Geolocator study reveals east African migration route of Central European Common Terns

Background: The majority of European Common Terns(Sterna hirundo) migrate south along the western coast of Europe and Africa, while birds from eastern regions are known to cross the Mediterranean Sea from east to west or migrate along the eastern African coast. The migration route of north European terns wintering along the coast of western Africa was already described using geolocator data, while knowledge about movements of the European inland populations is based only on relatively scarce recoveries of ringed birds.Methods: We used light-level geolocators in inland Common Tern colonies in Hungary and Croatia to study their migration route and to identify wintering areas along with stopover sites. Results revealed by geolocators were compared with recoveries of ringed birds.Results: All tracked birds used the east African migration route with autumn stopovers at Lower Nile and in the southern part of the Red Sea, and short spring stopover in Israel. Terns wintered along Kenyan coasts and in the southern Mozambique Channel. Autumn migration lasted four times longer than spring migration.Conclusions: This is the first geolocator study that describes the east African migration route of the Common Tern. Important stopover sites were identified. More studies of inland populations are needed to better elucidate tern winter movements.

Effect of seasonal barrier layer on mixed-layer heat budget in the Bay of Bengal

Time series measurements (2010–2017) from the Research Moored Array for African–Asian–Australian Monsoon Analysis and Prediction (RAMA) moorings at 15°N,90°E and 12°N,90°E are used to investigate the effect of the seasonal barrier layer (BL) on the mixed-layer heat budget in the Bay of Bengal (BoB).The mixed-layer temperature tendency (?T/?t) is primarily controlled by the net surface heat flux that remains in the mixed layer(Q’) from March to October,while both Q’and the vertical heat flux at the base of the mixed layer (Q_(h)),estimated as the residual of the mixed-layer heat budget,dominate during winter (November–February).An inverse relation is observed between the BL thickness and the mixed-layer temperature (MLT).Based on the estimations at the moorings,it is suggested that when the BL thickness is≥25 m,it exerts a considerable influence on ?T/?t through the modulation of Q_(h) (warming) in the BoB.The cooling associated with Q_(h) is strongest when the BL thickness is≤10 m with the MLT exceeding 29°C,while the contribution from Q_(h) remains nearly zero when the BL thickness varies between 10 m and 25 m.Temperature inversion is evident in the BoB during winter when the BL thickness remains≥25 m with an average MLT<28.5°C.Furthermore,Q_(h) follows the seasonal cycle of the BL at these RAMA mooring locations,with r>0.72 at the 95%significance level.

Screening potential genotoxic effect of aquatic plant extracts using the mussel micronucleus test

Objective:To assess the genotoxic potential of selected aquatic macrophytes:Ceratophyllum demersum L.(hornwort,family Ceratophyllaceae),Typha angustifolia L.(narrowleaf cattail,family Typhaceae),Stratiotes aloides L.(water soldier,family Butomaceae),and Oenanthe aquatica(L.)Poir.(water dropwort,family Umbelliferae).Methods:For genotoxicity assessment,the mussel micronucleus test was applied.Micronucleus frequency was determined from the haemolymph of Unio pictorum L.(painter’s mussel).In parallel,total and hydrolisable tannin contents were determined.Results:All plant extracts elucidated significant mutagenic effect.Significant correlation was determined between tannin content and mutagenic capacity.Conclusions:The significant correlation between genotoxicity as expressed by micronucleus frequency and tannin content(both total and hydrolisable tannins)indicate that tannin is amongst the main compounds being responsible for the genotoxic potential.It might be suggested that genotoxic capacity of these plants elucidate a real ecological effect in the ecosystem.

River Water Quality Assessment in Selected Yangtze Tributaries: Background and Method Development

Water pollution is among the most severe environmental problems in China, particularly in the vicinity of residential and urban areas. In almost all Asian countries, river monitoring is predominantly based on the analysis of chemical data. However, biological data are a worthwhile addition for the determination of the long-term ecological status of rivers and are particularly well-suited in case of steep pollution and disturbance gradients. A tool for river water quality assessment using benthic invertebrates has been developed for selected tributaries of the middle reach of the Yangtze River. Site selection was supported by a preclassification considering physico-chemical and hydromorphological conditions. Following a stratified sampling design, 34 samples were taken in small and large streams in the subtropical mountainous area of western Hubei （湖北） （China） covering a pollution gradient, accompanied by an extensive field protocol on stream characteristics and （physico-） chemical water analyses. The proposed assessment system is computed as an average score per taxon. The challenge to further consider the additional impact from global change into the development of such tools is discussed.

A novel Methylomirabilota methanotroph potentially couples methane oxidation to iodate reduction

Impact statement Methane oxidizing microbes play a key role in reducing the emission of this potent greenhouse gas to the atmosphere.The known versatility of the recently discovered anaerobic Methylomirabilota methanotrophs is limited.Here,we report a novel uncultured Methylomirabilis species,Candidatus Methylomirabilis iodofontis,with the genetic potential of iodate respiration from biofilm in iodine‐rich cavern spring water.Star‐like cells resembling Methylomirabilis oxyfera were directly observed from the biofilm and a high‐quality metagenome‐assembled genome(MAG)of Ca.M.iodofontis was assembled.In addition to oxygenic denitrification and aerobic methane oxidation pathways,the M.iodofontis MAG also indicated its iodate‐reducing potential,a capability that would enable the bacterium to use iodate other than nitrite as an electron acceptor,a hitherto unrecognized metabolic potential of Methylomirabilota methanotrophs.The results advance the current understanding of the ecophysiology of anaerobic Methylomirabilota methanotrophs and may suggest an additional methane sink,especially in iodate‐rich ecosystems.