Ion content and ion excretion of Spartina anglica in relation to salinity and redox potential of salt marsh soil

Concentrations of Na, K, Ca, Mg, Fe, Mn, and Zn were determined in polluted estuarine (Western Scheldt) and non-polluted (Eastern Scheldt) salt marsh soil, in the shoot tissue of plants of Spartina anglica and in the excretion of the salt glands of Spartina anglica. Excretion of ions by the salt glands of Spartina anglica was analysed with increasing salinity (0, 300, and 500 mM NaCl) and with increasing values of the redox potential of the salt marsh soil (from ?300 mV to +600 mV). Salt glands of Spartina anglica, growing in containers filled with salt marsh soil in the greenhouse excreted Na-ions at a rate of 1.0–1.8 mmol Na⁺ g^?1 dry wt of the shoot tissue over a period of 18 days implying that about every 6–18 days the amount of Na⁺ present in the shoot tissue is being removed by the salt glands. The excretion rate of K-ions was 0.02–0.14 mmol g^?1 dry wt/18 days. Zinc ions are excreted by the salt glands to such a rate (0.03–0.11 μmol g^?1 dry wt/18 days) that every 36–900 days the amount of zinc present in the leaves is removed. There was no relation between excretion of Zn ions by the plants and the concentration of zinc in the soil. The excretion of Fe and Mn is reported and was found to be related to increasing values of the redox potential.     

Study of the main constituents of some authentic hazelnut oils

This paper describes the composition of authentic hazelnut oils obtained from nuts collected from five countries that are major suppliers of hazelnut oil. Oils were analyzed using standard methods for fatty acids, fatty acids in the triacylglycerol 2-position, tocopherols and tocotrienols, triacylglycerols, sterols, steradienes, and iodine value. The results were generally in good agreement with those of other publications. Tocotrienols, previously unreported in hazelnut oil, were detected in one sample. There were no major differences in the composition of oils from different countries. Roasting the nuts prior to pressing had little effect on oil composition.     

Influence of processing on quality parameters of strawberries

To determine the effects of different processing steps, such as enzymatic treatment of the mash and pasteurization, on selected quality parameters, strawberries were processed to juices and purees. To identify the processing steps causing the highest losses, samples were taken after each step, and ascorbic acid, total phenols, anthocyanins, and antioxidant capacity were analyzed. To assess the antioxidant capacity, three different methods were applied: the trolox equivalent antioxidant capacity (TEAC), the ferric reducing antioxidant power (FRAP), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, showing correlation coefficients of 0.889 to 0.948. The antioxidant capacity decreased with processing steps except heat treatment, which partly caused an increase due to the formation of antioxidant active products. The content of ascorbic acid, in comparison to that in the frozen strawberries, decreased significantly during the processing of the fruit to puree by 77%. In the pressed cloudy juices, the loss of ascorbic acid was 37%. The decline of phenolic compounds, measured as total polyphenols and anthocyanins, was smaller (between 30-40%). Pressing and pasteurization were the most critical steps for the decrease of these compounds. The enzymatic treatment of the mash within 90 min supported the release of secondary plant metabolites, while ascorbic acid is reduced up to 20%.     

Dynamics of total suspended matter and phytoplankton loads in the river Elbe

Purpose

Identifying sources and fluxes of suspended matter within the catchment is vitally important for the water quality of rivers and for establishing sediment management plans. Constituents of suspended particles are of abiotic and biotic origin. In the Elbe, the biotic fraction of suspended particles is mainly composed of phytoplankton biomass. In this study, total seston and phytoplankton are analyzed for their seasonality, their interdependence and temporal trends over three or five decades, respectively.

Materials and methods

The biotic load was separated from the total suspended matter load, and time series of total suspended substances (seston) (1964 to 2015) and chlorophyll a values (1985 to 2015) were analyzed. Our analyses focused on the seasonal dynamics, long-term trends, and the correlation to hydrological events.

Results and discussion

The mean share of phytoplankton in total seston accounted for 24% in summer months (April–September), with a negative correlation between discharge and total seston, and 11% in winter months (October–March), with a weak positive correlation between discharge and total seston. The long-term trend of seston load was decreasing, while phytoplankton load did not show a significant trend.

Conclusions

Autochthonous biogenic portions should not be neglected in the budget of total suspended matter loads in the Elbe catchment. Our results indicate that land-use and industrial changes subsequent to the German reunification mainly caused the observed trend. Phytoplankton growth superimposes the seasonal dynamics of seston in summer, whereas in the long term, decreasing mineral fraction dominates the significantly decreasing trend.