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

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.

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Organic carbon burial in a large, deep alpine lake (southwest China) in response to changes in climate, land use and nutrient supply over the past ~100 years

CATENA ◽

10.1016/j.catena.2021.105240 ◽

2021 ◽

Vol 202 ◽

pp. 105240

Author(s):

Qi Lin ◽

Enfeng Liu ◽

Enlou Zhang ◽

Bibhash Nath ◽

Richard Bindler ◽

...

Keyword(s):

Land Use ◽

Organic Carbon ◽

Southwest China ◽

Nutrient Supply ◽

Alpine Lake ◽

The Past ◽

Carbon Burial ◽

Organic Carbon Burial

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Sediment Organic Carbon Sequestration of Balkhash Lake in Central Asia

Sustainability ◽

10.3390/su13179958 ◽

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.

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Oceanic Changes Correlate with Methane Seepage

Eos ◽

10.1029/2020eo145301 ◽

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.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1908783116 ◽

2019 ◽

Vol 116 (49) ◽

pp. 24433-24439 ◽

Cited By ~ 6

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.

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

Paleoceanography and Paleoclimatology ◽

10.1029/2020pa003849 ◽

2020 ◽

Vol 35 (7) ◽

Cited By ~ 1

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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Past climate variations recorded in needle-like aragonites correlate with organic carbon burial efficiency as revealed by lake sediments in Croatia

Scientific Reports ◽

10.1038/s41598-021-87166-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ivan Razum ◽

Petra Bajo ◽

Dea Brunović ◽

Nikolina Ilijanić ◽

Ozren Hasan ◽

...

Keyword(s):

Organic Carbon ◽

Stable Carbon Isotope ◽

Climate Variations ◽

Before Present ◽

Stable Carbon ◽

Climate Trends ◽

Geochemical Proxies ◽

Carbon Burial ◽

Organic Carbon Burial ◽

Burial Efficiency

AbstractThe drivers of organic carbon (OC) burial efficiency are still poorly understood despite their key role in reliable projections of future climate trends. Here, we provide insights on this issue by presenting a paleoclimate time series of sediments, including the OC contents, from Lake Veliko jezero, Croatia. The Sr/Ca ratios of the bulk sediment are mainly derived from the strontium (Sr) and calcium (Ca) concentrations of needle-like aragonite in Core M1-A and used as paleotemperature and paleohydrology indicators. Four major and six minor cold and dry events were detected in the interval from 8.3 to 2.6 calibrated kilo anno before present (cal ka BP). The combined assessment of Sr/Ca ratios, OC content, carbon/nitrogen (C/N) ratios, stable carbon isotope (δ13C) ratios, and modeled geochemical proxies for paleoredox conditions and aeolian input revealed that cold and dry climate states promoted anoxic conditions in the lake, thereby enhancing organic matter preservation and increasing the OC burial efficiency. Our study shows that the projected future increase in temperature might play an important role in the OC burial efficiency of meromictic lakes.

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