Zoobenthos and oceanographical parameters in the Kemskaya Guba (Bay) - estuary of the Kem' River entering the Onega Bay, White Sea

Data on distribution of zoobenthos in the Kemskaya Guba (or Kemskaya Bay - the estuary of the Kem' River entering the Onega Bay of the White Sea), which is strongly influenced by river runoff, are presented. The number of species at sampling stations varied from 4 to 65. Density of communities and zoobenthos biomass varied from 342±68 to 4293±96 #/m**2 and from 0.418±0.081 to 1975.22±494.36 g/m**2, respectively. Shannon index values varied between 1.19 to 4.7 bit/ind. At the upper part of the estuary, detritivores dominated, while in the central part and at outlets sestonophages prevailed. Changes in quantitative parameters of the zoobenthos along gradient of water salinity were traced, and relations of these parameters with seven other environmental factors were revealed. It was found that species composition, biodiversity, and trophic structure of the zoobenthos significantly correlated with some of parameters mentioned above. Multiple regression analysis was used to assess combined effect of factors, and it revealed which of them played a determining role in Kemskaya Guba: for species composition - depth, water color, and total concentration of suspended matter; for number of species - contents of <0.01 mm grain size (pelite) fraction and organic carbon in bottom sediments. Biomass depended on water salinity, water chromaticity, and organic carbon contents in bottom sediments and suspended matter. Values of the Shannon index of diversity are determined by water color, and contents of organic carbon and pelite fraction in bottom sediments. Calculations of ecological stress values revealed two zones with unstable state of the zoobenthos.

Isotopic composition of modern ice wedges and winter precipitation in the Laptev Sea region (Table 2)

The first step for the application of stable isotope analyses of ice wedges for the correct paleoclimatic reconstruction supposes the study of the isotopic composition of modern ice wedges and their relationship with the isotopic composition of modern precipitation. The purpose of this research is to present, to analyze and to discuss new data on isotopic composition (d18O, dD, 3H) of modern ice wedges obtained in the Laptev Sea region in 1998-99. Investigations were carried out at two sites: on Bykovsky Peninsula in 1998 and on Bol'shoy Lyakhovsky Island in 1999 and were based on the combined application of both tritium CH) and stable isotope (d18O, dD) analyses. Tritium analyses of the atmospheric precipitation collected during two field seasons show seasonal variations: high tritium concentration in snow (to a maximum of 207 TU) and low values of tritium concentration (<20 TU) in rain. High tritium concentrations are also observed in the surface water, in suprapermafrost ground waters, and in the upper part of permafrost. High tritium concentrations range between 30-40 TU and 750 TU in the studied modern ice wedges (active ice wedges), which let us believe that they are of modern growth. Such high tritium concentrations in ice wedges can not be associated with old thermonuclear tritium because of the radioactive decay. High tritium concentrations found in the snow cover in 1998/99, in the active layer and in the upper part of permafrost give evidence of modern (probably the last decade) technogenic tritium arrival from the atmosphere on to the Earth surface in the region. The comparison of the isotopic composition (d18O, dD and d-excess) of active ice wedges and modern winter precipitation in both sites shows: 1) the isotopic composition of snow correlates linearly with a slope close to 8.0 and parallel to the GMWL at both sites; 2) the mean isotopic composition of active ice wedges on Bykovsky Peninsula is in good agreement with the mean isotopic composition of modern snow; 3) the isotopic composition of active ice wedges and snow on Bol'shoy Lyakhovsky Island are considerably different. There are low values of d-excess in all studied active ice wedges (mean value is about 4.8 per mil), while in snow, the mean value of d-excess is about 9.5 per mil. Possible reasons for this gap are the following: 1) the modification of the isotopic composition in snow during the spring period; 2) changes in the isotopic composition of ice wedges due to the process of ice sublimation in open frost cracks during the cold period; 3) mixing of snowmelt water with different types of surface water during the spring period; 4) different moisture source regions.

Villefranche MedSeA mesocosm experiment 2013: perturbation studies and field studies

A joint mesocosm experiment took place in February/March 2013 in the bay of Villefranche in France as part of the european MedSeA project. Nine mesocosms (52 m**3) were deployed over a 2 weeks period and 6 different levels of pCO2 and 3 control mesocosms (about 450 µatm), were used, in order to cover the range of pCO2 anticipated for the end of the present century. During this experiment, the potential effects of these perturbations on chemistry, planktonic community composition and dynamics including: eucaryotic and prokaryotic species composition, primary production, nutrient and carbon utilization, calcification, diazotrophic nitrogen fixation, organic matter exudation and composition, micro-layer composition and biogas production were studied by a group of about 25 scientists from 8 institutes and 6 countries. This is one of the first mesocosm experiments conducted in oligotrophic waters. A blog dedicated to this experiment can be viewed at: http://medseavillefranche2013.obs-vlfr.fr.

Stareso MedSeA mesocosm experiment: field and perturbation studies 2012

A joint mesocosm experiment took place in June/July 2012 in Corsica (bay of Calvi, Stareso station;http://www.stareso.com/) as part of the european MedSeA project. Nine mesocosms (52 m**3) were deployed over a 20 days period and 6 different levels of pCO2 and 3 control mesocosms (about 450 µatm), were used, in order to cover the range of pCO2 anticipated for the end of the present century. During this experiment, the potential effects of these perturbations on chemistry, planktonic community composition and dynamics including: eucaryotic and prokaryotic species composition, primary production, nutrient and carbon utilization, calcification, diazotrophic nitrogen fixation, organic matter exudation and composition, micro-layer composition and biogas production were studied by a group of about 25 scientists from 8 institutes and 6 countries. This is one of the first mesocosm experiments conducted in oligotrophic waters. A blog dedicated to this experiment can be viewed at: http://medseastareso2012.wordpress.com/.

Proliferation of retrovirally transduced CFU-E cells after incubation with increasing Epo-concentration (Figure 5c)

Data contain source data for Figure 5c from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. Retrovirally transduced CFU-E cells were incubated with increasing Epo concentrations for 14 h and proliferation was measured by [3H]-thymidine incorporation.