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  • 1
    Electronic Resource
    Electronic Resource
    210Pb and210Po analysis in sediments and soils by microwave acid digestion (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 227 (1998), S. 19-22 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A microwave acid digestion method prior to the determination of210Pb and210Po in sediments and soils is described. It involves an acid (HNO3, HCl, HF and H3BO3 mixture) digestion with microwave heating in closed vessels at high pressures. Analyses carried out for various reference materials showed that the results were statistically equal to certified values and reproducibility was also assured. The advantage of the microwave technique compared to the traditional leaching procedures is that the solid materials are completely dissolved and, therefore, ca. 100% efficiency is achieved in the extraction of210Po and210Pb, even though a fraction is associated to the silica net. Moreover, time of analysis is drastically reduced, as are the risks associated to vapour inhalation and material corrosion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386425
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Historical Variations in Lead Fluxes in the Pyrenees (Northeast Spain) from a Dated Lake Sediment Core (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 439-449 
    Details
    ISSN: 1573-2932
    Keywords: Lake Redó ; lake sediments ; lead ; metal pollution ; mining ; 210Pb-dating ; Pyrenees ; stable Pb isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Variations in Pb concentration in lake sediments reflect changes in the fluxes of this element in the past. A sediment core from a lake in the Pyrenees (Lake Redó at 2,240 m a.s.l., NE Spain) was studied, with the aim of reconstructing past environmental and climatic conditions in the lake and its catchment area. The core was dated using both 210Pb and 14C. A surface peak of Pb concentration, which was about 10 times higher than the background level, was found. This peak is attributed to mining activities since the beginning of this century. Although Pb pollution due to the combustion of gasoline is expected to be present, no evidence can be deduced from Pb isotope ratios of sediment due to the masking effect of Pb from mines. A second peak appeared in a deeper layer, with a maximum Pb concentration of about 17 times higher than the background level. The origin of this peak is unclear. All evidence suggests that the ancient peak is due to mining operations in the central Pyrenees area, which were not documented historically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005005625972
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    Paper (German National Licenses)
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  • 3
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    Trawling-induced degradation of the deep sea [Environmental Sciences] (2014)
    National Academy of Sciences
    Details
    Publication Date: 2014-06-19
    Description: Bottom trawling has many impacts on marine ecosystems, including seafood stock impoverishment, benthos mortality, and sediment resuspension. Historical records of this fishing practice date back to the mid-1300s. Trawling became a widespread practice in the late 19th century, and it is now progressively expanding to greater depths, with the concerns...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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  • 4
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    Organic carbon sequestration and storage in vegetated coastal habitats along the western coast of the Arabian Gulf (2018)
    Institute of Physics (IOP)
    Details
    Publication Date: 2018-06-28
    Description: Certain coastal ecosystems such as mangrove, saltmarsh and seagrass habitats have been identified as significant natural carbon sinks, through the sequestration and storage of carbon in their biomass and sediments, collectively known as ‘blue carbon’ ecosystems. These ecosystems can often thrive in extreme environments where terrestrial systems otherwise survive at the limit of their existence, such as in arid and desert regions of the globe. To further our understanding of the capability of blue carbon ecosystems to sequester and store carbon in such extreme climates, we measured carbon sediment stocks in 25 sites along the Western Arabian Gulf coast. While seagrass meadows and saltmarsh habitats were widely distributed along the coast, mangrove stands were much reduced as a result of anthropogenic pressures, with 90% of stands having been lost over the last century. Carbon stocks in 1 m deep surface sediments were similar across all three blue carbon habitats, with comparable ...
    Print ISSN: 1748-9318
    Electronic ISSN: 1748-9326
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering
    Published by Institute of Physics (IOP)
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  • 5
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    SGD to the Mediterranean Sea [Environmental Sciences] (2015)
    National Academy of Sciences
    Details
    Publication Date: 2015-04-01
    Description: The Mediterranean Sea (MS) is a semienclosed basin that is considered one of the most oligotrophic seas in the world. In such an environment, inputs of allochthonous nutrients and micronutrients play an important role in sustaining primary productivity. Atmospheric deposition and riverine runoff have been traditionally considered the main external...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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    PAPER CURRENT
  • 6
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    Submarine Groundwater Discharge in Europe and Effects on Coastal Zones (2015)
    In:  EPIC3Future Coast - Europe Symposium, Berlin, 2015-10-05-2015-10-07
    Details
    Publication Date: 2016-12-01
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 7
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    Carbon export in a bloom region from the Atlantic sector of the Southern Ocean derived from 234Th and sediment traps (2015)
    In:  EPIC32015 Aquatic Sciences Meeting, Granada, 2015-02-22-2015-02-27
    Details
    Publication Date: 2016-01-21
    Description: Significant attenuation on sinking Particulate Organic Carbon (POC) takes place within the upper hundreds meters of the water column. The study of the transfer efficiency is essential to improve our understanding of the ocean’s role in sequestering carbon. Here we present results on downward POC fluxes as well as export efficiency (i.e. export/production ratio) in the Southern Ocean, which is a key regulator of the global carbon cycle. We followed a vast algal bloom occurred around 51ºS 13ºW during three weeks in summer 2012 and used Th-234 as a particle tracer in combination with sediment traps (ST). The estimated POC fluxes at 100 m were high, averaging 19 ± 9 and 33 ± 10 mmol m-2 d-1 (ST and ST+Th-234, respectively), and they were reduced by a factor of 2 at 300 m in most of the stations. The export efficiency at 100 m was generally low (〈10%), but it was 〉30% in some locations. Phytoplankton and sinking particles composition data will be also considered to better comprehend the dynamics affecting POC fluxes in the Southern Ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 8
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    Tracing the Three Atlantic Branches Entering the Arctic Ocean With 129 I and 236 U (2018)
    AGU
    In:  EPIC3Journal of Geophysical Research: Oceans, AGU, ISSN: 21699275
    Details
    Publication Date: 2018-10-08
    Description: This study presents the data on 129I and 236U concentrations in seawater samples and sea ice cores obtained during two expeditions to the Arctic Ocean that took place onboard R/V Polarstern (PS94) and R/V Lance (N-ICE2015) in summer 2015. Carbon-14 was also measured in the deep water samples from the Nansen, Amundsen, and Makarov Basins. The main goal was to investigate the distribution of 129I and 236U in a transect from the Norwegian Coast to the Makarov Basin to fully exploit the potential of combining 129I and 236U as a dual tracer to track Atlantic waters throughout the Arctic Ocean. The use of the 129I/236U and 236U/238U atom ratios allowed identifying a third Atlantic branch that enters the Arctic Ocean (the Arctic Shelf Break Branch) following the Norwegian Coastal Current that carries a larger proportion of the European reprocessing plants signal compared to Fram Strait Branch Water and Barents Sea Branch Water. The combination of 129I and 236U also allowed quantifying the different proportions of the La Hague stream, the Scottish stream, and Atlantic waters forming the three Atlantic branches of the Arctic Ocean Boundary Current. The results show that the 129I/236U atom ratio can now be used to identify the different Atlantic branches entering the Arctic Ocean. New input functions for 129I, 236U, and 129I/236U have also been described for each branch, which can be further used for calculation of transit time distributions of Atlantic waters.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 9
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    Latitudinal distributions of particulate carbon export across the North Western Atlantic Ocean. (2017)
    PERGAMON-ELSEVIER SCIENCE LTD
    In:  EPIC3Deep-Sea Research Part I-Oceanographic Research Papers, PERGAMON-ELSEVIER SCIENCE LTD, 129, pp. 116-130, ISSN: 0967-0637
    Details
    Publication Date: 2017-11-06
    Description: 234Th-derived carbon export fluxes were measured in the Atlantic Ocean under the GEOTRACES framework to evaluate basin-scale export variability. Here, we present the results from the northern half of the GA02 transect, spanning from the equator to 64°N. As a result of limited site-specific C/234Th ratio measurements, we further combined our data with previous work to develop a basin wide C/234Th ratio depth curve. While the magnitude of organic carbon fluxes varied depending on the C/234Th ratio used, latitudinal trends were similar, with sizeable and variable organic carbon export fluxes occurring at high latitudes and low to negligible fluxes occurring in oligotrophic waters. Our results agree with previous studies, except at the boundaries between domains, where fluxes were relatively enhanced. Three different models were used to obtain satellite-derived net primary production (NPP). In general, NPP estimates had similar trends along the transect, but there were significant differences in the absolute magnitude depending on the model used. Nevertheless, organic carbon export efficiencies were generally 〈 25%, with the exception of a few stations located in the transition area between the riverine and the oligotrophic domains and between the oligotrophic and the temperate domains. Satellite-derived organic carbon export models from Dunne et al. (2005) (D05), Laws et al. (2011) (L11) and Henson et al. (2011) (H11) were also compared to our 234Th-derived carbon exports fluxes. D05 and L11 provided estimates closest to values obtained with the 234Th approach (within a 3-fold difference), but with no clear trends. The H11 model, on the other hand, consistently provided lower export estimates. The large increase in export data in the Atlantic Ocean derived from the GEOTRACES Program, combined with satellite observations and modeling efforts continue to improve the estimates of carbon export in this ocean basin and therefore reduce uncertainty in the global carbon budget. However, our results also suggest that tuning export models and including biological parameters at a regional scale is necessary for improving satellite-modeling efforts and providing export estimates that are more representative of in situ observations.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 10
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    Soluble radionuclides as tracers for circulation and mixing in the Southern Ocean (2009)
    In:  EPIC3IPY BONUS-Goodhope first post-cruise meeting, January 23-24, 2009, Villefranche-sur-Mer, France.
    Details
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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