Movement Of Water Masses Research Articles

Ecosystem Variability along the Estuarine Salinity Gradient: A Case Study of Hooghly River Estuary, West Bengal, India

Hooghly River, a ~460 km long distributary of the Ganga River, passes through a highly industrialized Metropolis-Kolkata in West Bengal, India, and eventually empties into the Bay of Bengal at Gangasagar. To determine the patterns and drivers of planktonic community, spatiotemporal variations in water quality and micronutrient content and planktic prokaryotic and microeukaryotic abundance and diversity across the salinity gradient (0.1 to 24.6 PSU) in the Hooghly River estuary (HRE) were studied. Plankton and water samples were collected at six sites during October 2017, February 2018, and June 2018. The biotic parameters—phytoplankton (Chlorophyll a), total bacterial abundance (cfu), and copepods—were significantly higher in the downstream estuarine sites than in the upstream riparian sites; conversely, rotifer and cladoceran abundances were significantly higher at upstream stations. The most culturable bacterial strains were isolated from the two freshwater sites and one at the confluence (estuarine) and are characterized as Bacillus subtilis, Pseudomonas songnenesis, and Exiguobacterium aurantiacum. Among zooplankton, rotifers (0.09 ± 0.14 ind L−1) and cladocerans (5.4 ± 8.87 ind L−1) were recorded in higher abundance and negatively correlated with bacterial concentrations at upstream stations. On the temporal scale, February samples recorded lower proportions of bacterivorous zooplankton at the three upstream stations. Cluster analysis separated samples on the basis of seasons and water mass movement. The February samples showed distinct spatial characteristics, as three freshwater (FW) stations grouped together and segregated at second 2nd hierarchical level, whereas the three estuarine stations formed a separate cluster at the 50% similarity level. Samples collected in October 2017 and June 2018 exhibited mixed attributes. June samples recorded higher influence of freshwater discharge. The zooplankton abundance showed significant negative correlation with Chl a. Our results demonstrate the relative role of river continuum, land-driven lateral discharge, and seawater intrusion in shaping community structure, which needs to be considered in management and conservation planning of aquatic ecosystems, especially in highly productive and overexploited HRE.

Lake Kisezers: analysis of factors influencing morphometry and hydrological regime

Abstract This study describes dynamics in hydrology, morphometry, and water mass movement in Lake Kisezers. The analysis of Lake Kisezers’ morphometry dynamics according to the rapidly changing environment has been carried out. The determination of dynamics in morphometry comes before understanding potential exploitation and environmental sustainability of water body. Lake Kisezers is situated in a densely populated area. Without understanding and deciphering all possible environmental factors influencing Lake Kisezers, the water body can degrade and become of poor environmental quality. Such changes can lead to irreversible changes in the lake ecosystem and degradation of the surrounding landscape. This study aims to identify and explain the elements that influence Lake Kisezers’ hydrological regime, catchment area, and bathymetry. Lake Kisezers is hardly influenced body of water with rapid hydrological and morphometric dynamics. The research is possible due to extensive data availability and the importance of the water body location. Lake Kisezers affects the city of Riga and its surrounding area with a danger of flooding and decreasing land exploration potential. This study results in better understanding in the factors influencing hydrology and morphometry in Lake Kisezers and possible environmental sustainability endangerment in the future. The main impact factor is the connectivity to the River Daugava and its unique hydrological regime. For Lake Kisezers, environmental balance is necessary to continue research and develop a hydrological change model. This study was conducted with fieldwork data and open-source cartographic, geospatial, water level, and mass movement data. The research seeks to understand what is necessary to maintain environmental sustainability in Lake Kisezers.

Three‐Dimensional Temperature Responses to Northward‐Moving Typhoons in the Shallow Stratified Yellow Sea in Summer

AbstractCharacterized by a sharp thermocline and large cold‐water mass below, the Yellow Sea (YS) in summer is a shelf sea that is one of the most vulnerable to typhoons in the world. With observations and high‐resolution numerical simulations, we investigated the three‐dimensional temperature changes and underlying dynamics during the passage of Typhoon Bavi in August 2020, which was representative of northward‐moving typhoons in the eastern YS. Bavi's cyclonic strong winds caused intense turbulent mixing and Ekman divergence. The intense vertical mixing generated spatially coherent temperature cooling in the surface layer and partly caused temperature warming in the subsurface layer on both sides of the typhoon track. The largest surface cooling and subsurface warming both occurred on the right side of the typhoon track. Wind‐induced Ekman divergence generated two overturning circulation systems zonally across the YS, consisting of upper layer shoreward currents, coastal downwelling, lower layer seaward currents and upwelling on the typhoon track. Downwelling and seaward currents caused temperature warming below the thermocline, especially in the bottom layer. Upwelling shoaled the thermocline, resulting in subsurface cooling on the typhoon track. Additionally, Ekman divergence produced sea surface height minima on the typhoon track, causing strong southward barotropic currents to the left, which subsequently drove strong temperature cooling above the southern bottom slope of the South YS and fast southward movement of the YS Cold Water Mass. Further numerical experiments indicated that the magnitudes of the above changes increased with increasing maximum wind speeds and/or decreasing moving speeds of typhoons.

Water mass-driven multiple ecological effects determine the biodiversity and community assembly of microbial flagellates in subtropic-tropic marginal seas of China

Marine microbial flagellates form an important part of marine ecosystems, and play an essential role in maintaining ecosystem functions. However, the underlying biogeographic processes and ecological effects that shape marine microbial flagellate communities (MFCs) on the geographical scale (∼2000 km) remain unclear, especially how their composition is related to movements of water masses. In this study, high-throughput sequencing of 18S rRNA genes was conducted to survey two size-fractioned groups (0.8–2.0 μm for pico-sized and 2.0–20 μm for nano-sized groups) of MFCs in three subtropic-tropic marginal seas of China. In addition, the impacts of environmental factors, spatial factors, and water masses on MFCs were explored and compared across different spatiotemporal conditions. The results demonstrate non-random biogeographic distributions of MFCs in the studied area. These distributions were affected by several ecological processes, such as environmental selection, dispersal limitation, neutral process, and interactions within communities. These processes were driven by complex water masses that formed on a geographical scale. Notably, environmental heterogeneity was identified as the principal determinant of MFCs in each sea area. However, the importance of spatial factors increased with the spatial scale, which weakened biotic interactions within the community on a geographical scale. This effect was more apparent in nano-sized MFCs, indicating stronger dispersal limitation because of their larger cells and weaker dispersal ability. In summary, this study expands the available knowledge on the dynamic biogeographic patterns of MFCs associated with water masses on a geographical scale where strong spatial and environmental gradients exist.

Comprehensive simulation of salinity transport in irrigated watersheds using an updated version of SWAT-MODFLOW

Salinity can have major detrimental impacts on soil health, crop yield, and environmental ecosystem services. In this paper we introduce SWAT-MODFLOW-Salt, a version of SWAT-MODFLOW that simulates the fate and transport of major salt ions (SO42−, Cl−, CO32−, HCO3−, Ca2+, Na+, Mg2+, K+) in watershed systems, and focus on its development and application to irrigated stream-aquifer systems. The modeling code accounts for water and salt mass storage in soils, aquifer, and streams, and the movement of water and salt mass in surface runoff, soil lateral flow, percolation and recharge, groundwater flow, and groundwater-surface water exchange. The model is applied to a highly managed, irrigated 700 km2 region of the saline Lower Arkansas River Valley in Colorado, USA. The model is tested against groundwater salt concentrations and in-stream salt mass loadings, and then used to quantify the impact of soil salinity on crop yield.

Time Shift of Wind Influence on the Movement of Surface Water Masses in the Szczecin Lagoon

Time Shift of Wind Influence on the Movement of Surface Water Masses in the Szczecin Lagoon

Stable carbon isotopes of dissolved inorganic carbon in the Western North Pacific Ocean: Proxy for water mixing and dynamics

The uptake of atmospheric CO2 and the cycle of dissolved inorganic carbon (DIC) in the ocean are the major mechanisms and pathways controlling global climate change and carbon cycling. The stable carbon isotope (δ13C) of DIC, therefore, provides an important tracer for processes such as air-sea exchange, photosynthesis, and water dynamics in the ocean. Here, we present new δ13C-DIC data on water samples collected from a north-south transect (13°N–40°N, 150°E) in the western North Pacific (NP) Ocean in November 2019 and compare the results with those previously reported for similar transects (149.3°E) during WOCE and CLIVAR projects over the past three decades. The values of δ13C-DIC, ranging from -0.83‰ to 0.86‰, were higher in the surface waters and decreased with depth. The high δ13C-DIC values in the surface waters were influenced primarily by isotopic fractionation during air-sea exchange and photosynthesis. With depth, the movement of different water masses and mixing, as well as bathypelagic respiration in the dark water of the ocean, all play important roles in influencing the distribution and isotopic signatures of δ13C-DIC in the western NP Ocean. The δ13C-DIC values of the 0–200 m water layer varied from -0.17‰ to 0.86‰, with lower values at high latitudes, affected by the low δ13C-DIC values carried by the Oyashio Current to the Kuroshio Extension (KE) region. A downward trend was present in the δ13C-DIC signature from north to south in the North Pacific Intermediate Water (NPIW) and Pacific Deep Water (PDW) in the western NP, which reflected the remineralization of organic matter with a horizontal transport of NPIW and PDW. We found a strong 13C Suess Effect in the upper 2,000 m in the western NP Ocean, and δ13C-DIC at the surface (<50 m) has decreased by 0.60‰-0.85‰ since 1993. The mean δ13C-DIC change in the surface ocean was estimated at 0.28‰ per decade between 1993 and 2019. The air-sea exchange and water mixing in the study area may have accelerated the absorption of anthropogenic CO2 in recent years, which likely caused a slightly faster rate of decrease in the δ13C-DIC from 2005–2019 than that observed from 1993–2005.

Automation algorithms for water bodies characteristics calculation on the example of the Volga-Akhtuba floodplain

Introduction. Organization and implementation of a special spring release, carried out annually in the interests of the agriculture and fisheries of the Lower Volga, is the most important and complex problem of the Volga-Kama cascade management. The way to increase the efficiency of solving this problem is to use of mathematical models for calculating the movement of water along the Volga-Akhtuba floodplain. However, the currently functioning mathematical hydrodynamic models of the Lower Volga do not provide enough accuracy and speed. It is planned to create an algorithm for modeling the movement of water masses, combining the use of nomograms of dynamic volumes and a tank model. The characteristics of water bodies and streams that form the water system of the Lower Volga should be obtained at the first stage.
 
 Materials and methods. The materials for the work were a raster digital elevation model with 30 m resolution, obtained from Earth remote sensing data. Algorithms for determining the position and boundaries of water bodies and calculating their characteristics are implemented in the Fortran programming language.
 
 Results. The description of algorithms of smoothing the digital elevation model, searching for local minima, and determining the boundaries of floodplain reservoirs developed to prepare information structures using in the created mathematical model of a water system with a developed network of floodplain streams and lakes is given on the example of the Volga-Akhtuba floodplain. The results of testing the developed algorithms are shown.
 
 Conclusions. The results of the algorithms for searching for local minima on the digital elevation model and determining the position and boundaries of floodplain reservoirs make it possible to calculate the characteristics of water bodies, building a model graph, and developing a data storage system at the next stages of work.

The water electric activation method with a part of energy concentrated in its flow

Of the widely used types of water purification its disinfection by the method of electric activation makes it possible to cleanse bacteria, spores, fungi of microorganisms due to the electrical effect of the directional deviation of the electrons activity in the aquatic environment from the equilibrium state and reduces toxicity due to highly active reducing agents. When using of the electrically activated water for irrigation, an increase in the energy of germination and plants germination ability is observed. Supply of electric activated water by droplet outlets is fraught with relaxation of the water mass state due to the long time it takes for the liquid to pass from the electric activation unit to the plant. To minimize this time, the authors propose to organize an autonomous supply of the water electrical activation process used for irrigation. The paper proposes a new water electric activation method, which differs from the existing ones in that the energy for the installation of electrochemical activation is generated due to the movement of water masses. It is expected that, in practice, the water electric activation by part of the kinetic energy concentrated in its flow will help to minimize losses in the supplying process to irrigated crops, which will significantly increase their yield.

Dinoflagellate cysts production, excystment and transport in the upwelling off Cape Blanc (NW Africa)

To extend the understanding of dinoflagellate cysts production, excystment and vertical/lateral transport in the water column, we compared upper water cyst export production with cysts associations and concentrations in the subsurface nepheloid layer, bottom nepheloid layer and deeper water column during active upwelling off Cape Blanc (NW Africa) in August 2020. Export production was collected by two drifting trap surveys; DTS1 in an active upwelling cell for 4 days and DTS2 in an offshore drifting upwelling filament for 2 days. Subsurface, bottom nepheloid layers and deeper waters were sampled by in-situ pumps along two transects perpendicular to the shelf break. During DTS1, light limitation hampered phytoplankton production which might have influenced cyst production negatively due to up- and downward movement of water masses. Cyst export production increased at the rim of the upwelling cell. For DTS2, upwelling filament cyst export production was up to 3 times lower than that of DTS1. Echinidinium delicatum had highest relative and absolute abundances in the active upwelling, Echinidinium zonneveldiae and Bitectatodinium spongium in the upwelling filament, and Impagidinium spp. and cysts of Gymnodinium microreticulatum/nolleri at the most distal stations. Comparison of concentrations of cysts with and without cell contents showed that the majority of cysts hatched before reaching deeper waters and displayed a dormancy period of less than 6 days. About 5% of the living cysts reached deeper waters and/or the ocean floor. Living cysts were transported offshore in the upwelling filament. In case ships exchange ballast waters in the studied region, they will take up laterally transported living cysts. Upon release of the ballast waters in the port of arrival, these cysts have the potential to become “invader species” that can threaten economy and/or health. Lateral transport of cysts was observed in the bottom nepheloid layer and in deeper waters (800 - 1200m depth) with a maximal extension of about 130km off the shelf break. Therefore, sediments in the region will contain a mixture of regionally and locally produced dinoflagellate cysts. This insight contributes to the improvement of environmental reconstructions of the Cape blanc upwelling system based on downcore cyst associations.

Micro- and macrofauna of benthic invertebrates of the estuary section of the Mokra Moskovka, a small river in the City of Zaporizhzhia

Nowadays, in the period of scientific and technological progress, the anthropogenic impact on the environment keeps increasing. At the same time, its forms and its degree are very diverse. The study of aquatic ecosystems, including ecosystems of small rivers, is one of the applied environmental researches. Small rivers form water resources, hydrochemical composition and water quality of medium and large rivers. They form natural landscapes and contribute to human economic activities.
 Most of the indicators classify the current environmental state of small and medium rivers of Zaporizhzhia Region as unsatisfactory. The main reason for this situation is an excessive anthropogenic load on environmental systems of small rivers that have a noticeable reaction to any interference. One of the consequences of this process includes siltation of small rivers. A small river Mokra Moskovka is not an exception to the above-described characteristics of aquatic ecosystems. The river flows through the territory of Zaporizhzhia Region and its lower part of about 11 km long flows in the densely built-up part of the City of Zaporizhzhya. The mouth section of the Mokra Moskovka River is 2.6 km long and runs through the territory of Aleksandrovsky and Kommunarsky districts of Zaporizhzhia from the river's mouth to the Zaporizhzhia-1-Zaporizhzhia-2 railway bridge. Over the years of its existence, the mouth section of the small river's bed silted up considerably and has an unsatisfactory condition. This is due to the rising of the Kakhovka Reservoir water level and daily fluctuations of the Dnipro's water level that together lead to the reverse movement of water masses and emergence of stagnant phenomena within the studied portion of the river's bed. In addition, the outlets of the municipal rainwater drainage system present a significant source of the sediment, debris and pollutants entering the river.
 In order to improve the environmental condition of the Mokra Moskovka and remove its silt sediments within the bounds of the city, the riverbed was being cleared during 2004-2013. Our data indicate that the thickness of the river's silt sediments reaches 1.0-1.5 m in some places. To restore and maintain favorable hydrological regime and sanitary condition of the mouth section of the Mokra Moskovka it is planned to clean the mouth section of the river channel from silt sediments using hydromechanization technologies and dredging mechanisms in 2022-2023 (scheduled activities).
 The research is aimed at studying the structural organization of the bottom fauna of the estuary section of a small river Mokra Moskovka within the urban ecosystem. The work is based on the results of our own hydrobiological research. During the observation that took place in 2021 53 species of benthic invertebrates were recorded at the mouth of the watercourse. It was found that, out of the total number, 21 species belonged to the macrozoobenthos and 32 – to the benthic microfauna groupings. The conducted saprobiological assessment of the studied river sections for the indicated organisms of micro- and macrozoobenthos revealed that the surveyed part of the watercourse belongs to the α-mesosaprobic zone and is classified as "polluted waters" according to the surface water quality classification. In order to improve the environmental condition of the mouth section of the Mokra Moskovka River it is necessary to implement certain measures of biological water treatment using modern biotechnological solutions developed in Ukraine.

The Analysis of Water Mass Movement in Lake Kisezers for Evaluation of Environmental Sustainability

Abstract Lake Kisezers is located near the Baltic Sea, the lake has a catchment area of 1903.26 km2 with a high potential for anthropogenic impacts both from water quantity and quality perspectives. This research aims to analyse the movement of water mass in Lake Kisezers and determine how to manage and help keep the lake sustainable. Lake Kisezers was selected as the study site, because of water level and flow data availability and hydrological vulnerability. The methodology used in this research is modifiable and different parts of the research can be used for the analysis of water mass movement in other lakes. Lake Kisezers is an example of how to perform an analysis of the hydrological regime. The research territory is complex because it is possible to study how water mass from the Baltic Sea, catchment area, Daugava River, and Riga HPP interact and influence the hydrological regime in Lake Kisezers. The data sets of water level used in this study are available since 1929. Lake Kisezers has a maximum water level change of 3.17 m. The study evaluates how water mass movements can affect the environmental sustainability of the lake. The results from the hydrological regime analysis can be used for further research and territory management in the favor of lake’s environmental quality and economic development. The research tasks are accomplished as the suggestions on how to manage Lake Kisezers in a sustainable manner have been elaborated.

Hospital Effluents and Wastewater Treatment Plants: A Source of Oxytetracycline and Antimicrobial-Resistant Bacteria in Seafood

The present study employs a data review on the presence and aggregation of oxytetracycline (OTC) and resistance (AMR) bacteria in wastewater treatment plants (WWTPs), and the distribution of the contaminated effluent with the aid of shallow and deep ocean currents. The study aims to determine the fate of OTC and AMR bacteria in seafood, and demonstrate a relationship between AMR levels and human health. This review includes (1) OTC, (2) AMR bacteria, (3) heavy metals in aquatic environments, and their relationship. Few publications describe OCT in surface waters. Although OTC and other tetracyclines were found in 10 countries in relatively low concentrations, the continuous water mass movement poses a contamination risk for mariculture and aquaculture. There are 10 locations showing AMR bacteria in treated and untreated hospital effluent. Special effort was made to define the geography distribution of OTC, AMR bacteria, and heavy metals detected in WWTPs to show the likely dissemination in an aquatic environment. The presence of OTC in surface waters in Asia, USA, and Europe can potentially impact seafood globally with the aid of ocean currents. Moreover, low concentrations of heavy metals exert environmental pressure and contribute to AMR dissemination. Recommended solutions are (1) quantitative analysis of OTC, heavy metals, and AMR bacteria to define their main sources; (2) employing effective technologies in urban and industrial wastewater treatment; and (3) selecting appropriate modelling from Global Ocean Observing System to predict the OTC, heavy metals, and AMR bacteria distribution.

Experimental determining of horizontal movements of the water tower reservoirs by GB-RAR

Ground-based radar interferometry (GBRI) with ground-based real aperture radar (GB-RAR) is most often used for monitoring vertical deflections of bridge structures caused by vehicle passages. This paper presents an experimental determining of the horizontal dynamic movements of water tower reservoirs by GB-RAR. Determining the dynamic movements of water tower reservoirs is more complicated precisely because the movement of the reservoir is influenced not only by external influences, such as wind, but also by the movement of water mass in the reservoir. The resulting oscillation is then a composite oscillation of multiple frequencies. Next, in the case of routine determination of vertical deflections of bridge structures, it is reasonable to assume a predominant deflection of the structure in this one particular direction. But in the case of tower structures such as reservoirs, it is necessary to assume their movements (oscillations) in the entire horizontal plane. The movements can be circular, elliptical, straight, spiral, or even completely irregular. This means using at least two radars to simultaneously determine 2D movements (in both perpendicular directions of the horizontal plane). In the optimal case, the radars aim at the monitored object in approximately perpendicular directions to each other, and the resulting motion vectors in the horizontal plane are calculated from LOS measurements. The processing of measurements from both radars raises other problems, namely accurate time synchronization of radar measurements. In case of tower structures, time synchronization cannot be solved by coincidence of oscillation amplitude peaks, since the peaks from different radar views may not occur simultaneously. Therefore, alternative solution is offered in this contribution. Purpose of this contribution is to design and verify a procedure for accurate determination of horizontal movements of tower reservoirs with sufficiently accurate oscillation characteristics. The procedure was experimentally verified in practice on a real water reservoir in central Bohemia. The results of the experiment confirm the expected benefits of simultaneous measurements by two radars for determining horizontal dynamic movements of water tower reservoirs by GB-RAR.

The Use of Neural Networks for Modeling the Movement of Surface Water Masses in Enclosed Sea Areas

The Use of Neural Networks for Modeling the Movement of Surface Water Masses in Enclosed Sea Areas

Preliminary Identification to Local Coral Bleaching Event in Manjuto Beach, Pesisir Selatan Regency, West Sumatra: Hydro-Oceanographic Perspectives

Highlight ResarchThe cause of local coral bleaching in Manjuto Beash has been addressed.The influence of ebb-tide cycles on salinity mixing and stratification was analyzed.Spatial analysis Digital Shoreline Analysis System (DSASv5) was conducted to determine the coastline changes in Manjuto Beach.Flow model flexible mesh was simulated to determine the flow pattern within Sungai Pinang Bay.AbstractIn October 2019, the local community reported the occurrence of coral bleaching of a colony of Acropora sp. at Manjuto Beach, Pesisir Selatan Regency experienced bleaching. It was published in several local news, becoming a trending topic among local and central government authorities and coastal communities. There were many inaccuracies about the cause of this phenomenon. This study aimed to identify the causes of local coral bleaching in Manjuto Beach based on oceanographic perspectives. The water quality data collected using TOA DKK water quality checker in the surrounding Manjuto Beach were assessed descriptive-statistically. This study also analyzed the spatial changes of the coastline using DSASv5. A time series of tidal data was also used to analyze the tidal range-induced salinity stratification. A flow model with a flexible mesh was also simulated to determine the water mass movement and longshore current patterns in Manjuto Beach. Dissolved oxygen (DO), temperature, and salinity showed anomalies compared to the water quality standard to support marine life. During both flood and ebb tides, it ranged from 5.8-11.2 mg/L, 28-28.3oC, and 25-28 o/oo, respectively. The other parameters measured (pH, conductivity, turbidity, and density) were suitable for marine biota. The findings show that tidal range has a unique influence on salinity stratification. The intrusion of groundwater supply resulted in lowering of salinity, inducing local coral bleaching in Manjuto Beach. Changes in salinity levels were also triggered by tidal current ranging from 0-0.31 m/s resulting in cumulative salinity shock. Currently, Manjuto Beach is experiencing accretion ranging from 2.36-3.17 m/year, altering the water coverage through the flood-ebb cycles. Those states cause cumulative sun rays’ exposures and salinity shock induced by flood-ebb cycles. That is why local coral bleaching event is undoubtedly avoided.

Hydrodynamics, sediment transport, and water quality of two contrasting dredge pits on the Louisiana shelf

Sediment is needed for coastal restoration in Louisiana and is often excavated offshore from mud-capped and sandy dredge pits. To better understand the post-dredging effects on hydrodynamics, sediment transport, and water quality, two tripods were deployed at sandy Caminada pit and mud-capped Sandy Point pit in summer 2018 and 2019, respectively, and profiling data were collected during a total of 34 casts in 2018 and 2019. The results reveal similarities and differences between pit and adjacent waters and are used to compare two pits. Tropical storm events were observed during each deployment which provided insight concerning the effects these storms have on dredge pits. Water masses inside Caminada pit were relatively stable and sluggish which resulted from the pit's deep depth and location. Sandy Point dredge pit was highly impacted by the Mississippi River plume due to its proximity, which effectively stratified the water column in summer 2019, affecting ventilation near the seabed. Strong winds, taller waves, higher shear stresses, elevated turbidity and increased dissolved oxygen were generally found during the passages of tropical storms over both pits. Comparing with outside tripod station, the inside station of Caminada pit experienced a longer duration of low dissolved oxygen in bottom waters. Water mass movements and oxygen consumption from resuspension of pit bottom are likely key mechanisms driving oxygen dynamics. Our results provide observational data for future studies on post-dredging morphologic change, marine communities, and oxygen dynamics of dredge pits on the Louisiana shelf and other coastal dredge areas worldwide.

ПРОГНОЗНОЕ МОДЕЛИРОВАНИЕ ПЕРЕНОСА СУСПЕНЗИЙ ПРИ РАЗЛИЧНЫХ СЦЕНАРИЯХ ИЗВЛЕЧЕНИЯ ЖЕЛЕЗОМАРГАНЦЕВЫХ КОНКРЕЦИЙ СО ДНА ТИХОГО ОКЕАНА

The article is devoted to the suspensions’ distribution mathematical modeling in the Eastern Pacific Ocean for various scenarios for the ferromanganese nodules extraction. The suspensions propagation model with complex granulometric composition that can interact in an aqueous medium takes into account the suspensions microturbulent diffusion caused by the turbulent aqueous medium movement and the suspensions convection caused by the advective movement of water mass in the ocean; gravitational suspensions deposition under the gravity influence; mutual transitions between different fractions that make up the suspension; interaction of particles with the bottom and with the free surface.

Comparison of Physical and Numerical Model on Dam Break Flood Wave Propagation in Horizontal Channel

This paper presents experimental results and the development of a numerical model for simulating dam break flood wave propagation. Floods caused by dam breaks have special flow characteristics due to potential energy caused by upstream and downstream elevation differences, and very high flow rates, from the collapse of the dam wall. The physical model is built on a horizontal channel, with 10 meters length and 1-meter width. The reservoirs used are upstream and downstream. Channels used are made of steel materials with negligible friction. The building used is made from wood with a volume of 10x10x40 cm. Flood wave propagation is modelled as a flash flood due to the mass movement of water in large quantities with the sudden opening of water gates. As the initial conditions, the door will be closed. On the upstream of the door, given the initial conditions of water level. Physical models result is used as calibration of numerical models. The developed numeric model is open foam that produces 3D modeling. The result of the physical model and numerical model show the highest flow velocity and good agreement of the pattern of flow velocity profiles during the first 3 seconds. The comparison of the Numerical model and Physical Model indicates whether the numerical model is feasible for use in dam-break modeling. For better results, it is necessary to develop a further model. Solutions to this physical and numerical model can be part of the mitigation effort in case the disaster phenomenon occurs.

A Novel Approach to Obtain Diurnal Variation of Bio-Optical Properties in Moving Water Parcel Using Integrated Drifting Buoy and GOCI Data: A Case Study in Yellow and East China Seas

Ocean processes that can influence rapidly changing ocean color include water-mass movement and bio-optical property changes in the water parcel. Traditionally, diurnal variability of bio-optical properties relies on daily time series at fixed locations by satellite sensors or in situ observations. There is a lack of an effective way to observe diurnal variation of bio-optical properties in a moving water parcel on a large scale. In this paper, we propose a new method to acquire diurnal variation of bio-optical properties in a moving water parcel. The novel approach integrates drifting buoy data and GOCI data. The movement of surface current was tracked by a drifting buoy, and its spatiotemporally matching bio-optical properties were obtained via the GOCI data. The results in the Yellow and East China seas during the summers of 2012 and 2013 show that the variation of time series following the movement of water parcel was obviously different from that obtained at fixed locations. The hourly differences of the former are 15.7% and 16.3% smaller than those of the latter for Chl a and total suspended sediment (TSS), respectively. The value of ag440 was more stable within the moving water parcel than in the fixed location. Our approach provides a simple and feasible way for observing diurnal variability of bio-optical properties in a moving surface water parcel.