Sounding Out the Carbon: The Potential of Acoustic Backscatter Data to Yield Improved Spatial Predictions of Organic Carbon in Marine Sediments

Marine sediments hold vast stores of organic carbon (OC). Techniques to spatially map sedimentary OC must develop to form the basis of seabed management tools that consider carbon-rich sediments. While the natural burial of carbon (C) provides a climate regulation service, the disturbance of buried C could present a significant positive feedback mechanism to atmospheric greenhouse gas concentrations. We present a regional Scottish case study that explores the suitability of integrating archived seafloor acoustic data (i.e., multibeam echosounder bathymetry and backscatter) with physical samples toward improved spatial mapping of surface OC in a dynamic coastal environment. Acoustic backscatter is a proxy for seabed sediments and can be collected over extensive areas at high resolutions. Sediment type is also an important predictor of OC. We test the potential of backscatter as a proxy for OC which may prove useful in the absence of exhaustive sediment data. Overall, although statistically significant, correlations between the variables OC, sediment type, and backscatter are relatively weak, likely reflecting a combination of limited and asynchronous data, sediment mobility over time, and complex environmental processing of OC in shelf sediments. We estimate linear mixed models to predict OC using backscatter and Folk sediment type as covariates. Our results show that incorporating backscatter in the model improves the precision of OC predictions by 14%. Backscatter discriminates between coarse and fine sediments, and therefore low and high OC regimes; however, was not able to discriminate amongst finer sediments. Although sediment type is a stronger predictor of OC, these data are available at a much lower spatial resolution and do not account for fine-scale variability. The resulting maps display varying spatial distributions of OC reflecting the different scales of the predictor variables, demonstrating a need for further methodological development. Backscatter shows considerable promise as a high-resolution predictor variable to improve the precision of surface OC maps, or to reduce the number of OC measurements required to achieve a specified precision. Applications of such maps have potential in improved C-stock estimates and the design of conservation and management strategies that consider marine sediments as valuable C stores.

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Tracking Changes on Soil Structure and Organic Carbon Sequestration after 30 Years of Different Tillage and Management Practices

Agronomy ◽

10.3390/agronomy11020291 ◽

2021 ◽

Vol 11 (2) ◽

pp. 291

Author(s):

Ramón Bienes ◽

Maria Jose Marques ◽

Blanca Sastre ◽

Andrés García-Díaz ◽

Iris Esparza ◽

...

Keyword(s):

Triticum Aestivum ◽

Organic Carbon ◽

Management Practices ◽

Management Strategies ◽

Triticum Aestivum L ◽

Field Trials ◽

Conventional Tillage ◽

Soil Parameters ◽

Wilting Point

Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), minimum tillage (MT), and no-tillage (NT), and with two crop rotations, monoculture winter-wheat (Triticum aestivum L.) and wheat-vetch (Triticum aestivum L.-Vicia sativa L.), widely present in the center of Spain. The soil under NT experienced the largest change in organic carbon (SOC) sequestration, macroaggregate stability, and bulk density. In the MT and NT treatments, SOC content was still increasing after 32 years, being 26.5 and 32.2 Mg ha−1, respectively, compared to 20.8 Mg ha−1 in CT. The SOC stratification (ratio of SOC at the topsoil/SOC at the layer underneath), an indicator of soil conservation, increased with decreasing tillage intensity (2.32, 1.36, and 1.01 for NT, MT, and CT respectively). Tillage intensity affected the majority of soil parameters, except the water stable aggregates, infiltration, and porosity. The NT treatment increased available water, but only in monocropping. More water was retained at the permanent wilting point in NT treatments, which can be a disadvantage in dry periods of these edaphoclimatic conditions.

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Effects of Urban Forest Types and Traits on Soil Organic Carbon Stock in Beijing

Forests ◽

10.3390/f12040394 ◽

2021 ◽

Vol 12 (4) ◽

pp. 394

Author(s):

Xinhui Xu ◽

Zhenkai Sun ◽

Zezhou Hao ◽

Qi Bian ◽

Kaiyue Wei ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Stock ◽

Urban Forest ◽

Coniferous Forest ◽

Predictor Variable ◽

Urban Forests ◽

Least Squares Regression ◽

Forest Types ◽

Organic Carbon Stock

Forests can affect soil organic carbon (SOC) quality and distribution through forest types and traits. However, much less is known about the influence of urban forests on SOC, especially in the effects of different forest types, such as coniferous and broadleaved forests. Our objectives were to assess the effects of urban forest types on the variability of SOC content (SOC concentration (SOCC) and SOC density (SOCD)) and determine the key forest traits influencing SOC. Data from 168 urban forest plots of coniferous or broadleaved forests located in the Beijing urban area were used to predict the effects of forest types and traits on SOC in three different soil layers, 0–10 cm, 10–20 cm, and 20–30 cm. The analysis of variance and multiple comparisons were used to test the differences in SOC between forest types or layers. Partial least squares regression (PLSR) was used to explain the influence of forest traits on SOC and select the significant predictors. Our results showed that in urban forests, the SOCC and SOCD values of the coniferous forest group were both significantly higher than those of the broadleaved group. The SOCC of the surface soil was significantly higher than those of the following two deep layers. In PLSR models, 42.07% of the SOCC variance and 35.83% of the SOCD variance were explained by forest traits. Diameter at breast height was selected as the best predictor variable by comparing variable importance in projection (VIP) scores in the models. The results suggest that forest types and traits could be used as an optional approach to assess the organic carbon stock in urban forest soils. This study found substantial effects of urban forest types and traits on soil organic carbon sequestration, which provides important data support for urban forest planning and management.

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Total Organic Carbon Assessment in Soils Cultivated with Agave tequilana Weber in Jalisco, Mexico

Sustainability ◽

10.3390/su13010208 ◽

2020 ◽

Vol 13 (1) ◽

pp. 208

Author(s):

Celia De La Mora-Orozco ◽

José G. Flores-Garnica ◽

Lucia M. Vega-Ramírez ◽

Irma J. González-Acuña ◽

Juan Nápoles-Armenta ◽

...

Keyword(s):

Organic Carbon ◽

Total Organic Carbon ◽

Management Practices ◽

Water Saturation ◽

Management Strategies ◽

Information Criterion ◽

Agave Tequilana ◽

Tukey Test ◽

Significant Difference ◽

Agriculture Management

The Agave tequilana Weber is an important commercial crop in the State of Jalisco, Mexico. However, the agave cultivation generates significant soil loss. For that reason, knowledge about the implementation of the agriculture management practices, such as manure application and the combination of inorganic fertilizers and manure, are relevant. The objective of this research was to determine the effect of agricultural management practices on the total organic carbon (TOC) in the soil in three study locations: Arandas, Tepatitlán, and Acatic in the Altos Sur region of Jalisco. A random sampling was carried out in each study location, 12 samples were obtained for each location at 0–30 cm deep, and a total of 36 samples were analyzed. The evaluated parameters were the potential hydrogen (pH), electrical conductivity (EC), bulk density (BD), soil-water saturation (SWS), total nitrogen (TN), and total organic carbon (TOC). Basic statistics and correlations between parameters were generated. In addition, to estimate TOC from a multivariate analysis, models were developed based on the lowest Akaike information criterion (AIC) and of the classification and regression trees (CART). ANOVA and Tukey test were determined. Results demonstrated a significant difference in the TOC percentages between the study locations. The Tukey test showed that there is no difference in TOC content between the Tepatitlán and Arandas sites, but there is a difference between these two sites and the Acatic. The latter resulted with the lowest values of TOC. Long-term studies are recommended to develop crop management strategies.

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Determination of organic carbon remineralization in near-shore marine sediments (Gulf of Trieste, Northern Adriatic) using stable carbon isotopes

Organic Geochemistry ◽

10.1016/s0146-6380(03)00023-8 ◽

2003 ◽

Vol 34 (5) ◽

pp. 681-692 ◽

Cited By ~ 20

Author(s):

Nives Ogrinc ◽

Jadran Faganeli ◽

Joze Pezdic

Keyword(s):

Organic Carbon ◽

Carbon Isotopes ◽

Marine Sediments ◽

Stable Carbon Isotopes ◽

Stable Carbon ◽

Northern Adriatic ◽

Gulf Of Trieste ◽

Carbon Remineralization ◽

Near Shore

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Spectroscopic and Chromatographic studies of organic carbon in Recent marine sediments from the Peruvian Upwelling Zone

Organic Geochemistry ◽

10.1016/s0146-6380(86)80009-2 ◽

1986 ◽

Vol 10 (4-6) ◽

pp. 725-732 ◽

Cited By ~ 5

Author(s):

W.T. Cooper ◽

A.S. Heiman ◽

R.R. Yates

Keyword(s):

Organic Carbon ◽

Marine Sediments

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Relation between sedimentation rate and burial of organic phosphorus and organic carbon in marine sediments

Geochimica et Cosmochimica Acta ◽

10.1016/0016-7037(90)90326-g ◽

1990 ◽

Vol 54 (2) ◽

pp. 373-386 ◽

Cited By ~ 199

Author(s):

Ellery D Ingall ◽

Philippe Van Cappellen

Keyword(s):

Organic Carbon ◽

Marine Sediments ◽

Sedimentation Rate ◽

Organic Phosphorus

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Effect of termite activity on soil under different land management strategies

Semina Ciências Agrárias ◽

10.5433/1679-0359.2017v38n1p143 ◽

2017 ◽

Vol 38 (1) ◽

pp. 143

Author(s):

Liane Barreto Alves Pinheiro ◽

Rodrigo Camara ◽

Marcos Gervasio Pereira ◽

Eduardo Lima ◽

Maria Elizabeth Fernandes Correia ◽

...

Keyword(s):

Organic Carbon ◽

Management Strategies ◽

Chemical Properties ◽

Clay Content ◽

Exchange Capacity ◽

Termite Mounds ◽

Eucalyptus Plantation ◽

Exchangeable Acidity ◽

Calcium And Magnesium ◽

Surrounding Soil

Mound-building termites are important agents of soil bioperturbation, but these species have not been extensively studied thus far. The present study aimed to evaluate the soil particle-size and the chemical attributes of termite mounds and the surrounding soil under different land use strategies. A one-hectare plot was defined for an unmanaged degraded pasture, planted pasture, and for a eucalyptus Corymbia citriodora plantation. In each plot, the top, center, and base sections of five Cornitermes cumulans mounds, and the surrounding soil at the depths of 0-5; 5-10; 10-20 cm, were sampled in the Pinheiral, Rio de Janeiro state. In the three areas, the center of the mounds contained higher clay content, organic carbon, phosphorous, calcium and magnesium, total bases, and cation exchangeable capacity, when compared to the top, base, and the surrounding soils. However, the center had lower values of exchangeable acidity and potassium, of the three areas. In the eucalyptus plantation, the values of pH, total bases, calcium, and magnesium were lower, whereas aluminum, exchangeable acidity, sodium, and cation exchange capacity were higher both in the mounds and in the surrounding soil, in relation to the pastures. There were no differences among the three areas in terms of organic carbon, potassium, phosphorous, and total bases, in the mounds and adjacent soil. Thus, the termite activity altered the clay content and most of the soil chemical properties in all of the studied areas, but only for the center of the mounds. However, the effect of these organisms was different in the eucalyptus plantation in relation to the pasture areas.

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