Suspended Organic Matter Research Articles (Page 6)

Quantification of microplastics in a freshwater suspended organic matter using different thermoanalytical methods – outcome of an interlaboratory comparison

Abstract Aquaculture is an economic activity that faces the unavoidable problem of water quality detriment, which is mainly generated by the improper management of production ponds, including inadequate water circulation and aeration, accumulation of undigested food residues, excretion of metabolic by‐products by the cultivated organisms and other. In addition, the increase in suspended organic matter together with the presence and generation of nitrogen compounds can severely affect the physiology of the animal, leading to significant losses in production. Ammonia (NH3), nitrite (NO2) and nitrate (NO3) are toxic in different scales and environmental conditions; therefore, reducing their concentrations in the culture units has paramount relevance. In this regard, bioflocs are an efficient alternative to transform nitrogen compounds into a non‐toxic form, taking advantage of the capabilities of the microbial communities conforming them. Also, nitrogen can be harnessed and incorporated as organic nitrogen, making the biofloc a source of useful natural food for the cultivated organism. The substantial reduction in the rate of water exchange favoured by the biofloc technology (BFT) is a beneficial advantage for both the production systems and the environment, diminishing the risk of introducing pathogens into the pond in parallel with the improvement in the water quality of effluents. Ammonia oxidation is an advantage adding value to the BFT systems and is discussed in this review.

The study aimed to assess the variation of surface water quality and evaluate the monitoring frequency at threecontinuous monitoring stations on the Tien river (MT1 station) and Hau river (MH1 and MH2 station) over a 10-year period (2009-2018), with a monitoring frequency of 12 times per year (monthly). The water quality variables comprised of temperature (oC), pH, dissolved oxygen (DO, mg/L), total suspended solids (TSS, mg/L), nitrate (N-NO- 3 , mg/L), orthophosphate (P-PO3 4- mg/L), chemical oxygen demand (COD, mg/L), and coliforms (MPN/100 mL). The individual water quality parameters were assessed by comparison with National Technical Regulation on surface water quality (QCVN 08-MT: 2015/BTNMT). Monitoring frequency was evaluatedusing Cluster Analysis (CA). The findings revealed that surface water on both Tien and Hau rivers was perpetually polluted with suspended solids, organic matter, nutrients, and microorganisms. The CA identified that the frequencies of current water monitoring could be reduced from 12 times to 5 times per year, resulting in a 58% reduction in monitoring costs. Future study should focus on evaluating water quality parameters toencompass all water quality characteristics in the Tien and Hau rivers. International collaboration with countries that impact the river before flowing into Vietnam in water management should be enhanced to solve continuing water problems.

This paper presents research on the influence of suspended sediments on selected aspects of a reservoir’s functioning. As the amount of sediment suspended in water (SS) there was found to correlate significantly with sedimentation rate (Us), it was possible to develop a function allowing the rate of accumulation of sediments to be predicted by reference to known amounts of suspended sediment. The latter factor was also shown to correlate significantly with the content of organic matter in suspension (OMSS), in sediment captured in a sediment trap (OMS), and of bottom sediment (OMSB). Analysis of amounts of suspended sediment can provide for estimates of total loads of organic pollutants deposited in the sediments of a reservoir. A further significant correlation with SS was noted for the concentration of total phosphorus in water (TPW), confirming the importance of internal production where the circulation of this biogenic substance in a reservoir ecosystem is concerned. Analysis of stable carbon isotopes in turn showed that entrapped sediments were depleted of—or enriched in—13C, in line with whether concentrations of total P in those sediments (TPS) were at their highest or lowest levels. This dependent relationship may thus be of key importance in assessing sources of phosphorus, as well as in forecasting concentrations present in reservoir sediments. The results obtained make it clear that sediments suspended in the water of a reservoir unify phenomena and processes ongoing there, between elements of the water-sediment system.

The manila clam Ruditapes philippinarum is widely distributed in the sandy mud sediments of tidal flats and plays a role in seawater purification by filtering suspended organic matter. This study was designed to evaluate differences in seawater purification based on the filtration rate of the manila clam in terms of particulate organic matter (POM) between two tidal flats with different hydrographic regimes. In situ experiments were carried out at Geunso and Sihwa tidal flats, along the west coast of Korea. The amount of POM removed from the water column by the feeding activity of the clam was measured in the field using a closed circulation chamber. The filtration rate of clams for POM at Sihwa tidal flat (2.86 for POC, 2.29 for PON and 5.46 L h-1 gDW-1 for Chl a) was higher than that at Geunso tidal flat (0.61 for POC, 0.89 for PON and 2.54 L h-1 gDW-1 for Chl a) which resulted from differences in the hydrographic regime, including tide characteristics, current speed and submergence time, and food quantity and quality. The current speed was much greater at Geunso tidal flat than at Sihwa tidal flat, but the submergence time by tide was longer at the latter site than the former, resulting in different feeding times for clams. The food quantity in terms of chlorophyll a was higher at Sihwa tidal flat than at Geunso tidal flat, and the food quality based on the C/N ratio of POM was better at the former site than the latter, with values of 12.8 and 15.6, respectively. These findings suggest that hydrographic regime could be important in understanding in situ filtration rates of R. philippinarum.

The main purpose of this study was to investigate the ability of cross-flow microfiltration technique to treat urban wastewater effluents. Experimental results demonstrated that this technique is reliable and very effective in removing wastewater impurities. Results showed that hollow fiber membranes achieved a significant removal rate of all parameters tested except ammonium nitrogen. This study confirmed that cross-flow microfiltration process is very efficient concerning the abatement of suspended solids and organic matter. All pathogenic bacteria indicators were removed by this process. The experimental study demonstrated that quality of permeate produced by hollow fiber microfiltration membranes is suitable for industrial reuse.

Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morphology. The protocol reveals that gross elemental soil profile distributions do provide evidence that certain pedogenic processes are operating within a group of soils. Concentration differences between instrumental neutron activation analysis and an aqua regia digestion protocol infer that alkali metals, alkaline earth metals, transition metals and the rare earth elements are only incompletely weathered from primary minerals. Transition metals, alkali metals, alkaline earths, metalloids, and the rare earth elements all show inter-horizon mobility. Lessivage and the mobility of elements presumably adsorbed on soluble or suspended organic materials are the dominant soil processes influencing the soil profile redistribution of elements and the majority of these elements are shown to correlate with the soil profile distribution of Fe. Base cycling by the forest vegetation was shown to support A horizon enrichment of Ca, Sr, Ba, P, S, Mn, Zn, Sn and Pb. For clinical practice, elemental analysis may reveal important soil profile elemental differences when applied to variation of one soil forming factors, such as a chronosequence or toposequence within a landscape or soil association. Advantages and limitations of the protocol in identifying pedogenic pathways are discussed.

We have shown that the number of heterotrophic bacteria in the surface microlayer and periphyton is reliably higher than in the water column, which characterizes these biotopes as sites of intense destruction of suspended organic matter. Average values of the total bacterial number, the number of cultured heterotrophic bacteria and the K index indicate the elevated supply of labile organic matter at the stations near the Listvyanka settlement, the Olkhonskiye Vorota Strait and Aya Bay.

Effects of moisture and carbon/nitrogen ratio on gaseous emissions and maturity during direct composting of cornstalks used for filtration of anaerobically digested manure centrate

Ecosystem engineering can control the spatial and temporal distribution of resources and movement by engineering organisms within an ecosystem can mobilize resources across boundaries and distribute engineering effects. Movement patterns of fishes can cause physical changes to aquatic habitats though nesting or feeding, both of which often vary in space and time. Here we present evidence of ecosystem engineering by the Sonora sucker Catostomus insignis, a dominant fish in streams of the southwestern United States, and show how cryptic nocturnal movement patterns and bioturbation activities control heterogeneity in benthic substrates, and in sediment and carbon export. Sonora suckers exhibit distinct diel movement patterns, spending daylight hours in refuge habitats (typically deep pools) while moving into shallow habitats at night to feed. Feeding by suckers creates substantial disturbance in soft sediments that are patchy in space and time. These disturbances moved up to 2.4 × 104 cm3 of sediment per square meter per week in locations that are up to hundreds of meters away from sucker daytime refuges. The diel cycles in feeding activity (i.e. nocturnal digging in benthic substrates) caused nighttime pulses in suspended sediment that comprised up to 32% of the daily suspended load and organic matter transport of a stream reach. During the daytime, this particulate transport settles in habitats beyond the location of the initial disturbance, thus redistributing both sediment and organic matter. Our data indicate that cryptic movement by ecosystem engineers can distribute their effects in space and time generating heterogeneity in resources and suggest that habitat modifications restricting consumer movement may alter the impact of engineering activities.

The aim of this study was to investigate the sediment dynamics in the largest lagoon in Europe (Curonian Lagoon, Lithuania) through the analysis of in situ data and the application of a sediment transport model. This approach allowed to identify the propagation pathway of the riverine suspended sediments, to map erosion-accumulation zones in the lagoon and calculate the sediment budget over a 13-year-long simulation. Sampled suspended sediment concentration data are important for understanding the characteristics of the riverine and lagoon sediments, and show that the suspended organic matter plays a crucial role on the sediment dynamics for this coastal system. The numerical experiments carried out to study sediment dynamics gave satisfactory results and the possibility to get a holistic view of the system. The applied sediment transport model with a new formula for settling velocity was used to estimate the patterns of the suspended sediments and the seasonal and spatial sediment distribution in the whole river–lagoon–sea system. The numerical model also allowed understanding the sensitivity of the system to strong wind events and the presence of ice. The results reveal that during extreme storm events, more than 11.4 × 106 kg of sediments are washed out of the system. Scenarios without ice cover indicate that the lagoon would have much higher suspended sediment concentrations in the winter season comparing with the present situation with ice. The results of an analysis of a long-term (13 years) simulation demonstrate that on average, 62% of the riverine sediments are trapped inside the lagoon, with a marked spatially varying distribution of accumulation zones.

How does urban wastewater treatment affect the microbial quality of treated wastewater?

Dispersal potential of neritic benthic foraminifera in the coastal areas of the Japanese Islands and its application to paleoenvironmental studies

Perspectives on provenance and alteration of suspended and sedimentary organic matter in the subtropical Pearl River system, South China

Anthropogenic carbon as a basal resource in the benthic food webs in the Neva Estuary (Baltic Sea)

Correlations between silt density index, turbidity and oxidation-reduction potential parameters in seawater reverse osmosis desalination

The present study aimed to understand sources and transformations of organic matter along with cycling of nitrogen and carbon in sediments of two geographically close but ecologically distinct wetlands located on the east coast of India viz. Chilika lagoon (Asia’s largest brackish water lagoon) and Bhitarkanika mangrove. The study also investigates potential nitrogen loss pathways in the bottom sediments and explores stables isotopes as a proxy for the source identification of sediment organic matter in shallow aquatic ecosystems. For this purpose, the isotopic compositions of organic carbon and nitrogen (δ13Corg and δ15N) and its contents (% Corg and % N) were measured at different depths in sediment cores collected from the Chilika lagoon (eight cores) and Bhitarkanika mangrove forest (three cores). Overall, the mean δ13Corg and % Corg in the lagoon were − 21.10 ± 0.79‰ and 0.84 ± 0.47%, respectively; whereas the same for mangrove cores were − 24.56 ± 0.80‰ and 1.04 ± 0.26%, respectively. Similarly, average δ15N and % N in the lagoon cores were 4.15 ± 0.63‰ and 0.11 ± 0.05%, respectively; for mangrove cores, the values were 4.28 ± 0.50‰ and 0.07 ± 0.01%, respectively. Isotopic composition and elemental ratios indicated organic matter in the sediments of Bhitarkanika mangrove to be a mixture of terrigenous and marine origin with relative dominance of terrestrial influence. A significant increase in δ13Corg of sediment organic matter compared to suspended particulate organic matter in the Chilika indicated transformation of organic matter in the water or sediment column through mineralization and diagenetic alterations. The δ15N of sediment or particulate organic matter did not show clear evidence of nitrogen loss in the recent past in these two ecosystems through processes such as denitrification. The absence of a relationship between δ13Corg of particulate and sediment organic matter in the Chilika indicated lack of efficient exchange between suspended and sediment organic matter.

Influence of rainfall intensity and pollution build-up levels on water quality and quantity response of permeable pavements

The soft-bottom macrobenthos of Bahía San Julián intertidal was surveyed to identify infaunal assemblages and analyze their relationships with the main environmental factors determining species distribution. Four seasonal surveys (summer, autumn, winter and spring) were performed in the middle and lower intertidal levels at seven sampling stations established on both sides of an urban sewage discharge point, and water and sediment variables were measured. To explore possible spatial variations in the community, environmental and biological data were analyzed using univariate and multivariate statistics. Community composition varied with intertidal level, sediment characteristics and distance to sewage discharge site. In sediment with high mud content, the community was characterized by Darina solenoides, Mysella patagona, Eteone sculpta, Scolecolepides uncinatus and Capitella sp., in the middle intertidal, and was characterized by M. patagona and Ampelisca sp. in the lower intertidal. In sediment with dominance of fine sand, the community was characterized by Aricidea sp. at both intertidal levels. Near the effluent discharge site, the community was largely dominated by M. patagona. Intertidal level and sediment particle size are the main factors determining the composition of benthic assemblages in the study area. Sewage discharge also affects the composition of the infaunal community, possibly as a result of the contribution of particulate organic matter in suspension that stimulates the populations of detritus feeders.

This study investigated the performance of composting cornstalks after used as the filtering materials for the pretreatment of anaerobically digested manure centrate. Results show that cornstalks could effectively remove suspended solids and organic matter in digested centrate. Direct composting of the used cornstalks could be achieved. The composting temperature increased rapidly and maintained at the thermophilic phase for more than 10 days. During 28 days of composting, the used cornstalks could be mature as indicated by the matrix pH of 7.37, electrical conductivity of 1.13 mS/cm, and germination index of higher than 100%. During composting, the carbon/nitrogen ratio of the used cornstalks decreased from 16.81 to 13.62. Moreover, cellulose in the used cornstalks was degraded by approximately 35.4% during composting.