Distribution of seabirds and waterbirds in the German Baltic Sea throughout the year

Die Verbreitungsmuster ausgewählter See- und Wasservogelarten in den Offshore-Bereichen der deutschen Ostsee werden erstmals für die vier Jahreszeiträume Frühjahr, Sommer, Herbst und Winter dargestellt. Dabei zeigen sich bei den einzelnen Arten sowohl räumliche als auf saisonale Verbreitungsunterschiede. Die deutschen Ostseewässer stellen für See- und Wasservögel ein wichtiges Rast-, Mauser- und Überwinterungsgebiet dar, einige Arten kommen in international bedeutsamen Konzentrationen vor. Für das im Mai 2004 an die EU-Kommission gemeldete Seevogelschutzgebiet „Östliche Pommersche Bucht“ im Ostteil der deutschen Ostsee werden erstmals aktuelle Bestandszahlen der wichtigsten Seevogelarten vorgestellt. Für im Untersuchungsgebiet nur selten auftretende Seevogelarten werden die Gesamtzahlen aller Nachweise aus den Schiffszählungen angegeben. Ziehende oder nur im Küstenbereich vorkommende Wasservogelarten werden lediglich namentlich aufgelistet. In Ergänzung zu früheren Publikationen liefert der vorliegende Artikel umfassende Informationen über das Vorkommen und die jahreszeitlichen Unterschiede der häufigen See- und Wasservogelarten im Offshore-Bereich der deutschen Ostsee.The German Baltic Sea is a very important area for seabirds and waterbirds. 38 species are regularly found in coastal or offshore waters. Many of them occur in international important concentrations and are subject to various conservation-related conventions and directives, especially the EU Birds Directive and the African-Eurasian Waterbird Agreement (AEWA). From 2000 to 2005, several research projects were dedicated to describe and analyse the distribution and abundance of seabirds in the offshore area in the German Baltic Sea at high spatial and temporal resolutions. In this study, we present for the first time the distribution of seabirds and waterbirds in the German Baltic Sea throughout the year, based on transect counts from ships. The main focus is on the offshore areas. For the most numerous species we present the distribution for the four seasons summer, autumn, winter and spring, defined species-specific. The maps clearly show spatial and temporal differences in the distribution of the various species. While Red-breasted Mergansers, Great Crested Grebes or Great Cormorants occur predominantely close to the coast, Red-necked Grebes, Slavonian Grebes and Common Guillemots, among others, prefer offshore-areas. The most numerous and characteristic species are the sea ducks Common Eider, Long-tailed Duck, Common Scoter and Velvet Scoter. They prefer areas with low water depth along the coast or on shallow banks in the offshore area. While Common Eiders occur chiefly in the western parts of the German Baltic Sea, Velvet Scoters are mainly found in the eastern parts. Both species have high densities in the winter half-year but only small numbers during summer. Long-tail Ducks and Common Scoters are distributed over large areas of the German Baltic Sea, but while the former species occurs in the winter half-year only, the latter species is present throughout the whole year. Gulls are widespread throughout the study area and show only local and/or short-term concentrations. Aggregations are often in the vicinity of high fishing activities. The most frequent gull species is the Herring Gull. Terns occur only in very small numbers in the German Baltic Sea, with Black Terns exhibiting small concentrations in the eastern part during late summer. Species that occur predominantly in coastal areas of the German Baltic Sea are not presented in detail. However, for Mute Swan, Greater Scaup, Common Goldeneye and Goosander we present maps for the winter half-year (October-April), as the nearshore distribution of these species sometimes extent into offshore areas. For species occuring only seldom within the study area we present a list with the total number of individuals seen during the surveys. Coastal or migrating waterbird species are only named. Together with previously published information on the distribution of seabirds and waterbirds in the German Baltic Sea, available mainly for the winter and spring periods, this study gives a comprehensive overview about the spatial and temporal distribution of the most numerous and widespread seabirds and waterbirds in the German Baltic Sea. In addition, current population estimates of these species are given for the recently designated Special Protection Area “Pommersche Bucht” in the Exclusive Economic Zone (EEZ) of the eastern part of the German Baltic Sea

Stress and Protists: No life without stress

We report a summary of the symposium “Stress and Protists: No life without stress”, which was held in September 2015 on the VII European Congress of Protistology in partnership with the International Society of Protistologists (Seville, Spain). We present an overview on general comments and concepts on cellular stress which can be also applied to any protist. Generally, various environmental stressors may induce similar cell responses in very different protists. Two main topics are reported in this manuscript: (i) metallic nanoparticles as environmental pollutants and stressors for aquatic protists, and (ii) ultraviolet radiation – induced stress and photoprotective strategies in ciliates. Model protists such as Chlamydomonas reinhardtii and Tetrahymena thermophila were used to assess stress caused by nanoparticles while stress caused by ultraviolet radiation was tested with free living planktonic ciliates as well as with the symbiont-bearing model ciliate Paramecium bursaria. For future studies, we suggest more intensive analyses on protist stress responses to specific environmental abiotic and/or biotic stressors at molecular and genetic levels up to ecological consequences and food web dynamics

Modulation of microbial predator-prey dynamics by phosphorus availability: Growth patterns and survival strategies of bacterial phylogenetic clades

We simultaneously studied the impact of top-down (protistan grazing) and bottom-up (phosphorus availability) factors on the numbers and biomasses of bacteria from various phylogenetic lineages, and on their growth and activity parameters in the oligo-mesotrophic Piburger See, Austria. Enhanced grazing resulted in decreased proportions of bacteria with high nucleic acid content (high-NA bacteria) and lower detection rates by FISH. There was a change in the composition of the bacterial assemblage, whereby Betaproteobacteria were heavily grazed while Alphaproteobacteria and Cytophaga—Flavobacterium—Bacteroides were less affected by predators. Changes in bacterial assemblage composition were also apparent in the treatments enriched with phosphorus, and even more pronounced in the incubations in dialysis tubes (allowing relatively free nutrient exchange). Here, Betaproteobacteria became dominant and appeared to act as successful opportunistic competitors for nutrients. In contrast, Actinobacteria did not respond to surplus phosphorus by population growth, and, moreover, maintained their small size, which resulted in a very low biomass contribution. In addition, significant relationships between high-NA bacteria and several bacterial phylogenetic clades were found, indicating an enhanced activity status. By combining several single-cell methods, new insight is gained into the competitive abilities of freshwater bacteria from a variety of phylogenetic lineages under contrasting sets of bottom-up and top-down constraint

Modulation of microbial predator-prey dynamics by phosphorus availability: Growth patterns and survival strategies of bacterial phylogenetic clades

We simultaneously studied the impact of top-down (protistan grazing) and bottom-up (phosphorus availability) factors on the numbers and biomasses of bacteria from various phylogenetic lineages, and on their growth and activity parameters in the oligo-mesotrophic Piburger See, Austria. Enhanced grazing resulted in decreased proportions of bacteria with high nucleic acid content (high-NA bacteria) and lower detection rates by FISH. There was a change in the composition of the bacterial assemblage, whereby Betaproteobacteria were heavily grazed while Alphaproteobacteria and Cytophaga—Flavobacterium—Bacteroides were less affected by predators. Changes in bacterial assemblage composition were also apparent in the treatments enriched with phosphorus, and even more pronounced in the incubations in dialysis tubes (allowing relatively free nutrient exchange). Here, Betaproteobacteria became dominant and appeared to act as successful opportunistic competitors for nutrients. In contrast, Actinobacteria did not respond to surplus phosphorus by population growth, and, moreover, maintained their small size, which resulted in a very low biomass contribution. In addition, significant relationships between high-NA bacteria and several bacterial phylogenetic clades were found, indicating an enhanced activity status. By combining several single-cell methods, new insight is gained into the competitive abilities of freshwater bacteria from a variety of phylogenetic lineages under contrasting sets of bottom-up and top-down constraint

Seasonality of Planktonic Freshwater Ciliates: Are Analyses Based on V9 Regions of the 18S rRNA Gene Correlated With Morphospecies Counts?

Ciliates represent central nodes in freshwater planktonic food webs, and many species show pronounced seasonality, with short-lived maxima of a few dominant taxa while many being rare or ephemeral. These observations are primarily based on morphospecies counting methods, which, however, have limitations concerning the amount and volume of samples that can be processed. For high sampling frequencies at large scales, high throughput sequencing (HTS) of freshwater ciliates seems to be a promising tool. However, several studies reported large discrepancy between species abundance determinations by molecular compared to morphological means. Therefore, we compared ciliate DNA metabarcodes (V9 regions of the 18S rRNA gene) with morphospecies counts for a 3-year study (Lake Zurich, Switzerland; biweekly sampling, n = 74). In addition, we isolated, cultivated and sequenced the 18S rRNA gene of twelve selected ciliate species that served as seeds for HTS analyses. This workflow allowed for a detailed comparison of V9 data with microscopic analyses by quantitative protargol staining (QPS). The dynamics of V9 read abundances over the seasonal cycle corroborated well with morphospecies population patterns. Annual successions of rare and ephemeral species were more adequately characterized by V9 reads than by QPS. However, numbers of species specific sequence reads only partly reflected rank orders seen by counts. In contrast, biomass-based assemblage compositions showed higher similarity to V9 read numbers, probably indicating a relation between cell sizes and numbers / sizes of macronuclei (or 18S rRNA operons). Full-length 18S rRNA sequences of ciliates assigned to certain morphospecies are urgently needed for barcoding approaches as planktonic taxa are still poorly represented in public databases and the interpretation of HTS data depends on profound reference sequences. Through linking operational taxonomic units (OTUs) with known morphospecies, we can use the deep knowledge about the autecology of these species

Sources of mycosporine-like amino acids in planktonic Chlorella-bearing ciliates (Ciliophora)

Mycosporine-like amino acids (MAAs) are a family of secondary metabolites known to protect organisms exposed to solar UV radiation. We tested their distribution among several planktonic ciliates bearing Chlorella isolated from an oligo-mesotrophic lake in Tyrol, Austria. In order to test the origin of these compounds, the MAAs were assessed by high performance liquid chromatography in both the ciliates and their symbiotic algae.Considering all Chlorella-bearing ciliates, we found: (i) seven different MAAs (mycosporine-glycine, palythine, asterina-330, shinorine, porphyra-334, usujirene, palythene); (ii) one to several MAAs per species and (iii) qualitative and quantitative seasonal changes in the MAAs (e.g. in Pelagodileptus trachelioides). In all species tested, concentrations of MAAs were always <1% of ciliate dry weight.Several MAAs were also identified in the Chlorella isolated from the ciliates, thus providing initial evidence for their symbiotic origin. In Uroleptus sp., however, we found evidence for a dietary source of MAAs.Our results suggest that accumulation of MAAs in Chlorella-bearing ciliates represents an additional benefit of this symbiosis and an adaptation for survival in sunlit, UV-exposed waters

ARTEFACTS: How do we want to deal with the future of our one and only planet?

The European Commission’s Science and Knowledge Service, the Joint Research Centre (JRC), decided to try working hand-in-hand with leading European science centres and museums. Behind this decision was the idea that the JRC could better support EU Institutions in engaging with the European public. The fact that European Union policies are firmly based on scientific evidence is a strong message which the JRC is uniquely able to illustrate. Such a collaboration would not only provide a platform to explain the benefits of EU policies to our daily lives but also provide an opportunity for European citizens to engage by taking a more active part in the EU policy making process for the future. A PILOT PROGRAMME To test the idea, the JRC launched an experimental programme to work with science museums: a perfect partner for three compelling reasons. Firstly, they attract a large and growing number of visitors. Leading science museums in Europe have typically 500 000 visitors per year. Furthermore, they are based in large European cities and attract local visitors as well as tourists from across Europe and beyond. The second reason for working with museums is that they have mastered the art of how to communicate key elements of sophisticated arguments across to the public and making complex topics of public interest readily accessible. That is a high-value added skill and a crucial part of the valorisation of public-funded research, never to be underestimated. Finally museums are, at present, undergoing something of a renaissance. Museums today are vibrant environments offering new techniques and technologies to both inform and entertain, and attract visitors of all demographics.JRC.H.2-Knowledge Management Methodologies, Communities and Disseminatio

Effectiveness of Photoprotective Strategies in Three Mixotrophic Planktonic Ciliate Species

Mixotrophic ciliate assemblages often prevail in summer in the surface layers of lakes. During this time, they are potentially exposed to damaging levels of incident solar ultraviolet radiation (UVR) and need efficient photoprotective mechanisms to minimize the damage. Herein, we tested the algal-bearing species of Pelagodileptus trachelioides, Stokesia vernalis, and Vorticella chlorellata for how they handled stress under exposure to the artificial sunlight spectrum (i.e., UV treatment), just photosynthetically active radiation (PAR), or in the dark (i.e., control). In addition to measurements of their survival, changes in behavior, shape, and whether dark or photoenzymatic repair (PER) mechanisms are present, we measured the concentration of UV-absorbing compounds (i.e., mycosporine-like amino acids). In contrast to the response in the PAR and dark treatments, sublethal effects were observed in all species when exposed to UVR. A wavelength-specific test for P. trachelioides revealed that UV-B was especially lethal. These results suggest that the photoprotective mechanisms found in these ciliates are not sufficient to allow for their survival directly at the surface and that, accordingly, they need to shift their position further down in the water column

Factors involved in the distribution pattern of ciliates in the water column of a transparent alpine lake

International audienceThe recurrent depth preference of three ciliate species (two prostomatids and one haptorid) in a transparent alpine lake indicates the existence of niche partitioning among them involving potential factors such as avoidance of high UVR levels and zooplankton predation, as well as competition for food resources