0000000000236505

AUTHOR

Elga Apsite

showing 3 related works from this author

Assessment of the changes of COD and color in rivers of Latvia during the last twenty years

1998

Analysis of long-term records of the concentrations of water color and chemical oxygen demand for nine river sites in Latvia is reported. The period of observations lasted for the last 20 years. Characteristic features of data include non-normal distributions, serial correlation, seasonality and presence of mostly significant downward trends. In Latvia, the main water quality changes could be explained by the changes of anthropogenic impact and the type of catchment management over the last 20 years.

lcsh:GE1-350geographygeography.geographical_feature_categoryChemical oxygen demandDrainage basinWater colorSeasonalitymedicine.diseaseEnvironmental protectionmedicinePeriod (geology)Environmental sciencePhysical geographyWater qualitylcsh:Environmental sciencesGeneral Environmental ScienceEnvironment International
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Recent Change—River Run-off and Ice Cover

2015

This chapter compiles and assesses information on run-off and discharge from rivers within the Baltic Sea drainage basin. Some information is also available on ice duration on inland waterways. Although decadal and regional variability is large, no significant long-term change has been detected in total river run-off to the Baltic Sea over the past 500 years. A change in the timing of the spring flood has been observed due to changes in the timing of snowmelt . Change in temperature seems to explain change in run-off better than does precipitation. Later start dates for ice formation on waterways, and earlier ice break-up dates have resulted in shorter periods of ice cover.

geographyHydrology (agriculture)Oceanographygeography.geographical_feature_categoryFlood mythSnowmeltDrainage basinClimate changeCryosphereEnvironmental sciencePrecipitationArctic ice pack
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Sedimentary humic substances from lakes in Latvia

1997

Humic and fulvic acids, isolated from sediments of lakes in different trophic states (Latvia) were studied. The humic substances (HS) were characterized by their elemental and functional composition, their spectral properties, and molecular mass. The humus properties strongly depend on the origin of the sedimentary HS. Substantial similarity between sedimentary HS from oligotrophic and dystrophic water bodies was found, unless the biology of these lakes greatly differs. Humic molecules from sediments of oligotrophic and dystrophic lakes are smaller, more uniform, and contain lower amounts of carboxyl- and hydroxyl-groups than HS from meso- and eutrophic water bodies. On the other hand, sedi…

lcsh:GE1-350ChemistrySpectral propertiesMineralogyHumuschemistry.chemical_compoundEutrophic waterNitrateEnvironmental chemistryComposition (visual arts)Sedimentary rockEutrophicationlcsh:Environmental sciencesGeneral Environmental ScienceTrophic levelEnvironment International
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