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Suspended solids are present in every river, but high quantities can worsen the ecological conditions of streams; therefore, effective monitoring and analysis of this hydrological variable are necessary. Frequency, seasonality, inter-correlation, extreme events, trends and lag analyses were carried out for peaks of suspended sediment concentration (SSC) and discharge (Q) data from Slovenian streams using officially monitored data from 1955 to 2006 that were made available by the Slovenian Environment Agency. In total more than 500 station-years of daily Q and SSC data were used. No uniform (positive or negative) trend was found in the SSC series; however, all the statistically significant trends were decreasing. No generalization is possible for the best fit distribution function. A seasonality analysis showed that most of the SSC peaks occurred in the summer (short-term intense convective precipitation produced by thunderstorms) and in the autumn (prolonged frontal precipitation). Correlations between Q and SSC values were generally relatively small (Pearson correlation coefficient values from 0.05 to 0.59), which means that the often applied Q–SSC curves should be used with caution when estimating annual suspended sediment loads. On average, flood peak Q occurred after the corresponding SSC peak (clockwise-positive hysteresis loops), but the average lag time was rather small (less than 1 day). Editor M.C. Acreman; Associate editor Y. Gyasi-Agyei [ABSTRACT FROM AUTHOR]

Emissions of nitrous oxide (N2O) from aquatic systems such as rivers and estuaries are enhanced as a result of human activities on land resulting in enhanced nitrogen availability in aquatic systems. These human activities include agricultural activities such as fertilizer use, as well as industrial activities resulting in nitrogen (N) losses to the environment. In this article, we analyze past and future trends in global emissions of N2O from rivers and estuaries. We calculate aquatic N2O emissions from trends in the export of nitrogen to coastal waters by world-wide rivers. These trends in riverine N exports are from the Global NEWS models, which are global, regionally explicit models developed in the NEWS (Nutrient Export from WaterShed) framework. The NEWS models calculate nutrient exports from land to coastal waters, taking into account different human activities on the land, as well as biological N2 fixation and different ways in which nitrogen is retained in watersheds, including the effect of dams. We present global total emissions of N2O for the years 1970, 2000, and for four scenarios for 2050, as well as regional patterns. [ABSTRACT FROM AUTHOR]