Dissolved Organic Carbon Fractions Formed during Composting of Municipal Solid Waste: Properties and Significance

The properties and transformation of dissolved organic matter (DOM) extracted (10 L water per kilogram compost) from municipal solid waste (MSW) compost at five stages (days 47, 77, 105, 126, and 187) of composting were investigated. The DOM was fractionated into hydrophobic or hydrophilic neutrals, acids, and bases. The unfractionated DOM, the hydrophobic acids and neutrals (HoA and HoN, respectively), and the hydrophilic neutrals (HiN) fractions were studied using solid-state ¹³C-NMR, FTIR, and DRIFT spectroscopy. The HoA fraction was found to be the dominant (percentage of total DOM) hydrophobic fraction, exhibiting a moderate increase during composting. The HoN fraction increased sharply from less than 1% to 18% of the total DOM during 187 days of composting, while the hydrophobic bases (HoB) exhibited the opposite trend. The HiN represented the major fraction of the hydrophiles up to 120 days of composting, decreasing thereafter by 38%. The relative concentration of the hydrophilic acids and bases (HiA and HiB, respectively) exhibited no consistent trend during composting. DRIFT spectra of the unfractionated DOM taken from the composting MSW revealed a decreasing level of polysaccharide structures with time. The ¹³C-NMR and FTIR spectra of the HoA fraction exhibited a polyphenol-humic structure, whereas the HoN spectra exhibited strong aliphatic features. The spectra of the HiN fraction confirmed its polysaccharide nature. During the final stage of composting, the DOM concentration was steady, while a relative decrease of HiN concomitant with an increase of HoA and HoN fractions was observed. These indicate that the DOM contained a low concentration of biodegradable organic matter and a higher content of macromolecules related to humic substances. The biological significance and heavy metal binding of these fractions are being studied based on earlier observations showing enhanced plant growth in the presence of DOM extracted from mature as opposed to immature compost.     

Middle Permian organic carbon isotope stratigraphy and the origin of the Kamura Event

Large carbon cycle perturbations associated with the Middle Permian (Capitanian) mass extinction have been widely reported, but their causes and timing are still in dispute. Low resolution carbon isotope records prior to this event also limit the construction of a Middle Permian chemostratigraphic framework and global or local stratigraphic correlation, and hence limit our understanding of carbon cycle and environmental changes. To investigate these issues, we analyzed the ¹³C_org values from the Middle Permian chert-mudstone sequence (Gufeng Formation) in the Lower Yangtze deep-water basin (South China) and compared them with published records to build a chemostratigraphic scheme and discuss the underlying environmental events. The records show increased δ¹³C_org values from late Kungurian to early Guadalupian, followed by a decrease to the late Wordian/early Capitanian. The early-mid Capitanian was characterized by elevated δ¹³C_org values suggesting the presence of the “Kamura Event”: an interval of heavy positive values seen in the δ¹³C_carb record. We propose that these heavy Capitanian δ¹³C values may be a response to a marked decline in chemical weathering rates on Pangea and associated reduction in carbonate burial, which we show using a biogeochemical model. The subsequent negative δ¹³C excursion seen in some carbonate records, especially in shallower-water sections (and in a muted expression in organic carbon) coincide with the Capitanian mass extinction may be caused by the input of isotopically-light carbon sourced from the terrestrial decomposition of organic matter.     

Effects of mineral-organic fertilizer on the biomass of green Chinese cabbage and potential carbon sequestration ability in karst areas of Southwest China

The karst mountain areas of Southwest China contain barren farmland soils and suffer from nutritional and water deficiencies that affect crop productivity. Hence,it is imperative to apply suitable fertilizers to restore soil fertility and maintain crop yield. The aim of this study is to investigate the effects of mineral-organic fertilizer(MOF)made of potassic rock and organic waste on the growth of crops. For this purpose, green Chinese cabbage grown using three different fertilization methods including MOF,inorganic fertilizer(IF), and a control was evaluated. We determined soil water content, agronomic characteristics,and biomass of green Chinese cabbage in different treatments. Furthermore, surface runoff from the pot experiments and soil leachate from pot experiments were collected to determine water temperature, pH, and cation and anion concentrations. The results demonstrate thatMOF can improve the soil water-holding capacity of soil,and the basic agronomic characteristics of the cabbage treated with MOF were superior to those with IF. Using MOF can promote the increase in cabbage biomass.Additionally, the concentration of inorganic carbon(largely in the form of HCO_3^-) in surface runoff water treated by MOF was higher than the other treatments, establishing carbon sequestration potential. This work provides a novel and environmentally friendly fertilization pattern in karst areas, which will improve crop yield and also increase the carbon sequestration potential of crops.     

Untersuchungen zur adsorptiven Abtrennung von leichtflüchtigen chlorierten Kohlenwasserstoffen (LCKW) aus huminstoffhaltigen Wässern mit neuartigen Adsorberpolymeren und Aktivkohlen. Teil II:: Dynamik der Adsorption

Investigations of the Adsorptive Separation of Volatile Chlorinated Hydrocarbons (VCHC) from Water with Humic Substance by Novel Polymeric Adsorbents and Activated Carbons. Part II: Dynamics of Adsorption In this publication, the dynamics of adsorption of different volatile chlorinated hydrocarbons (VCHC) (1,2-dichloroethane, 1,1,1-trichloroethane, trichloroethene) and a humic substance from water as well as of these VCHC from water with humic substance onto novel polymeric ad-[QJ][HR] sorbents (WOFATIT EP 63, DOWEX XUS 43493, MACRONET MN 100 and MN 200) was studied in comparison to activated carbons (NORIT ROW 0.8 SUPRA, PRECOLITH BKK 3, HYDRAFFIN CG). The obtained breakthrough curves and the following predicted characteristic values reveal that the polymeric adsorbents do not remove or remove the humic substance only with low adsorption capacity in contrast to the activated carbons. At the adsorption of the VCHC from water with humic substance it was determined that the influence of the humic substance on the adsorption capacity is substantially less on polymeric adsorbents than on activated carbons.     

Total Organic Carbon (TOC) as a Sum Parameter of Water Pollution in Selected Polish Rivers (Vistula,Odra, and Warta)

This paper reports on total organic carbon (TOC) and its fractions dissolved organic carbon (DOC) and particulate organic carbon (POC) studied in different Polish rivers. The samples investigated came from the Vistula, Odra, and Warta rivers, and were compared with similar data on river waters available in the literature. The DOC concentrations ranged from 10.0 to 14.2 mg/L and did not vary during the vegetative season. The POC values considerably increased from May through September and reached a maximum in summer. Results for the years 1991τ1996 evidenced a significant increase in the POC value for the Polish rivers from 10.8 to 24.5 mg/L, in comparison with analogous values for West European rivers and North American ones. The enhanced values of TOC and POC were interpreted as being due to anthropogenic pollution.     

Carbon and oxygen isotopic constraints on paleoclimate and paleoelevation of the southwestern Qaidam basin,northern Tibetan Plateau

We investigate the growth of the northern Tibetan Plateau and associated climate change by applying oxygen and carbon isotopic compositions in Cenozoic strata in the southwestern Qaidam basin. The X-ray diffraction and isotopic studies reveal that the carbonate minerals are mainly authigenic and they do not preserve any evidence for detrital carbonate and diagenesis. The isotope data show large fluctuations in the δ¹⁸O and δ¹³C values in the middle–late Eocene, indicating relatively warm and seasonal dry climate. The positive correlation of the δ¹⁸O and δ¹³C values in the Oligocene and the positive shift of the δ¹³C values from the Eocene to Oligocene suggest that the climate changed to arid in the Oligocene. However, the δ¹⁸O values show negative shift, which is closely related to the global cooling event. During the Miocene, the δ¹³C values vary between –2‰ and –4‰, whereas the δ¹⁸O values show continuous negative shift. The mean δ¹⁸O values decrease from –8.5‰ in the early Miocene to –10.0‰ in the late Miocene. The stable isotope-based paleoaltimetry results suggest that the elevation of the southwestern Qaidam basin was approximately 1500 m in the middle–late Eocene and Oligocene. Subsequently, during Miocene the crustal uplift process started and the elevation reached approximately 2000 m in the early Miocene and 2500 m in the late Miocene, which suggests large-scale growth of the northern Tibet Plateau during the Miocene.     

北京城区二氧化碳浓度和通量的梯度变化特征——I浓度与虚温

根据北京塔7层涡动系统2012年5月至2013年12月的湍流观测数据,分析了北京城区二氧化碳浓度在不同高度层次的日变化和月变化特征,并初步给出不同季节和日变化时间段内二氧化碳的浓度垂直廓线.结果表明:二氧化碳浓度整体随高度而下降;各观测层均有浓度的明显日变化,夏季最为明显,冬季相对平缓;近地层浓度直接受城市供暖、地表植被、交通运输等碳源影响,更高观测层浓度则受对流输送和天气过程影响较大;垂直方向上,冬季浓度变化范围最大,夏季层间浓度变化最明显;在一天中的任何时刻,近地面层二氧化碳浓度的日变化最低值一般出现在夏季,50m以上则出现在春季,浓度最高值总是出现在冬季;根据对二氧化碳浓度四季垂直廓线变化的分析可以看出,边界层二氧化碳浓度强烈受到碳源、下垫面植被、大气稳定度、环境温度和天气过程等因素的影响.     

Quantifying and modelling the carbon sequestration capacity of seagrass meadows – A critical assessment

Seagrasses are among the planet’s most effective natural ecosystems for sequestering (capturing and storing) carbon (C); but if degraded, they could leak stored C into the atmosphere and accelerate global warming. Quantifying and modelling the C sequestration capacity is therefore critical for successfully managing seagrass ecosystems to maintain their substantial abatement potential. At present, there is no mechanism to support carbon financing linked to seagrass. For seagrasses to be recognised by the IPCC and the voluntary C market, standard stock assessment methodologies and inventories of seagrass C stocks are required. Developing accurate C budgets for seagrass meadows is indeed complex; we discuss these complexities, and, in addition, we review techniques and methodologies that will aid development of C budgets. We also consider a simple process-based data assimilation model for predicting how seagrasses will respond to future change, accompanied by a practical list of research priorities.     

Drivers of phytoplankton,bacterioplankton, and zooplankton carbon biomass in tropical hydroelectric reservoirs

Studies of carbon sources in plankton communities are important because carbon content has become the main currency used in functional studies of aquatic ecosystems. We evaluated the contribution to the total organic carbon pool from different plankton communities (phytoplankton, bacterioplankton, and zooplankton – C-biota) and its drivers in eight tropical hydroelectric reservoirs with different trophic and hydrological status and different physical features. Our systems were separated into three groups based on trophic status and water residence time: (i) mesotrophic with low residence time (ML); (ii) mesotrophic with high residence time (MH); and (iii) eutrophic with low residence time (EL). Our hypothesis that reservoirs with low water residence times and low nutrient concentrations would show the lowest C-biota was supported. Phytoplankton carbon (C-phy) showed the highest concentrations in the EL, followed by MH and ML systems. The EL group also showed significantly higher zooplankton carbon (C-zoo). No significant difference was observed for bacteria carbon (C-bac) among the three system groups. In addition to trophic status and water residence time, regression analyses revealed that water temperature, light, pH, and dissolved organic carbon concentrations were the main drivers of plankton communities in these large tropical hydroelectric reservoirs.