Dynamics of dissolved oxygen and benthic release of nutrients in the bottom water layer in shallow versus deep areas in Hong Kong waters

2010 ◽  
Author(s):  
Kit Yee Chong
Keyword(s):  
Hong Kong ◽  
Dissolved Oxygen ◽  
Bottom Water ◽  
Water Layer ◽  
Bottom Water Layer ◽  
Hong Kong Waters

scholarly journals Changes in the concentration of selected water quality parameters in Lake Starzec in the vegetation periods / Zmiany stężenia wybranych wskaźników jakości wody w jeziorze Starzyc w okresach wegetacyjnych

2012 ◽  
Vol 17 (1) ◽  
pp. 53-59
Author(s):  
Piotr Wesołowski ◽  
Adam Brysiewicz
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Bottom Water ◽  
Water Layer ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Ammonium Ions ◽  
Bottom Water Layer ◽  
The Third ◽  
Lake Waters

Abstract Studies were carried out in the years 2008-2010 in Lake Starzyc, zachodniopomorskie voivodship. The aim was to determine differences in the concentrations of selected water quality parameters between particular months of the vegetation seasons 2008-2010. Monthly mean concentrations of dissolved oxygen between April and October were by 1.91 g O2m-3 higher in surface than in near-bottom water layer. Differences in the concentration of dissolved oxygen were also noted between particular months. Recorded concentrations fell within the range required for lake waters of the first and second water quality. Concentrations of mineral nitrogen in the years 2008-2010 corresponded to those of the third class of water quality and phosphorus concentrations exceeded this standard. Concentrations of ammonium ions did not exceed the values permitted for the second water quality class.

Effect of bacteria from the bottom water layer of lake baikal on degradation of diatoms

2013 ◽  
Vol 47 (9) ◽  
pp. 1030-1034 ◽  
Author(s):  
Yu. R. Zakharova ◽  
M. I. Kurilkina ◽  
A. V. Likhoshvay ◽  
S. M. Shishlyannikov ◽  
O. V. Kalyuzhnaya ◽  
...  
Keyword(s):  
Lake Baikal ◽  
Bottom Water ◽  
Water Layer ◽  
Bottom Water Layer

Spatial structure of the macroand meiobenthic communities in homogenous conditions (on the example of the Pechora Sea)

2019 ◽  
Vol 59 (3) ◽  
pp. 405-412
Author(s):  
V. V. Kozlovskiy ◽  
M. V. Chikina ◽  
N. V. Shabalin ◽  
A. B. Basin ◽  
V. O. Mokievskiy ◽  
...  
Keyword(s):  
Grain Size ◽  
Spatial Structure ◽  
Bottom Water ◽  
Barents Sea ◽  
Water Layer ◽  
Bottom Water Layer ◽  
South Eastern ◽  
Leading Role ◽  
Serripes Groenlandicus ◽  
Historic Data

Spatial structure of the macroand meiobenthic communities of the south-eastern Barents Sea (also known as Pechora Sea) was investigated in 2003 during the expedition of the RV «Professor Shtokman». One grid of the stations was used for both benthic size classes. Community dominated by Serripes groenlandicus occupied the most part of the investigated polygon, Astarte borealis dominated the easternmost station. Described communities are in correspondence with historic data. In the meiobenthic communities, nematodes played a leading role, accounting for 86–94% of the total number. Nematode Richtersia inaequalis was dominant on most stations, at the northernmost station the nematodes Cervonema papillatum and Microlaimus affinis dominated. The temperature and the salinity of the near-bottom water layer were homogenous, macroand meiobenthic communities were not influenced by grain size. In contrast to our expectations, communities of the macroand meiobenthos were distributed independently of each other on the mesoscale area (30×11 km).

scholarly journals Ecological–microbiological studies of lake Beloe in winter and spring with the use of innovation test-systems

2019 ◽  
Vol 46 (6) ◽  
pp. 621-628
Author(s):  
I. V. Mosharova ◽  
V. V. Il’inskii ◽  
S. A. Mosharov ◽  
A. Yu. Akulova
Keyword(s):  
Chlorophyll A ◽  
Bottom Water ◽  
Water Layer ◽  
Coliform Bacteria ◽  
Microbial Count ◽  
Bacterial Cells ◽  
Chlorophyll A Concentration ◽  
Bottom Water Layer ◽  
Test Systems ◽  
Microbiological Characteristics

Chlorophyll a concentration, the total abundance of bacteria, the number of bacterial cells with active metabolism, and the abundance of saprotrophic bacteria were studied in the surface and bottom water layers of Lake Beloe in winter and spring 20152016. The abundance of sanitary-indicator microorganisms was determined for the first time with the use of Petrifilm test-systems (3MTM Petrifilm). In most cases, Lake Beloe water in spring and winter was found to correspond to eutrophic level (in terms of chlorophyll a concentration in water) and polysaprobic status (in terms of microbiological indices). By its sanitary-microbiological characteristics, the lake is clearthe values of the total microbial count, determined with the use of test-systems 3M Petrifilm Aqua (AQHC), were 1000 CFU/mL, and the abundance of coliform bacteria, determined with the use of test-systems 3M Petrifilm Aqua (AQСC), varied from 20 to 135 CFU/100 mL. Coliform bacteria were mostly found in the bottom water layer. It was shown that, in the organization of ecologicalmicrobiological studies, special attention is to be paid to the bottom horizons of water bodies.

scholarly journals Production Performance Analysis of Class II Hydrate-Bearing Layers Based on an Analytic Aquifer Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Jing Yu ◽  
Lubin Zhuo ◽  
Yang Chen ◽  
Wenchao Sun ◽  
Yongge Liu
Keyword(s):  
Bottom Water ◽  
Coupled Model ◽  
Water Layer ◽  
Class Ii ◽  
Gas Production ◽  
Production Performance ◽  
Water Volume ◽  
Calculation Time ◽  
Bottom Water Layer ◽  
Bearing Layer

In the current numerical simulation studies, bottom water in Class II hydrate-bearing layers is represented by grids with high water saturation that significantly extends the calculation time if the volume of the bottom water is large or grid size is small. Moreover, the influence of the bottom water volume on the depressurization performance of Class II hydrate-bearing layers has not been fully investigated. In this study, the Fetkovich analytic aquifer model was coupled with a simulation model of a hydrate reservoir to accelerate the simulation of Class II hydrate-bearing layers. Then the simulation results and calculation time were compared between the coupled model and the model in which the bottom water layer is only represented by grids. Finally, the influence of the bottom water volume on the productivity of gas and water in the depressurization method was investigated and the variation of pressure, temperature, and hydrate saturation during the production process was analyzed. The results show that the coupled model can significantly reduce the simulation time of Class II hydrate-bearing layer while ensuring calculation accuracy. When the pore volume of the aquifer increases to 20 times that of the bottom water layer, the computation time of a single model in which the bottom water layer is represented by grids is 18.7 times that of the coupled model. Bottom water invasion slows down the depressurization, and therefore, the larger the aquifer, the lower the peak value of gas production, and the later it appears. However, the invading bottom water can provide heat for hydrate dissociation; therefore, the gas production rate of the hydrate-bearing layer with bottom water is higher than that of the hydrate-bearing layer without bottom water in the late development stage. Generally, the presence of bottom water reduces the cumulative gas production and increases the cumulative water production; therefore, the larger the aquifer, the more unfavorable the depressurization development of the hydrate-bearing layer.

scholarly journals PECULIARITIES OF THE THERMAL REGIME OF THE SURFACE SEDIMENTS IN LAKE TAPELIAI

2010 ◽  
Vol 2 (5) ◽  
pp. 66-70
Author(s):  
Anastasija Moisejenkova ◽  
Nikolaj Tarasiuk ◽  
Aloyzas Girgždys
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Bottom Sediments ◽  
Bottom Water ◽  
Surface Sediments ◽  
Exchange Process ◽  
Water Layer ◽  
Bottom Water Layer ◽  
Mineral Substances ◽  
Heat Exchange Process

The article discusses the process of heat transfer in the water sediment system having an impact on the input of nutrients and mineral substances from sediments to the bottom water layer. Therefore, conductivity sharply increases on the surface of bottom sediments and reaches more than 400 μS∙cm–1. The heat exchange process is analyzed in Lake Tapeliai classified as a “temporally warm” lake (see K. Kilkus). The paper defines heat transfer from bottom sediments to water applying the convection method and describes isotherm deepening of 4 ºC into sediments. The temperature of surface sediments in Lake Tapeliai was 3,3–3,9 ºC in 2007–2009, whereas the isotherm of 4 ºC slid 20–30 cm deeper to bottom sediments.

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