Excess Organic Matter Research Articles

Artropodofauna de los Bosques de Polylepis (Rosaceae) de la Zona de Conchucos, Ancash

En este estudio de la diversidad de la artropodofauna de doce bosques de Polylepis en el departamento de Ancash (Tacarpo Gague, Pacchac, Yanacocha, Pumahuain, Checacmonte, Canrash, Juproc, Pachapaqui, Huinco, Jupaimarca, Huamanhueque), se reporta un total de 19 órdenes y 62 familias de artrópodos terrestres en los bosques evaluados. Los órdenes ampliamente representativos son los Diptera y Collembola. Especies de las familias Dytiscidae (Rhantus), Elmidae (Stenelmis), Psephenidae, Cucujidae, Dascillidae (Orden Coleoptera); Notonemouridae (Neonemoura) (Orden Plecoptera); Baetidae (Baetis, Cloeodes), Leptophlebiidae (Thraulodes) (Orden Ephemeroptera); Limnephilidae (Anomalocosmoecus), Helicopsychidae (Helicopsyche), Hidropsychidae (Cailloma) (Orden Trichoptera); y Corixidae (Orden Hemiptera) representan nuevos reportes de entomofauna en los bosques de Polylepis, a la vez que en Ancash y a nivel del país. La metodología comprendió el uso de trampas Malaise, de caída (pitfall), trampas de luz, mangueo, muestreo directo, y en el caso de la entomofauna acuática, barridos del lecho de los cuerpos de agua. Los índices de diversidad indican que el bosque más diverso en cuanto a familias de artrópodos terrestres es el bosque de Huinco, con un índice de diversidad de 2.66 y uniformidad de 74.24%, y el bosque menos diverso es Canrash, con un índice diversidad de 0.98 y uniformidad de 26.73%. Ambos bosques no alcanzan un porcentaje mayor al 70% y 80% de similitud, respectivamente, con los demás bosques evaluados. De la revisión de la artropodofauna bentónica y con base en los taxones encontrados donde se pueden observar los grupos Ephemeroptera y Trichoptera, además de representantes del orden Plecoptera y las dos familias de coleópteros acuáticos (Elmidae y Psephenidae), todos ellos con características conocidas de baja tolerancia a agentes extraños en su medio, se podría concluir que aunque las zonas de estudio se hallan sometidas a la presión antropogénica, esta no ha alterado los cuerpos de agua con la introducción de agentes sintéticos ni el exceso de materia orgánica. Además, el hecho de que grupos como los trichópteros, élmidos y ephemerópteros requieran de agua con alto grado de oxigenación y corriente rápida indicaría que estos cuerpos de agua todavía no han sido afectados significativamente en proporción a la reducción de los bosques de Polylepis

Isotopic composition of pyritic sulfur from the mud volcanic ejecta in Azerbaijan

Geochemical studies of pyrite crystals from the mud volcanic ejecta in Azerbaijan were studied. It is shown that all of them have cubic shape. Determination of the sulfur isotope composition revealed a wide variation range of δ34S values from–27.0 to +26.4‰. Signs of spatial zonation were recorded in the distribution of δ34S values—lower values are confined to the present-day coastline of the Caspian Sea. Appearance of pyrite with a high share of 34S is attributed to sulfate reduction that takes place in an environment with excess organic matter. It is supposed that the isotopically heavy sulfides represent the “neck” facies that are formed at the periphery of mud volcanic conduits at the contact of the hydrocarbon-rich mud volcanic fluids with stratal waters of host sediments.

Diseño de una Granja Productora de Trucha Arcoiris en Guachochi, Chihuahua

Se evaluó la viabilidad de un proyecto que consiste en el establecimiento de una granja acuícola dedicada a la cría y venta de trucha arcoíris con el fin de aprovechar el clima y calidad del agua proveniente de un manantial, que son óptimos para la especie. El proyecto busca impactar en la creación de empleos estables en la región y derivar en un beneficio para sus propietarios. Se realizó una investigación de mercado que se basó en la aplicación de un cuestionario aleatorio de 190 encuestas en la comunidad de Guachochi, Chihuahua. Para codificar los datos se utilizó el programa SPSS versión 19. Los principales resultados indicaron que un 91% consumen trucha arcoiris y un 99.5%, están dispuestas a comprarla. Con base a este resultado se elaboró un proyecto de inversión el cual arrojo resultados positivos con una VAN (15%)= $51,491.76, una TIR del 20% y una relación Beneficio/Costo (15%)= 1.081, lo cual significa que el proyecto es viable. El impacto ambiental será mitigado mediante el uso de un cedazo para eliminar el exceso de materia orgánica para luego usar el agua para riego. Para desechar los peces muertos de la producción se contará con un lugar adecuado para su enterramiento. El proyecto no modificará la dinámica natural de ningún cuerpo de agua. El suelo no se verá afectado, ya que no se expondrá a materiales corrosivos. Se reducirá el impacto del consumo de energía eléctrica mediante el uso de paneles solares para el suministro de energía de la granja.

Soil Evolution par for the [golf] Course

Soil Evolution par for the [golf] Course

Anthropogenic shift of planktonic food web structure in a coastal lagoon by freshwater flow regulation

Anthropogenic modification of aquatic systems has diverse impacts on food web interactions and ecosystem states. To reverse the adverse effects of modified freshwater flow, adequate management of discharge is required, especially due to higher water requirements and abstractions for human use. Here, we look at the effects of anthropogenically controlled freshwater flow regimes on the planktonic food web of a Ramsar listed coastal lagoon that is under recovery from degradation. Our results show shifts in water quality and plankton community interactions associated to changes in water flow. These shifts in food web interactions represent modifications in habitat complexity and water quality. At high flow, phytoplankton-zooplankton interactions dominate the food web. Conversely, at low flow, bacteria, viruses and nano/picoplankton interactions are more dominant, with a substantial switch of the food web towards heterotrophy. This switch can be associated with excess organic matter loading, decomposition of dead organisms, and synergistic and antagonistic interactions. We suggest that a lower variability in flow amplitude could be beneficial for the long-term sustaining of water quality and food web interactions, while improving the ecosystem health of systems facing similar stresses as the Coorong.

The impact of organic and intensive farming on the tropical estuary

Two marine farm ponds, one practicing the organic method and the other practicing the intensive method of shrimp farming located near the Guaraíras estuary (Rio Grande do Norte, Brazil), have the potential of causing eutrophication of the estuary by disposal of excess organic matter and nutrients. Here we report nutrients, chlorophyll concentrations and stable carbon isotope ratios from the respective ponds to access differences in their potential impact on estuary water quality. Total phosphate and chlorophyll-a concentrations of pond water under the organic and intensive management method were different (i.e., 3.39 ± 0.63 μM and 17.87 ± 7.89 μM for total phosphate and 11.88 ± 9.91 μg/L and 64.46 μg/L for chlorophyll-a, respectively). With the exception of pCO2, parameters related to carbonate system also showed greater values in the organic pond compared to the intensive pond. Sediment total phosphorus concentrations were: 1.48 ± 0.13 mg/g for the organic pond and 5.99 ± 1.30 mg/g for the intensive pond. The mean stable carbon isotopic composition of the shrimp muscle tissues from the organic pond (δ13C = -17.1 ± 0.0‰) and intensive pond (δ13C = -18.2 ± 0.1‰) were very similar, despite the fact that, compared to the δ13C value shrimp tissue, the feed in the intensive pond had very different carbon isotope ratios (δ13C = -25.3 ± 0.1‰). Pond water and sediments from the intensive shrimp farm, by having a higher phosphorus concentration, have a greater potential for causing estuary eutrophication compared to the organic shrimp farm. The small range in carbon isotope ratio between the shrimps from the two types of management indicates that the commercial shrimp feed had little contribution to the biomass of the cultured shrimp in the intensive shrimp pond.

Life Under Exceptional Conditions—Isotopic Niches of Benthic Invertebrates in the Estuarine Maximum Turbidity Zone

The estuarine maximum turbidity zone (MTZ) can be assumed to be a stressful environment featuring special conditions of great biological importance with an excess of organic matter, high-deposition rates, large variations in salinity, and dredging activities. Under such harsh conditions, populations may remain below the carrying capacity and competition is assumed to be of little importance, as predicted by the stress-gradient hypothesis. Therefore, we hypothesized that invertebrates of similar feeding types may utilize the same resources. To test our hypothesis, we chose the three most abundant taxa classified in literature as deposit feeders (Bathyporeia pilosa, Boccardiella ligerica, Marenzelleria sp.) and two taxa classified as predominately predacious (Palaemon longirostris, Crangon crangon) and determined their isotopic niches based on a stable isotope analysis for the MTZ of the Elbe Estuary (Germany). We expected the isotopic niches of similar feeding types to show a clear overlap if our hypothesis was true. Our results showed that the isotopic niches of no two taxa overlapped within each feeding group, indicating different resource use and the absence of competition. The sediment analysis revealed that two of the deposit feeders inhabited significantly different mean grain sizes. The lack of overlap of isotopic niches within each feeding group may be due to differences in habitat and feeding behavior in the case of the deposit feeders and due to different migration behavior in the case of the predominately predacious species. However, competition may have occurred in the past, resulting in a divergence of feeding niches during evolution.

Links between contaminant hotspots in low flow estuarine systems and altered sediment biogeochemical processes

The urbanisation of coastal zones is a major threat to the health of global estuaries and has been linked to increased contamination (e.g. metals) and excess organic matter. Urban stormwater networks collect and funnel contaminants into waterways at point sources (e.g. stormdrains). Under dry, low flow conditions, these stormwater contaminants can accumulate in sediments over time and result in modifications to benthic sediment biogeochemical processes. To quantify these processes, this field study measured differences in benthic metabolism (CR, GPP, NEM) and sediment-water nutrient fluxes (NH3, NOx, PO4) associated with stormdrains (0 m, 200 m and 1000 m away) and increased water-retention (embayments vs channels). Significant changes to benthic metabolism were detected with distance from stormdrains, and with differences in water-retention rates, above natural spatial and temporal variation. Oxygen consumption was ∼50% higher at stormdrains (0 m) compared to 1000 m away and >70% higher at stormdrains (0 m) located in embayments compared to channels. Oxygen production also appeared to decrease with distance from stormdrains in embayments, but patterns were variable. These changes to benthic metabolism were of a magnitude expected to influence benthic nutrient cycling, but NH3, NOx and PO4 fluxes were generally low, and highly spatially and temporally variable. Overall, metal (Cu) contamination explained most of the variation in sediment biogeochemical processes between embayments and channels, while sediment grain size explained differences in fluxes with distance from stormdrains. Importantly, although there was evidence of increased productivity associated with stormdrains, we also detected evidence of early hypoxia suggesting that systems with legacy stormwater contaminants exist on a tipping point. Future work should investigate changes to sediment processes after a major rainfall event, when large and sudden inputs of potentially toxic contaminants occur. Monitoring benthic O2 fluxes could be a sensitive measure of ecological change under these conditions.

Beyond the urban stream syndrome: organic matter budget for diagnostics and restoration of an impaired urban river

In response to water quality standard violations linked to excessive organic matter (OM) and a lack of sampling data informing the Total Maximum Daily Load (TMDL), an organic matter budget was created to quantify and identify sources of OM in the lower Jordan River (Salt Lake City, UT). By sampling dissolved, fine, and coarse particulate OM, as well as measuring ecosystem metabolism at seven different sites, the researchers aimed to identify the origin of excess OM, and understand pathways by which different size classes of the OM pool are generated. The dissolved fraction (DOM; 94 %) was found to be the dominant form of OM transported within the river with fine particulate organic matter (FPOM; 6 %) the second most abundant, and coarse particulate organic matter (CPOM; 1 %) transport relatively insignificant in the overall OM budget. Primary production exceeded respiratory losses in the upper river, and this, along with OM inputs from two tributaries (where water reclamation facilities discharge into the river) delivered excess OM to the impaired lower reaches. Increasing stream metabolism index (SMI) with distance downstream (>1 in the lower river) further demonstrated that transport of excessive organic matter into the lower river was from upstream sources and not due to lateral inputs. This simple approach to characterizing the organic matter budget as it relates to water quality in the Jordan River was effective and could serve as a model for future studies attempting to quantify and identify sources of OM in urban ecosystems.

Characteristics and distribution of biodegradable compounds of surface sediments in Lake Chaohu

富营养化湖泊的藻类残体大量沉降到湖底,其中易降解成分的降解和转化快速消耗底层水体中的溶解氧,极易造成水土界面缺氧,影响湖泊生态系统的健康.于2014年对巢湖12个样点的表层沉积物进行周年跟踪研究,分析样品中有机质来源、总有机碳(TOC)、蛋白质、总糖、总脂以及生物聚合物碳(BPC)等成分含量,揭示易降解有机质的成分特征及在巢湖的分布规律.研究表明:巢湖表层沉积物TOC含量较高,全湖样点平均含量达到1.24%.BPC含量占TOC含量的30.99%~60.48%,有机质中易降解成分含量较高,并且在冬季和夏季时在巢湖西北部湖区有明显累积;有机质及其中的生物易降解部分均主要集中在粒径4~8μm的表层沉积物上,在应用工程技术手段处理、降解表层沉积物中的过量有机质时,更应该关注粒径为4~8μm的沉积物颗粒.;In eutrophic lakes large amount of algae detritus fall down to the lake bottoms every year. Dissolved oxygen in water would be consumed rapidly by labile compositions during degradation and transformation of the organic detritus, which can easily cause water hypoxia, affecting the health of lake ecosystem. Throughout the 4 seasons of 2014, 12 sampling sites for collected from surface sediments in Lake Chaohu were chosen to study the biodegradable organic components. In order to study characteristics of the labile components within the detritus and the distribution in the lake, source of organic matter, TOC, PRT, CHO, LPD and BPC contents in the samples were analyzed. Results have shown that the content of organic matter of surface sediments in Lake Chaohu is high, the average content reached 1.24%. BPC content accounts for 30.99% to 60.48% of TOC. The biodegradable organic components were relatively high, which accumulated obviously in northwestern Chaohu in winter and summer. The organic matter and biodegradable parts of surface sediments mainly adsorbed on the particle size of 48μm, so that the particles ranged from 48μm should be concerned when we use engineering measures to deal with excess organic matter in surface sediments.

Establishing the optimal conditions of the process of water treatment by ultrasound

The efficiency of water treatment from chemical and biological contamination using ultrasound in the presence of oxygen was investigated in the paper. It was found that the necessary water quality parameters are obtained already after an hour of acoustic cavitation action in the presence of oxygen. Oxidation of water-soluble organic compounds during sonication is the first-order reaction. Dispersion of microorganisms is heterogeneous system and oxidation is the pseudo-second-order reaction. High COD decrease efficiency during sonication of oxygen in the atmosphere is caused by the fact that peroxy radicals, peroxides and oxoradicals, participating in the radical-chain oxidation of organic compounds are generated under cavitation and provide high process speed. In aerobic conditions of storing dispersions, not treated with ultrasound, the COD value increases slowly, reaching a maximum for 6-10 days and remains constant. During storage of solutions with an excess of organic matter under aerobic conditions, the COD value decreased from 7181 mg/dm3 to 6504 mg/dm3 for 2 weeks. During storage of water, treated with ultrasound, the COD value remained constant for 2 weeks. After ultrasonic treatment of contaminated water, post-effect of acoustic cavitation, which lies in reducing the number of microorganisms per unit volume and COD occurs. In the US-treated water, growth of microorganisms starts only after 24 hours. The results allow to choose optimal conditions for the water treatment process and use ultrasonic units to treat sewage of the food industry enterprises or use mobile ultrasonic units for household purposes, such as cleaning private pools.

Effects of organic pollution and physical stress on benthic macroinvertebrate communities from two intermittently closed and open coastal lagoons (ICOLLs)

Benthic macroinvertebrate communities and environmental conditions were studied in two intermittently closed and open coastal lakes and lagoons (ICOLLs), located in southern Algarve (Foz do Almargem e Salgados), with the purpose of evaluating the effects of organic pollution, originated mainly from wastewater discharges, and the physical stress caused by the irregular opening of the lagoons. Most of the year, lagoons were isolated from the sea, receiving the freshwater inputs from small rivers and in Salgados, also from the effluents of a wastewater plant. According to environmental and biotic conditions, Foz do Almargem presented a greater marine influence and a lower trophic state (mesotrophic) than Salgados (hypereutrophic). Benthic macroinvertebrate communities in the lagoons were distinct, just as their relations with environmental parameters. Mollusca were the most abundant macroinvertebrates in Foz do Almargem, while Insecta, Oligochaeta and Crustacea were more relevant in Salgados. Corophium multisetosum occurred exclusively in Salgados stations and, just as Chironomus sp., other Insecta and Oligochaeta, densities were positively related to total phosphorus, clay content and chlorophyll a concentration in the sediment, chlorophyll a concentration in water and with total dissolved inorganic nitrogen. Abra segmentum, Cerastoderma glaucum, Peringia ulvae and Ecrobia ventrosa occurred only in Foz do Almargem, with lower values of the above mentioned parameters. Both lagoons were dominated by deposit feeders and taxa tolerant to environmental stress, although in Salgados there was a greater occurrence of opportunistic taxa associated to pronounced unbalanced situations, due to excess organic matter enrichment.

Mortalidade de tambacus (Colossoma macropomum x Piaractus mesopotamicus) infectados por Edwardsiella tarda

<p>O presente trabalho relata um surto de mortalidade de tambacus (<em>Colossoma macropomum </em>x <em>Piaractus mesopotamicus</em>) criados em tanques escavados da Fazenda-Escola da UCDB. Os peixes apresentaram sintomas clínicos de letargia, anorexia, aumento da produção de muco, nado desordenado e comportamento de buscar a superfície da água. Ao exame necroscópico de três peixes foram evidenciadas hemorragias nas nadadeiras e pele, opacidade de córnea, hemoperitôneo, distensão e repleção da vesícula biliar e congestão e hemorragia do tubo digestivo. O exame microbiológico dos materiais coletados das lesões dos tambacus foi positivo para a bactéria <em>Edwardsiella tarda</em>. A análise de qualidade de água indicou grande quantidade de fitoplânctons que proliferaram em função do excesso de matéria orgânica, caracterizando a eutrofização da água. Atribuiu-se a causa da morte dos tambacus à infecção oportunista pela <em>E. tarda</em>, favorecida pelo desequilíbrio devido ao excesso de matéria orgânica em suspensão na água. As mortes cessaram após a correção dos parâmetros da qualidade da água do tanque.</p>

Effect of shrimp farm effluent on water and sediment quality parameters off the coast of Sonora, Mexico

The effect of shrimp aquaculture effluents on some environmental parameters of the receiving coastal waters was assessed. Water and sediment samples were taken at different distances from the discharge point (50, 150, and 300 m) when shrimp farms had ceased operations (survey 1), had initiated operations (survey 2), and during the early harvest (survey 3). Water and sediment samples were likewise taken at the same distances from the shore in a non-impacted area. During surveys 1 and 2, the effluents had a negative effect at all three distances (50, 150, and 300 m) on the water quality variables (transparency, seston [total suspended solids, total inorganic solids, particulate organic matter], chlorophyll a, N-NO2–, N-NO3–, N-NH4+), on the sediment quality parameters (organic nitrogen), and on the TRIX index. Contrarily, no differences were observed when the impacted and non-impacted areas were compared during survey 3, probably because the effluents had diminished due to the premature harvesting. The results suggest that at the end of the farming period, the nutrient and organic matter load exceeded the assimilation capacity of the ecosystem, whereas during the recess period, the environment was capable of assimilating the excess organic matter accumulated. The levels reached by the monitored parameters did not exceed the limits established and the impact on the ecosystem is not severe, but they could represent a risk factor in the long term. Additionally, there is evidence that the temporary suspension of shrimp farming operations is beneficial for the environment.

Managing declining yields from ageing tea plantations

Strong growth in the demand for tea requires further increases in the productivity of plantations. Declining or stagnant yields are commonly observed in older plantations. Possible controlling factors for yield decline are reviewed including ageing of plants, chronic disease and sub-optimal soil conditions such as excess soil acidity and low soil organic matter. Management options for addressing these factors are evaluated, including replanting. A systematic approach to decision-making about replanting is presented. Practice for replanting is reviewed and it is concluded that evidence to support a general case for replanting is limited, unless based on the introduction of more productive clones and/or better plant spacing.

Efficacy of Fungal Laccase to Facilitate Biodethatching in Bermudagrass and Zoysiagrass

Accumulation of excessive organic matter in form of a thatch and/or mat layer can cause several problems in turfgrass management systems. A previous greenhouse study on creeping bentgrass (Agrostis stolonifera L.) demonstrated that direct application of laccase solution every 2 wk reduced the rate of accumulation of organic matter and hence buildup of the thatch layer. A 2‐yr field study was conducted on an ultra‐dwarf bermudagrass [Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt Davy, ‘TifEagle’] research green, and zoysiagrass (Zoysia japonica Steud., ‘Meyer’) maintained as a home lawn to observe the influence of laccase enzyme applications on thatch development. Laccase solution was applied biweekly at the activity levels of 0 (control) and 2.1 units cm–2. Response to laccase enzyme applications by both the turfgrass species was recorded by measuring thatch layer physical and chemical properties after 6 mo of treatment applications within each year. A significant 18 to 22% and 21 to 30% reduction in thatch layer thickness was observed for bermudagrass and zoysiagrass, respectively. Organic matter content (0–2.5 cm) decreased by 23 to 24% while saturated hydraulic conductivity increased by 19 to 30% for bermudagrass in both years. Acid‐soluble and ‐insoluble lignin was reduced in both turfgrass species after laccase treatments. Results indicate that bi‐weekly application of laccase on bermudagrass and zoysiagrass has positive impact on thatch management.

Use of Fungal Laccases to Facilitate Biodethatching: A New Approach

Accumulation of excessive organic matter as thatch restricts permeability of putting greens and is one of the most difficult problems in turfgrass management. A greenhouse experiment using potted bentgrass (Agrostis stolonifera L.) determined the efficacy of a ligninolytic enzyme, laccase, in reducing organic matter accumulation in the thatch-mat layer. Laccase was added biweekly at 0, 0.206, 2.06, and 20.6 units of activity/cm2 with and without guaiacol (2-methoxyphenol), a mediator of laccase, and sampling was performed after two and nine months. Parameters investigated included thickness of the organic layer, thatch layer and mat layer, organic matter content, saturated hydraulic conductivity, and lignin content. Organic matter and thatch layer increased between the two sampling dates in all treatments. Laccase was shown to be effective in slowing the rate of accumulation of organic matter and thatch layer. After two months, application of 20.6 units/cm2 of laccase reduced organic layer thickness by 8.7% and extractive-free total lignin content by 8.4% when compared with non-treated control. After nine months, laccase application rates of 2.06 units/cm2 reduced organic matter and thatch layer thickness by 15.6% and 45.0%, respectively, below levels observed in the non-treated control. Applications using 0.206 units/cm2 of laccase were ineffective. Laccase applications had no influence on turf quality. These positive responses suggest laccase treatments could be a non-disruptive option for thatch and/or mat control in bentgrass.

Cleaning of marine sediment samples for large diatom stable isotope analysis

Diatom stable isotope analysis offers considerable potential in palaeoceanography, particularly where carbonate material is scarce or absent. However, extracting pure diatom frustules free of external labile organic matter from marine sediments is an essential requirement for their applications as paleoenvironmental proxies. Here, based largely on previous work, we developed a method including physical separation and chemical oxidation steps to concentrate and clean pure large diatoms from laminated diatom mat and diatomaceous clay sediment samples for their stable isotope analysis. Using the physical separation techniques consisting of the removal of carbonate and excess organic matter, sieving, differential settling, and heavy liquid floatation, pure diatoms can be successfully isolated from the sediment samples with opal concentration more than 10%. Subsequent time oxidation experiment shows that labile organic matter coating pure diatom valves can be effectively removed with 30% H2O2 at 65 degrees C for 2 h. Measurements of delta C-13 after every step of physical separation demonstrate that contaminants and lost diatoms can influence the original diatom stable isotope signal, highlighting the importance of a visual check for dominant diatom size in the initial sample and purity in the final sample. Although the protocol described here was only applied to diatom mats or diatom oozes containing large diatoms (Ethmodiscus rex), we believe that this method can be adapted to common diatoms of general marine sediment samples.

Antimicrobial Sand via Adsorption of Cationic Moringa oleifera Protein

Moringa oleifera (Moringa) seeds contain a natural cationic protein (MOCP) that can be used as an antimicrobial flocculant for water clarification. Currently, the main barrier to using Moringa seeds for producing potable water is that the seeds release other water-soluble proteins and organic matter, which increase the concentration of dissolved organic matter (DOM) in the water. The presence of this DOM supports the regrowth of pathogens in treated water, preventing its storage and later use. A new strategy has been established for retaining the MOCP protein and its ability to clarify and disinfect water while removing the excess organic matter. The MOCP is first adsorbed and immobilized onto sand granules, followed by a rinsing step wherein the excess organic matter is removed, thereby preventing later growth of bacteria in the purified water. Our hypotheses are that the protein remains adsorbed onto the sand after the functionalization treatment, and that the ability of the antimicrobial functionalized sand (f-sand) to clarify turbidity and kill bacteria, as MOCP does in bulk solution, is maintained. The data support these hypotheses, indicating that the f-sand removes silica microspheres and pathogens from water, renders adhered Escherichia coli bacteria nonviable, and reduces turbidity of a kaolin suspension. The antimicrobial properties of f-sand were assessed using fluorescent (live-dead) staining of bacteria on the surface of the f-sand. The DOM that can contribute to bacterial regrowth was shown to be significantly reduced in solution, by measuring biochemical oxygen demand (BOD). Overall, these results open the possibility that immobilization of the MOCP protein onto sand can provide a simple, locally sustainable process for producing storable drinking water.

Effect of temperature on biogeochemistry of marine organic-enriched systems: implications in a global warming scenario

Coastal biogeochemical cycles are expected to be affected by global warming. By means of a mesocosm experiment, the effect of increased water temperature on the biogeochemical cycles of coastal sediments affected by organic-matter enrichment was tested, focusing on the carbon, sulfur, and iron cycles. Nereis diversicolor was used as a model species to simulate macrofaunal bioirrigation activity in natural sediments. Although bioirrigation rates of N. diversicolor were not temperature dependent, temperature did have a major effect on the sediment metabolism. Under organic-enrichment conditions, the increase in sediment metabolism was greater than expected and occurred through the enhancement of anaerobic metabolic pathway rates, mainly sulfate reduction. There was a twofold increase in sediment metabolism and the accumulation of reduced sulfur. The increase in the benthic metabolism was maintained by the supply of electron acceptors through bioirrigation and as a result of the availability of iron in the sediment. As long as the sediment buffering capacity toward sulfides is not surpassed, an increase in temperature might promote the recovery of organic-enriched sediments by decreasing the time for mineralization of excess organic matter.