<i>Planothidium juandenovense</i> sp. nov. (Bacillariophyta) from Juan de Nova (Scattered Islands, Mozambique Channel) and other tropical environments: a new addition to the <i>Planothidium delicatulum</i> complex

Planothidium juandenovense sp. nov. (Bacillariophyta) is described from the marine tropical environments of Juan de Nova I. (Mozambique Channel), Rodrigues I. (Mascarene Archipelago) and from Guam (Northern Mariana Is., Pacific). This small and relatively rare taxon has short multiseriate striae on the sternum valve (SV), hooked raphe valve (RV) terminal raphe endings and no SV cavum or hoof–shaped area. This taxon has similarities with Planothidium delicatulum (Kütz.) Round et Bukht. and Planothidium septentrionale (Østrup) Round et Bukht. ex Rumrich et al., but also differences: e.g. a relatively narrow and rhombic SV sternum, void of areolae, with vestigial radiate structures and an uninterrupted marginal SV elevated crest or ‘crista marginalis’. P. juandenovense sp. nov. is compared to some other Achnanthales with short SV striae. Cocconeis quarnerensis var. lanceolata Jurilj and Planothidium quarnerense f. rhombica (Giffen) comb. nov. may be close to our new taxon

Provisional keys to the genera of seaweeds of Micronesia, with new records for Guam and Yap

Artificial keys to the genera of blue-green, red, brown, and green marine benthic algae of Micronesia are given, including virtually all the genera reported from Palau, Guam, Commonwealth of the Northern Marianas, Federated States of Micronesia and the Marshall Islands. Twenty-two new species or genera are reported here for Guam and 7 for Yap; 11 of these are also new for Micronesia. Note is made of several recent published records for Guam and 2 species recently raised from varietal status. Finally, a list is given of nomenclatural changes that affect the 2003 revised checklist (Micronesica 35-36: 54–99). An interactive version of the keys is included in the algal biodiversity website at www.uog.edu/ classes/botany/474

Blooms of a benthic ciliate, Maristentor dinoferus (Heterotrichea: Maristentoridae), on coral reefs of Guam, Mariana Islands. (Note)

Maristentor dinoferus is visible in situ with the naked eye; it forms aggregations at several scales: individuals form dynamic clusters within colonies that are normally widely scattered, but in recurrent blooms during the dry seasons of 2005 through 2007, colonies often formed close together in patches (metapopulations). Patches were extremely abundant in Guam, both in Apra Harbor and on the outer coast. This is the first time that long-term changes in a benthic ciliate population have been documented in situ and that multi-scale patchiness has been reported for a benthic ciliate. Colonies were mapped and monitored; some patches over 1 m diameter were recorded. Since 2008, the distribution has again consisted of scattered colonies, as it did from 1999–2004

Euplotes uncinatus (Ciliophora, Hypotrichia), a new species with zooxantellae

During the observations of a field collection of Maristentor dinoferus with fluorescence microscopy, we discovered a smaller ciliate with zooxanthellae. On the basis of morphological, morphometric and ultrastructural characters, this ciliate has been recognized as a new species of the genus Euplotes. To emphasize the peculiar shape and extension of the right buccal margin, the species has been named Euplotes uncinatus sp. n. The most distinctive traits of E. uncinatus are the presence of mucocyst-like vesicles, a kind of extrusome not previously found in Euplotes, and the presence of zooxanthellae. Evidence from ciliate behavior and zooxanthellae ultrastructure make it very likely that the zooxanthellae are symbiotic, even though some are evidently consumed by the host

Coral-reef diatoms (Bacillariophyta) from Guam: new records and preliminary checklist, with emphasis on epiphytic species from farmer-fish territories

The marine diatom flora of the tropical western Pacific island of Guam is all but unknown. Following several taxonomic/systematic papers, this floristics paper documents 179 new records of diatoms identified from light microscopy and/or scanning electron microscopy. Samples were collected from diverse habitats for several research projects in the authors’ laboratories, but the majority reported here are epiphytic, especially from pomacentrid farmer-fish territories. While many of the species are well known from other regions, some recently named, rarely seen, or poorly-described taxa include Amphora decussata Grunow;Ardissonea fulgens var. fulgens (Greville) Grunow and var. gigantea (Lobarzewsky) De Toni; Campylodiscus humilis Greville; Falcula paracelsianus Voigt; Hyalosira interrupta (Ehrenberg) Navarro; Olifantiella pilosella Riaux-Gobin; andTriceratium pulchellum (Grunow) Grunow. A preliminary checklist incorporating the new records and our previous records totals 237 taxa, which is a step towards the development of the regional flora. Many taxa remain to be identified from the documentation so far and few samples have been analyzed from other habitats such as sediments and mangroves. Only 28–42% of the species in this checklist also occurred in lists from the Society Islands, Mahé, Puerto Rico and The Bahamas—but all regions remain seriously undersampled. We do, however note some apparent differences in common and distinctive species

Phylogenetic analysis and antibiotic activity of bacteria isolated from the surface of two co-occurring macroalgae from the Baltic Sea

Bacteria associated with Fucus vesiculosus and Delesseria sanguinea, two macroalgae from the Kiel Fjord were investigated seasonally over two years by cultivation-based methods. A total of 166 bacterial strains were isolated from the macroalgae, affiliated to seven classes of bacteria (Actinobacteria, Bacilli, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Cytophagia and Flavobacteria). According to 16S rRNA gene sequence similarities they were arranged in 82 phylotypes of>99.0% sequence identity. Assuming that chemical factors rule the bacteriamacroalga and bacteriabacteria interactions on algal surfaces, we tested the antibiotic activity of the bacterial isolates not only against a panel of four standard test organisms (Bacillus subtilis, Candida glabrata, Escherichia coli and Staphylococcus lentus) but also four macroalga-associated microorganisms: Algicola bacteriolytica and Pseudoalteromonas elyakovii (macroalgal pathogens), and Bacillus algicola and Formosa algae (strains associated with algal surfaces). Organic extracts of more than 51% of the isolates from the two macroalgae inhibited the growth of at least one of the tested microorganisms. As much as 46% and 45% of the isolates derived from F. vesiculosus and D. sanguinea, respectively, showed antimicrobial activity against the set of macroalga-associated bacteria, compared with 13 and 19% against a standard set of microorganisms. High antibacterial activity against macroalgal pathogens and bacterial competitors support the assumption that complex chemical interactions shape the relationships of bacteria associated with macroalgae and suggest that these bacteria are a rich source of antimicrobial metabolites