Nitrogen retention in a river system and the effects of river morphology and lakes

Abstract

The mean annual transfer (loss and retention) of nitrogen in a river system was estimated using a conceptual approach based on water surface area and runoff. Two different approaches for the calculation of water surface area were applied to determine riverine nitrogen retention in four European catchments, ranging between 860-14,000 km2 in area, and differing considerably in the proportion and distribution of surface waters, specific runoff and specific nutrient emissions. The transfer rate was estimated sequentially as either the mean value for the total catchment, on a sub-catchment scale, or considering the distribution of water surface area within a sub-catchment. For the latter measure, nitrogen retention in larger lakes was calculated separately. Nitrogen emissions modelled with MONERIS and HBV-N were used to calculate nitrogen river loads and compare those with observed loads. Inclusion of the proportion of water area within a sub-catchment improved modelled results in catchment with large lakes in sub-catchments, but not where there was a homogenous distribution of surface waters among sub-catchments.

Quantifying seasonal export and retention of nutrients in West European lowland rivers at catchment scale

“…Conceptually, this agrees to our relation [Equation (6)]. A similar relation has been reported for N retention in a study of four lowland catchments (size range 850–14 000 km 2 ), with a power value of − 0·49 for total nitrogen (Venohr et al , 2005). However, these studies did not report confidence levels for the estimated parameters.…”

Impact of lake‐catchment processes on phytoplankton community structure in temperate shallow lakes

“…Pawlik-Skowronska and Toporowska (2016) showed that intensive and frequent flushing increased cyanobacteria species richness and biodiversity and lowered the biomass of Microcystis and Aphanizomenon in two hydrologically modified lakes despite their periodical supply with nutrient-rich river waters. In the case of deeper, dimictic Lakes Chuteckie and Tarnowskie, favoured in terms of groundwater input, longer flushing time increased the time of interaction between groundwater and sediments, leading to increment of leaching of carbonates rocks and, hence, improve water quality (Venohr et al, 2005). We also found that lakes with lower water level amplitude (lowest values of index of WLFs) had lower and more diverse phytoplankton biomass than lakes with high water level dynamics.…”

“…On the other hand, we did not observe a positive relationship between short flushing time and water quality in Lake Syczyńskie, affected by a heavy and longlasting P. agardhii bloom due to high nutrient loads and, consequently, Note. In the case of deeper, dimictic Lakes Chuteckie and Tarnowskie, favoured in terms of groundwater input, longer flushing time increased the time of interaction between groundwater and sediments, leading to increment of leaching of carbonates rocks and, hence, improve water quality (Venohr et al, 2005). Tarn.…”

Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

“…Wetlands (Jordan et al, 2011), lakes (Venohr et al, 2005) and man-made reservoirs ) play an important role in the biogeochemistry of river networks. Sediment, C and nutrient retention in lakes and reservoirs result from a number of processes, including temporary storage in plant biomass, trapping of sediment and particulate C, N and P , Si (Lauerwald et al, 2012), denitrification , and exchange of dissolved P between sediment and water column (Brett and Benjamin, 2008).…”