Evolution of White-Light Flares Observed by YOHKOH

We consider in detail the evolutionary patterns of few white-light flares observed by Yohkoh. The following data have been used in the analysis: sequences of de-convolved SXT images in X-ray and optical filters, MEM reconstructed HXT images and the other supporting data. The resolution in the de-convolved images is below 1 arc sec. Working with sequences of de-convolved images makes it also possible to investigate the dynamics of these structures with high spatial accuracy. Comparison of the morphology of flare brightenings as observed in hard, soft and optical ranges reveals that these emissions are not co-spatial and are most probably related to different plasma volumes at any instant. These observations cannot be easily accommodated within standard flare scenarios. Traditionally, the hard and optical flare emissions are expected to be co-spatial and the soft X-ray emission is presumed to fill the coronal portion of flaring loop(s) during rise phase. Present observations do not easily fit to such scenario.     

Seasonal transport pattern of chromium(III and VI) in a stream receiving wastewater from tanneries

Water, suspended matter and sediment samples from a system heavily impacted by wastewater from numerous small tanneries (the upper Dunajec River, southern Poland) were collected to establish the annual cycle of Cr. To study possible oxidation processes the speciation of Cr and Mn concentrations were also investigated. This study showed that Cr(III and VI) temporal and spatial distributions are regulated by coupled anthropogenic (source location and emissions) and hydrologic factors (water flow and particle transport). Chromium(III) concentrations in all compartments varied seasonally as a function of the hydrological regime, production cycle in tanneries and distance from the discharge location. Cr(III) was largely associated with the particulate phase and rapidly deposited in river bed sediments. Contaminated river sediments were however flushed during flood periods to the reservoir located downstream from tanneries. During the tanning season (November to March), Chromium(III) concentrations in the water column and total Cr concentration in sediments exceeded relevant ecotoxicological guidelines only upstream from the reservoir, which trapped about 70% of the annual Cr(III) load transported by the Dunajec river. A correlation between Cr(VI)/Cr(III) ratios and Mn concentration in sediments downstream from the reservoir suggests the possibility of Cr(III) oxidation in natural conditions.     

Evolution of the trophic state of Lake Annecy (eastern France) since the last glaciation as indicated by iron, manganese and phosphorus speciation

Lake Annecy sediments have been studied to provide an insight into the evolution of the lake trophic state in response to climate changes during the Holocene. Determination of the concentration of carbonate, Fe, Mn, and different forms of P in conjunction with total sediment fluxes derived from ¹⁴C ages allows an estimation of yearly fluxes of these sediment components. High fluxes of endogenic carbonate occur during the early to middle Holocene. Non apatitic inorganic phosphorus flux is variable but shows some higher-than-present values during this period. These observations are interpreted as being a result of enhanced productivity by favourable conditions for phytoplankton development. In addition, the low Mn/Fe ratio of the redox-sensitive forms of these elements recorded during this period suggests low oxygen concentrations in the bottom waters. Therefore it appears that the lake may have undergone oxygen depletion in the bottom water during the warmer-than-present periods, due to increased productivity and subsequent oxygen consumption from the decay of organic matter. With future climate changes, this suggests that lake water quality may likely degrade under global warming.     

Light curves of relativistic charged neutron star

Gravitational lensing properties and the influence of the electric charge on the light curves of a slowly rotating neutron star whose exterior is described by the Reissner-Nordström metric are considered. The polar cap emission model is assumed. No effect of the magnetosphere except for its possible contribution to the total charge is taken into account. In general, the lensing effect is reduced by the charge and the light curves become more similar to those typical in flat space rather than to the Schwarzschild spacetime.     

Biomarker responses in flounder (Platichthys flesus) and mussel (Mytilus edulis) in the Klaipeda-Būtinge area (Baltic Sea)

During the EU project BEEP a battery of biomarkers was applied in flounder (Platichthys flesus) and the blue mussel (Mytilus edulis) collected at three locations off the Lithuanian coast (Baltic Sea) in June and September 2001 and 2002. The elevated biomarker responses in specimens sampled in September 2001 were apparently related to the extensive dredging activities in the Klaipeda port area and subsequent dumping of contaminated sediments. High concentrations of organic pollutants (organochlorines and PBDEs) were also measured in the tissues of both indicator species. In addition, response levels of genotoxicity, cytotoxicity, immunotoxicity as well as concentrations of PAH metabolites in the bile of flounder showed elevations in 2002 after an oil spill in the Būtinge oil terminal in November 2001. In flounder, biomarker measurements 10 months after the spill indicated recovery processes but in mussels a high level of genotoxicity could still be observed 22 months later. The present study illustrates the usefulness of the multi-biomarker approach in the detection of biological effects of pollution in this region of the Baltic Sea.     

The BEEP project in the Baltic Sea: overview of results and outline for a regional biological effects monitoring strategy

Field studies in the framework of the EU funded BEEP project (Biological Effects of Environmental Pollution in Marine Coastal Ecosystems, 2001-2004) aimed at validating and intercalibrating a battery of biomarkers of contaminant exposure and effects in selected indicator species in the Mediterranean, the North Atlantic and the Baltic Seas. Major strategic goals of the BEEP project were the development of a sensitive and cost-efficient biological effects monitoring approach, delivery of information and advice to end-user groups, and the implementation of a network of biomarker researchers around Europe. Based on the main results obtained in the Baltic Sea component of the BEEP the present paper summarises and assesses the applicability of biomarkers for different regions and species in this sea area. Moreover, a general strategy and some practical considerations for the monitoring of biological effects in the Baltic Sea are outlined.