Comparison between modern polar and temperate skeletal carbonate mineralogy and oxygen and carbon isotopes, Antarctic and Tasmanian shelves

Modern bryozoan skeletal mineralogy varies with seawater temperature: polar Antarctic bryozoans are mainly low-Mg calcite, whereas temperate Tasmanian bryozoans are predominantly high-Mg calcite with variable amounts of aragonite. Bivalve molluscs from both polar and temperate regions are mainly aragonite with variable amounts of low-Mg calcite. The o180 and o13C isotope fields of polar skeletons are clearly separated from the temperate fields, due to differences in seawater temperatures, levels of o13C in seawater and the circulation of seawater masses. 0180 values of bryozoa, benthic foraminifera and bivalve molluscs give near-equilibrium seawater temperatures. Small differences in 0180 and o13C values between skeletons are due to their variable growth rates. Meltwater effects are small (7%) in the polar Antarctic Sea and high (<25%) in the shallow Arctic Sea because ice sheets do not melt in the Antarctic region, whereas significant melting of ice sheets occurs in summer in the Arctic regions. Skeletal carbonate mineralogy and 0180 and o13C variations can be used in the recognition of ancient, non-tropical carbonate skeletons and carbonate rocks

Structure of bryozoan communities in an Antarctic glacial fjord (Admiralty Bay, South Shetlands)

Bryozoans are among the most important groups of the Southern Ocean benthic macrofauna, both in terms of species richness and abundance. However, there is a considerable lack of ecological research focused on their distribution patterns and species richness on smaller scale, especially in the soft bottom habitats of Antarctic glacial fjords. The aim of this study was to describe those patterns in the Admiralty Bay. Forty-nine Van Veen grab samples were collected at the depth range from 15 to 265 m, in the summer season of 1979/1980, at three sites distributed along the main axis of the fjord. Among 53 identified species of bryozoans, 32 were recorded in the Admiralty Bay for the first time. The most common and abundant species were Himantozoum antarcticum, Inversiula nutrix and Nematoflustra flagellata. Genera such as Arachnopusia, Cellarinella and Osthimosia were the most speciose taxa. It was demonstrated that depth was important for the distribution of the bryozoans. More than half of the recorded species were found only below 70 m. An influence of glacial disturbance was reflected in the dominance structure of colony growth-forms. The inner region of the fjord was dominated almost entirely by encrusting species, while the diversity of bryozoan growth-forms in less disturbed areas was much higher. In those sites the highest percentage of branched, tuft like species represented by buguliform and flustriform zoaria was observed.The study was supported by a grant of Polish Ministry of Science and Higher Education No. 51/N-IPY/2007/0 as well as Census of Antarctic Marine Life Project. Krzysztof Pabis was also partially supported by University of Lodz internal funds. This research was also supported by the Polish Geological Institute-National Research Institute during the realization of the project numbered 40.2900.0903.18.0 titled “Bryozoan assemblage of Admiralty Bay—richness, diversity and abundance.” Urszula Hara is deeply grateful to Leszek Giro (Micro-area Analyses Laboratory at the Polish Geological Institute-National Research Institute, Warsaw), for providing SEM assistance during the project. We also want to thank two anonymous reviewers for their suggestions that helped us improve this article. Thanks are also due to Magdalena Błażewicz-Paszkowycz for language correction and polishing the final version of the manuscript

Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2016 : a systematic analysis for the Global Burden of Disease Study 2016

Background The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of risk factor exposure and attributable burden of disease. By providing estimates over a long time series, this study can monitor risk exposure trends critical to health surveillance and inform policy debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2016. This study included 481 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk (RR) and exposure estimates from 22 717 randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources, according to the GBD 2016 source counting methods. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. Finally, we explored four drivers of trends in attributable burden: population growth, population ageing, trends in risk exposure, and all other factors combined. Findings Since 1990, exposure increased significantly for 30 risks, did not change significantly for four risks, and decreased significantly for 31 risks. Among risks that are leading causes of burden of disease, child growth failure and household air pollution showed the most significant declines, while metabolic risks, such as body-mass index and high fasting plasma glucose, showed significant increases. In 2016, at Level 3 of the hierarchy, the three leading risk factors in terms of attributable DALYs at the global level for men were smoking (124.1 million DALYs [95% UI 111.2 million to 137.0 million]), high systolic blood pressure (122.2 million DALYs [110.3 million to 133.3 million], and low birthweight and short gestation (83.0 million DALYs [78.3 million to 87.7 million]), and for women, were high systolic blood pressure (89.9 million DALYs [80.9 million to 98.2 million]), high body-mass index (64.8 million DALYs [44.4 million to 87.6 million]), and high fasting plasma glucose (63.8 million DALYs [53.2 million to 76.3 million]). In 2016 in 113 countries, the leading risk factor in terms of attributable DALYs was a metabolic risk factor. Smoking remained among the leading five risk factors for DALYs for 109 countries, while low birthweight and short gestation was the leading risk factor for DALYs in 38 countries, particularly in sub-Saharan Africa and South Asia. In terms of important drivers of change in trends of burden attributable to risk factors, between 2006 and 2016 exposure to risks explains an 9.3% (6.9-11.6) decline in deaths and a 10.8% (8.3-13.1) decrease in DALYs at the global level, while population ageing accounts for 14.9% (12.7-17.5) of deaths and 6.2% (3.9-8.7) of DALYs, and population growth for 12.4% (10.1-14.9) of deaths and 12.4% (10.1-14.9) of DALYs. The largest contribution of trends in risk exposure to disease burden is seen between ages 1 year and 4 years, where a decline of 27.3% (24.9-29.7) of the change in DALYs between 2006 and 2016 can be attributed to declines in exposure to risks. Interpretation Increasingly detailed understanding of the trends in risk exposure and the RRs for each risk-outcome pair provide insights into both the magnitude of health loss attributable to risks and how modification of risk exposure has contributed to health trends. Metabolic risks warrant particular policy attention, due to their large contribution to global disease burden, increasing trends, and variable patterns across countries at the same level of development. GBD 2016 findings show that, while it has huge potential to improve health, risk modification has played a relatively small part in the past decade. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

Patterns of magnesium content in Arctic bryozoan skeletons along a depth gradient

A growing body of evidence suggests that ocean acidification acting synergistically with ocean warming alters carbonate biomineralization in a variety of marine biota. Magnesium often substitutes for Ca in the calcite skeletons of marine invertebrates, increasing their solubility. The spatio-environmental distribution of Mg in marine invertebrates has seldom been studied, despite its importance for assessing vulnerabilities to ocean acidification. Because pH decreases with water depth, it is predicted that levels of Mg in calcite skeletons should also decrease to counteract dissolution. Such a pattern has been suggested by evidence from echinoderms. Data on magnesium content and depth in Arctic bryozoans (52 species, 103 individuals, 150 samples) are here used to test this prediction, aided by comparison with six conceptual models explaining all possible scenarios. Analyses were based on a uniform dataset spanning more than 200 m of coastal water depth. No significant relationship was found between depth and Mg content; indeed, the highest Mg content among the analyzed taxa (8.7 % mol MgCO3) was recorded from the deepest settings (>200 m). Our findings contrast with previously published results from echinoderms in which Mg was found to decrease with depth. The bryozoan results suggest that ocean acidification may have less impact on the studied bryozoans than is generally assumed. In the broad context, our study exemplifies quantitative testing of spatial patterns of skeletal geochemistry for predicting the biological effects of environmental change in the oceans.© The Author(s) 2012. Open Access. This article is distributed under the terms of the Creative Commons Attribution 2.0 International License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The file attached is the Published/publisher’s pdf version of the article