The ecological impact of conquest and colonization on a medieval frontier landscape: combined palynological and geochemical analysis of lake sediments from Radzyń Chełminski, northern Poland

Slavic and German colonization of the southern Baltic between the 8th and 15th centuries A.D. is well-documented archaeologically and historically. Despite the large number of pollen profiles from Poland, few palaeoecological studies have examined the ecological impact of a process that was central to the expansion of European, Christian, societies. This study aims to redress this balance through multiproxy analysis of lake sediments from Radzyń Chełminski, Northern Poland, using pollen, element geochemistry (Inductively Coupled-Optical Emission Spectroscopy [ICP-OES]), organic content, and magnetic susceptibility. The close association between lake and medieval settlements presents the ideal opportunity to reconstruct past vegetation and land-use dynamics within a well-documented archaeological, historical, and cultural context. Three broad phases of increasing landscape impact are visible in the pollen and geochemical data dating from the 8th/9th, 10th/11th, and 13th centuries, reflecting successive phases of Slavic and German colonization. This involved the progressive clearance of oak-hornbeam dominated woodland and the development of an increasingly open agricultural landscape. Although the castles and towns of the Teutonic Order remain the most visible signs of medieval colonization, the palynological and geochemical data demonstrate that the major phase of woodland impact occurred during the preceding phase of Slavic expansion; Germans colonists were entering a landscape already significantly altered.

Biomineralisation by earthworms: an investigation into the stability and distribution of amorphous calcium carbonate

Background Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules which contain highly stable ACC. We analysed the milky fluid from which granules form and solid granules for amino acid (by liquid chromatography) and functional group (by Fourier transform infrared (FTIR) spectroscopy) compositions. Granule elemental composition was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and electron microprobe analysis (EMPA). Mass of ACC present in solid granules was quantified using FTIR and compared to granule elemental and amino acid compositions. Bulk analysis of granules was of powdered bulk material. Spatially resolved analysis was of thin sections of granules using synchrotron-based μ-FTIR and EMPA electron microprobe analysis. Results The milky fluid from which granules form is amino acid-rich (≤ 136 ± 3 nmol mg−1 (n = 3; ± std dev) per individual amino acid); the CaCO3 phase present is ACC. Even four years after production, granules contain ACC. No correlation exists between mass of ACC present and granule elemental composition. Granule amino acid concentrations correlate well with ACC content (r ≥ 0.7, p ≤ 0.05) consistent with a role for amino acids (or the proteins they make up) in ACC stabilisation. Intra-granule variation in ACC (RSD = 16%) and amino acid concentration (RSD = 22–35%) was high for granules produced by the same earthworm. Maps of ACC distribution produced using synchrotron-based μ-FTIR mapping of granule thin sections and the relative intensity of the ν2: ν4 peak ratio, cluster analysis and component regression using ACC and calcite standards showed similar spatial distributions of likely ACC-rich and calcite-rich areas. We could not identify organic peaks in the μ-FTIR spectra and thus could not determine whether ACC-rich domains also had relatively high amino acid concentrations. No correlation exists between ACC distribution and elemental concentrations determined by EMPA. Conclusions ACC present in earthworm CaCO3 granules is highly stable. Our results suggest a role for amino acids (or proteins) in this stability. We see no evidence for stabilisation of ACC by incorporation of inorganic components.

Record of natural and anthropogenic changes in reef environments (Barbados West Indies) using laser ablation ICP-MS and sclerochronology on coral cores

Coral growth rate can be affected by environmental parameters such as seawater temperature, depth, and light intensity. The natural reef environment is also disturbed by human influences such as anthropogenic pollutants, which in Barbados are released close to the reefs. Here we describe a relatively new method of assessing the history of pollution and explain how these effects have influenced the coral communities off the west coast of Barbados. We evaluate the relative impact of both anthropogenic pollutants and natural stresses. Sclerochronology documents framework and skeletal growth rate and records pollution history (recorded as reduced growth) for a suite of sampled Montastraea annularis coral cores. X-radiography shows annual growth band patterns of the corals extending back over several decades and indicates significantly lower growth rate in polluted sites. Results using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on the whole sample (aragonite, organic matter, trapped particulate matter, etc.), have shown contrasting concentrations of the trace elements (Cu, Sn, Zn, and Pb) between corals at different locations and within a single coral. Deepwater corals 7 km apart, record different levels of Pb and Sn, suggesting that a current transported the metal pollution in the water. In addition, the 1995 hurricanes are associated with anomalous values for Sn and Cu from most sites. These are believed to result from dispersion of nearshore polluted water. We compared the concentrations of trace elements in the coral growth of particular years to those in the relevant contemporaneous seawater. Mean values for the concentration factor in the coral, relative to the water, ranged from 10 for Cu and Ni to 2.4 and 0.7 for Cd and Zn, respectively. Although the uncertainties are large (60-80%), the coral record enabled us to demonstrate the possibility of calculating a history of seawater pollution for these elements from the 1940s to 1997. Our values were much higher than those obtained from analysis of carefully cleaned coral aragonite; they demonstrate the incorporation of more contamination including that from particulate material as well as dissolved metals.