scholarly journals Organic carbon rich sediments: benthic foraminifera as bio-indicators of depositional environments

2019 ◽  
Author(s):  
Elena Lo Giudice Cappelli ◽  
Jessica L. Clarke ◽  
Craig Smeaton ◽  
Keith Davidson ◽  
William E. N. Austin
Keyword(s):  
Organic Matter ◽  
Carbon Content ◽  
Benthic Foraminifera ◽  
Organic Content ◽  
Depositional Environments ◽  
Carbon Burial ◽  
Actual Change ◽  
Freshwater Inputs

Abstract. Fjords have been described as hotspots for carbon burial, potentially playing a key role within the carbon cycle as climate regulators over multiple timescales. Nevertheless, little is known about the long-term fate of the carbon that may become stored in fjordic sediments. One of the main reasons for this knowledge gap is that carbon arriving on the seafloor is prone to post-depositional degradation, posing a great challenge when trying to discriminate between an actual change in carbon deposition rate and post depositional carbon loss. In this study, we evaluate the use of modern benthic foraminifera as bio-indicators of carbon content in six voes (fjords) on the west coast of Shetland. Benthic foraminifera are sensitive to changes in carbon content in the sediments, and changes in their assemblage composition therefore reflect synchronous variations in the quantity and quality of carbon reaching the seafloor. We identified four environments based on the relationship between benthic foraminiferal assemblages and carbon content in the sediments: 1) Land-locked regions influenced by riverine/freshwater inputs of organic matter, namely the head of fjords with a restricted geomorphology; 2) Stressed environments with a heavily stratified water column and sediments rich in organic matter of low nutritional value; 3) Depositional environments with moderate organic content and mild or episodic current activity; 4) Marginal to coastal settings with low organic content, such as fjords with an unrestricted geomorphology. We conclude that foraminifera potentially provide a tool to disentangle primary carbon signals from post-depositional degradation and loss of carbon because of their environmental sensitivity and high preservation potential in the sedimentary record.

scholarly journals Organic-carbon-rich sediments: benthic foraminifera as bio-indicators of depositional environments

2019 ◽  
Vol 16 (21) ◽  
pp. 4183-4199 ◽  
Author(s):  
Elena Lo Giudice Cappelli ◽  
Jessica Louise Clarke ◽  
Craig Smeaton ◽  
Keith Davidson ◽  
William Edward Newns Austin
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Content ◽  
Benthic Foraminifera ◽  
Organic Content ◽  
Depositional Environments ◽  
Organic Carbon Content ◽  
Carbon Burial ◽  
Actual Change ◽  
Freshwater Inputs

Abstract. Fjords have been described as hotspots for carbon burial, potentially playing a key role within the carbon cycle as climate regulators over multiple timescales. Nevertheless, little is known about the long-term fate of the carbon that may become stored in fjordic sediments. One of the main reasons for this knowledge gap is that carbon arriving on the seafloor is prone to post-depositional degradation, posing a great challenge when trying to discriminate between an actual change in the carbon deposition rate and post-depositional carbon loss. In this study, we evaluate the use of modern benthic foraminifera as bio-indicators of organic carbon content in six voes (fjords) on the west coast of Shetland. Benthic foraminifera are known to be sensitive to changes in organic carbon content in the sediments, and changes in their assemblage composition therefore reflect synchronous variations in the quantity and quality of carbon reaching the seafloor. We identified four environments based on the relationship between benthic foraminiferal assemblages and organic carbon content in the sediments: (1) land-locked regions influenced by riverine and/or freshwater inputs of organic matter, namely the head of fjords with a restricted geomorphology; (2) stressed environments with a heavily stratified water column and sediments rich in organic matter of low nutritional value; (3) depositional environments with moderate organic content and mild or episodic current activity; and (4) marginal to coastal settings with low organic content, such as fjords with an unrestricted geomorphology. We conclude that foraminifera potentially provide a tool to disentangle primary organic carbon signals from post-depositional degradation and loss of organic carbon because of their environmental sensitivity and high preservation potential in the sedimentary record.

scholarly journals K-Mean Cluster Analysis for Better Determining the Sweet Spot Intervals of the Unconventional Organic-Rich Shale: A Case Study

2018 ◽  
Vol 7 (2) ◽  
pp. 200-213
Author(s):  
Muhammad Nur Ali Akbar ◽  
Septian Tri Nugraha
Keyword(s):  
Organic Matter ◽  
Water Saturation ◽  
Laboratory Data ◽  
Organic Content ◽  
Brittleness Index ◽  
Sweet Spot ◽  
Typing Method ◽  
Log Data ◽  
Gas Saturation

Abstract The petrophysical analysis is the crucial task for evaluating the quality of unconventional organic-rich shale and tight gas reservoirs. The presence of organic matter and the ultra-tight with over complex pore system have remained a lack of understanding of how to evaluate the extensive parameters of porosity considering organic content, gas saturation, organic richness, brittleness index, and sweet spot interval by only using conventional log. Therefore, this study offers effectively applied techniques and better analysis for interpreting these parameters by maximizing and integrating geological, geochemical, rock mechanical and engineering data. In general, the field data used in this study are from the first dedicated well for source rock exploration in the North Sumatra Basin, Indonesia. The developed method was derived by using conventional log. All interpretation results were validated by laboratory data measurements of routine and special core analysis, petrography, total organic carbon (TOC) and organic maturation, and brittleness index (BI) calculation. Moreover, the high quality of NMR log data was used as well to ensure our developed techniques present good estimations. Briefly about the methods, we started to determine the total and effective porosity based on the density log by including the presence of organic matter and multi-mineral analysis in these estimations. Then, we used the revised water saturation-TOC of water saturation while the TOC was predicted in advance by averaging three results from the correlation of TOC-Density, modified CARBOLOG and Passey’s ΔlogR methods. Equally important, in order to obtain the reliable gas saturation prediction, we used saturation exponent (n), cementation factor (m), and the tortuosity factor (a) parameters which obtained from laboratory measurement of formation resistivity factor and resistivity index (FFRI). In addition, the brittleness index was predicted based on sonic log data. Finally, all parameters needed for determining gas shale sweet spot have been made. Then, we developed a way to evaluate the sweet spot interval by using K-mean clustering. In conclusion, this clustering result properly follows the shale quality index parameters which consist of organic richness and maturation, brittleness index, the storage capacity of porosity and gas saturation. This study shows that these petrophysical applied techniques leads us to interpret the best position of shale interval to be developed with a simple, fast, and accurate prediction way. Furthermore, as a novelty, this method can be used as rock typing method and obviously can reduce uncertainty and risks in organic-rich shale exploration.

scholarly journals Effects of level and quality of organic matter input on carbon storage and biological activity in soil: Synthesis of a long-term experiment

2004 ◽  
Vol 18 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Holger Kirchmann ◽  
Georg Haberhauer ◽  
Ellen Kandeler ◽  
Angela Sessitsch ◽  
Martin H. Gerzabek
Keyword(s):  
Organic Matter ◽  
Biological Activity ◽  
Carbon Storage ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Organic Matter Input

scholarly journals Ancient Biomolecules and Evolutionary Inference

2018 ◽  
Vol 87 (1) ◽  
pp. 1029-1060 ◽  
Author(s):  
Enrico Cappellini ◽  
Ana Prohaska ◽  
Fernando Racimo ◽  
Frido Welker ◽  
Mikkel Winther Pedersen ◽  
...  
Keyword(s):  
Depositional Environments ◽  
Amino Acid Sequences ◽  
Data Sets ◽  
Exciting Field ◽  
Future Directions ◽  
Current State ◽  
Evolutionary Inference ◽  
Technical Innovations

Over the past three decades, studies of ancient biomolecules—particularly ancient DNA, proteins, and lipids—have revolutionized our understanding of evolutionary history. Though initially fraught with many challenges, today the field stands on firm foundations. Researchers now successfully retrieve nucleotide and amino acid sequences, as well as lipid signatures, from progressively older samples, originating from geographic areas and depositional environments that, until recently, were regarded as hostile to long-term preservation of biomolecules. Sampling frequencies and the spatial and temporal scope of studies have also increased markedly, and with them the size and quality of the data sets generated. This progress has been made possible by continuous technical innovations in analytical methods, enhanced criteria for the selection of ancient samples, integrated experimental methods, and advanced computational approaches. Here, we discuss the history and current state of ancient biomolecule research, its applications to evolutionary inference, and future directions for this young and exciting field.

Corrigendum to: Long-term watershed management is an effective strategy to reduce organic matter export and disinfection by-product precursors in source water

2019 ◽  
Vol 28 (10) ◽  
pp. 822 ◽  
Author(s):  
Hamed Majidzadeh ◽  
Huan Chen ◽  
T. Adam Coates ◽  
Kuo-Pei Tsai ◽  
Christopher I. Olivares ◽  
...  
Keyword(s):  
Organic Matter ◽  
South Carolina ◽  
Watershed Management ◽  
Prescribed Fire ◽  
Management Practices ◽  
Long Term Effects ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen

Watershed management practices such as prescribed fire, harvesting and understory mastication can alter the chemical composition and thickness of forest detritus, thus affecting the quantity and quality of riverine dissolved organic matter (DOM). Long-term effects of watershed management on DOM composition were examined through parallel field and extraction-based laboratory studies. The laboratory study was conducted using detritus samples collected from a pair of managed and unmanaged watersheds in South Carolina, USA. Results showed that dissolved organic carbon (DOC), total dissolved nitrogen (TDN) and ammonium (NH4+-N) concentrations were higher in water extracts from the unmanaged watershed than from the managed watershed (PPP

Removal of organic matter by the PAC-UF process: first two years of a full-scale application

2001 ◽  
Vol 1 (4) ◽  
pp. 253-263 ◽  
Author(s):  
I. Baudin ◽  
C. Campos ◽  
J.M. Laîne
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Distribution System ◽  
Positive Impact ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Organic Content ◽  
Uf Membranes ◽  
The Impact

At the end of 1997, an innovative membrane-adsorption process was integrated at the Vigneux-sur-Seine water treatment plant in the southeast suburbs of Paris, France. This hybrid process consisted of the application of powdered activated carbon (PAC) upstream of ultrafiltration (UF) membranes and recycled to a floc blanket reactor (FBR) after membrane backwashes (FBR-PAC/UF process). This process was designed to mitigate seasonal episodes of micropollutants (pesticides and taste and odors) and to reduce the content of natural organic matter responsible for disinfectant and disinfection by-products. An intensive monitoring campaign of the plant effluent and ten sites in the distribution system was conducted two years before (1996-1997) and two years after (1998-1999) the start up of the PAC/UF process to characterize the impact of this treatment on the water quality of the distributed water. The objective of this paper is to illustrate the positive impact of the PAC/UF process on the organic and biological water quality of the Vigneux-sur-Seine distribution system. Thus, the combination of coagulation and adsorption in the FBR-PAC/UF process resulted in a TOC concentration lower than 0.7 mg/l, BDOC values lower than the detection limit (<0.2 mg/l) and total trihalomethanes concentrations below 10 μg/l. This reduction in organic content results in a reduction of the chlorine consumption by the water produced, which translates in the maintenance of higher chlorine residuals throughout the distribution system while using the same chlorine doses at the plant (0.3 mg/l).

Comprehensive Spectral and Thermal Characterization of Oil Shales

2015 ◽  
Author(s):  
S.. Guven ◽  
S.. Akin ◽  
B.. Hascakir
Keyword(s):  
Organic Matter ◽  
Oil Shale ◽  
Thermal Characterization ◽  
Organic Content ◽  
Depositional Environments ◽  
Gravimetric Analysis ◽  
Dsc Analysis ◽  
Reserve Estimation ◽  
Oil Shales

Abstract The heterogeneous nature of oil shale resources associated to the depositional environments, lithology, and organic content make the reserve estimation complex and unpredictable. However, comprehensive laboratory studies on organic rich shale samples collected from different regions can increase the understanding about the organic content of oil shales, interaction of shale with organic matter and injected fluid used during enhanced oil recovery method. This study investigates the characterization of eight different Turkish and American oil shale samples with several spectral methods and a thermal analysis. The main purpose of this study is to characterize the oil shale samples to increase the understanding about the organic content and interaction of shale with organic matter. In this study, we used Thermal Gravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC) analysis to estimate organic content of each oil shale sample in air and nitrogen environments. X-Ray Diffraction (XRD) was used to define minerals in oil shale. Fourier Transform Infrared Spectroscopy (FTIR) was used to detect the mineral and kerogen in oil shale before and after the TGA/DSC analysis. Scanning Electron Microscope (SEM) was used to characterize the depositional environment of each oil shale samples. TGA/DSC results verified that oil shale samples have up to 50% of organic matter. XRD and FTIR results helped to identify the organic and inorganic compounds. Effects of minerals and ions were recognized by comparing TGA/DSC curves and FTIR spectra. It was recognized that the more carbonate ion in the oil shale the more increase in weight loss occurred. Diatoms identified from SEM results showed that depositional environments of the some oil shale samples are marine environments. This study provides insight for the reserve estimation of the eight different oil shale samples with comprehensive spectral and thermal characterization.

Seasonal variations in growth rate of phytoplankton in Hakata Bay, Japan

2002 ◽  
Vol 46 (11-12) ◽  
pp. 443-449
Author(s):  
M. Nakashima ◽  
I.-C. Lee ◽  
T. Kusuda
Keyword(s):  
Growth Rate ◽  
Organic Matter ◽  
Type Model ◽  
Monthly Data ◽  
Phytoplankton Population ◽  
High Concentrations ◽  
High Level ◽  
Long Term Measurement

Recently, water pollution with high concentrations of organic matter has occurred frequently in Hakata Bay. It is said that a high level of primary production provides much organic matter and affects water quality of the bay, and it is proved by the appearance of phytoplankton throughout the year. In this study, we simulated variations of phytoplankton population with a box-type model using monthly data in a long-term measurement and we analyzed the final growth rate changes of phytoplanktons that explain the conditions for its appearance. Consequently, we found that the final growth rate varies with pattern of half-year periodicity and water temperature and/or ambient nutrient controls the final growth rate to be low every January and July.

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