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There’s always something a bit scary about a ghost story. Somehow, though, when you read a collection of them you’re expecting to meet a spook or two. It takes a little more effort to frighten the reader. \ud We hope we’ve managed to do just that with this bunch of tales and our striking cover. We hope as well you’ll find the stories as different from each other as they are from the normal ghost story. \ud You’ll come across some old friends amongst the authors in this volume. Bridge House is beginning to es-tablish a brand and we have several writers now who have the measure of what we’re looking for. You’ll also meet some new names and writing styles. We’re sure both will please. \ud And now to the ghosts…. They too have a life of their own … precisely drawn by our authors. It’s that time of year isn’t it? When the nights are getting longer, the days are getting shorter, when strange shadows lurk and you begin to hear noises you don’t understand. We have traditional ghosts, more subtle ghosts, naughty ghosts, nice ghost, nasty ghost and in one or two of our stories it’s a little difficult to work out who is haunting whom. \ud Stoke up the fire, sit back, enjoy and prepare to be:\ud \ud \ud Spooked!

Very little information is available on the diversity and structure of microbial communities in marine subtidal sediments, especially for micro-eukaryotes. In the framework of the Belgian MICROMET project, we investigated spatial and seasonal (February vs July) variation patterns in the molecular diversity of archaeal, bacterial and eukaryotic communities in 9 subtidal stations in the Belgian Continental Plate (BCP) in relation to sediment granulometry, geochemistry and metal contamination. Microbial diversity was determined using DGGE and clone libraries based on the SSU rDNA gene; metals were determined using DET/DGT. Sediments ranged from sandy and well oxygenated to muddy, anoxic and heavily metal contaminated. Eukaryotic diversity was surprisingly high (20-50 phylotypes per station) and was dominated by Stramenopila (mainly diatoms), Metazoa and Fungi, and to a lesser degree by Protozoa (Alveolata, Cercozoa, Foraminifera). While no clear trends in eukaryotic diversity between stations or seasons were found, community composition showed pronounced differences between sandy and muddy stations; seasonal differences were less marked. Archaeal diversity was very low to non-detectable in all stations. Bacterial diversity was dominated by ?- and d-Proteobacteria and CFB bacteria; eubacterial diversity was significantly reduced in the muddy sediments.

The microbiota of the body wall lesions of the echinoid Tripneustes gratilla, initiated by the grazing action of the parasitic gastropod Vexilla vexillum, was investigated with a pluridisciplinary approach. Parasitised sea urchins showed body wall lesions strongly infected by bacteria that progressed through the test and reached the coelomic cavity after ca. 1 mo. We report here on the bacterial community observed in lesions of echinoids collected in situ and on the bacteria that successively appeared during laboratory experiments. Two Alphaproteobacteria, a CFB (Cytophaga-Flavobacterium-Bacteroides) bacterium, 3 Vibrio species and Exiguobacterium aestuarii were identified in the field-collected lesions by 16S rDNA sequencing. The last 4 bacteria were cultured and each induced the disease when inoculated on scalpel-made wounds, with 100 % of the individuals infected within 2 d. Scalpel-induced scarifications tended to heal within 3 wk, while gastropod-induced lesions evolved into disease, suggesting a role of Vexilla vexillum in the development of the infection. Denaturing gradient gel electrophoresis (DGGE) and sequencing suggest that (1) bacteria associated with healthy integument were not present in the lesions and were thus not responsible for their infection, (2) Alphaproteobacteria with close phylogenetic affiliation with other bacteria involved in several diseases affecting marine invertebrates were present, and (3) these Alphaproteobacteria were present from the beginning of the infection and appeared earlier in the infection than other bacteria such as CFB bacteria.

Comparative analysis of the 16S rRNA gene and fluorescent in situ hybridization (FISH) was used to identify epibiotic filamentous bacteria living on the marine amphipod crustacean Urothoe poseidonis. The epibionts belong to the gamma proteobacteria and represent a novel marine phylotype within the genus Thiothrix. FISH and denaturing gradient gel electrophoresis revealed that the Thiothrix filaments are present on the majority of the amphipods examined.

The Belgian Frasnian carbonate mounds occur in three stratigraphic levels in an overall backstepping succession. Petit-Mont and Arche Members form the famous red and grey "marble" exploited for ornamental stone since Roman times. The evolution and distribution of the facies in the mounds is thought to be associated with ecologic evolution and relative sea-level fluctuations. Iron oxides exist in five forms in the Frasnian mounds; four are undoubtedly endobiotic organized structures: (1) microstromatolites and associated forms (blisters, veils...), possibly organized in "endostromatolites''; (2) hematitic coccoids and (3) non dichotomic filaments. The filaments resemble iron bacteria of the Sphaerotilus-Leptothrix "group"; (4) networks of dichotomic filaments ascribable to fungi; (5) a red ferruginous pigment dispersed in the calcareous matrix whose distribution is related to the mound facies type. The endobiotic forms developed during the edification of the mounds, before cementation by fibrous calcite. The microbial precipitation of iron took place as long as the developing mounds were bathed by water impoverished in oxygen.

Rust-coloured shells of the gastropod Hydrobia ulvae collected in the Wadden Sea near Texel and in the Jade Busen were analysed under the scanning electron microscope. Most of the shells were found to be covered with a microbial community encrusted with an iron-rich mineral containing traces of Mn, Mg, Ca and Si (EDAX analysis). The community formed a biofilm including two morphotypes of diatoms identified as Cocconeis placentula and Achnanthes lemmermanni, two morphotypes of slender filamentous bacteria resembling Leucothrix and Flexibacter, aggregates of coccoid cells and large trichomes resembling members of the cyanobacterial orders Pleurocapsales and Stigonematales, respectively. The must frequent microorganisms of the biofilm were diatoms and filamentous bacteria.

The aim of the present study was to assess the value of Asterias rubens as a bioindicator of metal contamination in the field. Spatial gradients of Pb, Cd, and Zn contamination were identified along Sorfjord, and metal concentrations were consistently higher (1.7-8.3 times) in the body compartments of large asteroids sampled close to the smelters than in those sampled further away. Cd and Pb concentrations in the pyloric caeca varied along the fjord according to a decreasing sigmoidal relationship, while Cd and Pb concentrations in the body wall and the skeleton varied according to a decreasing exponential relationship. This suggests that the bioavailability of these metals has decreased over the last few years at the head of the fjord, which agrees generally with water chemistry data available from the State Pollution Monitoring Programme (Norway). The decrease in metal bioavailability could be a direct consequence of the 1992 remedial action taken in the fjord to reduce heavy metal release from the contaminated sediments. Lead concentrations in the skeletons of large asteroids (12-14 cm; 154 ± 63 µg Pb g-1 dry wt) were eight times higher than those in the skeletons of juvenile individuals (0.5-4cm; 19 ± 8 ?g Pb g-1 dry wt) in the population located at the head of the fjord. Asteroids of 12-14 cm length were likely to be 4-7 y old (i.e. born before the remedial action) while small asteroids were born after the remedial action. According to comparisons with allometric relationships in an uncontaminated population and experimental exposures, results indicate that the half-life of Pb in the skeleton is long (i.e. several years) while the half-life of Cd and Zn is much shorter (i.e. several weeks for Cd, and short but not precisely known for Zn). A smaller size and unusual reduction of the skeleton of adult individuals at the head of the fjord were observed and may result from the effects of heavy metal pollution. A comparison between possible sources of contamination in the fjord (metals in water, food, and sediments) indicates that sediment-associated metals are likely to be an important source of contamination in this environment due to the microphagic activity of asteroids.

The shell of the bivalve Montacuta ferruginosa, a symbiont living in the burrow of an echinoid, is covered with a rust- colored biofilm, This biofilm includes different morphotypes of bacteria that are encrusted with a mineral rich in ferric ion and phosphate, The aim of this research was to determine the genetic diversity and phylogenetic affiliation of the biofilm bacteria. Also, the possible roles of the microorganisms in the processes of mineral deposition within the biofilm, as well as their impact on the biology of the bivalve, were assessed by phenotypic inference. The genetic diversity was determined by denaturing gradient gel electrophoresis (DGGE) analysis of short (193-bp) 16S ribosomal DNA PCR products obtained with primers specific for the domain Bacteria. This analysis revealed a diverse consortium; II to 25 sequence types were detected depending on the method of DNA extraction used. Individual biofilms analyzed by using the same DNA extraction protocol did not produce identical DGGE profiles, However, different biofilms shared common bands, suggesting that similar bacteria can be found in different biofilms. The phylogenetic affiliations of the sequence types were determined by cloning and sequencing the 16S rRNA genes, Close relatives of the genera Pseudoalteromonas, Colwellia, and Oceanospirillum (members of the gamma-Proteobacteria lineage), as well as Flexibacter maritimus (a member of the Cytophaga-Flavobacter- Bacteroides lineage), were found in the biofilms. We inferred from the results that some of the biofilm bacteria could play a role in the mineral formation processes. [KEYWORDS: Ribosomal-rna genes; polymerase chain-reaction phylogenetic analysis; sequence-analysis; loihi-seamount; microbial mat; uncultured microorganisms; produce tetrodotoxin; defined populations; marine-sediments]