
Current Data ◽  
Selective Logging ◽  
Avicennia Germinans ◽  
Eastern Coast ◽  
Importance Value ◽  
Southern Caribbean ◽  
Carbon Reservoir

Mangroves are ecologically important and extensive in the Neotropics, but they are visibly threatened by selective logging and conversion to pastures in the Southern Caribbean. The objective of this paper was to summarize the impacts of both threats on forest structure, species composition, aboveground biomass and carbon reservoir, species introgressions, and benthic fauna populations by collating past and current data and by using an interdisciplinary approach in the Urabá Gulf (Colombia) as a case study. Mangroves in the Eastern Coast have been decimated and have produced unskewed tree-diameter (DBH) distributions due to the overexploitation of Rhizophora mangle for poles (DBH range: 7–17 cm) and of Avicennia germinans for planks and pilings (DBH >40 cm). Selective logging increased the importance value of the light-tolerant white mangrove Laguncularia racemosa, also increasing biomass and carbon storage in this species, thus offsetting reductions in other species. Introgressions (cryptic ecological degradation) by L. racemosa and Acrostichum aureum (mangrove fern) and low densities of otherwise dominant detritivore snails (Neritina virginea) were observed in periurban basin mangroves. Finally, basin mangroves were more threatened than fringing mangroves due to their proximity to expanding pastures, villages, and a coastal city.

A major ‘plateau’ in the radiocarbon time-scale at c. 9650 b.p.: the evidence from Star Carr (North Yorkshire)

Antiquity ◽  
1990 ◽  
Vol 64 (245) ◽  
pp. 836-841 ◽  
Author(s):  
Paul Mellars
Keyword(s):  
Iron Age ◽  
Time Scale ◽  
Upper Atmosphere ◽  
Detectable Change ◽  
Radiocarbon Dates ◽  
Fossil Carbon ◽  
The Past ◽  
Calibration Curves ◽  
Carbon Reservoir ◽  
Radiocarbon Calibration

Over the past 10-20 years archaeologists have become familiar with the problems of potential ‘aberrations’ in the radiocarbon time-scale, arising from factors such as the varying rates of production of I4C in the upper atmosphere, or from the delayed cycling of ‘fossil’ carbon in the overall carbon reservoir. In some cases these aberrations can lead to dramatic ‘wiggles’ in the radiocarbon calibration curves, while in other cases (as, for example, during the Iron Age, around 700 BC) they can lead to substantial ‘plateaux’ during which measured radiocarbon dates show no detectable change over periods of several centuries (Pearson &amp; Stuiver 1986; Stuiver &amp; Pearson 1986).

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