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: Polar Stratospheric Clouds (PSCs) play a primary role in polar stratospheric ozone depletion processes. Aside from recent improvements in both spaceborne monitoring as well as investigations on microphysics and modeling, there are still caveats on building a comprehensive picture of the PSC particle population, especially considering the fine optical signatures of some particles. In that regard, groundbased instruments provide fine and long term reference measurements that complement the global spaceborne coverage. Operated at the French antarctic station Dumont d’Urville (DDU) in the frame of the international Network for the Detection of Atmospheric Composition Change (NDACC), the Rayleigh/Mie/Raman lidar provides over the years a solid dataset to feed both process and classification studies, by monitoring cloud and aerosol occurrences in the upper troposphere and lower stratosphere. Located on antarctic shore (66°S – 140°E), the station has a privileged access to polar vortex dynamics. Measurements are weather-dependent with a yearly average of 130 nights of monitoring. Expected PSC formation temperatures are used to evaluate the whole PSC season occurrence statistics. We hereby present a consolidated dataset from 10 years of lidar measurements using the 532nm backscatter ratio, the aerosol depolarisation and local atmospheric conditions to help in building an aerosol/cloud classification. Overall, the DDU PSC pattern is very consistent with expected typical temperature controlled thresholds. Supercooled Ternary Solution (STS) particles are the most observed particle type, closely followed by Nitric Acid Trihydrate (NAT). ICE clouds are more rarely observed. The measurements also feature significant and detailed signatures of various aerosols events having reached the polar antarctic stratosphere, like the Calbuco eruption (2015) or the 2 australian wildfires episodes (2009 and 2019). We aim at refining the identification of those aerosols to include their impact in the scope of the scientific questions studied at DDU.

Abstract: The major histocompatibility complex (MHC) plays a crucial role in the resistance to parasites in vertebrates and is thus often suggested to be an important force driving social interactions, including mating preference. However, the phenotypic cues used by individuals to assess the MHC characteristics of conspecifics are generally unknown. Here, we used behavioral tests to investigate whether, in black-legged kittiwakes, females use odor cues to distinguish male MHC-II diversity and MHC-II dissimilarity. We found that females took less time to peck at an odor sample coming from a male with high or low MHC-II diversity compared to intermediate MHC-II diversity. However, this result is due to the single individual who has only one MHC-II allele. When excluding this individual, females took less time to peck at an odor sample coming from a male with high MHC-II diversity. In addition, when the odor sample came from a male with higher MHC-II dissimilarity, females took less time to peck at the sample, but once they pecked at it, they delayed the use of the sample. Altogether, our results add evidence for olfactory recognition of MHC characteristics in birds, but further studies are needed to determine whether kittiwakes use this ability to optimize fitness.