Effects of summer flooding on floodplain biogeochemistry in Poland; implications for increased flooding frequency

Abstract

The frequency of summer flood events has strongly increased in Eastern Europe during the last decades. The creation of water storage areas to avoid flooding is often combined with the recreation of more natural and biodiverse riverine systems. This urges the need to understand the consequences of summer inundation, when microbial activity is significantly higher than during winter inundation, for floodplain biogeochemistry. In order to test the interacting effects of temporal flooding, water quality and agricultural use we used a mesocosm design with sods including vegetation from an area along a tributary of the Vistula River, where water storage compartments have been planned. Concentrations of nitrate and sulphate in the flood water, expected to interfere with soil redox processes, were varied at environmentally relevant concentrations. Inundation led to increased nutrient mobilization in all treatments, particularly for phosphate which reached very high concentrations in both soil water (200-300 lmol l -1 ) and overlaying surface water (25-35 lmol l -1 ) as a result of iron reduction. The response was clearly linked to different soil characteristics like the Olsen P concentration, probably caused by varying kind of land use. Unexpectedly, the flood water quality played a less important role in the response to shortterm flooding. This could partly be explained by the relatively low infiltration rate into these waterlogged soils, indicating the importance of local hydrology. The findings of this study are important to understand and predict the effects of (more frequent) summer flooding of Eastern European rivers. It also indicates that it is necessary to take into account the soil quality in assessing the consequences of planned measures on biodiversity and ecosystem functioning.

The Influence of Biomass Ash on the Migration of Heavy Metals in the Flooded Soil Profile - Model Experiment

“…The effl uent from the cylinders obtained after 7 days of soil incubation had a reaction close to neutral (G) and slightly alkaline (GP). This was due to the high content of ammonium ions, indicating the process of reducing nitrate ions, more intensive than in the soil G fermentation of organic matter and ash additive used [2]. A higher content of soluble organic matter (DOM) expressed by COD Mn value and twice the ammonium ion content, provides a more intensive process of decomposition in the cylinders with the addition of ash (GP).…”

“…Moreover, they can be actively taken up by plants [6,19,22]. Even alkalinization of soils with Ca(OH) 2 does not have to effectively restrict the migration of certain metals (e.g, copper) moving along the profi le of the migrating groundwater [40]. The concentrations recorded in the …”

“…A common practice of sealing the ground surface with asphalt or concrete causes gathering large amounts of rainwater in a short period of time, while in natural conditions it is stored as a result of soil retention. Water spate results in fl ooding or permeation and has negative long-term economic, social and environmental effects [2]. The increasingly appearing phenomenon of fl oods forces us to build new polders and reservoirs and calls for forestation on additional areas of land [28], which signifi cantly changes the usage of terrain.…”

Effects of long-term flooding on biogeochemistry and vegetation development in floodplains; a mesocosm experiment to study interacting effects of land use and water quality

“…The microbially governed processes in soil strongly depend on the soil aeration state, and after inundation oxygen is depleted resulting in the mobilization of reduced (often toxic) substances such as nitrite, ammonium and sulphide. As a result of iron reduction, phosphate is mobilized during flooding (Gliński and Stępniewski, 1985;Laanbroek, 1990;Smolders et al, 2006;Banach et al, 2009b).…”

“…This measure is one of proposed strategies to counteract flooding risks; next to the creation of temporarily flooded areas for water storage during flood peaks which was investigated in our previous work (Banach et al, 2009b) and that of others (Antheunisse and Verhoeven, 2008). In order to study the effects of longterm flooding under controlled conditions, for which much less information is available in literature, a mesocosm design using intact sods was used.…”