scholarly journals Oceanic Changes Correlate with Methane Seepage

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Hannah Thomasy
Keyword(s):  
Organic Carbon ◽  
Sea Level ◽  
The Past ◽  
Methane Seepage ◽  
Carbon Burial ◽  
Organic Carbon Burial

Changes in sea level and organic carbon burial may have affected seafloor methane seepage over the past 150 million years.

A record of seafloor methane seepage across the last 150 million years

2020 ◽  
Author(s):  
Davide Oppo ◽  
Luca De Siena ◽  
David Kemp
Keyword(s):  
Organic Carbon ◽  
Sea Level ◽  
Methane Emission ◽  
Temporal Correlation ◽  
Biogenic Methane ◽  
Methane Seepage ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Rapid Generation ◽  
Extinction Events

<p>Methane seepage at the seafloor is a source of carbon in the marine environment and has long been recognized as an important window into the deep geo-, hydro-, and bio-spheres. However, the processes and temporal patterns of natural methane emission over multi-million-year time scales are still poorly understood. The microbially-mediated methane oxidation leads to the precipitation of authigenic carbonate minerals within subseafloor sediments, thus providing a potentially extensive record of past methane emission. In this study, we used data on methane-derived authigenic carbonates to build a proxy time series of seafloor methane emission over the last 150 My. We quantitatively demonstrate that variations in sea level and organic carbon burial are the dominant controls on methane leakage since the Early Cretaceous. Sea level controls variations of methane seepage by imposing smooth trends with cyclicities in the order of tens of My. Organic carbon burial shows the same cyclicities and instantaneously controls the volumes of methane released thanks to the rapid generation of biogenic methane. The identified fundamental (26-27 My) cyclicity matches those observed in the carbon cycle associated with plate tectonic processes, the atmospheric CO<sub>2</sub>, the oceanic anoxic events, and mass extinction events. A higher (12 My) cyclicity relates to modulations of Milankovitch eccentricity cycles and to variations in global tectonics. These analogies demonstrate that the seafloor methane seepage across the last 150 My relates to a large spectrum of global phenomena and thus has key implications for a better understanding of methane cycling at the present day. Temporal correlation analysis supports the evidence that the modern expansion of hypoxic areas and its effect on organic carbon burial may lead to higher seawater methane concentrations over the coming centuries.</p>

Organic carbon burial in Chinese lakes over the past 150 years

2017 ◽  
Vol 438 ◽  
pp. 94-103 ◽  
Author(s):  
Fengju Zhang ◽  
Shuchun Yao ◽  
Bin Xue ◽  
Xixi Lu ◽  
Zhifan Gui
Keyword(s):  
Organic Carbon ◽  
The Past ◽  
Carbon Burial ◽  
Organic Carbon Burial

What Controls Atmospheric Oxygen Concentrations?

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Black Sea ◽  
Atmospheric Oxygen ◽  
Fundamental Question ◽  
The Black Sea ◽  
Microbial Process ◽  
The Past ◽  
Carbon Burial ◽  
Organic Carbon Burial

This chapter deals with the fundamental question of why there is oxygen in the atmosphere at all. It seeks to identify the main processes controlling the oxygen concentration. Plants and cyanobacteria produce the oxygen, but it accumulates only because some of the original photosynthetically produced organic matter is buried and preserved in sediments. Another oxygen source is an anaerobic microbial process called sulfate reduction that respires organic matter using sulfate and produces sulfide. This process is quite common in nature but are most prominent in relatively isolated basins like the Black Sea, and in most marine sediments at depths where oxygen has been consumed by respiration. If there is iron around, the sulfide reacts with the iron, forming a mineral called pyrite. While organic carbon burial has been the main oxygen source to the atmosphere over the past several hundred million years, for some intervals further back in time, pyrite burial may well have dominated as an oxygen source.

scholarly journals Spatio-temporal patterns of organic carbon burial in the sediment of Lake Erhai in China during the past 100 years

2019 ◽  
Vol 31 (1) ◽  
pp. 282-292
Author(s):  
LIU Huiji ◽  
◽  
LIU Enfeng ◽  
YU Zhenzhen ◽  
ZHANG Enlou ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Temporal Patterns ◽  
The Past ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Lake Erhai ◽  
Spatio Temporal

scholarly journals Sediment Organic Carbon Sequestration of Balkhash Lake in Central Asia

2021 ◽  
Vol 13 (17) ◽  
pp. 9958
Author(s):  
Wen Liu ◽  
Long Ma ◽  
Jilili Abuduwaili ◽  
Gulnura Issanova ◽  
Galymzhan Saparov
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
The Past ◽  
Burial Rate ◽  
Carbon Burial ◽  
Sediment Organic Carbon ◽  
Organic Carbon Burial ◽  
Organic Carbon Burial Rate ◽  
Organic Carbon Sequestration ◽  
Global Carbon

As an important part of the global carbon pool, lake carbon is of great significance in the global carbon cycle. Based on a study of the sedimentary proxies of Balkhash Lake, Central Asia’s largest lake, changes in the organic carbon sequestration in the lake sediments and their possible influence over the past 150 years were studied. The results suggested that the organic carbon in the sediments of Lake Balkhash comes mainly from aquatic plants. The organic carbon burial rate fluctuated from 8.16 to 30.04 g·m−2·a−1 and the minimum appeared at the top of the core. The organic carbon burial rate continues to decline as it has over the past 150 years. Global warming, higher hydrodynamic force, and low terrestrial input have not been conducive to the improvement of organic carbon sequestration in Balkhash Lake; the construction of a large reservoir had a greater impact on the sedimentary proxy of total organic carbon content, which could lead to a large deviation for environmental reconstruction. This is the first study to assess the sediment organic carbon sequestration using the modern sediments of Central Asia’s largest lake, which is of great scientific significance. The results contribute to an understanding of organic carbon sequestration in Central Asia and may provide a scientific basis for carbon balance assessment in regional and global scales.

scholarly journals A diurnal carbon engine explains 13C-enriched carbonates without increasing the global production of oxygen

2019 ◽  
Vol 116 (49) ◽  
pp. 24433-24439 ◽  
Author(s):  
Emily C. Geyman ◽  
Adam C. Maloof
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Shallow Water ◽  
Dissolved Inorganic Carbon ◽  
The Past ◽  
Carbon Isotopic ◽  
Oxygen Paradox ◽  
Carbon Burial ◽  
Continental Shelves ◽  
Organic Carbon Burial

In the past 3 billion years, significant volumes of carbonate with high carbon-isotopic (δ13C) values accumulated on shallow continental shelves. These deposits frequently are interpreted as records of elevated global organic carbon burial. However, through the stoichiometry of primary production, organic carbon burial releases a proportional amount of O2, predicting unrealistic rises in atmospheric pO2 during the 1 to 100 million year-long positive δ13C excursions that punctuate the geological record. This carbon–oxygen paradox assumes that the δ13C of shallow water carbonates reflects the δ13C of global seawater-dissolved inorganic carbon (DIC). However, the δ13C of modern shallow-water carbonate sediment is higher than expected for calcite or aragonite precipitating from seawater. We explain elevated δ13C in shallow carbonates with a diurnal carbon cycle engine, where daily transfer of carbon between organic and inorganic reservoirs forces coupled changes in carbonate saturation (ΩA) and δ13C of DIC. This engine maintains a carbon-cycle hysteresis that is most amplified in shallow, sluggishly mixed waters with high rates of photosynthesis, and provides a simple mechanism for the observed δ13C-decoupling between global seawater DIC and shallow carbonate, without burying organic matter or generating O2.

scholarly journals The Impacts of Flood, Drought, and Turbidites on Organic Carbon Burial Over the Past 2,000 years in the Santa Barbara Basin, California

2020 ◽  
Vol 35 (7) ◽  
Author(s):  
Caitlyn T. Sarno ◽  
Claudia R. Benitez‐Nelson ◽  
Lori A. Ziolkowski ◽  
Ingrid L. Hendy ◽  
Catherine V. Davis ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Santa Barbara ◽  
Santa Barbara Basin ◽  
The Past ◽  
Carbon Burial ◽  
Organic Carbon Burial
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