Aquatic Sciences 

About: Aquatic Sciences is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Biology & Environmental science. It has an ISSN identifier of 1015-1621. Over the lifetime, 1548 publications have been published receiving 55131 citations. The journal is also known as: Research across boundaries & AS.

Canonical correspondence analysis and related multivariate methods in aquatic ecology

Abstract: Canonical correspondence analysis (CCA) is a multivariate method to elucidate the relationships between biological assemblages of species and their environment. The method is designed to extract synthetic environmental gradients from ecological data-sets. The gradients are the basis for succinctly describing and visualizing the differential habitat preferences (niches) of taxa via an ordination diagram. Linear multivariate methods for relating two set of variables, such as twoblock Partial Least Squares (PLS2), canonical correlation analysis and redundancy analysis, are less suited for this purpose because habitat preferences are often unimodal functions of habitat variables. After pointing out the key assumptions underlying CCA, the paper focuses on the interpretation of CCA ordination diagrams. Subsequently, some advanced uses, such as ranking environmental variables in importance and the statistical testing of effects are illustrated on a typical macroinvertebrate data-set. The paper closes with comparisons with correspondence analysis, discriminant analysis, PLS2 and co-inertia analysis. In an appendix a new method, named CCA-PLS, is proposed that combines the strong features of CCA and PLS2.

A global boom in hydropower dam construction

Abstract: Human population growth, economic development, climate change, and the need to close the electricity access gap have stimulated the search for new sources of renewable energy. In response to this need, major new initiatives in hydropower development are now under way. At least 3,700 major dams, each with a capacity of more than 1 MW, are either planned or under construction, primarily in countries with emerging economies. These dams are predicted to increase the present global hydroelectricity capacity by 73 % to about 1,700 GW. Even such a dramatic expansion in hydropower capacity will be insufficient to compensate for the increasing electricity demand. Furthermore, it will only partially close the electricity gap, may not substantially reduce greenhouse gas emission (carbon dioxide and methane), and may not erase interdependencies and social conflicts. At the same time, it is certain to reduce the number of our planet’s remaining free-flowing large rivers by about 21 %. Clearly, there is an urgent need to evaluate and to mitigate the social, economic, and ecological ramifications of the current boom in global dam construction.

Response of aquatic plants to abiotic factors: a review

Abstract: This review aims to determine how environ- mental characteristics of aquatic habitats rule species occurrence, life-history traits and community dynamics among aquatic plants, and if these particular adaptations and responses fit in with general predictions relating to abiotic factors and plant communities. The way key abiotic factors in aquatic habitats affect (1) plant life (recruitment, growth, and reproduction) and dispersal, and (2) the dynamics of plant communities is discussed. Many factors related to plant nutrition are rather similar in both aquatic and terrestrial habitats (e.g. light, temperature, substrate nutrient content, CO2 availability) or differ markedly in intensity (e.g. light), variations (e.g. temperature) or in their effective importance for plant growth (e.g. nutrient content in substrate and water). Water movements (water- table fluctuations or flow velocity) have particularly drastic consequences on plants because of the density of water leading to strong mechanical strains on plant tissues, and because dewatering leads to catastrophic habitat modifi- cations for aquatic plants devoid of cuticle and support tissues. Several abiotic factors that affect aquatic plants, such as substrate anoxia, inorganic carbon availability or temperature, may be modified by global change. This in turn may amplify competitive processes, and lead ulti- mately to the dominance of phytoplankton and floating species. Conserving the diversity of aquatic plants will rely on their ability to adapt to new ecological conditions or escape through migration.

Iron oxide dissolution and solubility in the presence of siderophores

Abstract: Iron is an essential trace nutrient for most known organisms. The iron availability is limited by the solubility and the slow dissolution kinetics of iron-bearing mineral phases, particularly in pH neutral or alkaline environments such as carbonatic soils and ocean water. Bacteria, fungi, and plants have evolved iron acquisition systems to increase the bioavailability of iron in such environments. A particularly efficient iron acquisition system involves the solubilization of iron by siderophores. Siderophores are biogenic chelators with high affinity and specificity for iron complexation. This review focuses on the geochemical aspects of biological iron acquisition. The significance of iron-bearing minerals as nutrient source for siderophore-promoted iron acquisition has been confirmed in microbial culture studies. Due to the extraordinary thermodynamic stability of soluble siderophore-iron complexes, siderophores have a pronounced effect on the solubility of iron oxides over a wide pH range. Very small concentrations of free siderophores in solution have a large effect on the solution saturation state of iron oxides. This siderophore induced disequilibrium can drive dissolution mechanisms such as proton-promoted or ligand-promoted iron oxide dissolution. The adsorption of siderophores to oxide surfaces also induces a direct siderophore-promoted surface-controlled dissolution mechanism. The efficiency of siderophores for increasing the solubility and dissolution kinetics of iron oxides are compared to other natural and anthropogenic ligands.

Current state of knowledge regarding the world’s wetlands and their future under global climate change: a synthesis

Abstract: Wetlands cover at least 6 % of the Earth’s surface. They play a key role in hydrological and biogeochemical cycles, harbour a large part of the world’s biodiversity, and provide multiple services to humankind. However, pressure in the form of land reclamation, intense resource exploitation, changes in hydrology, and pollution threaten wetlands on all continents. Depending on the region, 30–90 % of the world’s wetlands have already been destroyed or strongly modified in many countries with no sign of abatement. Climate change scenarios predict additional stresses on wetlands, mainly because of changes in hydrology, temperature increases, and a rise in sea level. Yet, intact wetlands play a key role as buffers in the hydrological cycle and as sinks for organic carbon, counteracting the effects of the increase in atmospheric CO2. Eight chapters comprising this volume of Aquatic Sciences analyze the current ecological situation and the use of the wetlands in major regions of the world in the context of global climate change. This final chapter provides a synthesis of the findings and recommendations for the sustainable use and protection of these important ecosystems.