Seasonal SIMS δ18O record in Astarte borealis from the Baltic Sea tracks a modern regime shift in the NAO

Introduction: Astarte borealis holds great potential as an archive of seasonal paleoclimate, especially due to its long lifespan (several decades to more than a century) and ubiquitous distribution across high northern latitudes. Furthermore, recent work demonstrates that the isotope geochemistry of the aragonite shell is a faithful proxy of environmental conditions. However, the exceedingly slow growth rates of A. borealis in some locations (<0.2mm/year) make it difficult to achieve seasonal resolution using standard micromilling techniques for conventional stable isotope analysis. Moreover, oxygen isotope (δ18O) records from species inhabiting brackish environments are notoriously difficult to use as paleoclimate archives because of the simultaneous variation in temperature and δ18Owater values. Methods: Here we use secondary ion mass spectrometry (SIMS) to microsample an A. borealis specimen from the southern Baltic Sea, yielding 451 SIMS δ18Oshell values at sub-monthly resolution. Results: SIMS δ18Oshell values exhibit a quasi-sinusoidal pattern with 24 local maxima and minima coinciding with 24 annual growth increments between March 1977 and the month before specimen collection in May 2001. Discussion: Age-modeled SIMS δ18Oshell values correlate significantly with both in situ temperature measured from shipborne CTD casts (r2 = 0.52, p<0.001) and sea surface temperature from the ORAS5-SST global reanalysis product for the Baltic Sea region (r2 = 0.42, p<0.001). We observe the strongest correlation between SIMS δ18Oshell values and salinity when both datasets are run through a 36-month LOWESS function (r2 = 0.71, p < 0.001). Similarly, we find that LOWESS-smoothed SIMS δ18Oshell values exhibit a moderate correlation with the LOWESS-smoothed North Atlantic Oscillation (NAO) Index (r2 = 0.46, p<0.001). Change point analysis supports that SIMS δ18Oshell values capture a well-documented regime shift in the NAO circa 1989. We hypothesize that the correlation between the SIMS δ18Oshell time series and the NAO is enhanced by the latter’s influence on the regional covariance of water temperature and δ18Owater values on interannual and longer timescales in the Baltic Sea. These results showcase the potential for SIMS δ18Oshell values in A. borealis shells to provide robust paleoclimate information regarding hydroclimate variability from seasonal to decadal timescales

Age and growth of Astarte borealis (Bivalvia) from the southwestern Baltic Sea using secondary ion mass spectrometry

Traditional isotope sclerochronology employing isotope ratio mass spectrometry has been used for decades to determine the periodicity of growth increment formation in marine organisms with accretionary growth. Despite its well-demonstrated capabilities, it is not without limitation. The most significant of these being the volume of carbonate powder required for analysis with conventional drill-sampling techniques, which limit sampling to early in ontogeny when growth is fast or to species that reach relatively large sizes. In species like Astarte borealis (Schumacher, 1817), a common component of Arctic boreal seas, traditional methods of increment analysis are difficult, because the species is typically long-lived, slow growing, and forms extremely narrowly spaced growth increments. Here, we use Secondary Ion Mass Spectrometry (SIMS) to analyze δ18O in 10-μm-diameter spots and resolve the seasonal timing of growth increment formation in Astarte borealis in the southeastern Baltic Sea. In the individaul sampled here, dark growth increments can form in either the fall, winter, or spring. Furthermore, growth increment data from two populations (RFP3S = 54.7967° N, 12.38787° E; WA = 54.86775° N, 14.09832° E) indicate that in the Baltic Sea, A. borealis is moderately long-lived (at least 43 years) and slow growing (von Bertalanffy k values 0.08 and 0.06). Our results demonstrate the potential of A. borealis to be a recorder of Baltic Sea seasonality over the past century using both live- and dead-collected shells, and also the ability of SIMS analysis to broaden the spectrum of bivalves used in sclerocrhonological work

A remarkable record of a very rare freshwater snail Borysthenia naticina (Menke, 1845) in North-East Germany compared with three Lithuanian records

Borysthenia naticina (Menke) is among the rarest and most threatened freshwater molluscs in Germany. Only in southern Germany, in the Bavarian part of the Danube River, previous studies clearly indicate a recent occurrence of this species. Some imprecise data were given for northern Germany from the Oder River; prehistoric records (Diluvium) also exist. However, all these "Oder River literature sources" are hard to locate and it was impossible to find any reliable recent records of B. naticina in the German parts of the Oder River. This study documents the occurrence of a recent population of this very rare Pontic-Baltic species in the lower course of the Oder River. Ecological information on the habitat and accompanying freshwater molluscs is given. The findings are compared with the data on the Lithuanian localities in the Nemunas River

Beyond salty reins – modelling benthic species' spatial response to their physical environment in the Pomeranian Bay (Southern Baltic Sea)

The brackish water environment of the Baltic Sea is dominated by a strong gradient of salinity and along with salinity the benthic diversity decreases – salinity is regarded as the master factor regulating benthic diversity in brackish habitats. In this scheme, consistently small patches of comparatively higher or lower benthic diversity do emerge in areas where either environmental or anthropogenic impacts on the benthic habitat change drastically over short spatial distances. Hence, spatial diversity of ecological factors creates diversity among benthic colonization and community structures. We show through a logistic modeling approach the possibility to predict thereby induced benthic colonization areas and community structures inside the broad scheme of a brackish water habitat. This study bases upon quantitative macrozoobenthic abundance data collected over a period of 4 years. It clearly demonstrates the need to analyze species’ relationships in gradient systems such as the Baltic Sea and provides a tool to predict natural and anthropogenic forced changes in species distribution

Zur Verbreitung und Oecologie von Pisidium moitessierianum (Paladilhe 1866) unter besonderer Beruecksichtigung von Nordostdeutschland.

Distribution, nomenclature and bibliography of Pisidium moitesserianum is given. Special attention is given to distribution and morphometrics in Nordeast Germany

Der biologische Zustand der Ostsee im Jahre 1998 auf der Basis von Phytoplankton-, Zooplankton- und Zoobenthosuntersuchungen

SIGLEAvailable from TIB Hannover: RR 6908(37) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Verbreitung des Makrozoobenthos in der Mecklenburger Bucht (suedliche Ostsee) - rezent und im historischen Vergleich

Available from TIB Hannover: RR 6908(42) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman