Organic carbon in soils of Germany: Status quo and the need for new data to evaluate potentials and trends of soil carbon sequestration

Uncertainties in estimates of soil carbon (C) stocks and sequestration result from major gaps in knowledge of C storage in soils, land‐use history, the variability of field measurements, and different analytical approaches applied. In addition, there is a lack of long‐term datasets from relevant land‐use systems. As in many European countries, a national database on soil organic carbon (SOC) including all relevant information for the determination of soil C stocks is likewise missing in Germany. In this paper, we summarize and evaluate the present state of knowledge on organic‐C contents/pools in soils of Germany and discuss the need for the acquisition and access to new data on soil organic carbon. Despite the number of agricultural sites under permanent soil monitoring, regional surveys on SOC, comprehensive ecosystem studies, and long‐term field experiments, there is a striking lack of data in Germany particularly with regard to agricultural soils. Apart from a missing standardization of methods and homogeneous baseline values, the implementation of a periodic, nation‐wide soil inventory on agricultural soils is required in order to simultaneously record information on land use, land‐use change, and agricultural practice. In contrast, the existing national inventory of forest soils provides information on C‐stock changes in forest soils, although there is some concern with regard to the representativeness of the sampling design to adequately address the problem of spatial heterogeneity and temporal variability. It is concluded that the lack of comprehensiveness, completeness, actuality, data harmonization, and standardized sampling procedures will further prevent the establishment of a SOC database in Germany with regard to the monitoring of trends in soil C pools and fluxes and the assessment of long‐term C‐sequestration potentials of soils under different land use. A future soil inventory should represent the heterogeneity of organic matter through functionally different SOC pools, topsoil characteristics as well as content, pool, and flux data for the deeper mineral‐soil compartments.     

Chronology for the Aegean Late Bronze Age 1700-1400 B.C

Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology contrasts with conventional archaeological dates and cultural synthesis: stretching out the Late Minoan IA, IB, and II phases by approximately 100 years and requiring reassessment of standard interpretations of associations between the Egyptian and Near Eastern historical dates and phases and those in the Aegean and Cyprus in the mid-second millennium B.C.     

Quantitative analysis of anti-inflammatory and radical scavenging triterpenoid esters in evening primrose seeds

Lipophilic triterpenoidal esters with radical scavenging and cyclooxygenase inhibitory properties were recently found in cold-pressed, nonraffinated evening primrose oil (EPO). A quantitative assay for the analysis of 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid in evening primrose seeds was developed and validated. Extraction efficiency >99% was achieved by means of pressurized liquid extraction with two extraction cycles and 80% (v/v) ethanol at 120 degrees C. Analysis of esters was by normal-phase high-performance liquid chromatography on a Diol column and hexane/ethyl acetate (containing 0.1% formic acid) (65:35) as the eluent. The analytes were determined without further prepurification. Seeds from defined cultures of Oenothera biennis, Oenothera lamarckiana, and Oenothera ammophila, grown under identical conditions, were analyzed. The cultures originated from seeds from eight collections in the wild and from selections from five cultivars. The content of total triterpenoidal esters in seeds varied between 1.34 and 2.78 mg/g. Three types of qualitative patterns were observed for the triterpenoidal esters. The influence of different harvest times and plant treatments was studied with the cultivar Anothera. Variations between 1.5 and 2.3 mg/g were found.     

Preparative continuous annular chromatography (P-CAC) enables the large-scale fractionation of fructans

Fructans (fructo-oligosaccharides and inulin) are of increasing physiological and nutritional interest due to their health-promoting effects. Fructans originally extracted from chicory roots were separated by continuous annular and fixed-bed conventional gel chromatography. Both columns were packed with Toyopearl HW 40 (S) and eluted with deionized water. A multicomponent fractionation was established to obtain single oligosaccharides in a low molecular weight range up to a chain length of five and fractions containing an overall size distribution in the high molecular weight range up to a chain length of 90 monosaccharide units. The productivity and resolution of the continuous annular size exclusion chromatograph (40 cm bed height) were investigated and compared with those of the fixed-bed counterpart (2 x 100 cm bed height). The eluting fractions were analyzed by high-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The productivity of the annular system was found to be 25-fold higher than the conventional system. Thus, annular chromatography exemplified for the fractionation of fructans is a powerful method for the large-scale and continuous fractionation of oligomeric and polymeric carbohydrates.     

Land Application of Wastewater in Brazil - A scientific challenge: Chemical Characterization of Soil at Populina, S?o Paulo State (9 pp)

Background, Aims and Scope   The rapid increase of wastewater worldwide and the consequently urgently needed treatment measures towards disposal purposes has led to an expansion of alternative treatment methods. Besides conventional and cost intensive systems, domestic wastewater treatment by overland flow process represents an effective and low-cost alternative. However, in addition to beneficial elements in wastewaters, there is a release of other elements of the Periodic Table into the environment, which can be considered as potentially toxic. This requires a reliable chemical characterization of the wastewater element composition as well as the soils onto which it will be applied. This paper aims at presenting the chemical fingerprint methodology to characterize concentrations of a large set of elements in a tropical ferralsol in order to provide information concerning chemical modifications after long-term application of wastewater by overland flow process. The results are also used to estimate environmental implications according to guiding values for soils in São Paulo State.Methods   The wastewater treatment in Populina has been operating for 18 years. Composite soil samples were taken in a treated plot and a control plot. Wastewater was chemically characterized by using AAS. Total C and total N of soil samples were determined by Delta Plus Mass Spectrometer. The remaining elements (32) were analyzed using ICP-OES. Grain size analysis was carried out after oxidation by H2O2, and soil dispersion with NaOH and Na4P2O7 treatments. pH was measured in water. Quality control of all measurements was verified by corresponding reference materials. Fingerprint graphs were generated by standardizing the values of the control plot and by graphically displaying positive/negative percentage deviations of the element values at the treated plot from values of the control site. Results and Discussion   Chemical analyses of the wastewater used showed high BOD, COD, TOC and N values, while the majority of metals were below the detection limit that is attributed to the limitations in the instrumental techniques (AAS) utilized. The comparison of the two selected sites revealed substantial changes of the element contents associated with long-term application of domestic wastewater. Fingerprint graphs of the treated field indicated higher values for the vast majority of macro and micro-nutrients (C, N, P, K, Ca, Mg, Mo, Zn, Cu), as well as for other elements, e.g. Ba, Sr, Na, Li, or La. Enrichments of ecotoxic elements (e.g. As or Pb) occurred in the surface horizon despite the low contents of those elements in the wastewater. Other elements analyzed, i.e. Ag, Be, Bi, Cd, Sb, Sn, W or Sc, that are partially considered to be toxic, did not show considerable differences. Due to limitations in the analytical techniques applied, these results do not imply that there is no existence or no release of elements from wastewater at trace or ultra-trace levels. It is expected that more sophisticated techniques will be available in the future. Typical soil elements (Ti, Al, Fe, V, Zr) show higher values at the control site suggesting higher contents of mineralogical components. The highly positive deviation of C-contents linked with higher values of many other elements in the treated soil suggest element enrichments associated with organic matter. Concerning environmental implications, the comparison with guiding values for an enhanced monitoring showed partly an excess of acceptable metal concentration levels. Proposed intervention values were not exceeded, except for with Ba. Comparisons with phytotoxic element concentrations in soils indicate critical values for As, Cu and Cr. Conclusion   Using multi-element analysis, the study represents a first approach to access wastewater application by overland flow on the basis of a rather large range of chemical elements in Brazil. The comparison of the two selected areas revealed distinctly higher values for the majority of elements in the treated plot. The study also highlighted the importance of organic matter for element retention. The environmental implications of domestic wastewater application to soil surfaces can be grave. Since also toxic elements are enriched in these treated soils, the areas can partly be classified as polluted, and require long-term monitoring and detailed investigations.Recommendation and Outlook   The analytical data obtained may only allow for some conclusions concerning long-term feasibility and geochemical preconditions of wastewater irrigation. Therefore, not only the total concentrations of metals are of interest, but also element speciation must be analyzed in order to predict, for instance, how long the ion uptake capacity of the soil will last. Aside from the analytical procedures used in speciation, theoretical chemical (thermodynamic) concepts such as the principles of Pourbaix diagrams should also be used to predict solubility, immobilization and bioavailability of different element species.     

Organic Tracers from Wild Fire Residues in Soils and Rain/River Wash-Out

The molecular compositions and alteration products of the major organic components in soils and litter subjected to controlled or wildfire burning, and subsequent erosion by rain and river transport have been determined by GC-MS. The major compound groups imparted to soils include n-alkanoic acids, n-alkanes, n-alkanols, phytosterols, and terpenoids. Biomarker tracer analysis indicates that organic compounds remain as internal lipid components of char and heavy particles and are deposited onto soil during wildfire and prescribed burning. The process of rain erosion and river transport releases some of these internal components into the surroundings where they are further subjected to biological alteration. The distributions and abundances ofhomologous compound series coupled with biomarker tracer analysis provides a chemical fingerprint which is useful for identifying the single or multiple plant species contributing organic matter by both thermal (burning) and biological processes. Such fingerprints are useful for tracking soils which are transported in the atmosphere by wind as suspended particles in dust storms and on land by rain erosion to rivers.     

Anatomical variations in cervical vertebrae in two species of neotropical canids: What is the meaning?

Anatomical variation in wild canids is rarely described. Altered shapes, uni- or bilaterally situated, were observed in ventral laminae of C6 and/or in C7 vertebral body of two fox species: Lycalopex gymnocercus and Cerdocyon thous. The specimens were young adults, collected dead on highways in southern Brazil. Deformities were considered anatomical variations because apparently there was no interference in function. The occurrence of such variations in two related species from the same area can suggest an environmental common cause rather than genetic issues. Future studies may deepen the understanding between cause and effect of these vertebral deformities in wild canids.