| 1. |
- Mollehave, L. T., et al.
(author)
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Register-based information on thyroid diseases in Europe: lessons and results from the EUthyroid collaboration
- 2022
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In: Endocrine Connections. - : Bioscientifica. - 2049-3614. ; 11:3
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Journal article (peer-reviewed)abstract
- ObjectiveRegisters of diagnoses and treatments exist in different forms in the European countries and are potential sources to answer important research questions. Prevalence and incidence of thyroid diseases are highly dependent on iodine intake and, thus, iodine deficiency disease prevention programs. We aimed to collect European register data on thyroid outcomes to compare the rates between countries/regions with different iodine status and prevention programs. DesignRegister-based cross-sectional study. MethodsNational register data on thyroid diagnoses and treatments were requested from 23 European countries/regions. The provided data were critically assessed for suitability for comparison between countries/regions. Sex- and age-standardized rates were calculated. ResultsRegister data on >= 1 thyroid diagnoses or treatments were available from 22 countries/regions. After critical assessment, data on medication, surgery, and cancer were found suitable for comparison between 9, 10, and 13 countries/regions, respectively. Higher rates of antithyroid medication and thyroid surgery for benign disease and lower rates of thyroid hormone therapy were found for countries with iodine insufficiency before approx. 2001, and no relationship was observed with recent iodine intake or prevention programs. ConclusionsThe collation of register data on thyroid outcomes from European countries is impeded by a high degree of heterogeneity in the availability and quality of data between countries. Nevertheless, a relationship between historic iodine intake and rates of treatments for hyper- and hypothyroid disorders is indicated. This study illustrates both the challenges and the potential for the application of register data of thyroid outcomes across Europe.
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| 2. |
- Andersson, Björn, et al.
(author)
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Strain-specific metabarcoding reveals rapid evolution of copper tolerance in populations of the coastal diatom Skeletonema marinoi
- 2023
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In: Molecular Ecology. - 0962-1083 .- 1365-294X.
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Journal article (peer-reviewed)abstract
- Phytoplankton have short generation times, flexible reproduction strategies, large population sizes and high standing genetic diversity, traits that should facilitate rapid evolution under directional selection. We quantified local adaptation of copper tolerance in a population of the diatom Skeletonema marinoi from a mining-exposed inlet in the Baltic Sea and in a non-exposed population 100 km away. We hypothesized that mining pollution has driven evolution of elevated copper tolerance in the impacted population of S. marinoi. Assays of 58 strains originating from sediment resting stages revealed no difference in the average tolerance to copper between the two populations. However, variation within populations was greater at the mining site, with three strains displaying hyper-tolerant phenotypes. In an artificial evolution experiment, we used a novel intraspecific metabarcoding locus to track selection and quantify fitness of all 58 strains during co-cultivation in one control and one toxic copper treatment. As expected, the hyper-tolerant strains enabled rapid evolution of copper tolerance in the mining-exposed population through selection on available strain diversity. Within 42 days, in each experimental replicate a single strain dominated (30%–99% abundance) but different strains dominated the different treatments. The reference population developed tolerance beyond expectations primarily due to slowly developing plastic response in one strain, suggesting that different modes of copper tolerance are present in the two populations. Our findings provide novel empirical evidence that standing genetic diversity of phytoplankton resting stage allows populations to evolve rapidly (20–50 generations) and flexibly on timescales relevant for seasonal bloom progressions.
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| 3. |
- Brinkmann, I., et al.
(author)
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Foraminiferal Mn/Ca as Bottom-Water Hypoxia Proxy: An Assessment of Nonionella stella in the Santa Barbara Basin, USA
- 2021
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In: Paleoceanography and Paleoclimatology. - 2572-4517. ; 36:11
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Journal article (peer-reviewed)abstract
- Hypoxia is of increasing concern in marine areas, calling for a better understanding of mechanisms leading to decreasing dissolved oxygen concentrations ([O2]). Much can be learned about the processes and implications of deoxygenation for marine ecosystems using proxy records from low-oxygen sites, provided proxies, such as the manganese (Mn) to calcium (Ca) ratio in benthic foraminiferal calcite, are available and well calibrated. Here we report a modern geochemical data set from three hypoxic sites within the Santa Barbara Basin (SBB), USA, where we study the response of Mn/Caforam in the benthic foraminifer Nonionella stella to variations in sedimentary redox conditions (Mn, Fe) and bottom-water dissolved [O2]. We combine molecular species identification by small subunit rDNA sequencing with morphological characterization and assign the SBB N. stella used here to a new phylotype (T6). Synchrotron-based scanning X-ray fluorescence (XRF) imaging and Secondary Ion Mass Spectrometry (SIMS) show low Mn incorporation (partition coefficient DMn < 0.05) and limited proxy sensitivity of N. stella, at least within the range of dissolved [O2] (2.7–9.6 μmol/l) and Mnpore-water gradients (2.12–21.59 μmol/l). Notably, even though intra- and interspecimen Mn/Ca variability (33% and 58%, respectively) was only partially controlled by the environment, Mn/Caforam significantly correlated with both pore-water Mn and bottom-water [O2]. However, the prevalent suboxic bottom-water conditions and limited dissolved [O2] range complicate the interpretation of trace-elemental trends. Additional work involving other oxygenation proxies and samples from a wider oxygen gradient should be pursued to further develop foraminiferal Mn/Ca as an indicator for hypoxic conditions.
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| 4. |
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| 5. |
- Ittermann, T., et al.
(author)
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Standardized Map of Iodine Status in Europe
- 2020
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In: Thyroid. - : Mary Ann Liebert Inc. - 1050-7256 .- 1557-9077. ; 30:9
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Journal article (peer-reviewed)abstract
- Background:Knowledge about the population's iodine status is important, because it allows adjustment of iodine supply and prevention of iodine deficiency. The validity and comparability of iodine-related population studies can be improved by standardization, which was one of the goals of the EUthyroid project. The aim of this study was to establish the first standardized map of iodine status in Europe by using standardized urinary iodine concentration (UIC) data. Materials and Methods:We established a gold-standard laboratory in Helsinki measuring UIC by inductively coupled plasma mass spectrometry. A total of 40 studies from 23 European countries provided 75 urine samples covering the whole range of concentrations. Conversion formulas for UIC derived from the gold-standard values were established by linear regression models and were used to postharmonize the studies by standardizing the UIC data of the individual studies. Results:In comparison with the EUthyroid gold-standard, mean UIC measurements were higher in 11 laboratories and lower in 10 laboratories. The mean differences ranged from -36.6% to 49.5%. Of the 40 postharmonized studies providing data for the standardization, 16 were conducted in schoolchildren, 13 in adults, and 11 in pregnant women. Median standardized UIC was <100 mu g/L in 1 out of 16 (6.3%) studies in schoolchildren, while in adults 7 out of 13 (53.8%) studies had a median standardized UIC <100 mu g/L. Seven out of 11 (63.6%) studies in pregnant women revealed a median UIC Conclusions:We demonstrate that iodine deficiency is still present in Europe, using standardized data from a large number of studies. Adults and pregnant women, particularly, are at risk for iodine deficiency, which calls for action. For instance, a more uniform European legislation on iodine fortification is warranted to ensure that noniodized salt is replaced by iodized salt more often. In addition, further efforts should be put on harmonizing iodine-related studies and iodine measurements to improve the validity and comparability of results.
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| 6. |
- Mojtahid, M., et al.
(author)
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Assessing the impact of different carbonate system parameters on benthic foraminifera from controlled growth experiments
- 2023
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In: Chemical Geology. - : Elsevier BV. - 0009-2541. ; 623
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Journal article (peer-reviewed)abstract
- Insights into past marine carbon cycling and water mass properties can be obtained by means of geochemical proxies calibrated through controlled laboratory experiments with accurate seawater carbonate system (C-system) manipulations. Here, we explored the use of strontium/calcium ratio (Sr/Ca) of the calcite shells of benthic foraminifera as a potential seawater C-system proxy through a controlled growth experiment with two deep-sea species (Bulimina marginata and Cassidulina laevigata) and one intertidal species (Ammonia T6). To this aim, we used two experimental set-ups to decouple as much as possible the individual components of the carbonate system, i.e., changing pH at constant dissolved inorganic carbon (DIC) and changing DIC at constant pH. Four climatic chambers were used with different controlled concentrations of atmospheric pCO2 (180 ppm, 410 ppm, 1000 ppm, 1500 ppm). Our results demonstrated that pH did not influence the survival and growth of the three species. However, low DIC conditions (879 μmol kg−1) negatively affected B. marginata and C. laevigata through reduced growth, whereas no effect was observed for Ammonia T6. Our results also showed that Sr/Ca was positively correlated with total Alkalinity (TA), DIC and bicarbonate ion concentration ([HCO3 −]) for Ammonia T6 and B. marginata; i.e., DIC and/or [HCO3 −] were the main controlling factors. For these two species, the regression models were coherent with published data (existing so far only for Ammonia T6) and showed overall similar slopes but different intercepts, implying species-specific effects. Furthermore, the Sr/Ca - C-system relationship was not impacted by ontogenetic trends between chamber stages, which is a considerable advantage for paleo-applications. This applied particularly to Ammonia T6 that calcified many chambers compared to the two other species. However, no correlation with any of the C-system parameters was observed for Sr/Ca in C. laevigata. This might imply either a strong species-specific effect and/or a low tolerance to laboratory conditions leading to a physiological stress, thereby impacting the Sr incorporation into the calcite lattice of C. laevigata.
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| 7. |
- Ni, S., et al.
(author)
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Early diagenesis of foraminiferal calcite under anoxic conditions : A case study from the Landsort Deep, Baltic Sea (IODP Site M0063)
- 2020
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In: Chemical Geology. - : Elsevier BV. - 0009-2541. ; 558
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Journal article (peer-reviewed)abstract
- The chemical composition of foraminiferal calcite is widely used for studying past environmental conditions and biogeochemistry. However, high rates of microbial organic matter degradation and abundant dissolved metal sources in sediments and pore waters may impede the application of foraminifera-based proxies due to formation of secondary carbonates or other authigenic minerals on and/or inside of foraminiferal tests. Secondary carbonate precipitation severely alters the bulk foraminiferal geochemistry and can be difficult to eliminate through standard foraminiferal trace element cleaning procedures. We present results showing the mineral composition and formation sequence of diagenetic coatings on foraminiferal tests formed under extreme anoxic conditions in the Baltic Sea's deepest basin (the Landsort Deep, IODP Exp. 347, Site M0063). Our study focuses primarily on the diagenetic carbonates present on and in the tests of the low-oxygen tolerant benthic foraminiferal species Elphidium selseyensis and Elphidium clavatum. We applied various geochemical and imaging methods to ascertain the diagenesis processes and the authigenic mineral formation sequence on foraminifera. The authigenic carbonates were enriched in Mn, Mg, Fe and Ba, depending on the environmental redox conditions when the authigenic carbonates were precipitated. Concentrations of redox-sensitive elements such as Mn and Fe were particularly elevated in bottom waters and sedimentary pore waters under oxygen-depleted conditions in the Landsort Deep, resulting in formation of carbonates with highly elevated Mn and Fe contents. In addition to Mn- and Fe carbonates, several other types of authigenic minerals also formed on and in the foraminiferal chambers, including authigenic calcite, and non-carbonate accessory minerals. The formation sequence reveals the redox sensitivities of different elements and the preferential sequence of oxidants used by the microbes during organic matter oxidation and secondary redox reactions. This study provides a case study of extreme early diagenesis of foraminiferal calcite and may serve as a valuable guide when interpreting foraminiferal trace element records from low oxygen environments.
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| 8. |
- Ni, S., et al.
(author)
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Holocene Hydrographic Variations From the Baltic-North Sea Transitional Area (IODP Site M0059)
- 2020
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In: Paleoceanography and Paleoclimatology. - 2572-4517. ; 35:2
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Journal article (peer-reviewed)abstract
- Deoxygenation affects many continental shelf seas across the world today and results in increasing areas of hypoxia (dissolved oxygen concentration ([O2]) <1.4 ml/L). The Baltic Sea is increasingly affected by deoxygenation. Deoxygenation correlates with other environmental variables such as changing water temperature and salinity and is directly linked to ongoing global climate change. To place the ongoing environmental changes into a larger context and to further understand the complex Baltic Sea history and its impact on North Atlantic climate, we investigated a high accumulation-rate brackish-marine sediment core from the Little Belt (Site M0059), Danish Straits, NW Europe, retrieved during the Integrated Ocean Drilling Program (IODP) Expedition 347. We combined benthic foraminiferal geochemistry, faunal assemblages, and pore water stable isotopes to reconstruct seawater conditions (e.g., oxygenation, temperature, and salinity) over the past 7.7 thousand years (ka). Bottom water salinity in the Little Belt reconstructed from modeled pore water oxygen isotope data increased between 7.7 and 7.5 ka BP as a consequence of the transition from freshwater to brackish-marine conditions. Salinity decreased gradually (from 30 to 24) from 4.1 to ~2.5 ka BP. By using the trace elemental composition (Mg/Ca, Mn/Ca, and Ba/Ca) and stable carbon and oxygen isotopes of foraminiferal species Elphidium selseyensis and E. clavatum, we identified that generally warming and hypoxia occurred between about 7.5 and 3.3 ka BP, approximately coinciding in time with the Holocene Thermal Maximum (HTM). These changes of bottom water conditions were coupled to the North Atlantic Oscillation (NAO) and relative sea level change.
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| 9. |
- Ni, S., et al.
(author)
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Last interglacial seasonal hydroclimate in the North Sea–Baltic Sea region
- 2023
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In: Quaternary Science Reviews. - 0277-3791 .- 1873-457X. ; 312
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Journal article (peer-reviewed)abstract
- The Last Interglacial (LIG) experienced substantial changes in seasonal insolation compared with the present day, which may have affected the hydrography and water-mass exchange in the North Sea and Baltic Sea region. Here we investigate the effects of solar radiation and greenhouse gas (GHG) forcing on the regional climate by analyzing model simulations of the LIG (127 ka BP), pre-industrial (PI, 1850 CE), and present-day (PD, 1990 CE) climates. We also interpret the reconstructed seasonal bottom water conditions using benthic foraminifera and geochemistry data. Our simulations reveal that during the LIG, the Baltic Sea region (including the Kattegat and the Danish Straits) experienced more saline and colder bottom waters than those in the PD, in agreement with the reconstruction data. This can be attributed to lower GHG levels and enhanced water exchange of cooler, saline North Sea water into the Baltic Sea during the LIG. The thermocline was stronger during the summer months in the LIG, mainly due to the higher sea surface temperature (SST) compared to that of the PD resulting from increased summer insolation. Further, the temperature anomalies (LIG–PD) show significant inverse correlations with the precipitation–minus–evaporation (P–E) at the Baltic Sea entrance. However, the P–E balance appears to have had minimal impact on salinity changes in the North Sea, the Baltic Proper, and the open sea area. Our findings indicate that monthly surface and bottom water salinity anomalies of LIG-PI exhibit strong positive correlations with the North Atlantic Oscillation (NAO) anomalies in the Baltic entrance region. During the LIG, a more positive phase of the NAO index in autumn played a crucial role in wind-driven major inflows and led to more intensive water exchange in the North Sea–Baltic Sea region compared to the late Holocene.
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| 10. |
- Ni, S., et al.
(author)
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Seasonal climate variations in the Baltic Sea during the Last Interglacial based on foraminiferal geochemistry
- 2021
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In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 272
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Journal article (peer-reviewed)abstract
- Climate during the Last Interglacial period (LIG, Marine Isotope Stage 5e) was on average warmer than the present, with a higher global sea level but also more unstable conditions. Today, the Baltic Sea interacts strongly with conditions in the North Atlantic region, and this interaction was likely even stronger during the LIG. We here present a reconstruction of seawater conditions during the LIG based on benthic foraminiferal geochemistry (stable isotopes and trace elements) and compare these records with modern marine monitoring data to evaluate seasonal hydrographic conditions in the western and southern Baltic Sea during the first half of the LIG (130–123 ka BP). Our reconstructions reflect the evolution of seasonal temperature and salinity, rather than annual mean conditions. The spring LIG bottom water temperatures in the Skagerrak and Kattegat were ∼2–3 °C higher compared to the modern spring bottom water temperatures. During the LIG, there was an increase in seasonality in bottom water temperature (progressively warmer summers and cooler springs) in the southern Baltic Sea, which can be linked to seasonal insolation changes. Moreover, our data suggest a decreased gradient of bottom water salinity along a transect through the Skagerrak-Kattegat-Danish Straits-southern Baltic Sea, supporting previous investigations inferring a stronger ocean-water influx into the Baltic Sea during the LIG than at present.
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