Organic Total Phosphorus Research Articles

Treatment and Reuse of Black Water by Novel Energy-saving Shaft/Anaerobic /Anoxic/ Aerobic (S/A/A/O) System: A Novel Energy-saving Shaft/Anaerobic /Anoxic/ Aerobic (S/A/A/O) System for black water

In this study the novel integrated anaerobic/anoxic/aerobic (A/A/O) and shaft aeration process system which could enhance the nutrient removal efficiency of wastewater with a low carbon nitrogen ratio (C/N) was investigated. Several dissolved oxygen (DO) ratios (1.0-2.0, 2.0-3.0, 3.0-4.0 mg/L) were applied in order to obtain more knowledge on the biological nitrogen and phosphorus removal performances. The experiment was carried out on a lab-scale Shaft-Anaerobic-Anoxic-Aerobic (S/A/A/O) wastewater treatment system. The average removal efficiencies of the total organic carbon, total nitrogen and phosphorus were 84.0%, 82.0% and 93.7%, respectively. The result showed that the proposed system was promising for the treatment of wastewater with a low C/N ratio because that in this system nitrification and denitrification happened simultaneously. Besides, the system had an automatic return system and its floor area was small, which made it energy-saving.

Humic substances from green waste compost: An effective washing agent for heavy metal (Cd, Ni) removal from contaminated sediments.

In this study, humic substances (HS) selected from 8 composting groups (peanut straw, sesame straw, corn straw and deciduous leaves, with or without grape marc) were used to remove Cd and Ni from artificially contaminated sediments. Sesame straw compost appeared to have the highest removal capacity for heavy metals through a series comparison on Cd removal efficiency, yield of HS and fulvic acids (FA), and seed germination index. The selected sesame HS was further used to wash two contaminated sediments of varying properties (a clay type for sediment 1 and a silty loam for sediment 2). Batch desorption experiments were conducted to determine the optimum HS concentration, equilibrium time, pH, solid-to-liquid ratio, and washing frequency. Under optimum conditions, a triple washing removed 74.16% of Cd and 42.91% of Ni from sediment 1, and 86.88% of Cd and 43.84% of Ni from sediment 2, respectively, whereas a commercial FA only achieved half of the efficiency. After washing, both sediments were identified with increased contents of total organic matter total nitrogen and phosphorus. Therefore, HS from the sesame straw compost is a cost-effective, efficient and environmental-friendly washing agent to remove heavy metals from contaminated sediments.

Responses of soil nutrients and biological characteristics to nitrogen deposition in Hulun Buir Grassland, China.

Studies on effects of nitrogen deposition were mainly focused on temperate grasslands in Inner Mongolia of China. In addition, there are substantial differences between the present simulation methods and the natural nitrogen deposition. A three-year experiment was carried out to compare the effects of simulation methods (common urea and slow-released urea) and nitrogen deposition rates (0, 25, 50, 75, 100, 150, 200 and 300 kg N·hm-2·a-1) on soil nutrients and biological characteristics in Hulun Buir Grassland. We found that simulated nitrogen deposition had significant influences on soil chemical properties, biological properties and enzyme activities. With the increases of nitrogen deposition, soil pH declined with the greatest extent of 0.2 units, while the highest concentrations of total dissolved nitrogen (TDN) and dissolved organic carbon (DOC) increased by 5-7 times and 12%-36%, respectively. There was a decline trend for soil total phosphorus (TP) and organic phosphorus (TOP). Microbial biomass and metabolic activity increased firstly and then decreased. Moderate simulated nitrogen deposition rates significantly increased soil carbon, nitrogen and phosphorus related enzyme activities. Compared to common urea, using slow-released urea to simulate nitrogen deposition decelerate the decline of soil pH and the increase of dissolved nutrients, and smoothed the change of microbial biomass, metabolic activity, and nitrogen hydrolyzed enzyme activities. Overall, the results confirmed that continuous nitrogen input caused the decline of soil pH and the increase of bioavailable carbon and nitrogen, and then changed microbial biomass and activity.

Large heterogeneity of water and nutrient supply derived from runoff of nearby rock outcrops in karst ecosystems in SW China

Rock outcrops are frequently visible in terrestrial landscapes, typically in karst. However, there has been insufficient research conducted on their effects on the formation of soil water and nutrients heterogeneity in nearby soil patches. In: 1) a rock desertification ecosystem, 2) an anthropogenic forest ecosystem, and 3) a secondary forest ecosystem in Shilin, Southwest China, rock occupancy ratio was measured, water received by and subsequently funneled off by rock outcrops was quantified, and their concentrations of the total organic carbon, nitrogen, phosphorus, and potassium were determined. Receiving rate Rr of those elements of the remaining soil patches in various 2 m × 2 m soil + rock outcrop samples were calculated, and r200 at which Rr of the remaining soil patch was twice that without rock emergence was calculated to evaluate the heterogeneity difference among different elements in different ecosystems. There were 1.43–5.44 folds differences between Rr under the highest rock ratio (79.4%) sample and the rate of non-rock emergence sample for water, organic carbon, nitrogen, phosphorus, and potassium in the three ecosystems respectively, indicating a large supply heterogeneity for those elements within an ecosystem and between ecosystems. The r200 were between 47% (water, at rock desertification ecosystem) to 90% (potassium at rock desertification ecosystem, depending on the receiving rate and funneling rate of the rock for different element in different ecosystem. In conclusion, large supply heterogeneity has derived from high variation of rock runoff determined by rock emergency ratio, the rate of receiving and the rate of funneling off by the rock. Our study provided new evidence to trace soil and water heterogeneity of microhabitats in rocky ecosystems. Additionally, rock outcrop is also an important factor in evaluating hydrological and related nutrient characteristics in rocky ecosystems.

The expression of early Aptian to latest Cenomanian oceanic anoxic events in the sedimentary record of the Briançonnais domain

Abstract The Brianconnais domain is an important paleogeographic unit in the Alps, which represents a structural high within the former Alpine Tethys Ocean. Expressions of the most important Cretaceous oceanic anoxic events (OAE1a-d and OAE2) are exceptionally well preserved in the Subbrianconnais unit at Roter Sattel in the Fribourg Prealps, Switzerland. The main objective of this study was to reconstruct oxygen contents and trophic levels in the water column for each OAE. To accomplish this we used an integrated multi-proxy approach, including total organic carbon (TOC), phosphorus (P), and redox and productivity-sensitive trace-element contents (RSTE, PSTE). RSTE enrichments associated with the highest TOC values (up to 5.4 and 4.8 wt%) and with the lowest Mn contents in sediments equivalent to the Selli and Paquier OAEs (1a and 1b) indicate the presence of intermittent anoxic to euxinic conditions during these events. Sediments equivalent to Bonarelli OAE2 near the Cenomanian-Turonian (CT) boundary are also characterized by significant trace-element enrichments in comparison to average shale values. Mo and U enrichment factors (EFs) in the lower Aptian and lower Albian intervals are characteristic of an unrestricted marine environment, and in the Cenomanian-Turonian boundary interval they indicate a relationship with a particulate Fe-Mn-oxyhydroxide shuttle within the water column. In the OAE1a interval the elevated total P content associated with higher Corg/Ptot ratios and maxima in TOC values suggests that a part of the remobilized P remained trapped in the sediments. By contrast, the lower Ptot values associated with RSTE and Corg/Ptot enrichments in the OAE1b and OAE2 intervals indicate that a significant part of P was remobilized and escaped to the bottom water. Our results highlight the combined roles of regional and global parameters in the development of oxygen-deficient conditions that may lead to anoxia and increase in organic matter preservation during the OAEs. The differentiated topography of the Brianconnais domain associated with global climate and sea-level change and its influence on weathering in general, and more specifically on the mobilization of sediments on the adjacent ridge, modulated nutrient availability in different proportions during the different “mid”-Cretaceous OAEs.

Pollution Reduction in Throughflow from Vegetated and Non-Vegetated, Foam-Based Surfaces and Green Roofs

The ability of foam-based unplanted and green surfaces (Aqualok™) to remove pollutants (total suspended solids (TSS), NO3, NH4, total organic carbon (TOC) and total phosphorus (TP)) from direct precipitation and roof runoff passing through the surfaces was assessed. The assessments were conducted using unplanted Aqualok™ and planted Aqualok™ roof panels and a bioswale Aqualok™ installed on two Fire and Emergency Medical Service Stations (FEMSs) in Washington, D.C., USA. During a three-year period, impacts on water chemistry were evaluated by examining overall averages as well as performance over time. Upon installation, all Aqualok™ surfaces released a “pulse” of TSS and NO3, which decreased over time. TP concentrations from the planted panels were elevated relative to conventional roof runoff throughout the study. TOC was generally higher for planted Aqualok™ compared to unplanted Aqualok™, and did not decrease over time. Excluding the three months post-installation, TSS in throughflow from planted and unplanted Aqualok™ surfaces was 88% and 90% lower, respectively, than in runoff from a conventional tar and gravel roof. No significant differences between green surface throughflow and conventional roof runoff for NO3 or NH4 were observed.

CARACTERIZACIÓN QUÍMICA Y FÍSICA DEL BAGAZO DE AGAVE TEQUILERO COMPOSTADO CON BIOSÓLIDOS DE VINAZA COMO COMPONENTE DE SUSTRATOS PARA CULTIVOS EN CONTENEDOR

The objectives of this study were to determine the chemical and physical properties of tequila blue agave bagasse composted with tequila vinasses’ biomass (compost) in coconut based powder substrates for potted plants and to compare their performance against two commercial substrates. The substrates evaluated included coconut powder, Canadian peat, 100 % compost, and 3-coconut powder based mixtures containing 30 %, 50 %, and 70 % compost. Chemical parameters analyzed comprise organic matter, pH, conductivity, cation exchange capacity, total organic carbon, C/N ratio, total nitrogen, phosphorus, potassium, and magnesium. The physical properties evaluated included apparent density, apparent specific density, total porous spaces, free water, bound water, absorbed water and particle size distribution. We were able to demonstrate that the formulations of agave bagasse compost and coconut powder could replace coconut powder and peat, since their physical and chemical characteristics are suitable for its use as substrate for plants cultivated in containers. The treatments with better results were those with 30 %, 50 %, and 100 % compost. Composting waste materials provide additional benefits including a reduction in environmental pollution as well as the local production of substrates for protected agriculture systems, which require substantial quantities of these type of materials.

Improving the dewaterability of citric acid wastewater sludge by Fenton treatment

Abstract The citric acid wastewater treatment produces a large quantity of sludge, which contains more organic matter and is more difficult to be dewatered by mechanical devices, compared to the municipal wastewater sludge. Fenton conditioning was a highly effective and affordable approach to improving the dewaterability of citric acid wastewater sludge while preserving the fertilizing properties. The optimal condition of Fenton treatment was pH 5.0, H2O2 dose of 20 mg g−1 dry solids, and Fe2+ dose of 80 mg g−1 dry solids. Capillary suction time was reduced from 19.3 s to 10.7 s, and the water content of sludge cake was reduced from 85.3% to 73.8% under this condition. There was no significant difference in capillary suction time and the water content of sludge cake reduction by Fenton treatment between the lab-scale and scale-up experiments. The mechanism investigations of extracellular polymeric substances, zeta-potential, particles size, and morphological changes of the sludge samples conditioned by Fenton treatment under the optimal condition demonstrated that the enhanced coagulation by Fenton treatment was the mechanism dominating the sludge dewaterability improvement. Most critically to the citric acid wastewater sludge, the majority of fertilizing properties of the sludge were preserved after Fenton treatment. The volatile suspended solids, total organic carbon, total nitrogen, potassium and phosphorus were mostly maintained in the solid phase. The cost of Fenton reagents under the optimal condition was approximately 49 US$/t dry solids, which made Fenton treatment a cost reasonable approach to citric acid wastewater sludge conditioning.

Restoration with pioneer plants changes soil properties and remodels the diversity and structure of bacterial communities in rhizosphere and bulk soil of copper mine tailings in Jiangxi Province, China.

To unravel the ecological function played by pioneer plants in the practical restoration of mine tailings, it is vital to explore changes of soil characteristics and microbial communities in rhizosphere and bulk soil following the adaptation and survival of plants. In the present study, the diversity and structure of rhizospheric bacterial communities of three pioneer plants in copper mine tailings were investigated by Illumina MiSeq sequencing, and the effects of pioneer plants on soil properties were also evaluated. Significant soil improvement was detected in rhizospheric samples, and Alnus cremastogyne showed higher total organic matter, total nitrogen, and available phosphorus than two other herbaceous plants. Microbial diversity indices in rhizosphere and bulk soil of reclaimed tailings were significantly higher than bare tailings, even the soil properties of bulk soil in reclaimed tailings were not significantly different from those of bare tailings. A detailed taxonomic composition analysis demonstrated that Alphaproteobacteria and Deltaproteobacteria, Chloroflexi, Acidobacteria, and Gemmatimonadetes showed significantly higher relative abundance in rhizosphere and bulk soil. In contrast, Gammaproteobacteria and Firmicutes were abundant in bare tailings, in which Bacillus, Pseudomonas, and Lactococcus made up the majority of the bacterial community (63.04%). Many species within known heavy metal resistance and nutrient regulatory microorganism were identified in reclaimed tailings, and were more abundant among rhizospheric microbes. Hierarchical clustering and principal coordinate analysis (PCoA) analysis demonstrated that the bacterial profiles in the rhizosphere clustered strictly together according to plant types, and were distinguishable from bulk soil. However, we also identified a large shared OTUs that occurred repeatedly and was unaffected by highly diverse soil properties in rhizosphere and bulk samples. Redundancy analysis indicated that water content and Cu and As concentrations were the main environmental regulators of microbial composition. These results suggest that the interactive effect of pioneer plants and harsh soil environmental conditions remodel the specific bacterial communities in rhizosphere and bulk soil in mine tailings. And A. cremastogyne might be approximate candidate for phytoremediation of mine tailings for better soil amelioration effect and relative higher diversity of bacterial community in rhizosphere.

Leaching disturbed the altitudinal distribution of soil organic phosphorus in subalpine coniferous forests on Mt. Gongga, SW China

Little information is available about the leaching effects on the altitudinal distribution of soil organic phosphorus (OP), even though this process commonly occurs in most humid montane. Our aims were to decipher spatial variations in OP fractions and to clarify the effects of leaching on these variations along the altitudinal gradient (2628, 2781, 3044 and 3210 m a.s.l.) on Mt. Gongga, southwest China. The results showed that the stocks of total OP (TOP) and moderately resistant OP (MROP) increased roughly upslope, with their minimums (824.69 and 410.56 kg ha−1, respectively) at 2781 m. The concentrations and stocks of labile OP (LOP) markedly increased with altitude. The stocks of moderately labile OP (MLOP) and highly resistant OP (HROP) did not vary significantly among the four sites. The TOP distribution was likely related to the decrease of mineralization rate caused by the decreasing temperature upslope, and also disturbed by the leaching process. In addition, distributions of other P fractions were also regulated by this process. A larger loss of bioavailable P (Bio-P) occurred at the lower altitudes (2628 and 2781 m) due to more intensive leaching. This larger loss was compensated by microbial processes, as sharp decline in microbial biomass P and intensive mineralization of LOP via higher enzyme activities were observed. The MLOP and MROP were the main OP fractions that were downward migrated with fulvic acids, amorphous Fe and Al. The results highlight the role of leaching in regulating distributions of OP and Bio-P along altitudinal gradients in montane ecosystems.

Spatial Distribution of Carbon, Nitrogen and Phosphorus within Surface Sediments in the Lower Lancang River: Pollution Assessment Related to Dams

Surface sediment is one of the main sources of nutrients in overlying water environments, and these can also indirectly reflect the degree of eutrophication. In this paper, the spatial distribution characteristics of total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) in the surface sediments of 11 sections in the lower Lancang River during flood season are analyzed, as well as the distribution of phosphorus in different forms. The main sources of TOC and its correlation with TN and TP are discussed and, finally, the pollution levels of the surface sediments are evaluated. The results show that the average content of TOC in the surface sediments of the lower Lancang River is 9003.75 mg/kg. The average TN content is 893.79 mg/kg, while the average TP content is 521.35 mg/kg. The TOC in the surface sediments of the lower Lancang River is derived mainly from algae and plankton in the river, and the TN and TP have similar sources. The total phosphorus in the surface sediments of the lower Lancang River is composed mainly of calcium-bound phosphorus (Ca-P). The evaluations of the organic pollution index and comprehensive pollution index show that the surface sediment pollution degree at the upper sections of the Nuozhadu and Jinghong Dams are more serious than those below the dams. Furthermore, the tributary sections are all slightly polluted, with the exception of the Mengyang River, which is considered moderately polluted.

Effects of Land Use on Concentrations and Chemical Forms of Phosphorus in Different-Size Aggregates

Land use has been recognized as an important driver of environmental change on all spatial and temporal scales. This study was conducted to determine the effects of land uses on phosphorus concentration in bulk soil and in water-stable aggregates in different soils. The study was conducted on three soil types (Ferrosols, Cambosols, and Primosols), which were collected from three different locations from southeast China and under three land uses (Uncultivated, Vegetable and forest land) the region is characterized as a hill and plain area. Accordingly, a total of 24 soil samples were collected. The results showed that average contents of total P were 0.55–1.55 g/kg, 0.28–1.03 g/kg and 0.14–0.8 g/kg for the soils: Cambosols, Ferrosols and Primosols respectively. Vegetable and forest land led to higher total phosphorus contents in these soils than in the uncultivated land. An aggregate fraction of >2 mm under forest land made up the largest percentage (30 up to 70%), whereas the size fraction <0.106 mm made the least contribution (5 up to 20%) in all soil types. Vegetable land increased the total phosphorus, organic phosphorus and Olsen P and phosphorus forms in the soils. It implies that the conversion of natural ecosystem to vegetable land increased the phosphorus proportion in the soils, which could have negative impact on the environmental quality.

GROWTH COMPARISON OF FOUR ARABLE CROPS ON THE POLLUTED AND UNPOLLUTED SOILS OF BODO CITY IN OGONI LAND RIVER STATE, NIGERIA

The aim of this research was to ascertain the effects of crude oil spill on agricultural soil and plant growth. The soil samples were collected from cultivated area that is not affected by spill and crude oil polluted site both in Bodo city in Gokana Local Government Area of River State and were taken to Campus II Delta State University, Abraka, Delta State. Four selected vital crops were sown on these soils to determine the plant growth response due to the presence of crude oil contamination. The unpolluted soil was used as a control as compared to the polluted one. The parameters analyzed were soil moisture content, pH, Electrical conductivity (E.C), total hydrocarbon content (THC), total organic carbon (TOC), total nitrogen, phosphorus, zinc, lead, cadmium, nickel, chromium, sand, silt and clay. The study revealed that there were adverse effects of crude oil pollution on soil nutrients, fertility as well as plant growth and production. It was also observed that the polluted agricultural land had high concentration of zinc, lead, cadmium and Chromium that are above the limit set in the National Standard for heavy metal pollution on soil. The people’s livelihood as well as their food security is a function of the healthy state of the soil for plant production for sustainability. Therefore, it is recommended that the UNEP Environmental Assessment Report on Ogoni land should be implemented with immediate effect to ameliorate the native effects of crude oil spill on vital food crops of the Ogoni people.

Alternative approach to the standard, measurements and testing programme used to establish phosphorus fractionation in soils

The fractionation of phosphorus in 9 soils was established according to the standards, measurements and testing (SMT) programme. Five fractions were so defined and phosphorus was analysed by spectrophotometry. In parallel, the phosphorus extracted in each fraction was determined using graphite furnace atomic absorption spectrometry (GFAAS) after validation of this technique using certified reference materials. Phosphorus in soils was named total phosphorus, inorganic and organic phosphorus, apatite and non-apatite inorganic phosphorus, depending on extractants. The use of both analytical techniques revealed differences between the concentration of phosphorus in soluble extracts and highlighted the fact that spectrophotometry was a selective analytical technique. In view of the resource- and time-consuming of the SMT procedure and the results obtained in the present study, an alternative method was proposed to estimate the fractionation of phosphorus in soil in order to precise the potential effects of phosphorus on plant nutrition when plant biomass is produced as part of metal-contaminated soil management.

Seasonal variation rather than stand age determines bacterial diversity in the rhizosphere of wolfberry (Lycium barbarum L.) associated with soil degradation

Soil degradation occurs in wolfberry (Lycium barbarum L.) fields with increasing stand age, but the effect of stand age on rhizosphere microbial communities is unclear. We examined the seasonal variation of rhizosphere bacterial communities under long-term cultivation of L. barbarum. We determined surface (0–20 cm) and subsurface (20–40 cm) soil properties in L. barbarum rhizosphere at four stand ages (3–15 years) across three growth seasons (spring–autumn). Soil bacterial communities were characterized by 16S rRNA high-throughput sequencing. Soil nutrient availability in the surface was higher than that in the subsurface. Total soil organic carbon (TOC), nitrogen (TN), and phosphorus (TP) occurred at the highest levels in the summer across different stand ages. Soil bacterial diversity in the autumn was lower than that in the spring and summer. More diverse communities were found at stand ages of 3 and 6 years compared with 9 and 15 years. The relative abundance of Proteobacteria was highest in the summer, whereas the relative abundance of Bacteroidete at stand age of 9 years was significantly higher than those at other stand ages across different seasons. Xanthomonadaceae abundance increased with stand age, while Bacillus and Pirellulaceae abundances decreased in the spring and summer compared with autumn. Soil electric conductivity was a key edaphic factor for the rhizosphere bacterial community structure. Seasonal fluctuation, rather than stand age, determines soil bacterial diversity in the rhizosphere of L. barbarum associated with soil degradation under long-term cultivation of L. barbarum.

Ecoenzymatic stoichiometry and microbial nutrient limitation in rhizosphere soil in the arid area of the northern Loess Plateau, China

Arid ecosystems are characterized as having stressful conditions of low energy and nutrient availability for soil microorganisms and vegetation. The rhizosphere serves as the one of most active microorganism habitats, however, the general understanding of the ecoenzymatic stoichiometry (exoenzymes) and microbial nutrient acquisition in rhizosphere soil is limited. Here, we investigated the vegetation communities and determined the soil physicochemical properties, microbial biomass, and enzymatic activities in rhizosphere under different vegetation and soil types in the arid area of the northern Loess Plateau. Type Ⅱ standard major axis (SMA) regression analysis showed that the plants played a more important role than soil properties in determining ecoenzymatic stoichiometry. Linear regression analysis displayed a microbial stoichiometric homeostasis (community-level) in rhizosphere. The Threshold Elemental Ratio (TER) revealed that the microbial nutrient metabolisms of rhizosphere were co-limited by N and P in the A. ordosica and A. cristatum communities of loess, and A. cristatum communities of feldspathic sandstone weathered soil. Binding spatial ordination analysis (RDA and CCA) demonstrated that soil physical properties (e.g., soil moisture, silt and clay contents) have more contribution to ecoenzymatic stoichiometry than the other investigated soil parameters, whereas soil nutrients (e.g., total organic carbon, nitrogen, and phosphorus) predominantly controlled microbial nutrient ratios. Therefore, the ecoenzymatic stoichiometry in rhizosphere is greatly regulated by plants and soil physical properties. The microbial N and P are co-limited under Gramineae plant in loess and feldspathic sandstone weathered soil regions. Meanwhile, the microbial nutrient limitation is mainly affected by soil nutrient supply. These findings could be crucial for illuminating rhizosphere microbial metabolism and revealing the nutrient cycling of root-soil interface under arid and oligotrophic ecosystems.

Chemical composition and trophic state of shallow saline steppe lakes in central Asia (North Kazakhstan).

The purpose of this study was to identify the prevailing chemical composition and trophic state of the shallow saline steppe lakes of North Kazakhstan along a wide size range (<1-454km2) and salinity gradient (2-322gL-1) on a large spatial scale (1000km), taking into account the potential effects of human disturbances. Water depth, Secchi disk transparency, temperature, pH, electric conductivity, major ions, total dissolved solids, total organic carbon, total nitrogen and phosphorus, nitrate, soluble reactive phosphorus, and chlorophyll a were measured. The equivalent percentage of major ions, Spearman rank correlation, multivariate analyses, equilibrium state of lakes, and spatial GIS autocorrelation were calculated. The impact of human disturbances (settlements, farms, and mines) on total organic carbon, nitrogen, phosphorus, and chlorophyll a were tested by Kruskal-Wallis ANOVA. The most common combinations of dominant ions were Na-Cl>SO4 and Na-Cl (n=16; 64%); the Ca, Mg, HCO3, and SO4 ions precipitate with increasing salinity (2-322gL-1); and ion composition shifts from Na>Mg-Cl>SO4 to Na-Cl. The most of the chemical variables positively, but chlorophyll a negatively, correlated with total dissolved solids, and the total phosphorus had no significant correlation with any variables. The trophic state of these lakes in most cases exceeded the hypertrophic level. The increase in salinity causes change in chemical composition and effects on the phytoplankton development independently from the size of water surface, and the human disturbances had negligible effect on the trophic state of shallow saline lakes in this region of Kazakhstan.

Characterization of Phosphorus Fractions in the Soil of Water-Level-Fluctuation Zone and Unflooded Bankside in Pengxi River, Three Gorges Reservoir

The concentrations of phosphorus fractions in the soils of the water-level-fluctuating zone (WLFZ) of Pengxi River in the Three Gorges Reservoir were analyzed. The total phosphorus (TP), inorganic phosphorus (IP), and organic phosphorus (OP) were studied using the standard measurement and test (SMT) procedure. The average TP concentration was 575.29 mg·kg-1 and the average OP concentration was 91.23 mg·kg-1 in the soils of WLFZ. The fractions of phosphorus were analyzed by the Hedley method. In the soils of WLFZ, the relative abundance of WA-Pi (weakly adsorbed inorganic phosphorus), PA-Pi(potential active inorganic phosphorus), and Fe/Al-Pi(Fe/Al-bound inorganic phosphorus) accounted for 11.61% of the extractable Pi, lower than that in the unflooded bankside soils. The relative abundance of WA-Po (weakly adsorbed organic phosphorus) and PA-Po (potential active organic phosphorus) accounted for 22.28% of the extractable Po and the Fe/Al-Po (Fe/Al-bound organic phosphorus) accounted for 66.30%. In addition, the Po content of the soils of WLFZ was lower than that of the unflooded bankside soils and the difference in the Fe/Al-Po content in both soil types was the highest. WA-Pt and PA-Pt were significantly correlated with TP in the soils of WLFZ, which indicated that the active phosphorus content was mainly affected by TP. There was no statistical correlation between different fractions of phosphorus, suggesting different sources of phosphorus fractions. The Fe/Al-Pt content was significantly correlated with OM, implying that the OM content may affect the Fe/Al-Pt content. Therefore, under flood conditions, the potential impacts of phosphorus in the soils of WLFZ on overlying water should not be neglected.

Composted Cattle Manure Increases Microbial Activity and Soil Fertility More Than Composted Swine Manure in a Submerged Rice Paddy.

Livestock waste composts with minimum inorganic fertilizer as a soil amendment in low-input intensive farming are a feasible agricultural practice to improve soil fertility and productivity and to mitigate soil degradation. The key benefits of the practice rely on the activities of soil microorganisms. However, the role of different livestock composts [composted cattle manure (CCM) vs. composted swine manure (CSM)] on soil microbes, their activities and the overall impact on soil fertility and productivity in a flooded paddy remains elusive. This study compares the effectiveness of CCM and CSM amendment on bacterial communities, activities, nutrient availability, and crop yield in a flooded rice cropping system. We used deep 16S amplicon sequencing and soil enzyme activities to decipher bacterial communities and activities, respectively. Both CCM and CSM amendment significantly increased soil pH, nutrient availability (C, N, and P), microbial biomass, soil enzyme activities indicative for C and N cycles, aboveground plant biomass and grain yield. And the increase in above-mentioned parameters was more prominent in the CCM treatment compared to the CSM treatment. The CCM amendment increased species richness and stimulated copiotrophic microbial groups (Alphaproteobacteria, Betaproteobacteria, and Firmicutes) which are often involved in degradation of complex organic compounds. Moreover, some dominant species (e.g., Azospirillum zeae, Azospirillum halopraeferens, Azospirillum rugosum, Clostridium alkalicellulosi, Clostridium caenicola, Clostridium termitidis, Clostridium cellulolyticum, Magnetospirillum magnetotacticum, Pleomorphomonas oryzae, Variovorax boronicumulans, Pseudomonas xanthomarina, Pseudomonas stutzeri, and Bacillus niacini) which have key roles in plant growth promotion and/or lignocellulose degradation were enhanced under CCM treatment compared to CSM treatment. Multivariate analysis revealed that soil pH and available carbon (C) and nitrogen (N) were the major, while total organic carbon (TOC), total nitrogen (TN), and available phosphorus (P) were the minor drivers of variation in bacterial communities. Overall, our observations suggest that CCM amendment is better than CSM amendment to improve soil fertility and crop yield in a submerged rice cropping system.

The Impact of Hydrodynamics, Authigenesis, and Basin Morphology On Sediment Accumulation In An Upwelling Environment: The Miocene Monterey Formation At Shell Beach and Mussel Rock (Pismo and Santa Maria Basins, Central California, U.S.A.)

ABSTRACT: In the sections at Shell Beach (Pismo Basin) and Mussel Rock (Santa Maria Basin)—both along the central California coast—the Miocene Monterey Formation is composed of laminated, biosiliceous, organic-rich and phosphate-rich sediments, which are intercalated with carbonates and volcanogenic deposits. The presence of small- and large-scale scours, conglomerates, gravity-flow deposits, slumps, and condensed intervals reveals the importance of sediment reworking, which is related to the presence of bottom currents, the general morphology of the basins, and recurrent high-energy events of likely seismic origin. The lithologies reflect strong upwelling, enhanced primary productivity, and the presence of an oxygen-minimum zone, which is indicated by ubiquitous lamination, a general absence of bioturbation (with the rare exception of traces related to the gravity-flow displacement of trace makers), high pyrite, Mo, and U concentrations, and molar ratios of total organic carbon and organic phosphorus (TOC/P org ) of up to 2000. Oxygen depletion was particularly severe during the early Langhian, and the late Serravallian and early Tortonian, and favored the preservation of organic matter. Episodes of deposition of organic-rich sediment were followed by longer phases of subdued sediment accumulation and early diagenetic phosphogenesis, which resulted in the formation of a low-porosity, less permeable “lid” in the near-surface sediments that assisted in preserving organic matter. Phosphogenesis occurred throughout the time interval considered (approximately 17.5–6.5 Ma), and phosphate-rich sediments formed especially during periods of sedimentary condensation in the Langhian and earliest Serravallian, and the latest Tortonian and early Messinian. A comparison of temporal trends in the type and quantity of deposited sediments between the two sections at Shell Beach and Mussel Rock, and three sections of the Santa Barbara Basin (El Capitan State Beach, Naples Beach, and Haskell Beach) confirms that towards the top of the Monterey Formation, sediments become enriched in biosilica in all three basins. The transition into this lithology occurred diachronously, during the Serravallian in the Pismo and Santa Maria basins and Tortonian in the Santa Barbara Basin, and was probably related to a diachronous shift to more intense upwelling in all three basins. A phase of important condensation and phosphogenesis terminated Monterey-“type” sedimentation during the latest Tortonian and early Messinian in both the Santa Maria and Santa Barbara basins. The uniform expression of this phase is interpreted as the result of improved connections between the two basins.