Bivalves as indicators of environmental variation and potential anthropogenic impacts in the southern Barents Sea

Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Pollution Bulletin 59 (2009): 193-206, doi:10.1016/j.marpolbul.2009.02.022.Identifying patterns and drivers of natural variability in populations is necessary to gauge potential effects of climatic change and the expected increases in commercial activities in the Arctic on communities and ecosystems. We analyzed growth rates and shell geochemistry of the circumpolar Greenland smooth cockle, Serripes groenlandicus, from the southern Barents Sea over almost 70 years between 1882 and 1968. The datasets were calibrated via annually-deposited growth lines, and growth, stable isotope (δ18O, δ13C), and trace elemental (Mg, Sr, Ba, Mn) patterns were linked to environmental variations on weekly to decadal scales. Standardized growth indices revealed an oscillatory growth pattern with a multi-year periodicity, which was inversely related to the North Atlantic Oscillation Index (NAO), and positively related to local river discharge. Up to 60% of the annual variability in the Ba/Ca could be explained by variations in river discharge at the site closest to the rivers, but the relationship disappeared at a more distant location. Patterns of δ18O, δ13C, and Sr/Ca together provide evidence that bivalve growth ceases at elevated temperatures during the fall and recommences at the coldest temperatures in the early spring, with the implication that food, rather than temperature, is the primary driver of bivalve growth. The multi-proxy approach of combining the annually integrated information from the growth results and higher resolution geochemical results yielded a robust interpretation of biophysical coupling in the region over temporal and spatial scales. We thus demonstrate that sclerochronological proxies can be useful retrospective analytical tools for establishing a baseline of ecosystem variability in assessing potential combined impacts of climatic change and increasing commercial activities on Arctic communities.We gratefully acknowledge past financial support from Norsk Hydro, and continuing financial support from StatoilHydro, the Norwegian Research Council, and the Howard Hughes Medical Institute through Bates College. This publication was made possible, in part, by NIH Grant Number P20 RR-016463 from the INBRE Program of the National Center for Research Resources

Häusliche Trinkwasserinstallation von Fällen mit Legionärskrankheit: Effizient ermitteln – systemisch sanieren

Im Rahmen der von 2016-2020 durchgeführten Berliner LeTriWa-Studie (LeTriWa = Legionellen in der Trinkwasserinstallation) wurden 19 nach Trinkwasserverordnung untersuchungspflichtige Trinkwasserinstallationen untersucht, wo im zugehörigen Haushalt eine Fallperson wohnhaft war. Im Beitrag wird dargestellt, an welchen Stellen in der Trinkwasserinstallation des Gebäudes und des betroffenen Haushalts monoklonale Antikörper (MAb) Typ 3/1-positive (virulenzassoziierte) Stämme mit welcher Wahrscheinlichkeit zu finden waren und ob auch Kaltwasserproben positiv waren. Wir untersuchten, welche Konsequenzen sich aus den Ergebnissen von Standard-Haushaltsproben sowie den Ergebnissen aus einer weitergehenden Untersuchung für die Ermittlung von Fällen von Legionärskrankheit generell ableiten lassen

Arctic quaternary ostracods and their use in paleoreconstructions

The paper deals with original and published data on fossil ostracodal assemblages from the Eurasian Arctic Kara, Laptev and Chuckchi seas. As a whole, six ecologically different assemblages were distinguished (freshwater, brackish water, marine of the inner, middle and outer shelves and upper continental slope), they replace each other upcore reflecting a gradual increase in water depth and distance from the coast. These assemblages are stable in the entire Arctic region and can be used for interpretation of environments in different Arctic areas

Membrane technology for the future treatment of paper mill effluents: chances and challenges of further system closure

The pressure on the European paper industry to further close its water circuits has increased significantly during the past decade. Since the technologies of the past can no longer meet the requirements of the future, new water treatment methods have become necessary. A constant rise in the interest in membrane technology expressed by the European paper industry confirms that in the future this method will evolve into a key technology for continued water savings. The publication provides an overview of current and future applications of membrane plants in the European paper industry. A range of technologies is briefly presented together with their advantages and drawbacks, and the economic potential of membrane use is discussed. Among other topics, the authors take a look at the utilization of membrane filtration for treating internal circulation water, partial flows containing coating colours, and biologically treated effluents. The technologies addressed include ultrafiltration, nanofiltration and membrane bioreactor technology. Possible recovery and treatment routes for the concentrates produced by the nanofiltration of biologically treated effluents are examined and evaluated.</jats:p

Biomarker records, organic carbon accumulation, and river discharge in the Holocene southern Kara Sea (Arctic Ocean)

Within the Russian-German research project on "Siberian River Run-off (SIRRO)" devoted to the freshwater discharge and its influence on biological, geochemical, and geological processes in the Kara Sea, sedimentological and organic-geochemical investigations were carried-out on two well-dated sediment cores from the Yenisei Estuary area. The main goal of this study was to quantify the terrigenous organic carbon accumulation based on biomarker and bulk accumulation rate data, and its relationship to Yenisei river discharge and climate change through Holocene times. The biomarker data at both cores clearly indicate the predominance of terrigenous organic matter, reaching 70 to 100% and 50 to 80% of the total organic carbon within and directly north of the estuary, respectively. During the last about 9 Cal. kyrs. BP represented in the studied sediment section, siliciclastic sediment and (terrigenous) organic carbon input was strongly influenced by postglacial sea-level rise and climate-related changes in river discharge. The mid-Holocene Climatic Optimum is documented by maximum river discharge between 8.2 and 7.3 Cal. kyrs. BP. During the last 2000 years river discharge probably became reduced, and accumulation of both terrigenous and marine organic carbon increased due to increased coagulation of fine-grained material

Reprint of: Evaluation of past stratification changes in the Nordic Seas by comparing planktonic foraminiferal δ18O with a solar-forced model

Density changes in the upper water column of the northern North Atlantic may enhance or reduce vertical convection of surface water with profound effects on meridional overturning and climate in the wider region. This study tests the capability of paired delta O-18 values of two planktonic foraminiferal species - Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba - for the reconstruction of near-surface density stratification in high latitudes or the glacial ocean. Foraminiferal data from two sediment cores of crucial areas of the Nordic Seas were compared with insolation-induced thermal stratification changes as obtained by simulations with the general circulation model ECHO-G. The comparison suggests that insolation was the chief mechanism to change thermocline strength during most of the Holocene. Prior to that, stratification depended by and large on the varying amounts of meltwater injected at the sea surface. Similar to the modern central Arctic Ocean, a pronounced and thick halocline prevented surface waters from deep convection in the central Nordic Seas. Parts of the Norwegian Sea, however, were also stratified but more analogous to the modern Greenland Sea, where deep convection can occur in late winter as a result of the density increase upon a combination of cold temperatures and wind stress. Our findings thus support previous results of an active meridional overturning also in a glacial ocea

Evaluation of past stratification changes in the Nordic Seas by comparing planktonic foraminiferal δ18O with a solar-forced model

Density changes in the upper water column of the northern North Atlantic may enhance or reduce vertical convection of surface water with profound effects on meridional overturning and climate in the wider region. This study tests the capability of paired delta O-18 values of two planktonic foraminiferal species - Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba - for the reconstruction of near-surface density stratification in high latitudes or the glacial ocean. Foraminiferal data from two sediment cores of crucial areas of the Nordic Seas were compared with insolation-induced thermal stratification changes as obtained by simulations with the general circulation model ECHO-G. The comparison suggests that insolation was the chief mechanism to change thermocline strength during most of the Holocene. Prior to that, stratification depended by and large on the varying amounts of meltwater injected at the sea surface. Similar to the modern central Arctic Ocean, a pronounced and thick halocline prevented surface waters from deep convection in the central Nordic Seas. Parts of the Norwegian Sea, however, were also stratified but more analogous to the modern Greenland Sea, where deep convection can occur in late winter as a result of the density increase upon a combination of cold temperatures and wind stress. Our findings thus support previous results of an active meridional overturning also in a glacial ocean

Comparison study of the modem ostracod associations in the Kara and Laptev seas: Ecological aspects

Recent ostracod assemblages were investigated from coretop sediment samples collected in the eastern Kara Sea from water depths down to 300 m. A total of 45 species were identified, 27 of them were reported for the Kara Sea for the first time. The Kara Sea data were compared with our results on the distribution of ostracods in the eastern Laptev Sea. The spatial distribution of recent taxa and the ecological groupings demonstrate a clear relation to dominant environmental factors which range from estuarine to full-marine conditions. Four assemblages related to average summer bottom water salinities were established: (1) a freshwater assemblage from the inner estuaries of the Ob' and Yenisei rivers with salinities less than 2 and from thermokarst lagoons of the southern Laptev Sea coast with strong salinization in winter; (2) a brackishwater assemblage of the outer estuaries of the Ob' and Yenisei rivers with salinities up to 26; (3) a mixed euryhaline–marine assemblage dominated by euryhaline species Paracyprideis pseudopunctillata and Heterocyprideis sorbyana from the inner shelf river-affected zone of the Kara and Laptev seas, where salinities range between 26 and 32; (4) a taxonomically diverse marine assemblage dominated by shallow-water marine taxa from the northern parts of the Kara and Laptev shelves and upper continental slope with stable bottom environments and a salinity higher than 32. Abundant euryhaline species found at greater water depths are identified as part of an ice-rafted assemblage. They are possibly entrained into the newly formed fast ice during autumn storms and freeze-up period and then transported to the distal open-sea areas during summer