scholarly journals Enhanced ecological indication based on combined planktic and benthic functional approaches in large river phytoplankton ecology

Hydrobiologia ◽  
2018 ◽  
Vol 818 (1) ◽  
pp. 163-175 ◽  
Author(s):  
Chao Wang ◽  
Viktória B-Béres ◽  
Csilla Stenger-Kovács ◽  
Xinhui Li ◽  
András Abonyi
2020 ◽  
Vol 42 (3) ◽  
pp. 355-367
Author(s):  
Zsolt Nagy-László ◽  
Judit Padisák ◽  
Gábor Borics ◽  
András Abonyi ◽  
Viktória B-Béres ◽  
...  

Abstract Assigning species to functional response groups in phytoplankton ecology reduces the number of functional units, which helps understand the processes that shape diversity and functioning of planktonic assemblages. Although the concept has become widespread in recent years, numerical characterization of the groups’ positions in the niche space remained a challenging task. Using a large river phytoplankton dataset, we characterized the functional groups (FGs) of phytoplankton by their niche position and niche breadth in the niche space defined by the relevant environmental variables using the Outlying Main Index approach. The niche space has been defined primarily by trophic-related (nutrients) and river size-related variables (water residence time, discharge). Although we hypothesized that FGs with central niche position would have wide, while those with marginal niche position have narrow niche breadth, these have not been corroborated by the results. Rather, FGs occurred both with central niche position and intermediate breadth, as well as with marginal niche position and wide breadth. Niche position of several FGs was different from that suggested by their known habitat templates in lakes. Furthermore, we found no significant relationship between niche position and niche breadth, suggesting that the occurrence of FGs in rivers is simultaneously influenced by both niche characteristics.


2021 ◽  
Vol 34 (2) ◽  
pp. 04020118
Author(s):  
Song Zhou ◽  
Guan-Lin Ye ◽  
Lei Han ◽  
Wang Jian-Hua

2020 ◽  
Vol 42 (3) ◽  
pp. 293-303
Author(s):  
VALERIY BONDAREV

The theoretical and methodological basis of the systems hierarchical spatial and temporal analysis of a drainage basin, which addresses the problems of effective management in socio-natural systems of different ranks, is considered. It is proposed to distinguish 9 orders of forms that are relevant to the analysis of drainage basins, where the first level is represented by individual aggregates and particles, and the last - by basins of large and the largest rivers. As part of the allocation of geological, historical and modern time intervals, the specificity of the implementation of processes in basins of different scales from changing states, through functioning to evolution is demonstrated. The interrelation of conditions and factors that determine the processes occurring within the drainage basins is revealed. It is shown that a specific combination of conditions and factors that determine processes in the drainage basin is associated with the hierarchy of the objects under consideration, i.e. the choice of a spatial-temporal hierarchical level is crucial for the organization of study within drainage basins. At one hierarchical level, some phenomenon can be considered as a factor, and at another - as a condition. For example, tectonic processes can be considered as an active factor in the evolution of large river basins in the geological perspective, but for small drainage basin, this is already a conservative background condition. It is shown that at the historical time the anthropogenic factor often comes to the fore, with the appearance of which in the functioning of the drainage basin, there is a need to take into account the entire complex of socio-environmental problems that can affect the sustainable state of various territories, especially in the field of water and land use. Hierarchical levels of managing subjects are identified, which are primarily responsible for effective management at the appropriate hierarchical level of the organization of the socio-natural system within the catchment area, starting from an individual to humankind as a whole.


1984 ◽  
Vol 16 (1-2) ◽  
pp. 243-252 ◽  
Author(s):  
J W van Sluis ◽  
L Lijklema

As a result of the construction of a barrage in the estuary of the Nakdong river the size of the estuary will be considerably reduced. In addition, a large river reservoir is created upstream of the barrage. Main points of interest are the effects of the discharge of raw sewage and treated effluent into the Nakdong river on the water quality in the projected reservoir and the water quality forecasts for the remaining part of the estuary, in relation with the existing plans for sewerage and sewage treatment for the city of Busan. In addition, measures to reduce the effects of the barrage and the outline of a water quality management programme are presented. Special consideration is given to the methodological aspects of the water quality study, i.e. the selection and use of mathematical models in a situation where input data are rather uncertain and only very few data for parameter estimation and model verification are available.


2018 ◽  
Vol 40 ◽  
pp. 04017
Author(s):  
Adrien Vergne ◽  
Céline Berni ◽  
Jérôme Le Coz

There has been a growing interest in the last decade in extracting information on Suspended Sediment Concentration (SSC) from acoustic backscatter in rivers. Quantitative techniques are not yet effective, but acoustic backscatter already provides qualitative information on suspended sediments. In particular, in the common case of a bi-modal sediment size distribution, corrected acoustic backscatter can be used to look for sand particles in suspension and provide spatial information on their distribution throughout a river crosssection. This paper presents a case-study where these techniques have been applied.


2020 ◽  
Vol 12 (24) ◽  
pp. 10677
Author(s):  
Ronghui Ye ◽  
Jun Kong ◽  
Chengji Shen ◽  
Jinming Zhang ◽  
Weisheng Zhang

Accurate salinity prediction can support the decision-making of water resources management to mitigate the threat of insufficient freshwater supply in densely populated estuaries. Statistical methods are low-cost and less time-consuming compared with numerical models and physical models for predicting estuarine salinity variations. This study proposes an alternative statistical model that can more accurately predict the salinity series in estuaries. The model incorporates an autoregressive model to characterize the memory effect of salinity and includes the changes in salinity driven by river discharge and tides. Furthermore, the Gamma distribution function was introduced to correct the hysteresis effects of river discharge, tides and salinity. Based on fixed corrections of long-term effects, dynamic corrections of short-term effects were added to weaken the hysteresis effects. Real-world model application to the Pearl River Estuary obtained satisfactory agreement between predicted and measured salinity peaks, indicating the accuracy of salinity forecasting. Cross-validation and weekly salinity prediction under small, medium and large river discharges were also conducted to further test the reliability of the model. The statistical model provides a good reference for predicting salinity variations in estuaries.


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