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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Phosphorus (P) is a key nutrient in the eutrophication of freshwater and external nutrient sources are considered one of the main causes of P enrichment. To try and control eutrophication, external loading can be reduced. However, P accumulated in the sediment can be cycled back into the water, due to the process of internal loading. Not every form of P in the sediment is likely to be released into the water column, and its release from sediment is influenced by several factors, such as temperature, dissolved oxygen concentration, organisms, pH, and sediment resuspension. P release under anoxic conditions is largely discussed, but oxygen is not the only factor affecting P release. In this study, we evaluate the potential contribution of internal P loading to the eutrophication of Lake Extremoz, which is a well mixed shallow system that has been suffering increasing eutrophication. The quality of its water is relevant as it is used for human consumption. To evaluate internal loading, we have carried out an experiment utilising sediment with lake water, and sediment with deionised water, under conditions similar to the sediment-water interface over a 40-day period. We have also analysed P forms in the sediment per depth range, and before and after the experiment. The main P fraction in the sediment was refractory organic P, and the main mobile fraction was P bound to Fe and Al oxides. Less than half of the P in the sediment is in mobile P forms. During the experiment, temperature varied up to 3.2°C, what led to P release from sediment into the water column, regardless of the aerobic conditions. By the end of the experiment, the majority of the P in the water overlying the sediment was organic (P-Org). In the units that had lake water, P-Org represented 99.5% of the total P. And, in the units that had deionised water, P-Org represented 93.6% of total P. Most of the P flux into the water after the increase in temperature was composed by organic phosphorus. We also saw an increase in organic P forms in the sediment of the experiment. The increase in the temperature, followed by the changes in phosphorus concentrations in the water, mainly P-Org, suggest that the effects of temperature and microorganisms’ metabolism control P flux in the presence of oxygen. O fósforo (P) possui um papel importante na eutrofização de ambientes de água doce e as fontes externas são consideradas uma das principais causas do enriquecimento dos corpos d’água por P. Para controlar a eutrofização, é necessário que o aporte externo seja reduzido, porém, P acumulado no sedimento pode retornar para a coluna d’água, através do processo de fertilização interna. No sedimento, nem todas as formas de P são móveis, e sua liberação depende de diversos fatores, tais como temperatura, oxigênio dissolvido, organismos, pH, e ressuspensão. A liberação de P em condições de anoxia é amplamente discutida, mas, o oxigênio não é o único fator que pode influeniar na liberaçãode P. Neste estudo, nós avaliamos a contribuição potencial da fertilização interna para a eutrofização da Lagoa de Extremoz, a qual é um ambiente raso com coluna d’água misturada, que vem sendo gradualmente eutrofizado. A qualidade da água desse sistema é relevante, visto que ela é utilizada para abastecimento humano. Para avaliar o processo de fertilização interna, nós realizamos um experimento utilizando sedimento da lagoa com água da lago, e sedimento com água deionizada, em condições semelhantes às da interface água-sedimento durante 40 dias. Além disso, quantificamos as frações de P no sedimento da lagoa em diferentes profundidades, bem como no sedimento do experimento inicial e final. A principal fração do sedimento foi P orgânico refratário, e a maior parte do P móvel está ligada a óxidos de Fe e Al. Menos da metade do fósforo presente no sedimento da lagoa é considerada móvel. Durante o experimento, a temperatura variou em até 3,2°C, fazendo o sedimento da Lagoa de Extremoz liberar P para a água, apesar da presença de oxigênio. No final do experimento, quase todo o fósforo presente na água sobre o sedimento foi orgânico (P-Org). Nos tratamentos com água da lagoa filtrada, P-Org representou 99,5% do P total. E, nos tratamentos com água deionizada, P-Org representou 93,6% do P total . A maior parte do fluxo de P para a água, após o aumento a temperatura, também foi composta por P orgânico. Também detectamos um aumento em formas orgânicas de P ao final do experimento. O aumento da temperatura, seguido das mudanças nas concentrações de fósforo na água, principalmente o P-Org, sugerem que os efeitos da temperatura e do metabolismo dos microorganismos controlam o fluxo do P na presença de oxigênio.

Chitin is the second most abundant polysaccharide after cellulose and is subject to rapid microbial turnover in the environment. Microbial degradation of chitin in soil substantially contributes to carbon cycling and release in terrestrial ecosystems. In aerated soil ecosystems, chitin occurs as a structural component in protists, arthropods, and fungi. Thereby, fungi represent the main source of chitin in such soils as fungi have cell walls with up to 25% chitin and account for up to 60-90% of the microbial biomass in aerated soils. Chitin degradation can theoretically occur via two major degradation pathways. It can be deacetylated to chitosan or can be hydrolyzed to N,N´-diacetylchitobiose and oligomers of N-acetylglucosamine by aerobic and anaerobic microorganisms. Which pathway of chitin hydrolysis is preferred by soil microbiomes was unknown prior to this thesis. Therefore, processes, metabolic responses and degradation products associated with chitin and chitosan hydrolysis were assessed. Chitin was immediately broken down by the tested microbiome, but chitosan only with a considerable time delay, which suggests that the microbiome is adjusted to chitin as a substrate, and the degradation of chitin probably likely does not take place via the deacetylation to chitosan. Another objective of this study was to study the trophic interactions and dynamics of members of a chitin-degrading microbiome and the influence of oxygen on the carbon flow from chitin degradation, as these topics are largely uninvestigated in aerated soils. Therefore, a time-resolved 16S rRNA stable isotope probing experiment was conducted to label and identify those members of a soil microbiome that are involved in the aerobic and anaerobic degradation of chitin. [13C]-chitin was largely mineralized within 20 days, and Cellvibrio, Massilia, and several Bacteroidetes families were identified as initial active chitin degraders under oxic conditions. Subsequently, Planctomycetes and Verrucomicrobia were labeled by assimilating carbon either directly from chitin or from the degradation of cell wall polysaccharides, biofilm-associated exopolysaccharides, and small metabolic byproducts of chitinolytic bacteria. Bacterial predators (e.g., Bdellovibrio and Bacteriovorax) were labeled and non-labeled micro-eukaryotic predators (Alveolata) increased in relative abundance towards the end of the incubation (70 days), indicating that chitin degraders were subject to predation. Under anoxic conditions, trophic interactions differed substantially compared to oxic conditions. Various fermentation types occurred along with iron respiration. While Acidobacteria and Chloroflexi were initially labeled, Firmicutes and uncultured Bacteroidetes were predominantly labeled, suggesting that the latter two bacterial groups were mainly responsible for the degradation of chitin, and also provided substrates for iron reducers. The collective data indicated (a) that hitherto unrecognized Bacteria were involved in the chitin-degrading food web of an agricultural soil, (b) that trophic interactions of the chitin-degrading microbial food web were substantially shaped by the oxygen availability, and (c) that predation was restricted to oxic conditions. The functional redundancy of the soil microbiome and the catabolic diversity likely enable continued biopolymer degradation independent of oxygen concentration. Furthermore, chitin was readily and nearly completely degraded, suggesting that chitin is not as recalcitrant as it is sometimes believed to be. Thus, ‘recalcitrance’ of chitin is relative, rather than absolute and a matter of accessibility to the soil microbiome that is collectively adapted to degrade ubiquitous and abundant naturally occurring structural polysaccharides like chitin and cellulose.

This paper presents the characteristics of sediment from core BS-36 (6°55.85’ S and 96°7.48’ E, 1147.1 m water depth) that was acquired in the Mergui Basin, Andaman Sea. The analyses involved megascopic description, core scanning by multi-sensor core logger, and carbonate content measurement. The purpose of this study is to determine the physical and chemical characteristics of sediment to infer the depositional environment. The results show that this core can be divided into 5 lithologic units that represent various environmental conditions. The sedimentation of the bottom part, Units V and IV were inferred to be deposited in suboxic to anoxic bottom condition combined with high productivity and low precipitation. Unit III was deposited during high precipitation and oxic condition due to ocean ventilation. In the upper part, Units II and I occurred during higher precipitation, higher carbonate production and suboxic to anoxic condition.Keywords: sediment characteristics, Mergui Basin, Andaman Sea, suboxic, anoxic, oxic, carbonate content Makalah ini menyajikan karakteristik sedimen contoh inti BS-36 (6°55,85’ LS dan 96°7,48’ BT, kedalaman 1147,1 m) yang diambil di Cekungan Mergui, Laut Andaman. Metode analisis meliputi pemerian megaskopis contoh inti, pemindaian contoh inti dengan menggunakan multi-sensor core logger, dan pengukuran kandungan karbonat. Tujuan penelitian adalah untuk mengetahui karakteristik fisik dan kimiawi sedimen untuk menafsirkan kondisi lingkungan pengendapan. Hasil penelitian menunjukkan bahwa contoh inti ini dapat dibagi menjadi 5 unit litologi yang mewakili kondisi lingkungan yang berbeda. Pada bagian bawah sedimen, Unit V dan IV ditafsirkan sebagai hasil endapan pada kondisi suboksik hingga anoksik pada saat produktivitas tinggi dan curah hujan rendah. Unit III diendapkan pada saat curah hujan tinggi dan kondisi oksik yang diperkirakan berkaitan dengan ventilasi samudera. Pada bagian atas, Unit II dan I diendapkan pada saat curah hujan cukup tinggi dengan produksi karbonat yang cukup besar dan kondisi dasar laut suboksik hingga anoksik. Kata kunci: karakteristik sedimen, Cekungan Mergui, Laut Andaman, suboksik, anoksik, oksik, kandungan karbonat

Bitumen samples collected from different locations in south-western Nigeria were analysed for trace metal constituents such as Fe, Pb, Cu, Cd, Ni, Mn and V using Atomic absorption spectroscopy. The concentration of Fe ranged from 38.00 to 1537.00 ppm, Pb ranged from 11.00 to 27.00 ppm, Cu ranged from 3.00 to 10.00 ppm, Cd ranged from 4.00 to 15.00 ppm, Ni ranged from 9.00 to 62.00 ppm, Mn varied between 3.00 and 6.00 ppm, V ranged 10.00–150.00 ppm. Some ratios of these trace metals such as V/Ni, V/(V + Ni) and Fe/V were calculated, and the results show V/Ni ranged from 0.24 to 16.67, V/(V + Ni) varied from 0.20 to 0.94 and Fe/V ranged from 3.8 to 15.37. The low values of V/Ni ratios of samples AB, OI and IL suggest high maturity, mixed marine and terrestrial source of bitumen while the calculated values of V/(V + Ni) suggest that the samples were formed under oxic condition. The results were correlated using Pearson’s correlation matrix. A high positive correlation among the four bitumen samples indicates that they are geologically and genetically related.

8 pages, 2 figures, 4 tables, The present study assesses the contribution of dark carbon fixation to the primary production in the oxic/anoxic interface of a shallow estuarine environment that develops a salt-water wedge with the presence of sulfide. Primary production was partitioned into oxygenic photosynthesis, anoxygenic photosynthesis and dark fixation. The results show the importance of dark fixation in the oxic/anoxic interface with values higher than 5 mg carbon fixed per cubic meter and per hour in some cases. The average rate of primary production in the dark during the anoxic season for the Ebro River salt wedge resulted in 42 mg C m-2 d-1 in the interface. This represents at least twice the contribution of oxygenic photosynthesis to the primary production in such interface. Because this process is probably important in other salt-wedge or highly stratified estuaries with oxic/anoxic interfaces containing sulfide, the estimates of carbon fixation made so far for these systems may have been underestimated, and should therefore be revised taking into account the contribution of dark processes, This work was financed by DGICyT grant PB87-0183 from the Spanish Ministerio de Educación y Ciencia. J.G.-C. was supported by a FPI scholarship from the Spanish Ministerio de Educación y Ciencia. During the writing of this work, E.O.C. was supported by MIDAS (MIcrobial Diversity in Aquatic Systems, MAS3-CT97-0154) from the European Union

The purpose of this research was develop a biological nutrient removal (BNR) system which has low energy consumption, sludge production, and land usage. These indicate that BNR system could be a alternative of future wastewater treatment in ubiquitous city(U-city). Organics and nitrogen compounds could be removed by this system so that secondary or tertiary stages of wastewater treatment satisfy their standards. This system was composed of oxic and anoxic filter filed with PVDC and POM media. Anoxic/oxic filter system operated under empty bed contact time of 4 hours by increasing recirculation ratio from 0 to 100 %. The system removals of total nitrogen and COD were 76.3% and 93%, respectively. To be observed internal behavior in this system SCOD, NH3-N, and NO3-N were conducted and removal shows range of 25~100%, 59~99%, and 70~100%, respectively., {"references":["OH, S, A,. (2008). A Study on the u-City Implementation Model-Focused on the Water and Sewer Facilities, Department of Civil\nEngineering Kyungwon University, Sungnam, Korea","Korean Ministry of Environment (2009). Enforcement Regulations of\nSewerage Law. Korean Ministry of Environment, Seoul, Korea.","Payraydeau, M., Pearce, A. R, Goldsmith, R., Bigot B. and Wicquart F.\n(2001). Experience with an up-flow biological aerated filter(BAF) for tertiary treatment: from pilot trials to full scale implementation, Wat. Sci. Tech, Vol. 44, No. 2-3, pp. 63~68","Mckinney R. E. , 1984, Activated Sludge Kinetics-Microbiology, Unpublished.","Jang, A, H., S. Kim, and I. S. Kim (2000), Effect of Nitrate and Nitrite\nLoad on Denitrification Reaction in Anoxic Biofilm Reactor, J. KSEE.\n22(9), 1617-1625.","Standard Methods for the Examination of water and wastewater, 21st\nEd., APHA/AWWA/WEF, Washington DC, 2000.","Korean Ministry of Environment (2000a). Korean Standard Methods for\nthe Examination of Water and Wastewater. Donghwa Technology,\nSeoul, Korea"]}

Microbial heterotrophic activity was investigated in oxic sub-seafloor sediments at North Pond, a sediment pond situated at 23°N on the western flank of the Mid-Atlantic Ridge. The North Pond sediments underlie the oligotrophic North Atlantic Gyre at 4580-m water depth and cover a 7-8 million-year-old basaltic crust aquifer through which seawater flows. Discrete samples for experimentation were obtained from up to ~9 m-long gravity cores taken at 14 stations in the North Pond area. Potential respiration rates were determined in sediment slurries incubated under aerobic conditions with (14)C-acetate. Microbial heterotrophic activity, as defined by oxidation of acetate to CO(2) (with O(2) as electron acceptor), was detected in all 14 stations and all depths sampled. Potential respiration rates were generally low (0.2 nmol of respired acetate cm(-3) d(-1)) in the sediment, but indicate that microbial heterotrophic activity occurs in deep-sea, oxic, sub-seafloor sediments. Furthermore, discernable differences in activity existed between sites and within given depth profiles. At seven stations, activity was increased by several orders of magnitude at depth (up to ~12 nmol of acetate respired cm(-3) d(-1)). We attempted to correlate the measures of activity with high-resolution color and element stratigraphy. Increased activities at certain depths may be correlated to variations in the sediment geology, i.e., to the presence of dark clay-rich layers, of sandy layers, or within clay-rich horizons presumably overlying basalts. This would suggest that the distribution of microbial heterotrophic activity in deeply buried sediments may be linked to specific lithologies. Nevertheless, high-resolution microbial examination at the level currently enjoyed by sedimentologists will be required to fully explore this link.

International audience; While soil water composition has long been recognised as being related to soil type (characteristics of the horizons), the influence of structures resulting from agricultural activities (hedges, ditches, wheel ruts, etc) is still under discussion. This work was undertaken to show that a snapshot of spatial variability of the geochemical characteristics of soil water at the scale of a plot can improve our understanding of soil geochemistry in a farmland setting. We selected a 3 hectare hedged plot located on a hillside, limited by a stream and used as pasture where soils have developed in weathered gneiss. The water depth, electrical conductivity, major ions, temperature, pH, dissolved organic carbon (DOC) content, dissolved oxygen content, fluorescence, alkalinity, Fe2+, Mn2+, NO2−, Fe(III) and F− contents were measured in 62 auger holes randomly drilled on the site. Four sectors were identified in order to describe the distribution of the main geochemical parameters. Electrical conductivity and some major ions, especially sulphate, had larger concentrations near hedges where oxic conditions prevailed. These features were attributed to the impact of the linear anthropogenic network on the circulation of subsurface soil waters and evapo-transpiration and represent sector I. Dissolved Mn was an indicator of well channelled runoff subsurfaces facilitating the circulation of more highly reducing water (sector III), while DOC probably marked areas drained less well, with a prolonged contact time between soil solutions and organic topsoil horizons (sector II). The presence of dissolved Mn and Fe(II) indicates bottomland anoxic conditions (sector IV). It is concluded that a survey of the chemical composition of soil water may be a direct approach to show the influence of permanent structures on current soil properties and dynamics.

Inorganic chlorine (Clinorg) is generally considered to be inert and has been used as a tracer for groundwater movements. This assumption is thereby fundamental for current knowledge about soil biogeochemistry. However, recent work showed that Clinorg can be retained, i.e. immobilised, in soil, which contradicts the previous assumptions. The aim of this laboratory study was to investigate if the processes that immobilise Clinorg in soil are affected by molecular oxygen (O2), and if the immobilisation occurs in the top soil layer only or also further down were the soil structure is different from the upper soil layer. Two experimental set-ups have been established. In the first experiment regarding the O2 regime (OXANIS), the immobilisation of Clinorg was studied in soil under oxic and anoxic conditions, respectively. In a second incubation study (SOLIS) the immobilisation was studied under oxic conditions in different layers of a coniferous forest soil. To investigate the immobilisation of Clinorg, a method using radiolabelled chloride 36 (36Clinorg) was applied. The use of radiolabelled chloride is an excellent and reliable method for studying transformation processes in soil systems. The results of the laboratory study showed that Clinorg retention rates under oxic conditions were much higher than retention rates under anoxic conditions, indicating an important role of O2. Furthermore, the immobilisation of Clinorg occurred in all soil layers were oxygen is provided, but rates were highest in the top soil layer (organic layer, O-horizon). Clearly, O2 influenced the net Clinorg retention, but additional studies are required to identify the processes behind this result. The calculated immobilisation rates for Clinorg in the three soil horizons correspond to the amount of organic material detected in the different soil horizons indicating a strong connection between the occurrence of organic matter in soil and the immobilisation of Clinorg.

De l'urée et du super phosphate triple ont été appliqués aux étangs d'alevinage de carpes chinoises de la station Deroua pour stimuler la croissance des algues. Toutefois, une forte proportion de ce phosphore est fixée par les sédiments et sera libérée en grande quantité dans les étangs lorsque les sédiments sont en conditions anaérobies.Nous avons étudié le relargage des orthophosphates par les sédiments provenant de deux étangs différents. L'un (A1) en terre ce qui permet la percolation des éléments nutritifs vers les couches profondes, l'autre (C1) dont le fond recouvert d'une fine membrane en polyéthylène, est parfaitement imperméable et empêche toute perte. Par ailleurs, nous avons étudié les effets de l'oxygène dissous, du pH, des nitrates et du glucose sur le relargage des orthophosphates par les sédiments.Les résultats obtenus montrent qu'en anaérobiose, la solubilité du phosphore augmente dans l'eau interstitielle. Les orthophosphates libérés, dont la concentration peut atteindre 873 µg/l, proviennent de la fraction minérale en particulier du Fe(OOH)=P. Le sédiment C1 qui accumule de grandes quantités de matière organique libère plus de phosphore que le sédiment A1.L'addition des nitrates limite la mobilisation du phosphore à partir des sédiments. Le pH acide provoque la dissolution du phosphore lié au calcium alors qu'un pH alcalin provoque celle du phosphore lié aux hydroxydes de fer et sa précipitation partielle sur les carbonates présents dans les sédiments., In the Deroua fish farm (Béni-Mellal, Morocco), a series of ponds was lined with polyethylene to prevent water seepage (lined ponds, C). Another series of ponds was not lined (unlined ponds, A). The lined ponds do not need much fertiliser to enhance phytoplankton growth. They receive a small quantity of urea and triple super phosphate and accumulate high levels of organic matter in their sediments. The unlined ponds receive a large quantity of fertilisers. In the ponds, an important increase in phytoplankton growth occurred particularly after fertilisation with triple super phosphate. The phosphate (P) released from the sediment is the essential source of P for phytoplankton when the ponds are not fertilised.Sediment samples used in this study were collected in June 1999 from the A1 and C1 ponds of the Deroua fish farm. The bottom sediments were collected with a core sampler to provide samples from the 0-5 cm layer. The samples were mixed and analysed for pH, total Kjeldahl nitrogen (NTK), nitrates (N-NO3-), ammonium (N-NH4+), total iron (tot-Fe) and P-fractionation in eight replicates, using the Golterman method (1996).In this work, experiments were conducted to evaluate the P released from sediments of lined and unlined ponds under controlled conditions. The samples included: untreated sediments, sediments treated with hydrogen peroxide (H2O2), and sediments treated with chloroform (CHCl3). H2O2 was used to destroy the organic matter of sediment. To inactivate bacteria, CHCl3 was added to the sediments. CHCl3 does not modify the mineral and organic structures of sediments but does reduce the bacterial biomass. Urea and triple super phosphate were added to Chinese carp rearing ponds at Deroua fisheries farm to stimulate algal growth. However, phosphate bound to the sediments was released into the water column during anaerobic conditions. The released phosphate from lined pond (C1) enhanced the algal production.We have tested the fertilisation capacity of A1 and C1 ponds as well as the effects of different factors such as dissolved oxygen, pH, nitrate, and organic matter (glucose) on the phosphate released from the sediments. The results show that under anoxic conditions, phosphate solubility increased in the interstitial water. The released phosphate (873 µg/l) comes from the mineral fraction, particularly from Fe(OOH)=P. The P released from the A1 untreated sediment under oxic and anoxic conditions was low in comparison to the P released from the C1 untreated sediment and did not exceed 9.1 µg.g-1 d.w. (Figure 1). The removal of organic matter with H2O2 had a positive effect on the P released from the C1 sediments only after the second day of incubation. The inactivation of bacteria with CHCl3 had an inhibitory effect on the P released from the C1 sediments under oxic and anoxic conditions; however for the A1 sediments, this inactivation of bacteria had no effect on the kinetics of P release. Phosphorus release from the C1 sediments was important under anoxic conditions; the P came from Fe(OOH)=P after the reduction of Fe(OOH).The addition of nitrates decreased the mobilisation of phosphate from the sediments. Acid conditions increased the dissolution of calcium-bound phosphate, while alkaline conditions increased the dissolution of iron-bound phosphate and its re-precipitation onto carbonate present in sediments. High concentrations of organic matter (glucose) increased oxygen demand and favoured the development of reducing conditions. The phosphate was released from Fe(OOH)=P.The conceptual model of P released in fish ponds shows that, in semiarid climates and in calcareous areas, the polyethylene lining of ponds prevents not only the seepage of water but also the percolation of nutrients. Consequently, the P was more available for algal uptake in the lined ponds. More phosphate will be released concomitant with the process of the ponds becoming anoxic, as nitrate concentrations and the pH of sediments decrease.

We found anoxic zones in aerated activated sludge flocs, and demonstrated denitrification under normal operating conditions. Sulfate reduction was not found. Micro-environments and microbial conversions in flocs from bulking and non-bulking activated sludge were determined with microsensors for H2S, O2, NO(2-) and N(O3-). Denitrification and sulfate reduction rates were measured with 15N- and 35S-tracer techniques. We showed that under normal reactor conditions (ca. 20% air saturation) anoxic zones develop within flocs allowing denitrification. The denitrification rates amounted to 40% of the rates under anoxic conditions. At 100% air saturation no anoxic zones were found and no denitrification occurred. However, in flocs from bulking sludge (at 20% air saturation) anoxic zones were absent and denitrification did not occur. In bulking sludge only at total anoxia was denitrification found. Confocal microscopy showed that flocs from bulking sludge were much looser than those from non-bulking sludge. The absence of anoxic zones and of denitrification was attributed to the open floc structure, allowing advective oxygen transport. Sulfate reduction was not detected in any of the sludges tested by microsensors or by tracer techniques even under anoxic conditions. This indicates that the sulfur cycle (sulfate reduction and sulfide oxidation) does not play a role in mineralization processes and bulking in activated sludge. Preliminary molecular work (in situ hybridization with the 16S-rRNA probe SRB385) indicated the presence of small amounts of sulfate reducing bacteria in all sludges. Either the probe is not specific or the sulfate reducers present are not active under reactor conditions.