| 1. |
- Emile-Geay, J., et al.
(author)
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Data Descriptor: A global multiproxy database for temperature reconstructions of the Common Era
- 2017
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In: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 4
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Journal article (peer-reviewed)abstract
- Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850-2014. Global temperature composites show a remarkable degree of coherence between high-and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python. Since the pioneering work of D'Arrigo and Jacoby1-3, as well as Mann et al. 4,5, temperature reconstructions of the Common Era have become a key component of climate assessments6-9. Such reconstructions depend strongly on the composition of the underlying network of climate proxies10, and it is therefore critical for the climate community to have access to a community-vetted, quality-controlled database of temperature-sensitive records stored in a self-describing format. The Past Global Changes (PAGES) 2k consortium, a self-organized, international group of experts, recently assembled such a database, and used it to reconstruct surface temperature over continental-scale regions11 (hereafter, ` PAGES2k-2013'). This data descriptor presents version 2.0.0 of the PAGES2k proxy temperature database (Data Citation 1). It augments the PAGES2k-2013 collection of terrestrial records with marine records assembled by the Ocean2k working group at centennial12 and annual13 time scales. In addition to these previously published data compilations, this version includes substantially more records, extensive new metadata, and validation. Furthermore, the selection criteria for records included in this version are applied more uniformly and transparently across regions, resulting in a more cohesive data product. This data descriptor describes the contents of the database, the criteria for inclusion, and quantifies the relation of each record with instrumental temperature. In addition, the paleotemperature time series are summarized as composites to highlight the most salient decadal-to centennial-scale behaviour of the dataset and check mutual consistency between paleoclimate archives. We provide extensive Matlab code to probe the database-processing, filtering and aggregating it in various ways to investigate temperature variability over the Common Era. The unique approach to data stewardship and code-sharing employed here is designed to enable an unprecedented scale of investigation of the temperature history of the Common Era, by the scientific community and citizen-scientists alike.
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| 2. |
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| 3. |
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| 4. |
- 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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| 5. |
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| 6. |
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| 7. |
- Völzke, Henry, et al.
(author)
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The krakow declaration on iodine: Tasks and responsibilities for prevention programs targeting iodine deficiency disorders
- 2018
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In: European Thyroid Journal. - : Bioscientifica. - 2235-0640 .- 2235-0802. ; 7, s. 201-204
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Research review (peer-reviewed)abstract
- © 2018 European Thyroid Association. Published by S. Karger AG, Basel. On April 18, 2018 the EUthyroid consortium released the Krakow Declaration on Iodine in response to the increasing concern about the deteriorating commitment of policymakers to address public health strategies against iodine deficiency disorders (IDD) in the European populations. Regulators and policymakers should harmonize obligatory Universal Salt Iodization to ensure free trade of fortified foodstuffs in Europe. Similarly, iodized animal feed requires regulatory approval to ensure free trade within the EU. National governments and public health authorities have to perform harmonized monitoring and evaluation of fortification programs at regular intervals to ensure optimal iodine supply to the population. Scientists, together with public health care workers, patient organizations, industry, and the public should support measures necessary to ensure that IDD prevention programs are sustainable, as appropriate within a rapidly changing environment and further social awareness of the issue. The declaration defines measures and responsibilities to optimize IDD prevention.
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| 8. |
- Ahmadi, Shilan Seyed, et al.
(author)
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Effect of liraglutide on anthropometric measurements, sagittal abdominal diameter and adiponectin levels in people with type 2 diabetes treated with multiple daily insulin injections: evaluations from a randomized trial (MDI-liraglutide study 5)
- 2019
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In: Obesity Science and Practice. - : Wiley. - 2055-2238. ; 5:2, s. 130-140
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Journal article (peer-reviewed)abstract
- Aim Use of the glucagon-like peptide 1 receptor agonist liraglutide has been shown to reduce weight. Different types of anthropometric measurements can be used to measure adiposity. This study evaluated the effect of liraglutide on sagittal abdominal diameter, waist circumference, waist-to-hip ratio and adiponectin levels in people with type 2 diabetes (T2D) treated with multiple daily insulin injections (MDI). Materials and methods In the multicentre, double-blind, placebo-controlled MDI-liraglutide trial, 124 individuals with T2D treated with MDI were randomized to either liraglutide or placebo. Basal values of weight, waist circumference, waist-to-hip ratio, sagittal abdominal diameter and adiponectin were compared with measurements at 12 and 24 weeks after randomization. Results Baseline-adjusted mean weight loss was 3.8 +/- 2.9 kg greater in liraglutide than placebo-treated individuals (p < 0.0001). Waist circumference was reduced by 2.9 +/- 4.3 cm and 0.2 +/- 3.6 cm in the liraglutide and placebo groups, respectively, after 24 weeks (baseline-adjusted mean difference: 2.6 +/- 4.0 cm, p = 0.0005). Corresponding reductions in sagittal abdominal diameter were 1.1 +/- 1.7 cm and 0.0 +/- 1.8 cm (baseline-adjusted mean difference: 1.1 +/- 1.7 cm, p = 0.0008). Hip circumference was reduced in patients randomized to liraglutide (baseline-adjusted mean difference between treatment groups: 2.8 +/- 3.8 cm, p = 0.0001), but there was no significant difference between the groups in either waist-to-hip ratio (baseline-adjusted mean difference: 0.0 +/- 0.04 cm, p = 0.51) or adiponectin levels (baseline-adjusted mean difference: 0.8 +/- 3.3 mg L-1, p = 0.17). Lower HbA1c and mean glucose levels measured by masked continuous glucose monitoring at baseline were associated with greater effects of liraglutide on reductions in waist circumference and sagittal abdominal diameter. Conclusions In patients with T2D, adding liraglutide to MDI may reduce abdominal and hip obesity to a similar extent, suggesting an effect on both visceral and subcutaneous fat. Liraglutide had greater effects on reducing abdominal obesity in patients with less pronounced long-term hyperglycaemia but did not affect adiponectin levels.
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| 9. |
- 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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| 10. |
- 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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| 11. |
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| 12. |
- Falhammar, H, et al.
(author)
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Fractures and Bone Mineral Density in Adult Women with 21-Hydroxylase Deficiency.
- 2007
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In: J Endocrinol Metab. - : The Endocrine Society. - 0021-972X .- 1945-7197.
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Journal article (peer-reviewed)abstract
- Context: Patients with classic congenital adrenal hyperplasia (CAH) receive lifelong, often supraphysiological, glucocorticoid therapy. Pharmacologic doses of glucocorticoids are an established risk factor for osteoporosis. Objectives: To evaluate bone mineral density (BMD), fracture prevalence and markers of bone metabolism in adult females with CAH. Design: This was a cross-sectional observational study. Setting: Tertiary care referral centers. Participants: We studied 61 women, aged 18-63 years, with genetically verified CAH due to 21-hydroxylase deficiency. They were patients with salt-wasting (n = 27), simple virilising (n = 28) and non-classic 21-hydroxylase deficiency (n = 6). Sixty-one age-matched women were controls. Main outcome measures: History of fractures was recorded. Total body, lumbar spine and femoral neck BMD were measured by dual-energy X-ray absorptiometry. The WHO criteria for osteopenia and osteoporosis were used. Serum marker of bone resorption, beta-C telopeptide (CTX) was studied. Results: The mean glucocorticoid dose in hydrocortisone equivalents was 16.9 +/- 0.9 mg/m(2). Patients had lower BMD than controls at all measured sites (P < 0.001). In patients < 30 years old 48% were osteopenic vs 12% in controls (P < 0.009). In patients >/= 30 years old 73% were osteopenic or osteoporotic vs 21% in controls (P < 0.001). BMD was similar in the two classic forms and had no obvious relationship to genotypes. CTX was decreased in older patients. More fractures were reported in patients than controls (P < 0.001). The number of vertebrae and wrist fractures almost reached significance (P = 0.058). Conclusion: Women with CAH have low BMD and increased fracture risk. BMD should be monitored, adequate prophylaxis and treatment instituted, and glucocorticoid doses optimized from puberty.
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| 13. |
- Filipsson, H. L., et al.
(author)
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Seasonal variability of stable carbon isotopes (delta C-13(DIC)) in the Skagerrak and the Baltic Sea: Distinguishing between mixing and biological productivity
- 2017
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In: Palaeogeography Palaeoclimatology Palaeoecology. - : Elsevier BV. - 0031-0182. ; 483, s. 15-30
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Journal article (peer-reviewed)abstract
- We documented the annual cycle of the carbon isotopic composition of dissolved inorganic carbon (delta C-13(DIC)) in the water columns of the Skagerrak and Baltic Sea to obtain an increased understanding of the processes involved controlling the carbon isotopic distribution in shelf seas. The lowest delta C-13(DIC) values (-4.9%.) were found in the low -oxygen, brackish Baltic bottom water whereas the highest values (+1.8%0 were observed in the surface water of the Skagerrak during late summer. Photosynthesis drove the high delta C-13(DIC) values (between 1.0 and 1.8%.) noted in the surface waters of both the Skagerrak and the Baltic. The delta C-13(DIC) values below the halocline in the Baltic reflect mixing of brackish water and the more saline water from the Skagerrak, and foremost organic matter remineralization processes that release significant amounts of low delta C-13 CO2. Similarly, in the stagnant fjord basins, little deep water exchange and the degradation of terrestrial and marine organic matter set the delta C-13 composition. Deep-water renewal in the fjord basins resulted in rapid increases of the delta C-13(DIC) on the order of 1 6., whereas remineralization processes caused a decrease in delta C-13(DIC) of 0.1-03%0 per month depending on location. The combined effects of water mixing and remineralization processes (estimated using apparent oxygen utilization (AOU) values) yielded the expression: delta C-13(DIC=) 0.032 * S = 0.01 * AOU = 0.12 for the Baltic Skagerrak region at water depths below the halocline. (C) 2016 Elsevier B.V. All rights reserved.
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| 14. |
- Fryk, Emanuel, et al.
(author)
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Microdialysis and proteomics of subcutaneous interstitial fluid reveals increased galectin-1 in type 2 diabetes patients
- 2016
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In: Metabolism-Clinical and Experimental. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 65:7, s. 998-1006
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Journal article (peer-reviewed)abstract
- Objective. To identify a potential therapeutic target for type 2 diabetes by comparing the subcutaneous interstitial fluid from type 2 diabetes patients and healthy men. Methods. Proteomics was performed on the interstitial fluid of subcutaneous adipose tissue obtained by microdialysis from 7 type 2 diabetes patients and 8 healthy participants. 851 proteins were detected, of which 36 (including galectin-1) showed significantly altered expression in type 2 diabetes. We also measured galectin-1 expression in: (1) adipocytes isolated from adipose tissue biopsies from these participants; (2) subcutaneous adipose tissue of 24 obese participants before, during and after 16 weeks on a very low calorie diet (VLCD); and (3) adipocytes isolated from 6 healthy young participants after 4 weeks on a diet and lifestyle intervention to promote weight gain. We also determined the effect of galectin-1 on glucose uptake in human adipose tissue. Results. Galectin-1 protein levels were elevated in subcutaneous dialysates from type 2 diabetes compared with healthy controls (p < 0.05). In agreement, galectin-1 mRNA expression was increased in adipocytes from the type 2 diabetes patients (p < 0.05). Furthermore, galectin-1 mRNA expression was decreased in adipose tissue after VLCD (p < 0.05) and increased by overfeeding (p < 0.05). Co-incubation of isolated human adipocytes with galectin-1 reduced glucose uptake (p < 0.05) but this was independent of the insulin signal. Conclusion. Proteomics of the interstitial fluid in subcutaneous adipose tissue in vivo identified a novel adipokine, galectin-1, with a potential role in the pathophysiology of type 2 diabetes. (C) 2016 Elsevier Inc. All rights reserved.
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| 15. |
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| 16. |
- Holmberg, M., et al.
(author)
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Treatment outcome 6-10 years after diagnosis of hyperthyroidism in 2916 patients : a longitudinal evaluation of a swedish incidence cohort
- 2018
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In: Thyroid. - : Mary Ann Liebert. - 1050-7256 .- 1557-9077. ; :S1
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Journal article (other academic/artistic)abstract
- Treatment of Graves’ disease (GD) and toxic nodular goiter (TNG) has the objectives to cure hyperthyroidism, prevent recurrent disease and preserve thyroid function. Treatment efficacies and long-termout comes of antithyroid drugs (ATD), radioactive iodine (RAI) or surgery varies in the literature. We report outcome of treatment, cure rate and risk factors for relapse for GD and TNG in an unselected cohort. A prospective incidence-cohort of de novo diagnosed GD and TNG patients (n = 2916) from 2003-05, were invited to a follow-up 6 - 10 years after diagnosis. Questionnaires were sent to 2430 patients regarding treatments, cure rate, recurrence, quality of life, demographic data, comorbidities and life-style factors. Patients were treated according to clinical routine with ATD, RAI or surgery. Of those included, 1186 (83.3%) had GD and 237 (16.7%) had TNG. In GD patients, 351 (45.3%), 264 (81.5%), and 52 (96.3%) were cured by ATD, RAI or surgery respectively as first line treatment. Of those, 77.0%, 15.4% and 3.8% respectively were without levothyr-oxine supplementation at follow-up at 8 – 0.9 years. Including all treatment modalities, 851 (71.8%) of GD patients were cured within one treatment period. At follow-up, 278 (23%) of GD patients had been operated. In TNG patients, RAI cured 88.6% and surgery 92.9%, whereof 52/154 (33.8%) and 3/15 (20%) had no levothyroxine supplementation post RAI and surgery, respectively.The proportion that did not feel fully recovered at follow-up was 25.3% of GD and 18.1% of the TNG patients. Overall, treatment of hyperthyroidism results in preserved thyroid function only in 35.3% and 44.7% of GD and TNG cases, respectively. As many as 23.4% of the GD patients end up with surgery although only 4.6% choose it from the beginning. Our treatment tradition cures 71.8% of GD patients and 78.1% of TNG patients within one treatment period. The high number of patients who do not feel recovered 6 -10 years after hyperthyroidism in GD and TNG is are minder of the chronic nature of hyperthyroidism.
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| 17. |
- 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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| 18. |
- Kotthoff, U., et al.
(author)
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Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)
- 2017
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In: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 14, s. 5607-5632
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Journal article (peer-reviewed)abstract
- Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past ∼ 8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until ∼ 7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish–marine conditions of the Littorina Sea stage (more saline and warmer) occurred within ∼ 200 years when the connection to the Kattegat became established after ∼ 7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg / Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from freshwater to marine conditions. Our study shows that particular caution has to be taken when applying and interpreting proxies in coastal environments and marginal seas, where water mass conditions can experience more rapid and larger changes than in open ocean settings. Approaches using a multitude of independent proxies may thus allow a more robust paleoenvironmental assessment.
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| 19. |
- 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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| 20. |
- 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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| 21. |
- 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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| 22. |
- 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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| 23. |
- 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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| 24. |
- Ning, W., et al.
(author)
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Anthropogenic and climatic impacts on a coastal environment in the Baltic Sea over the last 1000 years
- 2018
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In: Anthropocene. - : Elsevier. - 2213-3054. ; 21, s. 66-79
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Journal article (peer-reviewed)abstract
- Coastal environments have experienced large ecological changes as a result of human activities over the last 100−200 years. To understand the severity and potential consequences of such changes, paleoenvironmental records provide important contextual information. The Baltic Sea coastal zone is naturally a vulnerable system and subject to significant human-induced impacts. To put the recent environmental degradation in the Baltic coastal zone into a long-term perspective, and to assess the natural and anthropogenic drivers of environmental change, we present sedimentary records covering the last 1000 years obtained from a coastal inlet (Gåsfjärden) and a nearby lake (Lake Storsjön) in Sweden. We investigate the links between a pollen-based land cover reconstruction from Lake Storsjön and paleoenvironmental variables from Gåsfjärden itself, including diatom assemblages,organic carbon (C) and nitrogen (N) contents, stable C and N isotopic ratios, and biogenic silica contents. The Lake Storsjön record shows that regional land use was characterized by small-scale agricultural activity between 900 and 1400 CE, which slightly intensified between 1400 and 1800 CE. Substantial expansion of cropland was observed between 1800 and 1950 CE, before afforestation between 1950 and 2010 CE. From the Gåsfjärden record, prior to 1800 CE, relatively minor changes in the diatom and geochemical proxies were found. The onset of cultural eutrophication in Gåsfjärden can be traced to the 1800s and intensified land use is identified as the main driver. Anthropogenic activities in the 20th century have caused unprecedented ecosystem changes in the coastal inlet, as reflected in the diatom composition and geochemical proxies.
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| 25. |
- Nyström, Helena Filipsson, 1966, et al.
(author)
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Iodine status in the Nordic countries past and present
- 2016
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In: Food & Nutrition Research. - : SNF Swedish Nutrition Foundation. - 1654-6628 .- 1654-661X. ; 60
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Journal article (peer-reviewed)abstract
- Background: Adequate iodine nutrition is dependent on ground water content, seafood, and, as many countries use iodized cow fodder, dairy products. In most countries, salt fortification programs are needed to assure adequate iodine intake. Objectives: The objectives are threefold: 1) to describe the past and present iodine situation in the Nordic countries, 2) to identify important gaps of knowledge, and 3) to highlight differences among the Nordic countries' iodine biomonitoring and fortification policies. Design: Historical data are compared with the current situation. The Nordic countries' strategies to achieve recommended intake and urine iodine levels and their respective success rates are evaluated. Results: In the past, the iodine situation ranged from excellent in Iceland to widespread goiter and cretinism in large areas of Sweden. The situation was less severe in Norway and Finland. According to a 1960 World Health Organization (WHO) report, there were then no observations of iodine deficiency in Denmark. In Sweden and Finland, the fortification of table salt was introduced 5075 years ago, and in Norway and Finland, the fortification of cow fodder starting in the 1950s helped improve the population's iodine status due to the high intake of milk. In Denmark, iodine has been added to household salt and salt in bread for the past 15 years. The Nordic countries differ with regard to regulations and degree of governmental involvement. There are indications that pregnant and lactating women, the two most vulnerable groups, are mildly deficient in iodine in several of the Nordic countries. Conclusion: The Nordic countries employ different strategies to attain adequate iodine nutrition. The situation is not optimal and is in need of re-evaluation. Iodine researchers, Nordic national food administrations, and Nordic governmental institutions would benefit from collaboration to attain a broader approach and guarantee good iodine health for all. © 2016 Helena Filipsson Nyström et al.
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