Published in Encyclopedia of Inland Waters
Scientists and engineers specialized in geochemistry, chemistry, biology, and ecology of natural waters have collectively contributed thousands of published works dealing with natural organic matter (NOM). That body of scientific information is dispersed across a wide range of disciplinary journals and books, and it ranges in quality from the munda...
Published in Encyclopedia of Inland Waters
Submerged vegetation creates a zone of slow flow close to the bed, which may enhance nutrient and sediment retention. The velocity within the canopy is diminished in proportion to the canopy density. Above the canopy, the flow profile is logarithmic. The abrupt change in hydraulic resistance at the top of the canopy creates a region of strong shear...
Published in Encyclopedia of Inland Waters
Mechanisms by which forest ecosystems influence nutrient fluxes in freshwaters are initially disrupted by deforestation, which alters these fluxes in variable ways, depending upon the nutrient and the effects of deforestation on the factors controlling freshwater nutrient loading. These factors are geological weathering; precipitation and climate; ...
Published in Encyclopedia of Inland Waters
Nitrogen fixation is the process whereby molecular N 2 gas is converted to reactive, biologically available forms of nitrogen. The vast majority of nitrogen on Earth is present as molecular N 2, and before the advent of the agricultural and industrial revolutions, biological nitrogen fixation was the only significant process creating reactive nitro...
Published in Encyclopedia of Inland Waters
This article presents an overview of ground water hydrology. Ground water occurs almost everywhere beneath the land surface and is an integral part of the hydrologic cycle. Basic concepts of the movement of water within porous media and differences in behavior between unconfined and confined aquifers are reviewed. A discussion of natural recharge a...
Published in Encyclopedia of Inland Waters
The occurrence of bacteria attached to surfaces is characteristic of world inland water habitats. Attached bacteria are generally associated with other microorganisms, forming complex microbial consortia living in biofilms, microbial mats, and organic aggregates, or on other organisms as epibiotic communities. In all cases, bacteria largely dominat...
Published in Encyclopedia of Inland Waters
Gravitational forces applied to water masses on sloping surfaces drive the currents in fluvial systems. These currents as a rule develop in alluvial deposits composing the river channel and hence interact with deformable channel boundaries – the river bed and banks. Erosion and deposition of alluvium within a river channel and its valley result in ...
Published in Encyclopedia of Inland Waters
Human diseases transmitted by freshwater organisms result in death or debilitation to millions of people annually. Malaria, lymphatic filariasis or elephantiasis, Japanese encephalitis, dengue (all transmitted through the bites of certain species of mosquitoes), onchocerciasis or river blindness (transmitted by certain black flies), and schistosomi...
Published in Encyclopedia of Inland Waters
Lakes and reservoirs are found throughout North America. The combination of extensive glaciations and widespread dam building has resulted in a continent that is rich in lakes of all sizes, from the smallest features tens of meters across to the Great Lakes. The number of lakes in the Canadian Shield is very large. The 5 Great Lakes are joined by s...
Published in Encyclopedia of Inland Waters
The aquatic Hemiptera include a few inland semiaquatic Homoptera, but overwhelmingly belong to the Heteroptera. The aquatic and semiaquatic Heteroptera, consisting of the infraorders Leptopodomorpha, Gerromorpha, and Nepomorpha, comprise a significant component of the world's aquatic insect biota. Within these three infraorders as a whole there are...
