scholarly journals Biogeochemical Impact of Cable Bacteria on Coastal Black Sea Sediment

2020 ◽  
Author(s):  
Martijn Hermans ◽  
Nils Risgaard-Petersen ◽  
Filip J. R. Meysman ◽  
Caroline P. Slomp
Keyword(s):  
Organic Matter ◽  
Oxygen Uptake ◽  
Black Sea ◽  
Anaerobic Degradation ◽  
Rapid Development ◽  
Oxygen Demand ◽  
Depth Profiles ◽  
Sediment Biogeochemistry ◽  
Reduced Products ◽  
The Impact

Abstract. Cable bacteria can strongly alter sediment biogeochemistry. Here, we used laboratory incubations to assess whether cable bacteria can establish in iron (Fe) monosulphide-poor coastal Black Sea sediment and to determine the impact of their activity on the cycling of Fe, phosphorus (P) and sulphur (S). Microsensor depth profiles of oxygen, sulphide and pH in combination with electric potential profiling and FISH analyses showed a rapid development ( 200 days). During most of the experiment, the current density correlated linearly with the oxygen demand. Sediment oxygen uptake was attributed to activity of cable bacteria and the oxidation of reduced products from anaerobic degradation of organic matter, such as ammonium. Pore water sulphide was low (

scholarly journals Sensitivity of the N. AEGEAN SEA ecosystem to Black Sea Water inputs

2014 ◽  
Vol 15 (4) ◽  
pp. 790 ◽  
Author(s):  
G. PETIHAKIS ◽  
K. TSIARAS ◽  
G. TRIANTAFYLLOU ◽  
S. KALARONI ◽  
A. POLLANI
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Black Sea ◽  
Sea Water ◽  
Aegean Sea ◽  
Microbial Loop ◽  
Inorganic Nutrients ◽  
The North ◽  
North Aegean Sea ◽  
The Impact

The effect of Black Sea Water (BSW) inputs on the North Aegean Sea productivity and food web dynamics was investigated, by means of sensitivity simulations, investigating the effect of the inflowing BSW, in terms of inorganic nutrients and dissolved organic matter. The model used has been successfully applied in the area in the past and extensively presented. Considering the importance of the microbial loop in the ecosystem functioning, the role of the dissolved organics and in order to achieve a more realistic representation of the Dissolved Organic Matter pool, the bacteria sub-model was appropriately revised. The importance of the microbial loop is highlighted by the carbon fluxes where almost 50% of carbon is channelled within it. The impact of dissolved organic matter (DOM) (in the inflowing to the Aegean Sea, BSW) appears to be stronger than the impact of dissolved inorganic nutrients, showing a more extended effect over the N Aegean. Bacterial production and biomass is more strongly affected in the simulations by modified DOM, unlike phytoplankton biomass and production, which are more dependent on the inflowing nutrients and particularly phosphorus (inorganic and dissolved organic). In the phytoplankton composition, the dinoflagellates appear to be mostly affected, being favoured by higher nutrient availability at the expense of all other groups, particularly picoplankton, indicating a shift to a more classical food chain.

scholarly journals Pilot-scale study to investigate the impact of rotating belt filter upstream of a MBR for nitrogen removal

2019 ◽  
Vol 79 (3) ◽  
pp. 458-465
Author(s):  
V. A. Razafimanantsoa ◽  
D. Adyasari ◽  
A. K. Sahu ◽  
B. Rusten ◽  
T. Bilstad ◽  
...  
Keyword(s):  
Organic Matter ◽  
Municipal Wastewater ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Primary Treatment ◽  
Treated Wastewater ◽  
Transmembrane Pressure ◽  
Fine Mesh ◽  
The Impact

Abstract The goal of this study was to investigate what kind of impact the removal of particulate organic matter with 33μm rotating belt filter (RBF) (as a primary treatment) will have on the membrane bioreactor (MBR) performance. Two small MBR pilot plants were operated in parallel, where one train treated 2mm screened municipal wastewater (Train A) and the other train treated wastewater that had passed through a RBF with a 33μm filter cloth (Train B). The RBF was operated without a filter mat on the belt. About one third of the organic matter was removed by the fine mesh filter. The assessment of the overall performance showed that the two pilot plants achieved approximately the same removal efficiencies with regard to total suspended solids (TSS), chemical oxygen demand (COD), total phosphorus and total nitrogen. It was also observed that the system with 33μm RBF as a primary treatment produced more sludge, which could be used for biogas production, and required about 30% less aeration downstream. Transmembrane pressure was significantly lower for the train receiving 33μm primary treated wastewater compared to the control receiving 2mm screened wastewater.

scholarly journals Intensification of the Organic Matter Oxidation in Water Solutions in the Process of Processing with Pulsed High-voltage Discharges

2015 ◽  
pp. 120
Author(s):  
Keyword(s):  
Organic Matter ◽  
Chemical Oxygen Demand ◽  
High Voltage ◽  
Oxygen Demand ◽  
Water Solutions ◽  
Oxidation Processes ◽  
Ph Changes ◽  
Model Solutions ◽  
Organic Matter Oxidation ◽  
The Impact

Applied aspects of the intensification of organic matter oxidation processes in water solutions have been studied. Data on chemical oxygen demand (COD) decrease and pH changes of the model solutions under the impact of barrier and spark pulsed high-voltage discharges have been presented.

The Impact of Christchurch City (New Zealand) on Heavy Metals in Sediments of the Avon-Heathcote Estuary

1993 ◽  
Vol 28 (8-9) ◽  
pp. 369-382 ◽  
Author(s):  
J. Deely
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Heavy Metal Contamination ◽  
Clay Fraction ◽  
Clay Content ◽  
Sediment Surface ◽  
Core Sediment ◽  
Depth Profiles ◽  
Western Area ◽  
The Impact

This paper reviews heavy metal (Cr, Cu, Fe, Mn, Ni, Pb, Zn) content in the clay fraction (<4 µm) of soils, suspended sediment, surface sediment, and core sediment associated with the Avon-Heathcote Estuary. Despite the estuary's low clay content (<10%), significant metal and organic matter trends are apparent in the clay fraction, which are less obvious in parallel studies of silt (4-63 µm), sand (>63 µm), and total sediment. Clay fraction depth profiles record periods of high heavy metal input in sediments deposited slowly but not in sediments deposited rapidly. Most metals, organic matter, mud, and Fe oxides accumulate in a broad anaerobic band across the western area of the estuary. Organic matter and metal concentrations are increasing towards the surface in depth profiles of this zone. This pattern combined with the increasingly eutrophic state of the estuary suggests more serious heavy metal contamination in the future.

scholarly journals Biogeochemical impact of cable bacteria on coastal Black Sea sediment

2020 ◽  
Vol 17 (23) ◽  
pp. 5919-5938
Author(s):  
Martijn Hermans ◽  
Nils Risgaard-Petersen ◽  
Filip J. R. Meysman ◽  
Caroline P. Slomp
Keyword(s):  
Pore Water ◽  
Rapid Development ◽  
Subsurface Layer ◽  
In Situ Hybridisation ◽  
Oxygen Demand ◽  
Fluorescence In Situ Hybridisation ◽  
Fe Oxides ◽  
Sediment Biogeochemistry ◽  
Subsurface Layers

Abstract. Cable bacteria can strongly alter sediment biogeochemistry. Here, we used laboratory incubations to determine the potential impact of their activity on the cycling of iron (Fe), phosphorus (P) and sulfur (S). Microsensor depth profiles of oxygen, sulfide and pH in combination with electric potential profiling and fluorescence in situ hybridisation (FISH) analyses showed a rapid development (<5 d) of cable bacteria, followed by a long period of activity (>200 d). During most of the experiment, the current density correlated linearly with the oxygen demand. Sediment oxygen uptake was attributed to the activity of cable bacteria and the oxidation of reduced products from the anaerobic degradation of organic matter, such as ammonium. Pore water sulfide was low (< 5 µM) throughout the experiment. Sulfate reduction acted as the main source of sulfide for cable bacteria. Pore water Fe2+ reached levels of up to 1.7 mM during the incubations, due to the dissolution of FeS (30 %) and siderite, an Fe carbonate mineral (70 %). Following the upward diffusion of Fe2+, a surface enrichment of Fe oxides formed. Hence, besides FeS, siderite may act as a major source of Fe for Fe oxides in coastal surface sediments where cable bacteria are active. Using µXRF, we show that the enrichments in Fe oxides induced by cable bacteria are located in a thin subsurface layer of 0.3 mm. We show that similar subsurface layers enriched in Fe and P are also observed at field sites where cable bacteria were recently active and little bioturbation occurs. This suggests that such subsurface Fe oxide layers, which are not always visible to the naked eye, could potentially be a marker for recent activity of cable bacteria.

Research on behavior recognition based on feature fusion of automatic coder and recurrent neural network

2020 ◽  
Vol 39 (6) ◽  
pp. 8927-8935
Author(s):  
Bing Zheng ◽  
Dawei Yun ◽  
Yan Liang
Keyword(s):  
Neural Network ◽  
Recurrent Neural Network ◽  
Behavior Pattern ◽  
Rapid Development ◽  
Video Data ◽  
Support Vector ◽  
Behavior Recognition ◽  
Learning Methods ◽  
The Impact ◽  
Internet Of Things Technology

Under the impact of COVID-19, research on behavior recognition are highly needed. In this paper, we combine the algorithm of self-adaptive coder and recurrent neural network to realize the research of behavior pattern recognition. At present, most of the research of human behavior recognition is focused on the video data, which is based on the video number. At the same time, due to the complexity of video image data, it is easy to violate personal privacy. With the rapid development of Internet of things technology, it has attracted the attention of a large number of experts and scholars. Researchers have tried to use many machine learning methods, such as random forest, support vector machine and other shallow learning methods, which perform well in the laboratory environment, but there is still a long way to go from practical application. In this paper, a recursive neural network algorithm based on long and short term memory (LSTM) is proposed to realize the recognition of behavior patterns, so as to improve the accuracy of human activity behavior recognition.

The impact of urban effluents on the coastal marine environment of Mediterranean islands

1995 ◽  
Vol 32 (9-10) ◽  
pp. 85-94 ◽  
Author(s):  
Michael O. Angelidis
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Marine Environment ◽  
Suspended Particle ◽  
Pollution Source ◽  
Mediterranean Islands ◽  
Coastal Marine Environment ◽  
Coastal Marine ◽  
The Impact ◽  
The City

The impact of the urban effluents of Mytilene (Lesvos island, Greece) on the receiving coastal marine environment, was evaluated by studying the quality of the city effluents (BOD5, COD, SS, heavy metals) and the marine sediments (grain size, organic matter, heavy metals). It was found that the urban effluents of Mytilene contain high organic matter and suspended particle load because of septage discharge into the sewerage network. Furthermore, although the city does not host important industrial activity, its effluents contain appreciable metal load, which is mainly associated with the particulate phase. The city effluents are discharged into the coastal marine environment and their colloidal and particulate matter after flocculation settles to the bottom, where is incorporated into the sediments. Over the years, the accumulation of organic matter and metals into the harbour mud has created a non-point pollution source in the relatively non-polluted coastal marine environment of the island. Copper and Zn were the metals which presented the higher enrichment in the sediments of the inner harbour of Mytilene.

Fish farming in Denmark: environmental impact of regulative legislation

1995 ◽  
Vol 31 (10) ◽  
pp. 73-84 ◽  
Author(s):  
T. M. Iversen
Keyword(s):  
Organic Matter ◽  
Environmental Impact ◽  
Freshwater Fish ◽  
Aquatic Environment ◽  
Action Plan ◽  
Fish Farming ◽  
Fish Farms ◽  
Nitrogen And Phosphorus ◽  
Local Impact ◽  
The Impact

The main environmental problems associated with fish farming in Denmark are attributable to the dam, the “dead reach” and nutrient and organic matter discharge. The environmental regulation of fish farming in Denmark started with the Environmental Protection Act of 1974, the Statutory Order of 1985 forbidding wet feed, and the Action Plan on the Aquatic Environment of 1987. In the case of freshwater fish farms, the latter was implemented through the measures stipulated in the 1989 Statutory Order on Fish Farms. The impact of Danish legislative measures to reduce and regulate the environmental effects of freshwater fish farms can be summarized as follows: - the number of fish farms has been reduced from about 800 in 1974 to about 500 at present; - production has tripled since 1974 and has been stable since 1989; - a change from wet to dry feed has reduced the environmental impact of the farms; - the national goals of the Action Plan on the Aquatic Environment of 1987 for reducing fish farm discharges of organic matter, nitrogen and phosphorus have been fulfilled. The main remaining problems are that: - the local impact of fish farms on downstream stream quality is still much too high in about 15% of cases; - the problem of the passage of migrating invertebrates and fish is still unsolved at some farms; - the problems posed by “dead reaches” are still unsolved. It is concluded that sustainable fish farming is possible in Denmark, but with the present technology production will have to be significantly reduced.

Considering the impact of intermittent discharges when modelling overflows

1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Preliminary Investigation ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Combined Sewer Overflows ◽  
River Hydraulics ◽  
Combined Sewer ◽  
The Impact ◽  
Curve Equation

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.

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