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  • 11
    Publication Date: 2024-02-07
    Description: Supratidal sands are vitally important for coastal defence in the German Wadden Sea. They are less affected by human activities than other areas as they are located far off the mainland shore, touristical and commercial activities are generally prohibited. Therefore, supratidal sands are of high ecological interest. Nevertheless, the faunal inventory and distribution pattern of microorganisms on these sands were studied very little. The composition of living and dead foraminiferal assemblages was therefore investigated along a transect from the supratidal sand Japsand up to Hallig Hooge. Both assemblages were dominated by calcareous foraminifera of which Ammonia batava was the most abundant species. Elphidium selseyense and Elphidium williamsoni were also common in the living assemblage, but Elphidium williamsoni was comparably rare in the dead assemblage. The high proportions of Ammonia batava and Elphidium selseyense in the living assemblage arose from the reproduction season that differed between species. While Ammonia batava and Elphidium selseyense just finished their reproductive cycles, Elphidium williamsoni was just about to start. This was also confirmed by the size distribution patterns of the different species. The dead assemblage revealed 20 species that were not found in the living assemblage of which some were reworked from older sediments (e.g., Bucella frigida) and some were transported via tidal currents from other areas in the North Sea (e.g., Jadammina macrescens). The living foraminiferal faunas depicted close linkages between the open North Sea and the mainland. Key species revealing exchange between distant populations were Haynesina germanica, Ammonia batava and different Elphidium species. All these species share an opportunistic behaviour and are able to inhabit a variety of different environments; hence, they well may cope with changing environmental conditions. The benthic foraminiferal association from Japsand revealed that transport mechanisms via tides and currents play a major ecological role and strongly influence the faunal composition at this site.
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  • 12
    Publication Date: 2024-02-07
    Description: LivingAmmoniaspecies and an inventory of dead assemblages from Adriatic subtidal, nearshoreenvironments were investigated at four stations off Bellaria, Italy.Ammonia falsobeccarii, Ammonia parkinso-niana, Ammonia tepida, andAmmonia venetawere recognized in the living (rose-bengal-stained) fauna, andAmmonia bellarian. sp. is described herein for the first time.Ammonia beccariiwas only found in the deadassemblage. The biometry of 368 living individuals was analysed by using light microscopic and scanning elec-tron microscopic images of three aspects. A total of 15 numerical and 8 qualitative parameters were measuredand assessed, 5 of which were recognized to be prone to a certain subjectivity of the observer. The accuracy ofnumerical data as revealed by the mean residuals of parallel measurements by different observers ranged from0.5 % to 5.5 %. The results indicated a high degree of intraspecific variability. The test sizes of the individualspecies were log-normally distributed and varied among the stations. Parameters not related to the growth ofthe individuals, i.e. flatness of the tests, dimensions of the second-youngest chamber, proloculus, umbilical andpore diameter, sinistral–dextral coiling, and umbilical boss size, were recognized as being species-distinctive incombination. They may well supplement qualitative criteria that were commonly used for species discriminationsuch as a lobate outline, a subacute or rounded peripheral margin, or the degree of ornamentation on the spiraland umbilical sides. The averages of the measured parameters were often lower than the range of previouslypublished values, mainly because the latter were retrieved from a few adult specimens and not from the wholeassemblage as in the present approach. We conclude that the unprecedented high proportions ofAmmonia bec-cariiin the northern Adriatic may well be artificial. A robust species identification without genetic analyses ispossible by considering designated biometric parameters. This approach is also applicable to earlier literaturedata, and their re-assessment is critical for a correct denomination of recent genotypes.
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  • 13
    Publication Date: 2024-02-07
    Description: Heavy metal pollution originating from anthropogenic sources, e.g., mining, industry and extensive land use, is increasing in many parts of the world and influences coastal marine environments for a long time. The elevated input of heavy metals into the marine system potentially affects the biota because of their toxicity, persistence and bioaccumulation. An emerging tool for environmental applications is the heavy metal incorporation into foraminiferal tests calcite, which facilitates monitoring of anthropogenic footprints on recent and past environmental systems. The aim of this study is to investigate whether the incorporation of heavy metals in foraminifera is a direct function of their concentration in seawater. Culturing experiments with a mixture of dissolved chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag), cadmium (Cd), tin (Sn), mercury (Hg) and lead (Pb) in artificial seawater were carried out over a wide concentration range to assess the uptake of heavy metals by the near-shore foraminiferal species Ammonia aomoriensis, Ammonia batava and Elphidium excavatum. Seawater analysis exhibited the increasing metal concentrations between culturing phases and revealed high metal concentrations in the beginning of the culturing phases due to the punctual metal addition. Furthermore, a loss of metals during the culturing process was discovered, which lead to a deviation between the expected and the actual concentrations of the metals in seawater. Laser ablation ICP-MS analysis of the newly formed calcite revealed species-specific differences in the incorporation of heavy metals. The foraminiferal calcite of all three species reveals a strong positive correlation with Pb and Ag concentrations in the culturing medium. Ammonia aomoriensis further showed a correlation with Mn and Cu, A. batava with Mn and Hg and E. excavatum with Cr and Ni, and partially also with Hg. Zn, Sn and Cd showed no clear trend for the species studied, which may be caused by the little variation of these metals in seawater. Our calibrations and the calculated partition coefficients render A. aomoriensis, A. batava and E. excavatum as natural archives that enable the direct quantification of metals in polluted and pristine environments. This in turn allows monitoring of the ecosystem status of areas that are potentially under the threat of anthropogenic pollution in order to evaluate contemporary emission reduction measures.
    Type: Article , PeerReviewed
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