Chloropigments a in the Gulf of Gdańsk (Baltic Sea) as markers of the state of this environment

The Gulf of Gdańsk receives the waters of the Wis?a (Vistula), the largest Polish river and the second largest river flowing into the Baltic Sea. Chloropigments a (chlorophyll a and its derivatives) were determined in water and sediments from the Gulf. Samples were collected during cruises of R.V. 'Oceania' at 19 stations located at different water depths and distances from the shore, in May (2003) and October (2004), i.e., at the beginning and at the end of the growing season, respectively. Seawater was also sampled on the beach at Sopot in June, July and August 2004, i.e., during the height of the growing season. All water samples were collected with a bathometer and passed through Whatman GF/F filters. Recent sediments (0-10 cm) were collected with a core sampler and divided into sub-samples (0-1, 1-5 and 5-10 cm). The pigments were determined using HPLC-DAD. The results were first correlated with a set of parameters measured in situ during sample collection (salinity, temperature, oxygen content of seawater) and determined in the same material (organic carbon content, granulometry), then worked up statistically. Although this investigation shows that particular chloropigments a in recent sediments are indicative of the prevailing environmental conditions in the study area and the trends in their variations, they should be treated as a relative and not an absolute measure, since this is the first such study based on a large and coherent set containing both chloropigment a and environmental data. In addition, a chlorophyll a budget is estimated for the Gulf of Gdańsk on the basis of the literature and the authors' own data. Only c. 10% of the chlorophyll a produced annually in the Gulf of Gdańsk is transferred to sediments in the form of chloropigments a; 2.8% is in the form of undecomposed chlorophyll a and 7.2% in the form of chlorophyll a derivatives. About 90% of chlorophyll a is decomposed to colourless products.     

The impact origin of Eunomia and Themis families

Abstract— Criteria for finding asteroid families (Zappala et al. 1995) are applied to a large (205,770 member) data set of asteroid orbital elements. The cases of the Eunomia and Themis families are considered as examples. This is combined with the cratering criteria for catastrophic disruption of small bodies in the solar system (Leliwa‐Kopystyński et al. 2008). We find that the Eunomia parent body itself was not catastrophically disrupted in the family‐generating impact event; after impact, the current body contains as much as 70% of its primordial mass. However, by contrast with Eunomia, the present mass of 24 Themis is only about 21% of that of its primordial body. Limits are placed on the sizes of the impactors in both examples, and for the case of Eunomia, the radius of the just sub‐critical crater (which may be present on 15 Eunomia) is predicted as <58 km.     

The Maunder Minimum and the Sun as the Possible Source of Particles Creating Increased Abundance of the <Superscript>14</Superscript>C Carbon Isotope

The Maunder Minimum was the time during the second part of the 17th century, nominally from 1645 to 1717 AD, when unusually low numbers of sunspots were observed. On the basis of numerous recorded observations of auroras in the early 18th century, the end of the Minimum could be regarded as around 1700, but details of sunspot observations by Jan Heweliusz (Heweliusz, Machina Coelestis, 1679), John Flamsteed and Philippe de La Hire in 1684 allow us to interpret the Maunder Minimum as the period without a significant cessation of activity. This Minimum was also recognized in ¹⁴C data from trees which grew during the second part of 17th century. The variation in the production rate of radioactive carbon isotope ¹⁴C is due to modulation of the cosmic ray flux producing it by the changing level of solar activity and solar magnetic flux. Stronger magnetic fields in the solar wind make it more difficult for cosmic rays to reach the Earth, causing a drop in the production rate of ¹⁴C. However, more detailed analyses of ¹⁴C data indicate that the highest isotope abundances do not occur at the time of sunspot minima, as would be expected on the basis of modulation of the cosmic ray flux by the solar magnetic field, but two years after the sunspot number maximum. This time difference (or phase delay) can be accounted for if in fact there are both solar and non-solar cosmic ray contributions. Solar flares could also contribute high-energy particles and produce ¹⁴C and are generally not most frequent at the time of the highest sunspot numbers in the cycle.     

Neoproterozoic and Cambrian successions deposited on the East European platform and Cadomian basement area in Poland

Summary A short review of the Neoproterozoic and Cambrian sedimentary and volcanogenic successions in Poland is concerned with depositional and tectonic developments. The successions accumulated in shallow shelf and deeper slope environments. They overlie Palaeoproterozoic crystalline basement of the Baltic Craton and Gondwana-derived Neoproterozoic Cadomian basement. This discrepancy in the nature of the basement is viewed as indicating distinct terranes. During the course of Palaeozoic time, the discrete terranes were assembled along the Teisseyre-Tornquist Lineament and the Trans-European Suture Zone adjacent to the Baltica palaeocontinent.     

Variability of polar motion oscillations with periods from 20 to 150 days in 1979–1991

Variability of short period oscillations of polar motion with periods ranging from 20 to 150 days were investigated in the period 1979–1991. The new computation method of time variable band pass filter spectra and the Wavelet Transform method were applied. These oscillations are elliptical with variable amplitudes. Modulation periods of amplitude variations of these oscillations of about two and three years were found. Correlations of short period oscillations of polar motion and of effective atmospheric angular momentum (EAAM) excitation functions show annual variations and connections of their increases with El Niño phenomena.     

Mixing processes in wide open channels

The work contains analyses of two cases of stream diffusion under conditions of turbulent flow in an open channel. The analysed cases were: a source of rectangular cross-section placed in the channel axis and at the wall. To describe the mixing process the known equation of the turbulent diffusion was used. Verification of the solution for the considered cases was made based on research performed on models.     

Drainage area and the variation of channel geometry downstream

Recent geomorphological studies tend to deal with small basins. The understanding of small basin dynamics provides important information for the understanding of large basin dynamics assuming that the extrapolation of small basin data to larger basins is valid. This work tests the validity of this extrapolation of data with reference to channel geometry. An analysis of the variation of channel width downstream reveals that the value b =0.5 (W = aQ^b) is a ‘good’ average. However, the use of a one-line model consisting of a simple power function incurs a loss of a considerable amount of relevant information concerning the channel form and hence the channel processes. It has been shown that the –b– value for small basins and very big basins is lower than the one for the intermediate basins.     

The Casanova Complex of the Northern Apennines: A mélange formed on a distal passive continental margin

The Cretaceous-Palaeocene Casanova Complex occurs in two thrust sheets of the eugeosynclinal Ligurids of the Northern Apennines. It is a sedimentary mélange with ophiolitic and quartzose turbidites or limestone-shale olistostrome (submarine debris flows) as matrix. Exotic blocks of ophiolite and granite, serpentinite breccias and lenticular ophiolitic breccias and olistostromes contribute to the mélange character of the complex. Deformational structures include soft-sediment slump folds (indicating a SW-dipping palaeoslope) and boudins, a gradational slumped top to the mélange, small-scale faults in chert blocks and deformation associated with the emplacement of the exotic slide blocks. The blocks were shed as rotational slides from submarine fault scarps and are surrounded by haloes of debris created by submarine weathering. The stacking pattern of the blocks, with the originally stratigraphically highest ophiolite lithologies lowest in the pile of blocks, is explained by a diverticulation model with progressively deeper erosion. Mechanical analysis shows that the blocks were stable when partly exposed resting on a soft sediment substratum. Criteria which distinguish the Casanova Complex from a tectonic mélange, and which may be of value in other mélanges, are discussed. Previous interpretations of the complex as a precursor olistostrome to northeastward nappe emplacement (the Bracco ridge model) are rejected. The mélange is believed to have formed on ocean crust as a result of turbidite and debris flow sedimentation, soft sediment deformation, block faulting, gravity sliding and submarine erosion at the distal edge of a uniformly SW-dipping continental margin.     

Thermomagnetic properties of some Late Mesozoic diabase dikes of South Spitsbergen

Summary Laboratory investigations of thermomagnetic properties of specimens from seven diabase dikes of South Spitsbergen have been performed. Studies of temperature variation of isothermal saturation remanence combined with Hopkinson effect measurements and investigations of low temperature remanence give information on the mineral composition of the magnetic phases present in the magnetic fraction of the diabases. The experiments show that the clean natural remanence of these dikes has been acquired at the time of their, consolidation in the Late Mesozoic, though three of them may have been partially remagnetized at the time of Tertiary orogeny. Since the dikes reveal several normal and reversed directions of clean natural remanence, it is concluded that they were formed at different times in the Late Mesozoic, even though some of them may have been subjected to secondary influences at a later date.     

Nonlinearity of Nonradial Modes in Evolved Stars

We show that in evolved stars, even at relatively low surfaceamplitudes, nonradial modes become strongly nonlinear in thehydrogen shell source, where the Brunt-Väisälä frequency hasits absolute maximum. The measure of nonlinearity is the productof horizontal displacement times the radial wavenumber, . It becomes large already in evolved -Scuti stars.This nonlinearity presents a major problem for interpretations ofamplitude modulation in RR Lyrae stars in terms of nonradial modeexcitation.