Meeresalgen von Helgoland: Ergänzung

Complementary to a previous publication (Kornmann & Sahling, 1977), this investigation deals mainly with microscopic algae occurring in the rocky littoral of Helgoland island (North Sea). Based on the results obtained from cultivation experiments, the heterogeneousUlvella-complex of Dangeard has been rearranged and partly included in a new genusStromatella, andPlanophila respectively. The life history ofChlorocystis cohnii proved to be heteromorphic, the zygotes developing into a Codiolum-sporophyte. Also inHalochlorococcum marinum, some of the biflagellate swarmers give rise to Codiolum-like cells.Chlorocystis andHalochlorococcum, up to now members of the Chlorococcales, are incorporated into the new Codiolophycean order, Chlorocystidales. Three newHalochlorococcum species are described, the epiphytic“Chlorochytrium” moorei also being combined with this genus. Supplementary observations on some crustose red algae from transparent substrates are included in this study, as well as findings of some species not previously reported for the Helgoland area.     

Kreuzungsexperimente anLaminaria saccharina von Helgoland und von der Isle of Man

The brown algaLaminaria saccharina growing at Helgoland (North Sea) has smooth blades, whereas the blades of the same species occurring at the Isle of Man are covered with deep bullations. Gametophytes of both morphological types were grown in the laboratory and the resulting sporophytes of each type as well as hybrids were planted out in the sublittoral zone of Helgoland for four months. The Isle of Man type and the hybrids both formed bullations. The Isle of Man type differed further from the Helgoland type in that it had broader blades and did not tolerate the water temperatures above 14° C which prevail near Helgoland in summer. All experimental plants were removed from the sea before the blades became sporogenous.     

Genetic variability of milk fatty acids

The milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. The natural sources of variation, such as feeding or genetics, could be used to increase the concentrations of unsaturated fatty acids. The impact of feeding is well described. However, genetic effects on the milk FA composition begin to be extensively studied. This paper summarizes the available information about the genetic variability of FAs. The greatest breed differences in FA composition are observed between Holstein and Jersey milk. Milk fat of the latter breed contains higher concentrations of saturated FAs, especially short-chain FAs. The variation of the delta-9 desaturase activity estimated from specific FA ratios could explain partly these breed differences. The choice of a specific breed seems to be a possibility to improve the nutritional quality of milk fat. Generally, the proportions of FAs in milk are more heritable than the proportions of these same FAs in fat. Heritability estimates range from 0.00 to 0.54. The presence of some single nucleotide polymorphisms could explain partly the observed individual genetic variability. The polymorphisms detected onSCD1 andDGAT1 genes influence the milk FA composition. TheSCD1 V allele increases the unsaturation of C16 and C18. TheDGAT1 A allele is related to the unsaturation of C18. So, a combination of the molecular and quantitative approaches should be used to develop tools helping farmers in the selection of their animals to improve the nutritional quality of the produced milk fat.     

The recent arrival of the oceanic isopodIdotea metallica Bosc off Helgoland (German Bight, North Sea): an indication of a warming trend in the North Sea?

In 1988 a long-term study was started of the isopod fauna associated with surface drift material off Helgoland (German Bight, North Sea). In the summer of 1994 specimens ofIdotea metallica Bosc were recorded for the first time. There is no evidence that this species has ever been present in the German Bight before. The samples contained males, both gravid and non-gravid females, and juveniles, indicating that the species reproduced successfully in the Helgoland region. Interbreeding of specimens from Helgoland and the western Mediterranean produced fertile off-spring. As a neustonic species,I. metallica shows a high natural capacity for dispersal. It thus seems unlikely that the arrival of the species in the North Sea resulted from an accidental introduction by man. We are probably witnessing an extension of the species’ geographical range by natural means of dispersal, as a response to recent changes in the ecological conditions of the German Bight. Temperature data measured by the Biologische Anstalt Helgoland since 1962 show that the last decade (except 1996) was characterized by unusually mild winters. Following the severe winter of 1996,I. metallica was again absent from the Helgoland region. After the subsequent mild winters (1997 and 1998), however, the species reappeared in the summer of 1998 with higher numbers than ever before. This suggests that the observed phenomena are closely connected with the recent temperature anomalies.I. metallica can be regarded as a potential immigrant to a warmer North Sea, and may be useful as a sensitive indicator of the predicted long-term warming trend.     

The marine macroalgae of Helgoland (North Sea): an annotated list of records between 1845 and 1999

The earliest known records of marine macroalgae from Helgoland (German Bight, North Sea) date from the mid-19th century. Since then, 274 marine macroalgal species have been reported: 77 species of Chlorophycota, 100 species of Phaeophycota and 97 species of Rhodophycota. Additionally 11 species were only recorded as drift and 51 species as doubtful for Helgoland. The remains of the herbarium of Paul Kuckuck, the first curator for botany at the Helgoland Biological Station between 1892 and 1914, are still located there and consist of 173 macroalgal species from Helgoland. On comparing this 100-year-old herbarium and other old sources with recent macroalgal records, it became clear that changes in species composition have occurred. After World War II, several species such as Arthrocladia villosa, Corynophlaea crispa, Cutleria multifida, Eudesme virescens, Mesogloia vermiculata, Sporochnus pedunculatus, Antithamnion cruciatum, Apoglossum ruscifolium, Chondria dasyphylla, Helminthora divaricata, Jania rubens and Osmundea ramosissima were not found again. Other species such as Dictyota dichotoma, Leathesia difformis, Stictyosiphon soriferus, Helminthocladia calvadosii and Scinaia furcellata became very rare. Significantly, perhaps, most of these species have a heteromorphic life history with the appearance of the macroscopic phase restricted to (spring and) summer. Many new species of green algae were recorded for Helgoland after 1959, due to new substrata and the research activities of Peter Kornmann, curator for botany after 1959, and Paul-Heinz Sahling his technical assistant. Introductions of species during the considered time period were: Bonnemaisonia hamifera, Codium fragile, Mastocarpus stellatus and Sargassum muticum. Type material of the following species is located at the Marine Biological Station at Helgoland: Mikrosyphar porphyrae, Porphyra insolita and Ulva tenera. Received in revised form: 22 May 2000 Electronic Publication     

Rapid increase of the grey seal (<Emphasis Type="Italic">Halichoerus grypus</Emphasis>) breeding stock at Helgoland

Over the past 25 years, the grey seal (Halichoerus grypus) population in the North Sea increased on average at 5% per year, while founding a number of new colonies. Based on published data, this note compares recent trends in pup production at nine breeding sites, with focus on the German island of Helgoland. Since 1997, numbers born at Helgoland increased at 35% per year (95% CI: 29–42), reaching an all-time high of 53 in 2007. Yet, this was less than 1% of all grey seal offspring in the North Sea area. Some other small stocks had similarly high growth rates of 20–50%, which must be explained by immigration from the larger colonies, as sustained autochthonous increase cannot exceed 13% per year in the species. Further, the Helgoland breeding stock increased significantly faster than the neighbouring colonies at Amrum (13%) and in the Dutch Wadden Sea (20%), indicating higher offspring survival and/or higher relative influx of migrants. This is attributed to the fact that at Helgoland newborn seals are safe from floodwater. In the other two sites, in contrast, pups are born on sandbanks and are thus often hit by winterly storm tides, which poses a risk to their survival. Because of the favourable breeding conditions at Helgoland, this new colony is expected to soon become an important stronghold of the grey seal in the Dutch-German North Sea area.     

Ecological long-term research at Helgoland (German Bight,North Sea): retrospect and prospect—an introduction

This paper summarizes and evaluates ecological long-term observations at the island of Helgoland (German Bight, North Sea). It is an introduction to a series of seven contributions to an issue of Helgoland Marine Research (vol. 58, no. 4) dealing with observations on the physico-chemical environment and the local biota (pelagic bacteria, phytoplankton, zooplankton, macroalgae, macrozoobenthos). More than 150 years of research at Helgoland (at the Biologische Anstalt Helgoland, BAH, since 1892), and particularly the Helgoland Roads time-series which started in 1962, has provided a multitude of data which represents a valuable basis for analysing past changes, evaluating the present status and predicting future changes in ecosystem parameters. Predicting the consequences of the recent rapid ecological change on regional and global scales requires increased efforts of focus on long-term ecological observations. Future efforts in this field will rely on the application of innovative advanced technology and on the concerted activities of a large number of institutions which only collectively can establish the large-scale patterns of temporal and spatial change in ecosystem functions.     

THE TYPE SPECIES OF CERAMIUM (RHODOPHYTA), CERAMIUM VIRGATUM ROTH: TYPIFICATION AND PHYLOGENY

The type species of Ceramium is Ceramium virgatum Roth (1797, Cat. Bot I: 148, pl. VIII, fig. 1). This has been treated as a probable synonym of Ceramium nodulosum (Lightfoot) Ducluzeau, one of the species formerly confused under the illegitimate name Ceramium rubrum (Hudson) C. Agardh. However, in 1996 Silva showed that C. nodulosum (Lightfoot) Ducluzeau is a later homonym of C. nodulosum de Candolle 1805, and advocated conserving C. rubrum with a neotype. As an alternative to this, we investigated whether the name C. virgatum might be available for this species. The lectotype of C. virgatum is Roth's illustration of a much-branched, fully corticate, Ceramium specimen from Eckwarden, North Sea, which could represent any member of the ' C. rubrum' group. We obtained material resembling Roth's, from the North Sea island of Helgoland, as a potential epitype. Its rbc L sequence was aligned with sequences of all C. rubrum -like species in the British Isles, i.e. C. secundatum , C. botryocarpum , C. pallidum and ' C. nodulosum '. The Helgoland material was clearly conspecific with ' C. nodulosum ' from Ireland (0.08% divergence). We therefore suggest that the name C. virgatum Roth should be employed for this species. Phylogenetic analyses of these sequences aligned with various representatives of the tribe Ceramieae, placed the North Atlantic C. rubrum -like species in two well-supported clades. In one of these, C. virgatum is basal to C. secundatum and C. botryocarpum. The other clade consists of C. pallidum and a partly ecorticate species resembling C. diaphanum.     

Guest research facilities at the Biologische Anstalt Helgoland: Past and present

The Biologische Anstalt Helgoland (BAH) offers unique possibilities for research and education in marine sciences in the southern part of the North Sea. Besides its own research duties, the Institute provides research facilities and technical assistance for guest scientists, assists in the teaching and education of university student groups, and conducts its own courses. The Institute further supplies universities and research institutions on the mainland with marine organisms. The marine station on Helgoland has 14 laboratories, with a total of 32 working places available for guest scientists. The Wadden Sea Institute in List on the island of Sylt offers 6 laboratories with a total of 18 working places. Furthermore, laboratory classrooms are located on Helgoland and in List for 50 and 20 participants, respectively. For the convenience of the guest researchers staying at the BAH, guest-houses are run on Helgoland (Arthur-Hagmeier-Haus, Wilhelm-Mielk-Haus) und in List (Adolf-Bückmann-Haus). Guest researchers have been welcome since the founding of the Institute in 1892. Heincke gave a brief report on the activities of the first visitors from 1892 to 1897. Only sporadic reports are available for the first 60 years of this century. Guest scientists and their activities have only been recorded in detail in the annual reports of the BAH since 1962. The number of researchers and the length of their visits have increased continuously since 1962. The research facilities on Helgoland, in List and Hamburg have been modernized during the last 20 years. In 1971, four modern laboratories for guest researchers could be opened on Helgoland with financial support of the German Research Foundation (DFG). The number, of guest researchers in List and Hamburg increased after the completion of new buildings in 1979 and 1982. The recent increase in research activities by guest scientists is due to numerous students, from many different universities, using the superb research facilities to do their Masters thesis, or Ph.D. Guest researchers and students either perform their own research or cooperate with scientists of the BAH.     

A revised checklist of planktonic diatoms and dinoflagellates from Helgoland (North Sea,German Bight)

A checklist based on net samples taken twice weekly from 2001 until May 2003 is presented. Identification is based on observations under direct light microscopy and after taking some organisms in culture. The checklist includes 227 taxa observed at the Helgoland Reede sampling station. One hundred and thirty-two species of diatoms from 53 genera and 95 species of dinoflagellates from 35 genera have been recorded from net samples and cultures. Thirty-five diatom and 28 dinoflagellate taxa were documented in the Helgoland phytoplankton for the first time. The list does not claim to be complete, but provides an updated list of the taxa found at Helgoland and, for convenience, also includes data published for different adjacent areas.Communicated by K. Wiltshire     

The molecular genetic approach to malarial pathogenesis and immunity

It is poorly understood why some malarial infections are fatal while others resolve without complications. Host genetic factors are partly responsible. More than ten specific susceptibility determinants have already been defined, including both structural and regulatory polymorphisms of erythyrocytes and of the immune system, and it is likely that many more have yet to be discovered. A vast number of DNA polymorphisms, scattered throughout the human genome, cause individual variation in probably all immunological and biochemical processes. Advances in DNA technology offer the prospect of screening thousands of candidate genes for association with susceptibility to severe malaria in large multicentre case-control and family-based studies. Saturation mapping of candidate gene regions, combined with cellular and molecular analysis of disease-associated polymorphisms, is essential for understanding the functional basis of the genetic associations that such an exercise will generate. This information will pinpoint critical molecular pathways in immunity and pathogenesis and may lead to fundamentally new strategies for treatment and prevention of severe malaria.     

Natural selection of allozyme polymorphisms: a microgeographical differentiation by edaphic,topographical, and temporal factors in wild emmer wheat (Triticum dicoccoides)

Summary Allozymic variation in proteins encoded by 47 loci was analyzed electrophoretically in 1983/4 and 1984/5 in 356 individual plants of wild emmer wheat, Triticum dicoccoides, from a microsite at Tabigha, north of the Sea of Galilee, Israel. Each year the test involved two 100-meter transects, each equally subdivided into basalt and terra rossa soil types, and comparisons were based on 16 common polymorphic loci. Significant genetic differentiation, genetic phase disequilibria, and genome organization according to soil type were found over very short distances. Our results suggest that allozyme polymorphisms in wild emmer wheat are partly adaptive, and that they differentiate at both single and multilocus structures primarily from environmental stress of such ecological factors as soil type, topography, and temporal changes, probably through aridity stress.     

Candidate gene polymorphisms and the 9p21 locus in acute coronary syndromes

It is now widely accepted that the classic environmental risk factors for atherosclerosis only partly explain the incidence of coronary artery disease and the development of acute coronary syndromes. Therefore, genetic factors that vary among human populations seem to be involved in the clinical manifestations of such patients. Substantial data suggest that a significant proportion of genetic polymorphisms involved in endothelial function, inflammation, lipid metabolism, thrombosis and fibrinolysis are often present in patients with acute coronary syndromes. In particular, a common variant on chromosome 9p21 was recently identified to affect the risk of myocardial infarction. Here, we review the progress of candidate gene studies and genome-wide association studies in identifying the genetic bases of complex cardiovascular diseases such as acute coronary syndromes.     

Extraordinary high natal philopatry in a migratory passerine

Natal dispersal is a key component of population dynamics in birds. It guarantees the genetic exchange of populations, favours range expansions and reduces intraspecific competition. In general, natal philopatry of migratory passerines is quite low (0–13.5%). In this study, we give evidence that, under specific conditions, migratory populations of passerine birds may show a considerably elevated natal philopatry. In a Linnet Carduelis cannabina population on the remote island of Helgoland in the North Sea, we found an extraordinary high return rate of yearlings (38%), which corresponds exactly to the annual survival rate of the species. Despite being completely migratory, the Linnets of Helgoland apparently return to a large extent to their native area and consequently might support the population maintenance on the island. Further studies are needed to reveal if this high natal philopatry is only an unusual 1-year event or a general characteristic of this partially isolated island population.     

Glacial survival may matter after all: nunatak signatures in the rare European populations of two west-arctic species

Biogeographers claimed for more than a century that arctic plants survived glaciations in ice-free refugia within the limits of the North European ice sheets. Molecular studies have, however, provided overwhelming support for postglacial immigration into northern Europe, even from the west across the Atlantic. For the first time we can here present molecular evidence strongly favouring in situ glacial persistence of two species, the rare arctic-alpine pioneer species Sagina caespitosa and Arenaria humifusa. Both belong to the 'west-arctic element' of amphi-Atlantic disjuncts, having their few and only European occurrences well within the limits of the last glaciation. Sequencing of non-coding regions of chloroplast DNA revealed only limited variation. However, two very distinct and partly diverse genetic groups, one East and one West Atlantic, were detected in each species based on amplified fragment length polymorphisms (AFLPs), excluding postglacial dispersal from North America as explanation for their European occurrences. Patterns of genetic diversity and distinctiveness indicate that glacial populations existed in East Greenland and/or Svalbard (A. humifusa) and in southern Scandinavia (S. caespitosa). Despite their presumed lack of long-distance dispersal adaptations, intermixed populations in several regions indicate postglacial contact zones. Both species are declining in Nordic countries, probably due to climate change-induced habitat loss. Little or no current connectivity between their highly fragmented and partly distinct populations call for conservation of several populations in each geographic region.     

Genetic diversity of natural and cultivated populations ofOenanthe javanica in Korea

Enzyme electrophoresis was used to estimate genetic diversity and population structure in natural and cultivatedOenanthe javanica (Blume) DC. In the six natural populations, 8 of the 22 loci showed polymorphisms. Cultivated populations had fewer alleles per locus (1.84 vs. 1.91), fewer effective alleles per locus (1.47 vs. 1.52), a lower percentage of polymorphic loci (42.3 vs. 50.0), and lower diversity (0.210 vs. 0.228) than did natural populations. These parameters of genetic diversity indicate that the cultivated populations are genetically depauperate relative to their presumptive progenitor, and that the domestication process has partly eroded the level of genetic variation of this species. Nevertheless, the diversity of this species has higher-than-average values compared with other species having similar life-history traits. We propose that the mix-mating system; perennial, high gene flow; and large population sizes are possible factors contributing to this high diversity, which seemed to increase with distance from the coastlines.     

A survey of ciliates at the long-term sampling station “Helgoland Roads”, North Sea

This study presents a new checklist of ciliates at the long-term sampling station Helgoland Roads. The work is based on a microzooplankton monitoring programme from January 2007 to June 2009 and a ciliate monitoring programme from June 2010 to May 2012. The checklist includes 89 ciliate taxa from 46 different genera. The total abundance of the ciliate community at Helgoland Roads ranged between 0.14 and 67.7 × 10³ cells L^?1 with a distinct peak in June. The total carbon biomass ranged between 0.2 and 234.6 μg C L^?1. The ciliate community showed a clear temporal succession pattern during the monitoring periods. The present study is not only the first detailed and updated list of ciliates at Helgoland Roads, but also provides information on seasonality, i.e. the temporal variation of species composition, abundance and carbon biomass as well as information on the biogeographic distribution of dominant ciliates in comparison with other relevant studies.     

Die Wattenmeer-Lebensgemeinschaften im Königshafen von Sylt

Ohne ZusammenfassungPreuß. Marschenbauamt, Forschungs-Abt. Husum und Büsum, vorher Biolog. Anstalt auf Helgoland. (Aus der Biologischen Anstalt auf Helgoland und deren Zweiglaboratorium List auf Sylt.)Mit 67 Abbildungen im Text.