Search results: Found 4

Listing 1 - 4 of 4
Sort by
River and Lake Ice Processes—Impacts of Freshwater Ice on Aquatic Ecosystems in a Changing Globe

Authors: ---
ISBN: 9783038973881 / 9783038973898 Year: Pages: 210 DOI: 10.3390/books978-3-03897-389-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Environmental Sciences
Added to DOAB on : 2019-01-11 09:05:26
License:

Loading...
Export citation

Choose an application

Abstract

Most freshwater aquatic ecosystems have focused on open-water conditions, during spring, summer, and autumn. Studies in winter during ice-covered conditions are sparse due to the logistic difficulties of sampling during freezing weather and the assumption that these ecosystems are biologically inactive during winter. There is growing evidence, however, that ice conditions can have strong impacts on the flora, fauna, and water quality of freshwater systems, dependent on the severity and duration of the winter season. The magnitude of winter conditions and the duration of the ice-covered period can also set the stage of the biological succession of flora, fauna and water-quality constituents in the subsequent spring and summer seasons (e.g., higher probability of early algal blooms with earlier ice-off dates). Climate change and changes in the type and degree of anthropogenic impacts will also influence the ice regime and hence the ecosystems of northern freshwater systems. This Special Issue provides a venue to report new findings in field-based and modelling research to highlight the importance of the ice regime and ice-induced hydraulic regime of rivers and lakes on their aquatic ecosystems.

Diversity and environmental variability of riparian tall herb fringe communities of the order Convolvuletalia sepium in Polish river valleys

Author:
Book Series: Monographiae Botanicae ISSN: 2392-2923 ISBN: 9788395412325 Year: Volume: 108 Pages: 130 DOI: 10.5586/mb.2019.001 Language: English
Publisher: Polish Botanical Society
Subject: Botany
Added to DOAB on : 2020-01-07 13:10:34
License:

Loading...
Export citation

Choose an application

Abstract

The riparian tall herb fringe communities of the order Convolvuletalia sepium represent an integral part of the natural vegetation in river valleys. The major objective of this study was to assess the relationships between the diversity and variability of these communities and various environmental factors. The survey was conducted in northwestern Poland, along 101 randomly selected 1–2-km long sections of 24 rivers and the Szczecin Lagoon. Samples were collected in 2008–2013 in all types of tall herb fringe vegetation found in the surveyed river sections. Data collected included hydrogeomorphic variables, soil parameters, potential and actual vegetation, and dominant land use form. A total of 24 vegetation units were documented, based on 300 sample plots (relevés). Tall herb fringe communities occurring in valleys of large rivers (Senecionetum fluviatilis, Fallopio-Cucubaletum bacciferi, Achilleo salicifoliae-Cuscutetum lupuliformis, Convolvulo sepium-Cuscutetum europaeae typicum and chaerophylletosum bulbosi subass. nov., Rubus caesius community, Solidago gigantea community) exhibited floristic and ecological differences in comparison with plant communities from small rivers (Eupatorietum cannabini typicum, aegopodietosum and cardaminetosum amarae subass. nov., Epilobio hirsuti-Convolvuletum sepium, Soncho palustris-Archangelicetum litoralis, Convolvulo sepium-Cuscutetum europaeae aegopodietosum, Urtico-Convolvuletum sepium typicum and aegopodietosum, Urtica dioica community, Galeopsis speciosa community, Rubus idaeus community). This finding fully justified their division into two alliances: the Senecionion fluviatilis and the Archangelicion litoralis, respectively. Significant differences between the tall herb fringe communities associated with large rivers and the plant communities occurring along small rivers included plant species richness, moss layer cover, contribution of river corridor plants, level of invasion, influence of adjacent plant communities on the floristic composition, relative elevation and distance away from the riverbed, degree of shading, proportions of all grain size fractions, soil pH, contents of organic matter, humus, organic carbon, total nitrogen, bioavailable phosphorus, potassium, magnesium, and calcium in the soil. The differences in environmental characteristics of individual plant communities were significant as well; they showed that most vegetation units were well defined. The variables that best discriminated between riparian tall herb fringe communities included the natural potential vegetation unit Salici-Populetum, headwater seeps, soil pH, sample elevation above the river water level, river size, flooding, degree of shading, soil moisture, K2O and CaO contents, and C/N ratio. The integration of the main riparian gradients (longitudinal, lateral, vertical) and patch perspective (e.g., natural potential vegetation units, and land use forms) significantly improved the comprehensive riparian vegetation patterns, because these two perspectives underpin different processes shaping the vegetation. This study contributed significantly to the knowledge of riparian tall herb fringe communities. Two subassociations are described here for the first time, whereas six others have not been previously reported from Poland. The data summarized in the synoptic table indicated that the species diagnostic for individual plant communities should be revised at the supra-regional scale. Some syntaxonomic issues were also determined. The inclusion of the order Convolvuletalia sepium to the class Epilobietea angustifolii resolved the problem of classifying the community dominated by Eupatorium cannabinum, a species showing two ecological optima: one in riparian tall herb communities and the other in natural gaps of the tree stands and clearings of fertile alder carrs and riparian woodlands. This also resolved the problem of classifying the communities dominated by Galeopsis speciosa and Rubus idaeus, intermediate between riparian tall herb and clearing communities. The results of this study may serve as a reference for management of the vegetation in river valleys and promote their conservation. They may also be essential for any future syntaxonomic revision of riparian tall herb fringe communities at a larger geographical extent.

Turbulence in River and Maritime Hydraulics

Authors: --- ---
ISBN: 9783038975946 Year: Pages: 296 DOI: 10.3390/books978-3-03897-595-3 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Technology (General)
Added to DOAB on : 2019-03-21 15:50:41
License:

Loading...
Export citation

Choose an application

Abstract

Understanding of the role of turbulence in controlling transport processes is of paramount importance for the preservation and protection of aquatic ecosystems, the minimization of the deleterious consequences of anthropogenic activity, and the successful sustainable development of river and maritime areas. In this context, the present Special Issue collects 15 papers which provide a representation of the present understanding of turbulent processes and their effects in river and maritime environments. The presented collection of papers is not exhaustive, but it highlights the key priority areas and knowledge gaps in this field of research. The published papers present the state-of-the-art knowledge of complex environmental flows which are useful for researchers and practitioners. The paper contents are an overview of some recent topics of research and an exposure of the current and future challenges associated with these topics.

Keywords

breaking waves --- turbulence invariants --- laboratory experiments --- flow-through system --- tidal inlets --- residence time --- coastal lagoon --- MIKE 3 FM (HD & --- TR) --- MIKE 21 FM (HD) --- dense jet --- current flow --- velocity --- trajectory --- turbulence --- dissipation --- rivers --- meanders --- turbulence --- secondary motion --- prediction --- bedrock canyon --- ADCP --- eddy viscosity --- bed shear stress --- spatial analysis --- smoothed particle hydrodynamics models --- physical modelling --- plunging breaking waves --- vorticity --- turbulent jet --- wave–current interaction --- spectral dissipation --- bottom friction --- numerical model --- hydrodynamic model --- spectral model --- wave attenuation --- energy dissipation --- drag coefficient --- flexible vegetation --- Spartina maritima --- vegetation patch --- wake region --- submerged ratio --- SVF --- channel confluences --- junction angle --- flow deflection zone --- flow retardation zone --- flow separation zone --- numerical modelling --- PANORMUS --- jets --- waves --- turbulence --- mixing --- diffusion --- advection --- river mouth --- flow mixing --- nonlinear shallow water equations --- macrovortices --- sub-grid turbulence --- seabed friction --- flow resistance --- roughness --- gravel-bed rivers --- casting technique --- CFD --- Kelvin–Helmholtz --- billow --- lobe --- cleft --- gravity current --- surface waves --- inclined negatively buoyant jets --- regular waves --- dilution --- sea discharges --- rivers --- maritime areas --- turbulent processes

Sea Surface Salinity Remote Sensing

Authors: ---
ISBN: 9783039210763 / 9783039210770 Year: Pages: 296 DOI: 10.3390/books978-3-03921-077-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2019-12-09 11:49:15
License:

Loading...
Export citation

Choose an application

Abstract

This Special Issue gathers papers reporting research on various aspects of remote sensing of Sea Surface Salinity (SSS) and the use of satellite SSS in oceanography. It includes contributions presenting improvements in empirical or theoretical radiative transfer models; mitigation techniques of external interference such as RFI and land contamination; comparisons and validation of remote sensing products with in situ observations; retrieval techniques for improved coastal SSS monitoring, high latitude SSS and the assessment of ocean interactions with the cryosphere; and data fusion techniques combining SSS with sea surface temperature (SST). New instrument technology for the future of SSS remote sensing is also presented.

Keywords

sea surface salinity --- remote sensing --- mediterranean sea --- smos --- alboran sea --- data processing --- quality assessment --- MICAP --- forward model --- combined active/passive SSS retrieval algorithm --- different instrument configurations --- retrieval errors --- SMAP --- sea surface salinity --- Arctic Ocean --- sea ice --- river discharge --- Arctic Gateways --- sea surface salinity --- remote sensing --- aquarius --- SMAP --- retrieval algorithm --- calibration --- validation --- satellite salinity --- Gulf of Maine --- bias characteristics --- Scotian Shelf --- Aquarius satellite --- sea surface salinity --- Aquarius Validation Data System (AVDS) --- ocean salinity --- microwave remote sensing --- remote sensing --- sea surface salinity --- SMAP --- SMOS --- Gulf of Mexico --- validation --- coastal --- salinity --- upwelling --- sea surface salinity --- remote sensing --- Arctic ocean --- SMOS --- Arctic rivers --- data processing --- quality assessment --- Aquarius --- Argo --- Sea Surface Salinity --- Water Cycle Observation Mission (WCOM) --- interferometric microwave imager (IMI) --- one-dimensional (1D) aperture synthesis radiometer --- sea surface salinity (SSS) --- brightness temperature (TB) --- sea surface salinity --- microwave radiometry --- remote sensing --- calibration --- retrieval algorithm --- validation --- Aquarius --- SMOS --- SMAP --- sea surface temperature --- sea surface salinity --- SMOS --- retroflections --- surface velocity --- water transport --- salt transport --- n/a --- sea surface salinity --- ocean surface roughness --- microwave radiometry --- remote sensing --- forward model --- retrieval algorithm

Listing 1 - 4 of 4
Sort by
Narrow your search