Amount Of Organic Carbon Research Articles

Delineation of Soil Management Zone Maps at the Regional Scale Using Machine Learning

Applying fertilizers to soil in a site-specific way that maximizes yields and minimizes environmental damage is an important goal. Developing soil management zones (MZs) is a suitable method for achieving sustainable agricultural production. Thus, this work aims to investigate MZs delineated based on the different soil properties using machine learning methods. To achieve these, 202 soil samples were collected at the agricultural land of pomegranate, pistachio, and saffron. A “random forest” model was applied to map soil properties based on environmental covariates. The predicted “Lin’s concordance correlation coefficient” values in validation soil properties varied from 0.65 to 0.79. The maps indicated low amounts of soil organic carbon, available potassium, available phosphate, and total nitrogen in most of the region. Furthermore, the study identified four different MZs according to relationships between soil properties and environmental covariates. Generally, the ranking of zones in terms of soil fertility was MZ4 > MZ1 > MZ3 > MZ2 based on the investigated soil properties and the soil quality (SQ) map. The five grades of SQ (i.e., very high, high, moderate, low, and very low) indicated that there was heterogeneous SQ in each MZ in the study area. There were 1.65 ha identified in MZ4 with very low SQ. This result is important in determining the amount of fertilizer to add to the soil in the different areas. It confirms the need for more specific regional management of agriculture lands in this region.

Legacy Effects of Late Macroalgal Blooms on Dissolved Inorganic Carbon Pool through Alkalinity Enhancement in Coastal Ocean.

Taking the world's largest green tide caused by the macroalga Ulva prolifera in the South Yellow Sea as a natural case, it is studied here if macroalgae can perform inorganic carbon sequestration in the ocean. Massive macroalgae released large amounts of organic carbon, most of which were transformed by microorganisms into dissolved inorganic carbon (DIC). Nearshore field investigations showed that, along with seawater deoxygenation and acidification, both DIC and total alkalinity (TAlk) increased significantly (both >50%) in the areas covered by dense U. prolifera at the late-bloom stage. Offshore mapping cruises revealed that DIC and TAlk were relatively higher at the late-bloom stage than at the before-bloom stage. Laboratory cultivation of U. prolifera at the late-bloom stage further manifested a significant enhancement effect on DIC and TAlk in seawater. Sulfate reduction and/or denitrification likely dominated the production of TAlk. Notably, half of the generated DIC and almost all the TAlk could persist in seawater under varying conditions, from hypoxia to normoxia and from air-water CO2 disequilibrium to re-equilibrium. The enhancement of TAlk allowed more DIC to remain in the seawater rather than escape into the atmosphere, thus having the long-term legacy effect of increasing DIC pool in the ocean.

Benthic Invertebrates on the Move: A Tale of Ocean Warming and Sediment Carbon Storage

AbstractOngoing effects of climate change create a dual challenge of shifting distributions of organisms and concerns about the fate of organic carbon in nature. Marine sediments store vast amounts of organic carbon, but the fate of that material hinges on the biology of organisms associated with the seafloor and how they influence rates of carbon decomposition and burial. Shifts in large megafauna that disturb and thus help to oxygenate sediments could have important ramifications regarding whether sediments release or store carbon for long periods of time. We consider snow crab and lobster, two commercially important seafloor species in the Northeastern Atlantic, and the potential effects of ongoing changes in their distributions and that of their fisheries for future climate scenarios. These ongoing biogeographic shifts, considered in tandem with areas of seabed legislatively protected from fishing impacts and thus not confounded by cumulative effects of fishing gear disturbance, offer an opportunity to study how newly arrived species that disturb large areas of the seafloor might influence the global carbon cycle.

Study on profitability of sunhemp seed production over blackgram in rice follows of Srikakulam district of north coastal AP

The crops like sun hemp, pulses, daincha, pillipesra are used as green manure or cover crops grown primarily for soil incorporation. The green manuring is the easiest and cheapest way to enrich the soil fertility besides adding huge amount of organic carbon to the soil and also which prevents soil erosion. Lake of green manure seed availability precede to paddy is major a constraint at farmer’s level. In the farming system of rice fallow pulse yields are reduced due to climate constraints like low temperature and fog during Rabi, crop constraints like lake of YMV tolerant verities, the yields are reducing so that farmers are unable reap the pulses in rice fallow situations in the present scenario. The study on productivity of seed production of sunhemp crop for seed and profitability was a lacuna in this zone. The present study of productivity of sunhemp (Crotalaria juncea L.) seed production was studied for seed yield in rice fallow situation during Rabi, 2020-21 and Rabi, 2021-22 under rainfed situation by Krishi Vigyan Kendra, Amadalavalasa. The Front Line Demonstrations (FLD) were conducted at farmers’ fields in 10 locations randomly covering entire district during this period. Observations were recorded on days to maturity, seed yield, cost of cultivation, B:C ratio and net income. The results were revealed that significantly higher seed yield was observed in sunhemp when compared to black gram in rice fallow situation. The higher seed yield recorded in sun hemp (10.3 q/h) over black gram (5.7 q/h) and net income of sun hemp seed production (Rs.19,500/h) and black gram is (Rs.9,750) While the B:C ratio of sunhemp (1:2.34) and blackgram is (1:1.60) during two consequent years f Rabi, 2020-21 and 2021-22.The study revealed that growing of sun hemp in rice fallows is much remunerative in-terms of higher growth and yield components when compared to blackgram and add more green manure to soil and increased net income to the farmer. The farmers realized that, sunhemp seed production is best suitable after rice in Rabi season under rain fed condition in Srikakulam district of North Coastal Zone of Andhra Pradesh.

Effects of flood inundation on biogeochemical processes in groundwater during riverbank filtration

Well fields along rivers withdrawing groundwater through riverbank filtration (RBF) are popular for urban water supply, due to their good performance in assurance for both water quantity and quality. However, RBF sites are susceptible to flood inundation, which has been found to cause increase of N, Fe, and Mn contents in groundwater and threatens water safety, but the geochemical processes have not been fully understood. To bridge this gap, in situ monitoring of hydrodynamics, hydrochemistry, and stable isotopes for river water and groundwater were employed in a RBF site, NE China, to investigate into the geochemical processes in groundwater in RBF sites under long-term inundation. The results indicated that during long-term inundation, recharge from river water increased significantly, and a large amount of O2, NO3− and organic carbon (OC) from oxidizing river water could recharge far-shore groundwater vertically, whereas less NH4+ were input from regional groundwater, leading to a high content of NO3− and low content of the NH4+ in the groundwater. Meanwhile, limited NH4+ would be produced through dissimilatory nitrate reduction to ammonium (DNRA) and mineralization of organic nitrogen (MON). Moreover, along the infiltration path, aerobic respiration and denitrification (DNF) occurred rapidly. CO2 generated from OC oxidization in the two processes enhanced the dissolution of carbonate minerals, which could be used to trace the oxidizing-reducing (O-R) interface between river water and groundwater. As indicated, the inundation can cause the O-R interface which usually distributed near shore to extend to the entire well field during inundation. In this situation, the redox condition of groundwater used to be suitable for SO42− reduction in non-inundation period decreases to the level favoring the reduction of Mn(IV)/Fe(III) oxides during inundation, and the process of Fe2+ precipitation by reacting with HS− is weaken as the inhabitation of SO42− reduction, leading to a significant increase in Fe2+, Mn2+, and As contents, putting well field groundwater at risk of contamination.

Seasonal and spatial variation of stream macroinvertebrate taxonomic and functional diversity across three boreal regions

Abstract The exploration of biodiversity has predominantly been based on taxonomic measures, whereas functional diversity, a key component of biodiversity, is comparatively understudied. Therefore, studies simultaneously investigating patterns of taxonomic and functional diversity change in biological communities are of increasing interest. We collated high‐resolution macroinvertebrate and environmental data from 70 boreal headwater stream sites across three European countries (Germany, Finland, Sweden) to (1) investigate seasonal variation in taxonomic diversity, functional diversity, and redundancy, and (2) identify their potential drivers of spatial and seasonal variation. Seasonal changes in boreal macroinvertebrate taxonomic diversity were decoupled from changes in functional diversity. Seasonal shifts in environmental conditions, including acidity and nutrient variability, drove fluctuations in taxonomic diversity which were far more pronounced than those of functional diversity. Seasonal shifts in environmental conditions including variation in the quantity, quality, and state of organic carbon (dissolved vs particulate) facilitate an exchange of taxa, leading to taxonomically unique communities that exploit the pool of available seasonal resources. Thus, similar levels of functional diversity across seasons—even as taxonomic diversity changes—suggest limited differences in interspecific changes in community function, potentially indicating functional resistance rooted in redundancy. We highlight the spatial and seasonal discrepancies of freshwater communities, emphasising the need for both taxonomic and functional diversity patterns to be assessed in future biodiversity monitoring programmes.

Ecological Role of <i>Onthophagus taurus</i> (Schreber) in Soil Nutrient Mobilization

Dung beetles play a major role in the pasture ecosystem. The manure recycling activity of dung beetles is linked to their tunneling behavior. The present study was designed to analyze the tunnel pattern and nutrient mobilization by dung beetles, Onthophagus taurus (Schereber, 1759) in different soil types. A simple type of tunnel pattern was observed in all the four types of soil after 30th day of their introduction (10 pairs of male and female) into the experimental setup. However, the maximum number of tunnels was observed in the sandy and sandy clay loam (no. of openings - 15), followed by loamy soil (no. of openings -13). The physical (texture, water holding capacity, porosity, moisture content) and chemical parameters (pH and nutrients) of all the four types of soils were evaluated. Soil texture analysis revealed the texture to be of sandy (yellow soil), sandy clay loam (red and black soil), and loamy sand (brown soil) types. Water holding capacity and the soil porosity were recorded highest in the sandy soil, whereas moisture content was found maximum in the sandy clay loam. Soil nutrient analysis illustrated a significant increase in the amount of nitrogen (N), phosphorus (P), calcium (Ca), sulfur (S), sodium (Na), potassium (K), organic carbon and organic matter. Thus, the present study confirms that tunneling activity of O. taurus enhances the soil nutrients by carrying out dung decomposition.

Effect of using repeated and siderate crops on soil fertility, yield of cotton varieties, and technological quality indicators of cotton fiber in short rotation cropping systems

In the 1:1 (cotton:grain) system of short-rotation, soybean, bean, mung bean crops were harvested as a repeat crop after winter wheat. Their stem crop and mixed siderate crops (perco, oats, green peas) were planted in the second half of August, and the blue mass crop grown in October-November was harvested for livestock. The lower 15-20 cm part of the stem was plowed under the plow as a blue manure, at the end of one rotation, the amount of organic carbon in the soil increased by 0.041-0.073%, and the total nitrogen content by 0.012-0.016% compared to the initial values. The highest rate of dry mass accumulation of cotton was observed when using short-row rotation 1:1, winter wheat + mixed siderate crops (perco, oat, green pea):cotton system. The dry mass of the leaves of the Navroz variety of cotton was 22.6 g, the dry mass of the stem was 33.4 g, the dry mass of the bolls was 18.5 g, and the dry mass of the cotton was 48.0 g. The total dry mass of 1 plant was equal to 122.5 g. In the 1:1 (cotton:grain) system of short-rotation, when cotton was grown as a repeat crop after legume-cereal (soybean, mung bean) and mixed siderate (perco, oat, green pea) crops, it provided a higher and better quality cotton yield. Cotton yield was 3.2-5.8 tons/ha, fiber output was 1.0-1.5 percent, and 1000 seed mass was 9.0-11.0 g/ha. Besides, the length of the fiber was found to be higher by 1.4-2.0 mm.

Soil Fertility Status of Major Tobacco Growing Lands of Bangladesh

Tobacco cultivation is associated with the destruction of soil quality, productivity, and environmental pollution. An experiment was conducted to know the soil fertility status of tobacco and non-tobacco growing soils of major tobacco growing areas (Manikganj, Kushtia, Lalmonirhat, Nilphamari, Chattogram, Rangamati, Bandarban and Khagrachari) of Bangladesh. Soil samples were examined to check the level of various nutrient components of soil like Organic Carbon (OC), Nitrogen (N), Phosphorus (P), Potassium (K), Zinc (Zn) in the Laboratory of Soil Science at Bangladesh Institute of Nuclear Agriculture. Wet oxidation, Kjeldhal, Olsen, flame photometer and atomic absorption spectrophotometer methods were followed to determine the OC, total N, P, K and Zn respectively of the soil samples. Overall, the results showed a decrease in all the nutrients in the tobacco growing lands compared to non-tobacco growing lands. The amount of OC (p value 0.0271), total N (p value 0.0162) and exchangeable K (p value 0.0006) were significantly lower in the tobacco lands. The organic carbon content of both tobacco and non-tobacco land showed below standard limit (2%). The total nitrogen content of the soil samples for both tobacco and non-tobacco showed below 0.5% except the non-tobacco growing lands of Chattogram and Khagrachari. The available P and Zn content in tobacco lands also showed a decrease in compared to non-tobacco lands but statistically there were no significant differences between them. The available P and Zn content in all the soil were below 50 ppm (except Khagrachari in non-tobacco lands) which was very low. The K content was also low in the tobacco growing lands and low to medium in the non-tobacco growing lands. This result reveals the poor soil condition due to tobacco cultivation in the major tobacco growing areas of Bangladesh. So, effective measures should be taken immediately to retain the soil health.

Study of the Interaction of Dissolved Organic Carbon, Available Nutrients, and Clay Content Driving Soil Carbon Storage in the Rice Rotation Cropping System in Northern Thailand

The appropriate management of crop residues in a rice rotation cropping system (RRCS) can promote carbon storage and contribute to soil health. The objective of this study was to determine and analyze the amount of organic carbon in the soil, the amount of labile carbon in a dissolved state in the soil, and the physicochemical properties of the soil and their relationship with soil organic carbon dynamics under the RRCS in northern Thailand. The RRCS can be divided into the following four categories by pattern: (1) Rice_F (rice (Oryza sativa) followed by a fallow period); (2) Rice_S (rice followed by shallots (Allium cepa L.); (3) Rice_Mixed crop (rice followed by tobacco (Nicotiana tabacum), vegetables, or maize (Zea mays)); and (4) Rice_P (rice followed by potatoes (Solanum tuberosum)). These patterns can be classified according to the dissolved organic carbon (DOC), the availability of nutrients from fertilization, and clay contents. In our study, the Rice-F and Rice-S patterns led to higher soil organic carbon (SOC) and dissolved organic carbon (DOC) in the soil, but when the Rice-P pattern was followed, the soil had a lower clay content, lower available phosphorus (Avail P), the lowest DOC, and high contents of calcium (Ca2+) and magnesium (Mg2+). This study also revealed that on the basis of relationships, clay content, Avail P, and DOC were the most important factors for the formation of SOC, while Ca2+ and Mg2+ were the subordinate factors for the decreased formation of SOC and carbon storage when the RRCS was followed. In addition, low SOC/clay when the Rice-P pattern was followed could reflect carbon saturation, while the percentages of DOC/SOC could indicate the decomposition and formation of SOC.

Physio-chemical characterization of sewage sludge generated from sewage treatment plant at Varanasi, in relation to nutrients and heavy metals for agriculture use

Large amount of sewage sludge is generated during waste water treatment at sewage treatment plant (STP), as a result of the sedimentation and suspension of particles. The safe disposal and management of this concentrated sewage sludge posesa major challenge for town and city municipal corporations. However, this could also be used in agriculture as an input to partially replace recommended doses of fertiliser. Thus, the current study was conducted to investigate the physio-chemical and biological characteristics of sewage sludge (SS) and its potential application in agricultural fields as an organic manure. Sewage sludge samples were collected from sewage treatment plant (STP) at Bhagwanpur, Varanasi, India and sieved in 2 mm mesh before being analysed for various physical and chemical characteristics. The processed sewage sludge possessed both major [total nitrogen (1.76 %), total phosphorous (1.29%), total potassium (1.15%)] and micro nutrients (Fe, Mn, Zn and Cu) and significant amount of organic carbon (8.67 %). However, this sewage sludge was also containing considerable amount of heavy metals like Cadmium (7.3 mg kg-1), chromium (49.2 mg kg-1), nickel (total 27.43 mg kg-1), and lead (39.53 mg kg-1), which were reported to be harmful to human beings, but these were lower than threshold limit recommended by Council of the European Communities, 1988 for agricultural use. Further, Bulk density and water holding capacity was 1.18 g cm-3 and 54.5 % respectively. With respect to microfauna, fungi were found more dominating than actinomycetes and bacteria in this sewage sludge. Therefore,considering use of this sewage sludge for agriculture may decrease the use of chemical fertilisers and make it more sustainable. However, in order to increase soil health without posing an environmental risk, sewage sludge must be carefully evaluated before being applied to soil especially for heavy metals and other hazardous pollutants.

Assessing amount of soil organic carbon and some soil properties under different land uses in a semi-arid region of northern Türkiye

The objective of this study is to investigate the effects of representative land use types and land cover (LUT/LC) of heavily deforested areas on soil properties in semi-arid region of Türkiye. Some of the soil properties have been measured on a grid with a 50 m sampling distance on the top-soil (0-15 cm depth). Data has been analyzed by using Ordinary Kriging/Spherical geostatistical model. Results indicated that the soil properties differed in terms of organic carbon (SOC), pH, bulk density, and the amount of sand, depending on the land uses in the study areas. The SOC concentration of top-soil layers has referred a significant difference (P<0.05) according to the land use type. Top-soil SOC concentrations in the four LUTLCs have been in the following order: cultivated areas < grasslands < Scotch pine stands = Uludağ fir stands. The impacts of LUTLC change on SOC and soil properties have not been restricted to the soil surface; however, relative changes have equally been high in the sub-soil, stressing the importance of sufficiently deep sampling. Furthermore, it has been determined that some physical and chemical characteristics of the natural forest soil have been significantly changed after long term and continuous cultivation. SOC loss is remarkable under the land use conversion while cropland has considerable potential to sequester SOC.

Soil microbial trait-based strategies drive the storage and stability of the soil carbon pool in Robinia pseudoacacia plantations

Soil microorganisms play an essential role in soil carbon sequestration and stability in forest ecosystems. However, how trade-offs in distinct microbial traits affect soil carbon storage and stability remains largely unknown, especially for forest soils that stock significant amounts of organic carbon. Here, we assessed the influences of the chronosequence of Robinia pseudoacacia (8, 18, and 30 years) on soil organic carbon (SOC) fractions and further explored the specific roles of microbial taxa in regulating soil carbon sequestration on the Loess Plateau via high-throughput sequencing techniques and analysis of co-occurrence networks and assembly processes. The results showed that the concentrations of soil easily oxidizable carbon (EOC), recalcitrant organic carbon (ROC), and SOC storage increased with stand age. However, the dissolved organic carbon (DOC) and microbial biomass carbon (MBC) concentrations increased from 8 years to 18 years and then decreased after 30 years. Stand age significantly affected the soil bacterial and fungal structures and diversity. Stochastic processes, especially dispersal limitation, were the main assembly processes affecting the bacterial and fungal communities. Soil pH, DOC and the N:P ratio drove bacterial assembly. However, fungal assembly was not affected by soil properties. Moreover, network analysis showed that three major bacterial modules and one major fungal module (Bac_Mod 1, 3, 4 and Fun_Mod 2) showed strong relationships with soil carbon storage and were considered soil carbon pool-associated modules. These modules based on the co-occurrence network analysis were composed of microbial taxa with different taxonomic and functional traits. Both random forest and correlation analyses indicated that increases or decreases in these modules were strongly correlated to variations in SOC fractions. These results demonstrated that with R. pseudoacacia plantation development, the recalcitrant-related module attributed to SOC became more stable.

Redox oscillations destabilize and mobilize colloidal soil organic carbon

The onset of oxic-anoxic events in soil induces biogeochemical processes that may have profound influences on the fate and transport of soil organic carbon (OC). An 18-wk long laboratory soil column study was conducted to investigate the influence of static oxic (SO), static anoxic (SA), or redox oscillation (RO) events on the release of OC. Column leachate samples were collected after 9-wk and 18-wk of incubations and separated into dissolved (<2.3 nm), natural nanoparticle (2.3–100 nm), fine colloid (100–450 nm), and particulate (> 450 nm) fractions that were characterized through spectrofluorometric analyses. The concentration of released OC from different treatment columns followed the order of SA > RO > SO. After 9-wk, total OC concentrations in the leachate samples were increased by 4-fold and 54-fold in the SO and SA columns compared to the time-zero control columns, respectively. However, after 18-wk, the released amount of OC doubled in SO but decreased by 50 % in SA columns compared to the 9-wk incubation samples. The RO columns had intermediate OC concentrations between the SO and SA treatments. The RO events further led to widely varied dynamics in the release and molecular composition of the size-fractionated OC compared to static conditions, indicating the effects of redox oscillation on the organo-mineral association in soil. The wide variations in the aromaticity of OC released after the 1st and 2nd RO events further support the notion that alternating redox processes regulate OC cycling differently than the SO or SA condition. The observed increase in fine colloid and particulate OC fractions (i.e., >100 nm) from 7 % to 40 % between 1st and 2nd RO suggests the clustering of nanoaggregates and/or formation of colloidal size aggregates. The composition of the released OC as influenced by redox fluctuations provides a baseline for the size continuum of soil OC and its potential ecological and environmental roles.

Assessment of long-term land use and land cover change effects on soil erosion and soil organic carbon stock in humid ecosystem condition

This study examined the consequences of land use and cover (LULC) changes on soil erosion and soil organic carbon in the Ünye district of Ordu province in the Central Black Sea Region where humid conditions prevailed in 1999, 2009, and 2019. GIS-based Revised Universal Soil Loss Equation (RUSLE) modeling approach, geostatistics and remote sensing techniques were employed in the study. According to the results considering the long years in the study area, the most relative change among LULC species was hazelnut fields with an increase of 167%. In this process, it has been determined that there are few spatial changes that occurred in artificial areas and pasture lands. In addition, in the classes of soil erosion rates defined by RUSLE, the areas classified as Very Low–Low (< 5 tons ha−1 year−1) for many years inhabit the largest area in the study area. The loss in the amount of soil organic carbon (SOC) is determined to have occurred mostly in areas with Very Low and Low erosion rates. However, it has been determined that SOC loss ensues in areas with Very High (> 20 tons ha−1 year−1) erosion rates, albeit slightly. Therefore, even in the areas with very slight erosion, soil conservation practices should be expanded to secure the long-term sustainability of the production system, especially in agriculture and hazelnut areas.

Comparative analysis of soil organic carbon in selected river catchments

The present study deals with the investigation of soil organic carbon in two water catchments in Northern Rila, Western Bulgaria. Field research, combined with analysis, provided sufficient data. Six key sites were selected and sampled in order to estimate and compare the amount of organic and inorganic carbon in the topsoil. The applied criteria for the choice of sites included: vegetation cover, predominant soil group, level of anthropogenization and transport accessibility. A total number of 13 samples from both catchments were collected and analyzed in the Central laboratory of the Institute of Soil Science, Agrotechnologies and Plant Protection (ISSAPP) “N. Pushkarov“. The results concern the amount and composition of soil organic matter in different soils – Cambisols (Albic, Humic, Dystric), Fluvisols and Umbrosols. The total carbon content of all samples varies between 1.23 and 9.69%. The amount of organic carbon ranges between 0.45 and 3.73%. The results of the study prove once again that the preservation of natural vegetation and current condition of the soil is of great importance for carbon sequestration and climate change mitigation.

Waste carbon conversion and utilization in chemical wastewater treatment process: Experimental approaches from lab-to pilot-scale

Chemical wastewater often contains large amounts of waste organic carbon. The current chemical wastewater treatment plants are an open carbon emission system. Inspired by the topic of CO2 conversion and utilization, this study provided a redesigned flowchart of chemical wastewater treatment process via closed-loop carbon conversion and utilization system for the resource utilization of waste carbon from wastewater. Purified terephthalic acid (PTA) wastewater, a common chemical wastewater, was selected to test the feasibility of the proposed strategy. An integrated closed-loop system involving activated sludge-microalgae-pyrolysis process was employed. Initially, a laboratory-scale wastewater treatment system combining activated sludge with microalgae process was applied for the carbon conversion and utilization in PTA wastewater. The COD removal efficiency was obtained at 93.02%, and over 94% of CO2 was captured. Microbial DNA analysis of the activated sludge indicated that the functional microorganisms mainly included Proteobacteria, Bacteroidetes, and Chloroflexi. Metabolic analysis of the microalgae showed that the abundances of differential metabolites associated with carbon metabolism significantly increased after treatment. Furthermore, a pilot-scale integrated system was applied to test this strategy and in which obtained a good performance in COD removal and CO2 capture. The produced excess biomass during chemical wastewater treatment, which was usually viewed as hazardous solid waste, was converted to biochar and carbonaceous combustible gas via pyrolysis. The produced biochar could be used as photocatalysts to remove antibiotic. The findings provided a new design to simultaneously achieve water pollution control, carbon conversion & utilization, and resource & energy recovery in chemical wastewater treatment process.

Microfluidic Impedance Cytometry for Single-Cell Particulate Inorganic Carbon:Particulate Organic Carbon Measurements of Calcifying Algae.

Calcifying algae, like coccolithophores, greatly contribute to the oceanic carbon cycle and are therefore of particular interest for ocean carbon models. They play a key role in two processes that are important for the effective CO2 flux: The organic carbon pump (photosynthesis) and the inorganic carbon pump (calcification). The relative contribution of calcification and photosynthesis can be measured in algae by the amount of particulate inorganic carbon (PIC) and particulate organic carbon (POC). A microfluidic impedance cytometer is presented, enabling non-invasive and high-throughput assessment of the calcification state of single coccolithophore cells. Gradual modification of the exoskeleton by acidification results in a strong linear fit (R 2= 0.98) between the average electrical phase and the PIC:POC ratio of the coccolithophore Emiliania huxleyi 920/9. The effect of different CO2 treatments on the PIC:POC ratio, however, is inconclusive, indicating that there is no strong effect observed for this particular strain. Lower PIC:POC ratios in cultures that grew to higher cell densities are found, which are also recorded with the impedance-based PIC:POC sensor. The development of this new quantification tool for small volumes paves the way for high-throughput analysis while applying multi-variable environmental stressors to support projections of the future marine carbon cycle.

Mobilization of subsurface carbon pools driven by permafrost thaw and reactivation of groundwater flow: a virtual experiment

Permafrost thaw leads to an increase in groundwater circulation and potential mobilization of organic carbon sequestered in deep Arctic sediments (e.g. 3–25 m below surface). Upon thaw, a portion of this carbon may be transported along new groundwater flow paths to surface waters or be microbially transformed or immobilized by in-situ biogeochemical reactions. The fate of thaw-mobilized carbon impacts surface water productivity and global climate. We developed a numerical model to investigate the effects of subsurface warming, permafrost thaw, and resultant increased groundwater flow on the mobilization and reactive transport of dissolved organic carbon (DOC). Synthetic simulations demonstrate that mobilization and groundwater-borne DOC export are determined by subsurface thermo-chemical conditions that control the interplay of DOC production (organic matter degradation), mineralization, and sorption. Results suggest that peak carbon mobilization from these depths precedes complete permafrost loss, occurring within two centuries of thaw initiation with the development of supra-permafrost groundwater flow systems. Additionally, this study highlights the lack of field data needed to constrain these new models and apply them in real-word site-specific applications, specifically the amount and spatial variability of organic carbon in deep sediments and data to constrain DOC production rates for groundwater systems in degrading permafrost. Modeling results point to key biogeochemical parameters related to organic matter and carbon bioavailability to be measured in the field to bridge the gap between models and observations. This study provides a foundation for further developing a physics-based modeling framework to incorporate the influence of groundwater flow and permafrost thaw on permafrost DOC dynamics and export, which is imperative for advancing understanding and prediction of carbon release and terrestrial-aquatic carbon exchange in warming Artic landscapes in the coming decades.

Environmental changes during the MIS 6a–MIS 5e transition: the Parchliny 2016 profile, central Poland

We describe the penultimate glacial – last interglacial transition from the one of the numerous palaeolake successions in central Poland, which have yielded many documented Eemian and Early Weichselian floral records. In the new profile, Parchliny 2016, the lacustrine deposits were analysed lithologically, botanically, zoologically, and geochemically, providing new data that illustrate the environmental transition from the Late Saalian (MIS 6a) to the Eemian interglacial (MIS 5e). Five phases of palaeolake development have been distinguished. The first phase was related to the rapid melting of a dead ice block buried in the tills to form a lake. The second phase documented a Late Saalian initial succession, with the dominance of open steppe communities (Stadial 1), followed by a third phase with gradual increasing density of vegetation, the spread of boreal forests (Zeifen interstadial) and further increase in open communities and the retreat of pine (Kattegat stadial). The fourth phase reflected the beginning of Eemian interglacial by the expansion of pioneering birch-pine and purely birch forests and an increasing proportion of deciduous trees, including oak (Vth phase). Diatom, cladoceran and geochemical studies indicate at least two stages of lake development. The first stage (Late Saalian) was of an open lake (2–4 m deep), in relatively cold conditions and nutrient-poor water with the lowest amounts of organic carbon and nitrogen. The second stage (Eemian interglacial), shows warmer, shallower conditions in which the lake’s primary production increased, the water was well oxygenated, and there were more trophic levels.