Do mowing regimes affect plant and soil biological activity in the mountain meadows of Southern Poland?

The soil biological activity of mountain meadows is a significant factor that determines the health and utility of these regions. The climax stage of this area is forest, but to maintain semi-natural grassland, which is characterised by high biodiversity,low-intensity land use(mowing or grazing) is necessarily required. To understand the effect of various mowing regimes on the soil biological activity and plants, the soil microbial activity(microbial biomass carbon, dehydrogenase activity and number of the cultivable fraction of soil microbial community),annelids community(density and species composition earthworms and enchytraeids) and plant species composition were investigated. The study area was located in the Pieniny National Park in the Carpathian Mountains, in a meadow belonging to the association Dactylis glomerata-Poa trivialis. The investigated variants were divided according to mowing regime:traditional scything – hand mowing(HM), mechanical mowing(MM), or the abandonment of mowing – nonmowing(NM). The microbial activities(expressed by,e.g. microbial biomass carbon and the number of phosphorus bacteria) were affected by the mowing regime. The density of earthworms was higher in the HM and MM than in the NM variants. The largest changes in plant species composition were caused by the abandonment of mowing(NM). The mean number of plant species was positively correlated with soil moisture, earthworm density, and microbial activity(expressed indirectly by dehydrogenases activity). The soil microbial community, such as vegetative bacteria forms and ammonifying bacteria,were positively associated with pH value, and the microbial and total organic carbon content. The results presented here indicate that there is no single form of optimal management for all living organisms.Decisions about mowing regimes, or abandonment of use, should be preceded by multi-aspect studies,including plants and soil biota.     

Statistical modelling of the main features of the <Emphasis Type="Italic">Artemisia</Emphasis> pollen season in Wrocław,Poland, during the 2002–2011 time period

The aim of this article is to present statistical forecasting models concerning the dynamics of Artemisia pollen seasons in Wroc?aw, including the start and end, the date of maximum pollen concentration and seasonal pollen index (SPI). For statistical evaluation, use was made of aerobiological and meteorological data from the last 10 years (2002–2011). Based on this data, agroclimatic indicators, i.e. crop heat units (CHUs), were determined for various averaging periods. The beginning of the Artemisia pollen season in the studied time period, on average, took place on 23 June. Its length usually varied between 26 and 45 days, and maximum daily concentrations occurred between 31 July and 18 August. It was found that the beginning of the pollen season depends, above all, on the values of CHUs and photothermal unit (PTU) (p?<?0.05) in the period from March to June, for various thermal thresholds. The date of maximum daily concentration correlates with sunshine duration, PTU and air temperature for June and July (p?<?0.05). On the other hand, SPI is connected with thermal variables, i.e. average, maximum and minimum air temperatures and CHUs and heliothermal unit (HTU) for July (p?<?0.05) and the beginning of spring. Based on the correlation analysis and the chosen variables, regression models for the beginning date of Artemisia pollen season and SPI were prepared, which were then verified by using leave-one-out cross-validation. A better fit between modelled and actual values was found for the analysis concerning the season start date than for the SPI.     

Comets and asteroids in the Taurid complex: Remarks on a possible common origin

A supposition about the common origin of some cometary and asteroidal members of the Taurid complex is analyzed on the basis of their orbital evolution. It is shown that moments, in which the longitudes of perihelion of comet P/Encke, object (2201) Oljato and six other near-Earth asteroids amount to the value of longitude of perihelion of comet 1967 II Rudnicki, are close to the moment of previous perihelion passage of this long-period comet. Although the conjecture about the membership of comet Rudnicki in the Taurid complex is controversial one, nevertheless the presented results seem to be interesting in itself, and yield a contribution in favour of the hypothesis of the breakup of a giant comet some 10⁴ – 10⁵ years ago in the inner Solar System.     

Differential calibration of seismometers for measurement of rotation and strain

A method of correcting the seismometers’ responses discrepancy for differential measurements of strains and rotations in the seismic far field is proposed. The method concerns differential calibration of the whole seismometers’ array by electric current. A model of corrective filtering of the obtained differential signals in the Z domain is given. Two methods of the filter parameters’ estimation are introduced; they are based on the seismometers response to the calibration. A practical test of the methods — an analysis of a recorded seismic event — is added. Significant reduction of differences between simultaneous seismic recordings was obtained, which is interpreted as cleaning of differential signal from spurious elements.     

LAGEOS Sensitivity to Ocean Tides

Satellite Laser Ranging (SLR) to LAGEOS has a remarkable contribution to high-precise geodesy and geodynamics through deriving and validating various global geophysical models. This paper validates ocean tide models based on the analysis of satellite altimetry data, coastal tide gauges, and hydrodynamic data, i.e., CSR3.0, TOPEX4.0, CSR4.0A, FES2004, GOT00.2, and the CSRC Schwiderski model. LAGEOS orbits and SLR observation residuals from solutions based on different ocean tide models are compared and examined. It is found that LAGEOS orbits are sensitive to tidal waves larger than 5 mm. The analysis of the aliasing periods of LAGEOS orbits and tidal waves reveals that, in particular, the tidal constituent S₂ is not well established in the recent ocean tide models. Some of the models introduce spurious peaks to empirical orbit parameters, which can be associated with S₂, S_a, and K₂ tidal constituents, and, as a consequence, can be propagated to fundamental parameters derived from LAGEOS observations.     

A new magnetic index based on the external part of vertical geomagnetic variations

Variations of geomagnetic components X, Y, and Z recorded in 19 Intermagnet European observatories in 2004 were analysed. The original data from all observatories were preliminarily processed. In the first step, periods longer than three hours were filtered out. In the second step, variations of vertical geomagnetic component Z were separated into external and internal parts. We introduced a non-dimensional index η defined as the square root of a ratio of the energy of the external part of the vertical component to that of the horizontal components. Maps of the surface distribution of a new magnetic index η for the area of Europe at selected time periods were created, and their time changes are presented. The time changes of η for selected observatories are also shown. Moreover, we discuss a very interesting phenomenon we discovered, that has never been described in geophysical literature. Namely, in the recordings of all the observatories we noticed the presence of very regular variations, observed almost exclusively in the vertical component Z, which is quite unusual. These regular variations occur in the form of sinusoidal “wave packets”. The amplitudes of these variations do not depend on the geomagnetic latitude and appear in the records of all the observatories we analyzed. They occur in quiet days, which suggests that their source is in the ionosphere.     

Gas Chromatographic Determination of Extractable Compounds Composition and Emission Rate of Volatile Terpenes from Larch Needle Litter

A combination of solid-phase microextraction (SPME) and gas chromatography can be successfully used both for establishing the qualitative composition of volatile organic compounds (VOC) emitted by leaf litter and for determining their emission rates. Taking as an example European larch litter, it is shown that dead plant material contains considerable amounts of volatile components as well as non-volatile compounds that can be VOC precursors formed as a result of enzymatic reactions. It is proposed to include the determination of extractable compounds into the methodology of studying litter as a source of atmospheric VOC. Some data on litter mass are reported and it is concluded that this data may be included into special models for emission evaluation. In this work the distribution coefficients of monoterpene hydrocarbons between the gas phase and polydimethylsiloxane fiber coating necessary for quantitative determinations in SPME were estimated.     

The changes of groundwater chemistry of semi-confined buried valley aquifer during one decade of water exploitation

This article presents the analysis of the temporal changes in water chemistry in a semi-confined aquifer (Wielkopolska Buried Valley aquifer, Poland) during one decade of water exploitation. It is shown that the groundwater contamination, as documented in a previous work, still persists and has lead to steady groundwater quality deterioration. The most intensive changes in water chemistry due to contamination are observed in the regions recognized earlier as the most vulnerable parts of the aquifer. The influence of contamination is effective despite implementation of groundwater protection activities. The travails of groundwater quality protection of the confined or semi-confined aquifers were accented.     

Stable 18O and 13C isotope records of Viviparus diluvianus (Kunth, 1865) shells from Holsteinian (MIS 11) lakes of eastern Poland as palaeoenvironmental and palaeoclimatic proxies

The oxygen and carbon stable isotope composition of Viviparus diluvianus shells was determined in the palaeolakes of the Holsteinian interglacial (MIS 11) in eastern Poland: the Ortel Królewski, Hrud, Ossówka, Roskosz and Szymanowo lakes. The occurrence of V. diluvianus covers the Taxus zone, the so‐called intra‐interglacial cooling period (Pinus‐Larix zone), the climatic optimum (Carpinus‐Abies zone) and the post‐optimal period with an undefined pollen zone. The isotope record of V. diluvianus shells allowed palaeoclimate and palaeoenvironmental reconstructions. δ¹⁸O and δ¹³C vary from −8.7‰ in the post‐optimal period to −4.8‰ in the optimal period, and from −10.6‰ at the beginning of the Taxus zone to −4.2‰ at the climatic optimum, respectively. A positive correlation of the isotope curves indicates closed‐water bodies, and only at Roskosz was some occasional overflow inferred. Higher oxygen isotopes correspond to an increase in temperature and/or enhanced evaporation, which is well marked in the Carpinus‐Abies zone, whereas samples enriched in ¹³C are correlated with periods demonstrating a lower water level and higher productivity in the lakes. Episodes of lake shallowing and dense aquatic vegetation occurred in the Pinus‐Larix zone and during the climatic optimum. The isotope ratios for the climatic optimum significantly exceed those of the other periods, thus pointing to warmer conditions. An estimation of relative changes of average summer temperatures using the δ¹⁸O/temperature gradient yielded variation of 1–2 °C within the lakes. Absolute temperature reconstructions indicate the effects of specific local conditions. Hence, V. diluvianus shells offer a reliable proxy in qualitative studies of interglacial lake records.