Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Abstract Short term (2 days) laboratory experiments were performed to study the change in irradiance induced production of Fe(II) in seawater in the presence of two open oceanic Southern Ocean diatom species, Thalassiosira sp. and Chaetoceros brevis. Three irradiance conditions were applied: 1) UVB + UVA + VIS, 2) UVA + VIS, and 3) VIS, and Fe concentrations of 0 and 5 nM Fe were added to natural Southern Ocean seawater (containing 0.32 nM dissolved Fe and 1.69 equivalents of nM L − 1 Fe dissolved organic ligands, log K′ = 22.03). The photoproduced concentration of Fe(II) showed no relationship with the concentration of total dissolved Fe or the concentration of strongly chelated iron. During incubations with the diatoms an increase in the Fe(II) concentration during the second day suggested a modification of the Fe speciation. In the presence of Thalassiosira sp. photoreduction of Fe(III) was observed, whereas in the presence of C. brevis irradiance independent Fe(III) reduction played an important role in the Fe(II) production. Furthermore, a decrease in the strongly chelated Fe concentration, in concert with a decrease in the conditional stability constant, suggested a modification of the strongly chelated Fe fraction in the experiments with C. brevis. The chelated Fe fraction did not change in cultures with Thalassiosira sp. Overall, the presence of diatoms appeared to enhance the reactive Fe pool improving the biological availability of Fe.
The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.
1
European Heavy Metals in Mosses Survey
AbstractThe aim of this study was to identify the factors influencing Cd, Hg and Pb concentrations in mosses sampled within the framework of the European Heavy Metals in Mosses Surveys 1990Surveys -2005. The analyses encompassed data from 4661 (1990), 7301 (1995), 6764 (2000) and 5600 (2005) sampling sites. As exemplary case studies revealed that other factors besides atmospheric deposition of metals influence the element concentrations in mosses, the moss datasets of the above mentioned surveys were analysed by means of bi-and multivariate statistics in order to identify factors influencing metal bioaccumulation. In the analyses we used the metadata recorded during the sampling as well as additional geodata e.g. on depositions, emissions and land use. Bivariate Spearman correlation analyses showed the highest correlations between Cd and Pb concentrations in mosses and EMEP modelled total deposition data (0.62 ≤ r s ≤ 0.73). For Hg the correlations with all the tested factors were considerably lower (e.g. total deposition r s ≤ 0.24). Multivariate decision tree analyses by means of Classification and Regression Trees (CART) identified the total deposition as the statistically most significant factor for the Cd and Pb concentrations in the mosses in all four monitoring campaigns. For Hg, the most significant factor 8 in 1990 as identified by CART was the distance to the nearest Hg source recorded in the European Pollutant Emission Register, in 1995 and 2000 it was the analytical method, and in 2005 CART identified the sampled moss species. The strong correlations between the Cd and Pb concentrations in the mosses and the total deposition can be used to calculate deposition maps with a regression kriging approach on the basis of surface maps on the element concentrations in the mosses.
For the past few years, a strong and intensive combined study by analytical scientists and biologists on bioindication and biomonitoring has developed. To achieve a more public-related prophylactic healthcare feature derived from these biotechniques in the future, the collaboration between analytical scientists, ecotoxicologists and especially human toxicologists has to be strongly intensified and promoted. For this purpose, different forms of education and teaching of students on an international level combined with common research projects encompassing the different scientific fields and philosophies are important keys for common success. and Zechmeister, H. (2008) 'On the road from environmental biomonitoring to human health aspects: atmospheric deposition of heavy metals by epiphytic/epigeic plants: present status and future needs', Int.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.