Biogeochemistry of forest catchments in the Czech Republic with contrasting lithology under conditions of acidic deposition

Hydrobiogeochemical patterns were studied in two forested catchments in the Czech Republic, one underlain by leucogranite (Lysina), the other by serpentinite \rm(Pluh{\buildrel{\circ}\over{u}}v\ Bor). The objective was to compare and contrast element pools and fluxes in the catchments with similar topography, vegetation, climate, and atmospheric deposition, but different lithology. High weathering rates at the serpentinite site resulted in magnesium as the dominant cation on the soil exchange complex and in drainage water. Other basic cations (calcium, potassium, sodium) showed relatively low concentrations and outflow in streamwater. The catchment exhibited high base saturation (BS) in mineral soil, and near neutral soil and stream pH, despite elevated inputs of acidic deposition. Slow growth of Norway spruce may be caused by potassium deficiency, magnesium oversupply and/or nickel toxicity. In contrast, the leucogranite site showed low concentrations of exchangeable basic cations on the soil exchange complex and in streamwater. Soil and drainage water were highly impacted by acidic deposition. Soil pH was acidic throughout the soil profile, and the BS of the mineral soil was low. Supplies of basic cations from atmospheric deposition and soil processes were smaller than inputs of sulfate on an equivalence basis, resulting in low pH and high concentrations of aluminum in drainage water. Needle yellowing in Norway spruce was possibly the result of magnesium deficiency. These catchments served as valuable end-members of ecosystem sensitivity to severe levels of acidic deposition. The second objective was to apply a plant-soil-water model PnET-BGC/CHESS at Lysina. Forest growth and hydrobiogeochemistry were simulated for the period 1550-2050. Simulated concentrations of sulfate, fluoride, calcium, magnesium, sodium, potassium, silica, iron, and aluminum were similar to streamwater concentrations measured in 1990-1994. The model moderately overpredicted hydrogen ion, chloride and dissolved organic carbon, and highly overpredicted nitrate and especially ammonium. A scenario of sulfur inputs reductions by 67% of 1991-1994 values in 1995-2050 predicted a further decrease in soil BS between 1995 and 2050. A simulation in which inputs of sulfur were reduced by 90% showed an increase in BS after 2030. Simulations showed that desorption of previously stored sulfur to drainage Hydrobiogeochemical patterns were studied in two forested catchments in the Czech Republic, one underlain by leucogranite (Lysina), the other by serpentinite \rm(Pluh{\buildrel{\circ}\over{u}}v\ Bor). The objective was to compare and contrast element pools and fluxes in the catchments with similar topography, vegetation, climate, and atmospheric deposition, but different lithology. High weathering rates at the serpentinite site resulted in magnesium as the dominant cation on the soil exchange complex and in drainage water. Other basic cations (calcium, potassium, sodium) showed relatively low concentrations and outflow in streamwater. The catchment exhibited high base saturation (BS) in mineral soil, and near neutral soil and stream pH, despite elevated inputs of acidic deposition. Slow growth of Norway spruce may be caused by potassium deficiency, magnesium oversupply and/or nickel toxicity. In contrast, the leucogranite site showed low concentrations of exchangeable basic cations on the soil exchange complex and in streamwater. Soil and drainage water were highly impacted by acidic deposition. Soil pH was acidic throughout the soil profile, and the BS of the mineral soil was low. Supplies of basic cations from atmospheric deposition and soil processes were smaller than inputs of sulfate on an equivalence basis, resulting in low pH and high concentrations of aluminum in drainage water. Needle yellowing in Norway spruce was possibly the result of magnesium deficiency. These catchments served as valuable end-members of ecosystem sensitivity to severe levels of acidic deposition. The second objective was to apply a plant-soil-water model PnET-BGC/CHESS at Lysina. Forest growth and hydrobiogeochemistry were simulated for the period 1550-2050. Simulated concentrations of sulfate, fluoride, calcium, magnesium, sodium, potassium, silica, iron, and aluminum were similar to streamwater concentrations measured in 1990-1994. The model moderately overpredicted hydrogen ion, chloride and dissolved organic carbon, and highly overpredicted nitrate and especially ammonium. A scenario of sulfur inputs reductions by 67% of 1991-1994 values in 1995-2050 predicted a further decrease in soil BS between 1995 and 2050. A simulation in which inputs of sulfur were reduced by 90% showed an increase in BS after 2030. Simulations showed that desorption of previously stored sulfur to drainage water would delay recovery from acidic deposition

Ecotoxicity and speciation of Cr in a small ultramafic catchment.

International audienc

Biogeochemistry and ecotoxicity of chromium in a forested catchment

International audienc

Linking Foliar Chemistry to Forest Floor Solid and Solution Phase Organic C and N in Picea abies [L.] Karst Stands in Northern Bohemia

Dissolved organic carbon and nitrogen (DOC and DON) produced in the forest floor are important for ecosystem functions such as microbial metabolism, pedogenesis and pollutant transport. Past work has shown that both DOC and DON production are related to litterfall and standing stocks of C and N in the forest floor. This study, conducted in spring, 2003, investigated variation in forest floor water extractable DOC (WEDOC) and DON (WEDON) and forest floor C and N as a function of lignin, cellulose and N contained in live canopy foliage across eight Picea abies [L.] Karst stands in northern Bohemia. Based on Near Infrared Spectroscopy (NIR) analysis of foliar materials, lignin:N and cellulose:N content of the youngest needles (those produced in 2002) were positively and significantly related to WEDOC (R 2 = 0.82–0.97; P\u3c0.01) and to forest floor C:N ratio (R = 0.72–0.78; P\u3c0.01). Foliar N was strongly and negatively related to WEDOC and C:N ratio (R = −0.91 and 0.72; P\u3c0.05) among our study sites. WEDON was positively correlated to foliar lignin:N (R = 0.48; P\u3c0.05; n=40). Forest floor C pools were not positively correlated with foliar lignin and cellulose and forest floor N pools were not positively correlated with foliar N. Instead, a significant negative correlation was found between forest floor N pools and foliar cellulose (R=−0.41; P\u3c0.05), and between forest floor C pools and foliar N (R = −0.44; P\u3c0.05). From a remote sensing standpoint, our results are important because canopy reflectance properties are primarily influenced by the most recent foliage, and it was the chemistry of the most recently produced needles that showed a stronger relationship with forest floor WEDOC and C:N ratio suggesting forest floor production of WEDOC can be calculated regionally with remote sensing

Drivers of Cr and Ni Mobility in a Serpentine Catchment

International audienc

Spéciation et écotoxicité du Ni et Cr dans un ruisseau de tête de bassin ultramafique (Pluhuv Bor, Tchéquie)

National audienc

Protective role of colloids against Cr and Ni ecotoxicity in a small ultramafic catchment

International audienc