Spatial Distribution of Nutrient Limitation in the Danube River Floodplain in Relation to Hydrological Connectivity

Autor: Vesna Peršić, Janja Horvatić
Rok vydání: 2011
Předmět:
Zdroj: Wetlands. 31:933-944
ISSN: 1943-6246
0277-5212
Popis: In this paper, we describe the influence of flooding on nutrient conditions and phytoplankton Chl-a concentrations in a hydrologically dynamic Danube floodplain in North-Eastern Croatia. Based on hydrological typology, the connectivity gradient extends from the main river stream (Eupotamal) to the backwater channels and side-arms (Parapotamal) to the edge of the floodplain (Paleopotamal). A spatial gradient of phytoplankton Chl-a occurred during low water levels, while uniformity of Chl-a across wetland habitats was observed during high water levels. Nutrient enrichment assays indicated that inorganic nutrients in Eupotamal waters (N/P ratio 16–22) could support a higher growth rate of the assay alga Chlorella kessleri, while potential N limitation was found in Parapotamal and Paleopotamal waters (both with N/P ratios < 14). Spatial expansion of N limitation toward the main river was observed as inundation continued. Lateral flood pulse connectivity along with the duration of inundation period affects the input and the retention of nutrients, especially of nitrogen. Understanding of the relationship between spatial (location of the floodplain waterbodies regarding the river) and temporal (hydrological connectivity between the river and its floodplain) dimensions contribute to the importance of healthy floodplains for the maintenance of water quality and environmental conditions in the Danube River.
Databáze: OpenAIRE
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