Abstract: Moe, B., Hanssen, S. A., Ytrehus, B., Balk, L., Chastel, O., Christensen-Dalsgaard, S., Gustavsson, H. & Langset, M. 2020.Thiamine deficiency and seabirds in Norway. A pilot study. NINA Report 1720. Norwegian Institute for Nature Research. Thiamine (vitamin B1) is vital for life-sustaining enzymes in cells. Previous studies have reported episodes of thiamine deficiency in marine ecosystems, and suggested that this have contributed to population declines of seabirds breeding in the Baltic Sea and elsewhere. Many Norwegian seabird populations have shown a strong decline in population size, but thiamine status has never been assessed. The objective of this pilot study was, thus, to document thiamin levels in selected species and their associated food webs, and explore methodological issues relevant for future studies or monitoring. The methodological tests showed that storage freezing temperature did not affect thiamine levels in egg yolk samples, and that thiamine levels in eggs could not be corrected for incubation time. Furthermore, the quantified thiamine levels differed between two laboratories, and we developed a predictive equation to convert thiamine levels in egg yolk samples between the laboratories. This pilot study has, for the first time, investigated thiamine levels in seabird eggs from selected species and populations in Norway mainland and Svalbard, and in their food webs. We revealed variation among species, populations and prey types. The lowest levels were found in eggs from common eiders and in blue mussel which is their prey. Eggs from herring gulls had also relatively low levels. The levels for common eiders and herring gulls were higher than previously reported from the Baltic Sea. Nevertheless, the levels from common eiders, herring gulls and blue mussels should be classified as thiamine deficient according to effect-ranges reported in these previous studies. The highest levels were found in eggs from kittiwakes and Atlantic puffins. The diet samples from kittiwakes and Atlantic puffins had higher thiamine levels compared to blue mussels. This is the first time thiamine levels are reported for kittiwakes and Atlantic puffins. This pilot-study cannot answer whether Norwegian seabird population sizes are affected by thiamine levels, but we cannot rule out that thiamine can be a limiting factor for some Norwegian seabird populations. This report identifies knowledge gaps and provides recommendations for future studies and monitoring. We suggest more sampling of levels to better understand variation among years, areas, species and populations, and also clinical examinations and surveys. Studies investigating potential effects on reproduction and survival is ultimately need to better understand potential effects on population dynamics.

Abstract: Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth–ocean–atmosphere dynamic exchange of elements. The ratios’ dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previous data, to test the assumption of limited seawater Mg:Ca and Sr:Ca variability across marine environments globally. High variability was found in open-ocean upwelling and polar regions, shelves/neritic and river-influenced areas, where seawater Mg:Ca and Sr:Ca ratios range from ∼4.40 to 6.40 mmol:mol and ∼6.95 to 9.80 mmol:mol, respectively. Open-ocean seawater Mg:Ca is semiconservative (∼4.90 to 5.30 mol:mol), while Sr:Ca is more variable and nonconservative (∼7.70 to 8.80 mmol:mol); both ratios are nonconservative in coastal seas. Further, the Ca, Mg, and Sr elemental fluxes are connected to large total alkalinity deviations from International Association for the Physical Sciences of the Oceans (IAPSO) standard values. Because there is significant modern seawater Mg:Ca and Sr:Ca ratios variability across marine environments we cannot absolutely assume that fossil archives using taxa-specific proxies reflect true global seawater chemistry but rather taxa- and process-specific ecosystem variations, reflecting regional conditions. This variability could reconcile secular seawater Mg:Ca and Sr:Ca ratio reconstructions using different taxa and techniques by assuming an error of 1 to 1.50 mol:mol, and 1 to 1.90 mmol:mol, respectively. The modern ratios’ variability is similar to the reconstructed rise over 20 Ma (Neogene Period), nurturing the question of seminonconservative behavior of Ca, Mg, and Sr over modern Earth geological history with an overlooked environmental effect.

Abstract: Dome C in Antarctica provides exceptional conditions for photometry thanks to the continuous night during the Antarctic winter, a high clear sky fraction, low wind speeds, and a cold and dry atmosphere. The ASTEP project (Antarctic Search for Transiting ExoPlanets) aims at detecting and characterising transiting exoplanets and qualifying this site for photometry in the visible. The main instrument, a 40 cm telescope, has been designed to perform high precision photometry under the extreme conditions of the Antarctic winter and has operated at the Concordia station since 2010. It will be upgraded with two new cameras and a new camera box in order to provide simultaneous two-colour photometry and substantially increase its throughput. The new setup will be operational for the winter campaign 2021 and will allow us to discover transiting exoplanets orbiting bright stars in particular low mass exoplanets, temperate exoplanets, exoplanets around young stars, and to refine the ephemerides of exoplanets discovered by the TESS mission. These observations will provide targets for first characterisation with the CHEOPS mission and atmospheric studies with the JWST and ARIEL missions. In this talk, I will describe the science goals and the upgrade of the ASTEP telescope.