Nutrient dynamics of large river floodplains

The purpose of this investigation was to determine the influence of different phases of the hydrological cycle on the abundance of colony-forming units (CFU) of bacteria in the Kopacˇki Rit floodplain and to assess temporal and spatial variations in the proportion of eutrophic and oligotrophic bacteria (r-and K-strategists) as a biological indicator of dissolved organic carbon (DOC) availability. Determination of bacterial abundance was performed with abiotic variables (water temperature, depth, Secchi disc transparency, dissolved oxygen, pH, electrical conductivity, ammonia, nitrates+nitrites, total nitrogen and total phosphorus) and one biotic (chl-a) variable, and dimensionality reduced with principal component analysis (PCA). The component scores were used as independent variables in a multiple regression and the relationship between scores (indirect variables) and bacterial abundance was examined. An elevated bacterial abundance was observed during the limnophase (floodplain isolated from the river) and potamophase (flood). During the limnophase also the highest chl-a concentrations were found and in SakadasˇLake during September 2003 significantly higher numbers of eutrophic than oligotrophic bacteria emerged (p=0.026). During potamophase the opposite state was established. Elevated bacterial abundance occurred in parallel with minimal chl-a concentrations and during July 2004 in the Č onakut Channel a significantly higher number of oligotrophic than eutrophic bacteria emerged (p<0.001). Differentiation in the number of eutrophic and oligotrophic bacteria suggests the existence of a higher concentration of labile DOC during September 2003 than during July 2004. Multiple regression analysis explains 13.6% of the variation in abundance of eutrophic bacteria. The regression model for oligotrophic bacteria is not significant. The results suggest two different mechanisms control bacterioplankton numbers to some extent in the Kopacˇki Rit floodplain. In addition, two sources of DOC differentiating the quality of organic matter predominate under totally different hydrological regimes. Under these conditions, eutrophic bacteria may be partially bottom-up controlled, whereas it is not clear how the abundance of oligotrophs is controlled.

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“…Heiler et al, 1995;Anesio et al, 1997;Spink et al, 1998;Castillo, 2000;Johnston et al, 2001;Høberg et al, 2002;Zalocar de Domitrovic, 2003).…”

Section: Discussionunclassified

Alternation of Factors Affecting Bacterioplankton Abundance in the Danube River Floodplain (Kopački Rit, Croatia)

Palijan

Fuks

2006

Hydrobiologia

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“…In the floodplains of the Allier and Loire (France) vegetation was found to be N-limited, as indicated by the positive correlation with N mineralization . Species-rich fen grasslands in the floodplain of the less polluted river Shannon were found to be co-limited by N and P (Spink et al, 1998).…”

Section: Biogeochemistry and Biodiversitymentioning

confidence: 96%

“…Highly productive species-poor vegetation types such as those dominated by Glyceria maxima (Europe) or Scirpus fluviatilis (USA) appear not to be limited by nutrients (Wassen et al, 1995(Wassen et al, , 1998(Wassen et al, , 2003Spink et al, 1998). In eutrophic Dutch and American floodplains, nutrient availability was found to be a less important regulator of plant production than other factors such as flooding and drought (Spink et al, 1998).…”

Section: Biogeochemistry and Biodiversitymentioning

confidence: 99%

“…High connectivity seems to be a prerequisite for some aquatic species such as as Nymphoides peltata through the prevention of calcium deficiency (Smits et al, 1992). Surface water pollution by phosphate and nitrate increases the influx of these nutrients, both in the dissolved and the particulate fraction, in floodplain soils Knowlton & Jones, 1997;Kronvang et al, 1998;Spink et al, 1998;Darke & Walbridge, 2000). This direct pollution is known to be able to decrease biodiversity in floodplain streams and ponds through eutrophication Tre`molieres et al, 1994;Bornette et al, 2001;Bij de Vaate et al, 2006).…”

mentioning

confidence: 99%

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Biogeochemical Constraints on the Ecological Rehabilitation of Wetland Vegetation in River Floodplains

et al. 2006

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The European policy for river management during peak discharge periods is currently changing from exclusion strategies (reinforcement of dykes) to allowing a more natural situation by creating more floodplain space to reduce water levels during peak discharges. In addition, water retention and water storage areas have been created. The new measures are generally being combined with nature development strategies. Up till now, however, ecological targets of broadscale floodplain wetland restoration including sedge marshes, species-rich floodplain forests and carrs, riparian mesotrophic grasslands and other biodiverse riverine ecosystems, have hardly developed in these areas. Most studies on the conditions needed for sustainable ecological development of floodplains have focused on hydrological and geomorphological rather than biogeochemical issues (including nutrient availability and limitation). There are, however, large differences in the composition of river water and groundwater and in sediment quality between rivers in densely populated areas and those in more pristine areas, which serve as a reference. It is very likely that these factors, in combination with heavily altered hydrological regimes and the narrow areas confined between the dykes on both sides of the rivers, impose major constraints on sustainable ecological development of riverine areas. Another issue is that existing wetlands are generally considered to be very appropriate for water retention and conservation, although recent research has shown that this may pose a serious threat to their biodiversity. The present paper reviews the biogeochemical constraints on the combination of floodplain rehabilitation, water conservation and the conservation and development of wetlands. It is concluded that biogeochemical problems (mainly related to eutrophication) predominantly arise in less dynamic parts of the river system, to which the flood-pulse concept applies less. Sound knowledge of the biogeochemical processes involved will contribute to greater efficiency and a better prediction of the opportunities for restoration and development of riverine wetlands. This information can be directly applied in nature management, water management, policy-making and consultancy. Changing concepts, changing riversDuring peak discharge periods, regulated river systems in densely populated areas such as the Netherlands have to cope with excessive volumes of water in a narrow area confined by dykes. In the past, the only strategy was to avoid flooding by raising and reinforcing dykes (levees). Since this

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“…This is associated with the flood pulse (Junk et al 1989), in that they are frequently inundated with water bearing sediments rich in organic matter and nutrients (Spink et al 1998). River flooding influences floodplain nutrient cycling through eroding and depositing soil material and adsorbed nutrients, and changing soil physicochemical conditions, such as redox potential and pH (Pinary et al 1992;van Oorschot et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Spatial distribution of inorganic nitrogen contents of marsh soils in a river floodplain with different flood frequencies from soil-defrozen period

Bai

Deng

Wang

et al. 2007

Environ Monit Assess

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Contents of inorganic nitrogen (NH4(+)-N and NO3(-)-N) in soil profiles were measured in five typical zones ( including permanently flooded floodplain(B), 1-year floodplain (O), 5-year floodplain (F),10-year floodplain (T), and 100-year floodplain (H) )from Huolin River floodplain in Erbaifangzi, Jilin Province of China, in the soil-defrosted period (Mayof 1999). Contour maps and profile maps were constructed to describe the spatial distributions of NH4(+)-N and NO3(-)-N) in order to identify the influences of flood frequencies on them. Results showed that NH4(+)-N generally increased with depth in soil profiles from the five areas, but NH4(+)-N contents in T or H areas significantly differed from those in other areas. For NO3(-)-N, with the exception that there was a significant cumulative peak (6.77 +/- 0.08 mg kg(-1)) at 15-cm depth (10-20 cm) in B area, no significant difference was observed between NO3(-)-N contents in soil profiles from the other four areas. The horizontal distributions of NH4(+)-N and NO3(-)-N in top soils (0-10 cm) were different in the five areas,which were greatly influenced by flood frequencies. The highest content of NH4(+)-N or NO3(-)-N did not appear in B area but in the floodplain with certain flood frequency. For example, NH4(+)-N content (16.81 mg kg-(1)) in 5-year floodplain wetland was highest, and the highest content of NO3(-)-N(1.69 mg kg(-1)) appeared in 1-year floodplain wetland. In addition, NH4(+)-N contents were significantly correlated with soil pH, and NO3(-)-N contents had significant correlation with inorganic carbon, but there were no significant correlations between inorganic nitrogen and other selected soil properties.

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Nutrient dynamics of large river floodplains

Cited by 84 publications

References 19 publications

Alternation of Factors Affecting Bacterioplankton Abundance in the Danube River Floodplain (Kopački Rit, Croatia)

Alternation of Factors Affecting Bacterioplankton Abundance in the Danube River Floodplain (Kopački Rit, Croatia)

Biogeochemical Constraints on the Ecological Rehabilitation of Wetland Vegetation in River Floodplains

Spatial distribution of inorganic nitrogen contents of marsh soils in a river floodplain with different flood frequencies from soil-defrozen period

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