Nutrient Cycling and Retention Along a Littoral Gradient in a Dutch Shallow Lake in Relation to Water Level Regime

Abstract

Littoral zones are characterized by gradients in depth and vegetation biomass, influencing nutrient retention capacity. A field experiment was conducted in a Phragmites australis dominated littoral zone to investigate nutrient retention and its effect on surface water quality. Measurements were done in mesocosms where water levels could be manipulated. Nutrient status was investigated along a gradient perpendicular to the shore during two growing seasons, one with a stable water level and one with a gradually decreasing water level. Nutrient concentrations in sediment, soil pore water and surface water were significantly lower in the vegetated than in the unvegetated zone. The negative correlations of nutrients in sediment and water, with nutrient contents of the vegetation suggest a direct effect of the vegetation. Nutrient uptake and biomass of the vegetation was higher in continuously flooded soils than in seasonally emerging sediments higher along the littoral gradient, probably due to the increased salinity in drained zones. Denitrification rate was highest in the unvegetated zone and was positively related to water level. Flooded littoral zones did result in a higher nutrient retention than drained zones. On small scale, for an optimal nutrient retention a fluctuating regime is not necessarily better suited than a stable water level, but on a larger scale it can substantially increase the width of the vegetated zone. It is important to optimize conditions for helophyte growth since the positive effect of vegetation on nutrient retention, at least at local scale, has been demonstrated in this study.

Implication of Nitrifying and Denitrifying Bacteria for Nitrogen Removal in a Shallow Lake

“…Figure shows that the N storage in aboveground tissues increased from June to September, with a maximum of 61.4–74.5 g m −2 , and then decreased in the following months, reaching a minimum of 13.8–16.3 g m −2 in December. These results were higher than the corresponding values in Lake Volkerak of the Netherlands (7.1 g m −2 ) and the Dongtan wetland of the Yangtze River estuary of China (19.9 g m −2 ) . It was related with the higher reed biomass and nutrient concentrations in Baiyangdian Lake.…”

Spatial and temporal variation in denitrification and in the denitrifier community in a boreal lake

“…The data were compiled from various review articles (Table 1 in Seitzinger 1988, Table 5 and single studies (Ahlgren et al 1994, Mengis et al 1997, Nõges et al 1998, Risgaard-Petersen et al 1999, Svensson et al 2001, De Medina et al 2003, Schernewski 2003, Hasegawa & Okino 2004, Müller et al 2005, McCarthy et al 2007, Sollie & Verhoeven 2008, Nizzoli et al 2010. Hypolimnetic nitrate concentrations of Nizzoli et al (2010) and Ahlgren et al (1994) were kindly provided by D. Nizzoli and I. Ahlgren, respectively.…”

A shallow lake remediation regime with Phragmites australis : Incorporating nutrient removal and water evapotranspiration

“…They were higher than those observed in other studies. For example, in shallow Volkerak Lake of the Netherlands, the peak aboveground pools of reeds were 7.1 g N m À2 and 0.78 g P m À2 (Sollie and Verhoeven, 2008). In Dongtan wetland of the Yangtze River estuary of China, the reeds retained N at a rate of 19.9 g m À2 and P at 1.78 g m À2 in the aboveground tissues (Quan et al, 2007).…”

“…Mitigation measures to control eutrophication in lakes should primarily focus on reducing the inflow of excess nutrients from point and non-point sources. Besides that, it is necessary to take other measures to remove nutrients from polluted lakes (Sollie et al, 2008;Hamilton and Landman, 2011). Phytoremediation is an important measure; it can remove nutrients through plant uptake and rhizosphere denitrification.…”

“…Several studies have been carried out for nutrient removal by reeds in shallow lakes. For example, Sollie and Verhoeven (2008) investigated the nutrient cycling and retention by reeds in the littoral zone of a Dutch shallow lake, and indicated that the reed nutrient uptake and biomass were higher in continuously flooded soils than in seasonally emerging sediments. The denitrification rate was positively related to water level.…”