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ABSTRACT Ying, C.; Li, R.; Li, X., and Liu, Y., 2018. Anthropogenic Influences on the Tidal Prism and Water Exchange in Yueqing Bay, Zhejiang, China. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 961–965. Coconut Creek (Florida), ISSN 0749-0208. Yueqing Bay (YQB) is a semi-enclosed, calabash-shaped bay with shallow water depths and a large tidal range in the East China Sea that is relatively narrow in the middle and wide at its top and mouth. YQB has been subjected to considerable human activity, including reclamation and dam construction projects, over the past 50 years. To understand the changes in the hydrodynamics and water exchange abilities in YQB with respect to these anthropogenic influences, the tidal prism (TP) and water residence time (WRT) of YQB during the years 1964, 1984, 2002, and 2012 were investigated using a calibrated, two-dimensional hydrodynamic model based on the finite volume method. The simulation results show that the TP of YQB decreased by 21.3% and that the WRT increased by over 80%. The water exchange ability of YQB decreased continuously, especially during 1964–1984. The TP and WRT both show nonsynchronous historical changes with anthropogenic influences due to engineering intervention methods. The inner and outer parts of YQB exhibited considerably different sensitivities to anthropogenic influences due to the calabash shape of the bay. Large-scale engineering construction projects in coastal zones imposed significant impacts on the hydrodynamic characteristics in YQB that may have led to potential environmental and ecological issues. [ABSTRACT FROM AUTHOR]

The Tampa Bay response to Hurricane Irma in September 2017 is analyzed using a combination of in situ observations and numerical model sim u latio ns. The observations include winds and water levels from in situ recording stations. The model sim u la tio n s are by the Tampa Bay Coastal Ocean Model (TBCOM), which downscales from the continental shelf to the estuary by nesting the unstructured grid, Finite-Volume, primitive equation Community Ocean Model (FVCOM) in the West Florida Coastal Ocean Model, which in turn downscales from the deep ocean across the continental shelf by nesting FVCOM in the Gulf of Mexico Hybrid Coordinate Ocean Model. Both the observations and the model simulations show a rapid negative storm surge (a setdown of sea level) followed by a positive surge associated with the change of wind direction. The initial forecast underestimates the magnitude of the negative surge. After adjusting fo r the difference between the winds actually observed compared with the original forecast w inds, the hindcast sea level simulation very closely matches the observations. These findings imply that a massive exchange of water occurred between Tampa Bay and the adjacent continental shelf as the hurricane passed by the region. A large portion of the bay water was flushed out to the south, to be replaced by new waters advected in from the along the coast to the north. [ABSTRACT FROM AUTHOR]

Abstract: The Filchner Trough (FT) is a key site for exchange of water masses between the Weddell Sea continental shelf and the deep ocean. Cold and dense Ice Shelf Water (ISW), a precursor for Antarctic Bottom Water, flows north along the FT and overflows the Filchner Sill. Although access of warm water to the Weddell Sea continental shelf is limited due to the presence of the Antarctic Slope Front, southward transport of warm water is facilitated through the FT. We use moored current meters from the Filchner Sill region to show that the monthly scale variability of the ISW overflow is connected to the variability of the alongslope wind stress upstream. Periods with significant correlation between the wind and ISW overflow are characterized by (I) wind directed along the continental slope, (II) high ISW overflow speed, and (III) high variability in the 16–64 day period band for wind and current. We propose that a recirculation of the slope current, associated with the Antarctic Slope Front, may occur in the FT during periods of strong wind forcing, and that such recirculation could explain the correlation between the wind stress and the ISW overflow. We further show that an increased wind stress along the continental slope leads to increased current speed within the slope current and the Antarctic Coastal Current, with possible implications for the on‐shore heat transport. [ABSTRACT FROM AUTHOR]

We examined if minimum water exchange could spare dietary methionine (Met) required for maximum growth performance of juvenile Litopenaeus vannamei reared in an intensive outdoor system. Shrimp of 1.98 ± 0.13 g were stocked at 70 animals/m2 and reared for 72 days in 50 tanks of 1 m3 under flow-through (14.4% a day) and static (1.4%-2.9% a day) green-water conditions at 32.0 ± 3.7 g/L salinity. Five diets with a minimum inclusion of fishmeal supplemented with a dipeptide, dl-methionyl-dl-methionine, were formulated to contain increasing levels of Met, 4.8, 6.2, 7.2, 8.1 or 9.4 g/kg (on a dry matter basis). Each of the five diets were fed four times daily to five replicate groups. Dietary Met and water exchange significantly influenced shrimp survival, gained yield, apparent feed intake, food conversion ratio and final body weight (p < .05). Raising shrimp under limited water exchange, i.e., static versus flow-through spared the dependence on higher levels of dietary Met to maximize shrimp body weight, from 9.4 g/kg to 8.0 g/kg (14.0 and 12.6 g/kg Met+Cys respectively). In an intensive rearing system, a reduction in water exchange is desirable as it leads to a lower need for supplemental dietary Met. [ABSTRACT FROM AUTHOR]

Abstract Numerous studies have pointed out the importance of groundwater and surface water interaction (SW–GW) in a river system. However; those functions have rarely been considered in large scale hydrological models. The SWAT-LUD model has been developed based on the Soil and Water Assessment Tool (SWAT) model; and it integrates a new type of subbasin; which is called subbasin-LU (SL); to represent the floodplain area. New modules representing SW–GW exchanges and shallow aquifer denitrification are developed in the SWAT-LUD model. In this study; the SWAT-LUD model was applied to the middle floodplain area of the Garonne catchment in France. The results showed that the SWAT-LUD model could represent the SW–GW exchange and shallow aquifer denitrification appropriately. An annual 44.1 × 107 m3 of water flowed into the river from the study area; but the annual exchanged water volume was 6.4 × 107 m3; which represented just 1% of the river discharge. A total of 384 tons of N-NO3− (0.023 t·ha−1) was consumed by denitrification in the floodplain shallow aquifer annually. The nitrate concentration (N-NO3−) decrease in the channel was 0.12 mg·L−1; but in the shallow aquifer it reached 11.40 mg·L−1; 8.05 mg·L−1; and 5.41 mg·L−1 in LU1; LU2; and LU3; respectively. Our study reveals that; in the Garonne floodplain; denitrification plays a significant role in the attenuation of nitrate associated with groundwater; but the impacts of denitrification on nitrate associated with river water is much less significant. [ABSTRACT FROM AUTHOR]

Abstract: The geometric features of two pyclen‐based ligands possessing identical donor atoms but different site organization have a profound impact in their complexation properties toward lanthanide ions. The ligand containing two acetate groups and a picolinate arm arranged in a symmetrical fashion (L1) forms a Gd3+ complex being two orders of magnitude less stable than its dissymmetric analogue GdL2. Besides, GdL1 experiences a much faster dissociation following the acid‐catalyzed mechanism than GdL2. On the contrary, GdL1 exhibits a lower exchange rate of the coordinated water molecule compared to GdL2. These very different properties are related to different strengths of the Gd‐ligand bonds associated to steric effects, which hinder the coordination of a water molecule in GdL2 and the binding of acetate groups in GdL1. [ABSTRACT FROM AUTHOR]

Cracks in soil provide significant preferential pathways for contaminant transport and rainfall infiltration. Water exchange between the soil matrix and crack is crucial to characterize the preferential flow, which is often quantitatively described by a water exchange ratio. The water exchange ratio is defined as the amount of water flowing from the crack into the clay matrix per unit time. Most of the previous studies on the water exchange ratio mainly focused on cracked sandy soils. The water exchange between cracks and clay matrix were rarely studied mainly due to two reasons: (1) Cracks open upon drying and close upon wetting. The deformable cracks lead to a dynamic change in the water exchange ratio. (2) The aperture of desiccation crack in clay is narrow (generally 0.5 mm to 5 mm) which is difficult to model in experiments. This study will investigate the water exchange between a deformable crack and the clay matrix using a newly developed experimental apparatus. An artificial crack with small aperture was first fabricated in clay without disturbing the clay matrix. Water content sensors and suction sensors were instrumented at different places of the cracked clay to monitor the water content and suction changes. Results showed that the water exchange ratio was relatively large at the initial stage and decreased with the increasing water content in clay matrix. The water exchange ratio increased with increasing crack apertures and approached the largest value when the clay was compacted at the water content to the optimal water content. The effective hydraulic conductivity of the crack-clay matrix interface was about one order of magnitude larger than that of saturated soil matrix. [ABSTRACT FROM AUTHOR]

Hydrodynamics and associated environmental processes have always been of major concern to coastal-dependent countries, such as Kuwait. This is due to the environmental impact that accompanies the economic and commercial activities along the coastal areas. In the current study, a three-dimensional numerical model is utilized to unveil the main dynamic and physical properties of Kuwait Bay during the critical season. The model performance over the summer months (June, July and August 2012) is assessed against comprehensive field measurements of water levels, velocity, temperature and salinity data before using the model to describe the circulation as driven by tides, gravitational convection and winds. The results showed that the baroclinic conditions in the Bay are mainly determined by the horizontal salinity gradient and to much less extent temperature gradient. The gradients stretched over the southern coast of the Bay where dense water is found at the inner and enclosed areas, while relatively lighter waters are found near the mouth of the Bay. This gradient imposed a reversed estuarine circulation at the main axis of the Bay, particularly during neap tides when landward flow near the surface and seaward flow near the bed are most evident. The results also revealed that the shallow areas, including Sulaibikhat and Jahra Bays, are well mixed and generally flow in the counter-clockwise direction. Clockwise circulations dominated the northern portion of the Bay, forming a sort of large eddy, while turbulent fields associated with tidal currents were localized near the headlands. [ABSTRACT FROM AUTHOR]

Reservoirs provide important water resources for economic and social sustainable development. However, many shallow reservoirs are confronted with the problem of severe eutrophication. In this study, a method of optimizing the water exchange of reservoir was proposed to improve the water quality. The improvement was evaluated by the spatial and temporal eutrophic state of the reservoirs predicted by the water quality parameters, algal growth limitation factors and eutrophic state level. Three optimized schemes were designed, as an example, to improve the water exchange of Tianjin Erwangzhuang Reservoir. The results showed that the water quality of the reservoir is improved by the increase of water exchange. The best optimized design scheme for improving water quality was to open multiple gates and lift the amount of water in and out of the reservoir. The result indicated that the Trophic State Index was reduced from the range of 37.8 and 43.1 of the original scheme to that of 35.20 and 26.50 after about 160 day operations of the best optimized design scheme. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 399–409, 2018 [ABSTRACT FROM AUTHOR]

Integrated hydrologic and hydrodynamic modeling is useful in evaluating hydrodynamic characteristics (e.g. water exchange processes) in data-scarce water bodies, however, most studies lack verification of the hydrologic model. Here, water exchange (represented by water age) was investigated through integrated hydrologic and hydrodynamic modeling of the Hongfeng Reservoir, a poorly gauged reservoir in southwest China. The performance of the hydrologic model and parameter replacement among sub-basins with hydrological similarity was verified by historical data. Results showed that hydrological similarity based on the hierarchical cluster analysis and topographic index probability density distribution was reliable with satisfactory performance of parameter replacement. The hydrodynamic model was verified using daily water levels and water temperatures from 2009 and 2010. The water exchange processes in the Hongfeng Reservoir are very complex with temporal, vertical, and spatial variations. The temporal water age was primarily controlled by the variable inflow and outflow, and the maximum and minimum ages for the site near the dam were 406.10 d (15th June) and 90.74 d (3rd August), respectively, in 2010. Distinct vertical differences in water age showed that surface flow, interflow, and underflow appeared alternately, depending on the season and water depth. The worst water exchange situation was found in the central areas of the North Lake with the highest water ages in the bottom on both 15th June and 3rd August, in 2010. Comparison of the spatial water ages revealed that the more favorable hydraulic conditions on 3rd August mainly improved the water exchange in the dam areas and most areas of the South Lake, but had little effect on the bottom layers of the other deepest areas in the South and North Lakes. The presented framework can be applied in other data-scarce waterbodies worldwide to provide better understanding of water exchange processes. [ABSTRACT FROM AUTHOR]

The Three Gorges Project (TGP) is a world known project to utilize and manage the water resources of the Yangtze River. The reservoir stores water at the end of the flood season, and replenishes downstream reaches with water in dry seasons. In addition to such benefits, the TGP has irreversibly changed the hydrological process and the river-lake relation of the middle and lower reaches. In this paper, a hydrodynamic model was established to quantify the impact of the TGP׳s operation on the water exchange between Dongting Lake and the Yangtze River during 2009–2013. The results indicated that: the operation of the TGP has considerably reduced the peak discharge and the flood volume of the main stream and the Dongting Lake area. The inflow volume from the Yangtze River to Dongting Lake via three outlets decreased by 1.9–3.5 billion m 3 /yr, while the outflow volume from Dongting Lake to the Yangtze River at Chenglingji increased by 0.3–1.6 billion m 3 in September and 0.4–0.6 billion m 3 in October, respectively. This research provides valuable information for flood control, irrigation, and water allocation in the middle and lower reaches of the Yangtze River, and serves as a typical case for investigating the impact of other hydropower projects around the world. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to provide some calculations on the current water balance for the Vistula Lagoon, which is exceptionally valuable in terms of biology and hydrology. It is located along the southern coast of the Baltic Sea in both Poland and Russia. In the era of marked climate change, but first and foremost the plans of the Polish side of the cross-cutting of the Vistula Spit, there has been a need to update the balance data of the Vistula Lagoon. In the near future, they may be an excellent comparative material to changes in the proportions of individual water circulation components in the Vistula Lagoon and changes in its entire ecosystem, caused by the implementation of the project. In the literature on the subject, balance sheet data from 50 years ago are used (these data were compiled in the initial part of the study), hence the concept of attempting to update them has appeared. Due to the lack of data from the Russian part of the catchment area, the main emphasis in the work was put on the completion and modernization of the components of the balance sheet of the Polish catchment. A novelty at work is the refinement of the potamical inflow to the Vistula Lagoon with small but numerous streams flowing from the Elbląg Upland, as well as the inflow forced by polder discharges. Climate water balance data are shown based on data available from IMGW in Warsaw and include monthly precipitation totals for the period 1996-2010 obtained at six gauging sites located near the Vistula Lagoon. Evaporation was calculated using Tichomirov's formula. River water influx was determined based on data available in Kruk (2011), data from IMGW (Pasaka River) and data from papers Bogdanowicz (2007, 2009) and documents associated with the Program for biological passages in rivers in Warminsko-Mazurskie Province (2007). Raw data were also obtained from the Office of Water Management in the city of Elblgg for the period 2006-2011. These data covered water flow moving from the polders. Groundwater influx was estimated using values provided by Silicz (1975). The volume of seawater influx was estimated using the data provided by Silicz (1975) and Chubarenko and Chubarenko (2002). The study confirms that water exchange in coastal lagoons is quite complex due to the presence of several different sources of recharge and several different places where water is lost. The complexity of water cycle is enhanced by a complex hydrographic system of lagoon catchments and a complicated system of water exchange with the sea. The total water volume involved in circulation in the Vistula Lagoon is estimated to be 24,225 mln m³ per year. The largest part of the water received by a coastal lagoon comes from the sea. In this case, it is about 77% (18,130 mln m³ per year). In addition, an array of catchment sources yields about 21% of the studied lagoon's water. Its catchment provides an additional 4,974 mln m³ of water. The Pregolya River produces 55% of the catchment influx. The volume of water forcibly produced by area polders is so small that it does not produce an observable effect on the water balance in the Lagoon (about 0.04% of total influx). The precipitation constitutes 2.3% of the power supply source of the Vistula Lagoon. On the other hand, the Strait of Baltiysk constitutes the main outflow pathway for water exiting the Vistula Lagoon - close to 98% of all outflow (23,694 mln m³). The remaining 2% is lost due to evaporation. [ABSTRACT FROM AUTHOR]

Variations in water exchange through the Kerama Gap (between Okinawa Island and Miyakojima Island) from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model (HYCOM). The model results show that the mean transport through the Kerama Gap (KGT) from the Pacific Ocean to the East China Sea (ECS) was 2.1 Sv, which agrees well with the observed mean KGT (2.0 Sv) for 2009-2010. Over the time period examined, the monthly KGT varied from -10.9 Sv to 15.8 Sv and had a standard deviation of ± 5.0 Sv. The water mainly enters the ECS via the subsurface layer (300-500 m) along the northeastern slope of the Kerama Gap and mainly flows out of the ECS into the southwest of the Kerama Gap. The seasonal and interannual variations of the KGT and the Kuroshio upstream transport were negatively correlated. The Kuroshio upstream transport was largest in summer and smallest in autumn while the KGT was smallest in summer (1.02 Sv) and largest in spring (2.94 Sv) and autumn (2.44 Sv). The seasonal and interannual variations in the Kuroshio downstream (across the PN-line) transport differed significantly from the Kuroshio upstream transport but corresponded well with the KGT and the sum of the transport through the Kerama Gap and the Kuroshio upstream, which indicates that information about variation in the KGT is important for determining variation in the Kuroshio transport along the PN-line. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of stocking densities on productive performance of the freshwater prawn Macrobrachium rosenbergii in biofloc system. Experimental tanks (microcosms) with 0.20 m2 area were used as experimental units. The tanks were connected to two 300 L matrix tanks (macrocosm) with biofloc technology, used as recirculating units. M. rosenbergii juveniles, with an initial weight of 0.315 ± 0.06 g and initial length of 33.34 ± 2.26 mm, was randomly distributed in the experimental tanks at different stocking densities (50, 100, 150, 200 and 250 ind m-2) and reared during 60 days. The total biomass at the end of the experiment was significant higher (P < 0.05) with the use of higher stocking density (250 ind m-2). However, prawns stocked at the density of 50 m-2 showed significant higher (P < 0.05) survival (73%) and significantly lower values (P < 0.05) for feed conversion rate (1.28). The different stocking densities evaluated did not affect the weight and length of prawns. The recommended density for growing M. rosenbergii in the biofloc system is 50 ind m-2. [ABSTRACT FROM AUTHOR]

NADPH is the primary source of cellular reductant for biosynthesis, and strategies for increasing productivity via metabolic engineering need to take account of the requirement for reducing power. In plants, while the oxidative pentose phosphate pathway is the most direct route for NADPH production in heterotrophic tissues, there is increasing evidence that other pathways make significant contributions to redox balance. Deuterium-based isotopic labelling strategies have recently been developed to quantify the relative production of NADPH from different pathways in mammalian cells, but the application of these methods to plants has not been critically evaluated. In this study, LC-MS was used to measure deuterium incorporation into metabolites extracted from heterotrophic Arabidopsis cell cultures grown on [1-2H]glucose or D2O. The results show that a high rate of flavin-enzyme-catalysed water exchange obscures labelling of NADPH from deuterated substrates and that this exchange cannot be accurately accounted for due to exchange between triose- and hexose-phosphates. In addition, the duplication of NADPH generating reactions between subcellular compartments can confound analysis based on whole cell extracts. Understanding how the structure of the metabolic network affects the applicability of deuterium labelling methods is a prerequisite for development of more effective flux determination strategies, ensuring data are both quantitative and representative of endogenous biological processes.

The Bohai Sea is a semi-enclosed shallow sea in China, where the tides and wind are the dominant factors contributing to the water exchange with the Yellow Sea. However, existing studies on this water exchange primarily consider only the effect of tidal action, neglecting the contribution of wind. In this study, numerical models were used to simulate the hydrodynamic processes and tracer transport, with the consideration of both tides and wind. Based on the models, the two time scales, age and half-life, are applied to study the water exchange in the Bohai Sea quantitatively. The results show that the age and half-life decrease significantly when wind is included in the simulation, revealing that wind is an important contributor to the water exchange in such a semi-enclosed shallow sea. Under the combined forcing of tides and wind, the water transport in the Bohai Sea becomes clockwise, in contrast with the counterclockwise transport driven by the tides only. The seasonal-varying wind leads to a fluctuation of water exchange in an annual cycle, with the stronger water exchange in the northern (Liaodong Bay) and the western (Bohai Bay) regions of the Bohai Sea in winter and in the southern part (Laizhou Bay) in summer.

Variability of sea level in the North and Baltic Seas, enforced by weather patterns, affects the intensity of water exchange between these seas. Transfer of salty water from the North Sea is very important for the hydrography of the Baltic Sea. The volume of inflowing salty water can occasionally increase remarkably. Such incidents, called the Major Baltic Inflows (MBIs), are unpredictable, of relatively short duration, and difficult to observe using in situ data. We have shown that remote sensing altimetry can be used as a complementary source of information about the MBI events. The advantage of using such data is that large-scale spatial information about SLA is available with daily resolution. We have described changes in SLA during several MBI events observed in 1993–2017. The net volume of water transported into the Baltic Sea varied between the events due to differences in atmospheric forcing. Based on SLA data, the largest inflow of water happened during the 2014 MBI. This is in agreement with previously published results, based on in situ data.