Diversity of actinomycetes isolated from Challenger Deep sediment (10,898 m) from the Mariana Trench

Thirty-eight actinomycetes were isolated from sediment collected from the Mariana Trench (10,898 m) using marine agar and media selective for actinomycetes, notably raffinose-histidine agar. The isolates were assigned to the class Actinobacteria using primers specific for members of this taxon. The phylogenetic analysis based on 16S rRNA gene sequencing showed that the isolates belonged to the genera Dermacoccus, Kocuria, Micromonospora, Streptomyces, Tsukamurella and Williamsia. All of the isolates were screened for genes encoding nonribosomal peptide and polyketide synthetases. Nonribosomal peptide synthetase sequences were detected in more than half of the isolates and polyketide synthases type I (PKS-I) were identified in five out of 38 strains. The Streptomyces isolates produced several unusual secondary metabolites, including a PKS-I associated product. In initial testing for piezotolerance, the Dermacoccus strain MT1.1 grew at elevated hydrostatic pressures.     

Microbiome variation in corals with distinct depth distribution ranges across a shallow–mesophotic gradient (15–85 m)

Mesophotic coral ecosystems (MCEs) are generally poorly studied, and our knowledge of lower MCEs (below 60 m depth) is largely limited to visual surveys. Here, we provide a first detailed assessment of the prokaryotic community associated with scleractinian corals over a depth gradient to the lower mesophotic realm (15–85 m). Specimens of three Caribbean coral species exhibiting differences in their depth distribution ranges (Agaricia grahamae, Madracis pharensis and Stephanocoenia intersepta) were collected with a manned submersible on the island of Curaçao, and their prokaryotic communities assessed using 16S rRNA gene sequencing analysis. Corals with narrower depth distribution ranges (depth-specialists) were associated with a stable prokaryotic community, whereas corals with a broader niche range (depth-generalists) revealed a higher variability in their prokaryotic community. The observed depth effects match previously described patterns in Symbiodinium depth zonation. This highlights the contribution of structured microbial communities over depth to the coral’s ability to colonize a broader depth range.     

Adaptation strategies of copepods (superfamily Centropagoidea) in the White Sea (66°N)

Seasonal dynamics of major biochemical features were studied for three abundant egg-diapausing copepods Acartia bifilosa, Centropages hamatus and Temora longicornis, in the White Sea (66°N), between June 2002 and September 2002. Dry weight (DW) and prosome length varied from 0.54 μg ind⁻¹ and 0.163 ± 0.012 mm (A. bifilosa, CI) to 9.58 ± 0.72 μg ind⁻¹ and 1.135 ± 0.167 mm (C. hamatus, females). C_org and N_org content reached up to 5.91 ± 0.44 and 1.23 ± 0.09 μg ind⁻¹ (C. hamatus, females). Protein and lipid content varied greatly from 31.8 to 67.3% DW and from 8.7 to 42.6% DW, respectively. These species show somewhat different biology compared to species at lower latitudes. The copepods use lipid stores to survive during short-term food shortage (e.g. in autumn) and successfully complete their life cycle. In the isolated White Sea during last post-glacial period, species probably evolved some special biochemical features (especially wax esters presence). Food quality demands and long ice coverage are possible factors limiting early development of species in spring.     

The palynological assemblages from the J–K boundary beds of the Bureya Basin,Russian Far East

Palynological assemblages were studied from the coal-bearing Upper Jurassic (Talanja Formation) to the Lower Cretaceous (Dublikan Formation) deposits of the Bureya Basin, Russia. The palynological assemblages from the upper part of the Talanja Formation are dominated by gymnosperms, mainly Ginkgocycadophytus (up to 40%) and conifers related to Pinaceae (up to 70%). The contribution of non-seed plants is not great, but their diversity is considerable. The miospore assemblages of the Talanja sequence are characterized by the last appearance of the spore taxa Staplinisporites pocockii, Camptotriletes cerebriformis, Camptotriletes nitida, and Cingulatisporites sanguinolentus. The palynological assemblage from the Dublikan Formation is dominated by ferns (up to 84%), represented mainly by Cyathidites and Duplexisporites. Among gymnosperms the role of Classopollis increases (making up about 20%). Another feature is the first appearance of the spore taxa Stereisporites bujargiensis, Neoraistrickia rotundiformis, Contignisporites dorsostriatus, Appendicisporites tricostatus, and Concavissimisporites asper.     

Diversity of planktonic rotifer assemblages in the water bodies of the Gemenc floodplain (Duna-Dráva National Park,Hungary)

Gemenc floodplain lies between river kilometres km 1503 and 1469 of the Danube River; it is a part of the Danube-Dráva National Park in Hungary. The floodplain is one of the largest in Europe with an 18,000 hectares (Natura 2000) area, and various characteristic side arms and backwaters which lie completely in the floodplain. The area needs hydrological revitalization because of the sinking of the river bed caused by the regulation of the main arm at the end of the 19^th century. For this revitalization an exhaustive knowledge of the hydrobiological relationships among the different water bodies is required. The aims of this study were to explore connections among the hydrological events, physico-chemical parameters of the water bodies and the diversity of the planktonic rotifer assemblages. From 2002 to 2004, 56 planktonic and 15 tychoplanktonic rotifer taxa were found in the area. The diversity of rotifer assemblages was generally higher in the parapotamal water bodies than in the main arm and in the plesio/paleo-potamal water bodies, which could be explained by the intermediate disturbance hypothesis. The diversity, dominance, and evenness of the assemblages were correlated with water flow and water temperature. The most important factors influencing the diversity patterns were the occurrence of flow (retention time) as a disturbance, connectivity with the main arm, and habitat diversity of the given water body. Most of these factors are determined by the water level fluctuation of the main arm.     

Cumacean assemblages on the Levantine shelf (Mediterranean Sea) – spatiotemporal trends between 2005 and 2012

Cumacea (Crustacea, Peracarida) are an important component of soft-bottom macrofauna. Their assemblages are influenced by environmental parameters, including the presence of alien species. Cumacean assemblages from 443 samples collected between 2005 and 2012, at 148 sites along the Israeli Mediterranean coast were analysed. In all, the 31,508 cumaceans were identified to 18 species. Three of the species, Eocuma rosae, E. sarsii and Scherocumella gurneyi, are considered alien for the Mediterranean Sea. Pseudocuma longicorne, S. gurneyi and Cumopsis goodsir were the most abundant species in our samples. Cumacean densities were significantly higher in spring than in autumn, except on the shelf, where the opposite was observed. At the deeper sites (55–63?m) species composition changed between seasons, suggesting a migration of some shallow-bottom dwellers (P. longicorne, Iphinoe spp.) into deeper waters in wintertime. Comparison among years revealed great differences in density, especially in P. longicorne, which experienced an outbreak in 2009. Although seasonal changes may be explained by the natural dynamics of the species' life cycles, inter-annual variability is more difficult to explain. It may be related to environmental changes and especially to the infralittoral hypernutrification along the southern Israeli coast, causing an increase in food availability. Cumacean alien species occurred only in Haifa Bay.     

Resting Membrane Potentials Recorded On-site in Intact Skeletal Muscles from Deep Sea Fish (Sigmops gracile) Salvaged from Depths up to 1.000 m

The effect of elevated ambient pressures in deep sea fish residing at certain bottom depths or even covering different depth levels during migration is poorly understood. Elevated pressures are known to influence membrane properties of various excitable tissues in many species. Reliable results on membrane properties require freshly isolated living cells and short decompression times. During a scientific cruise south of Japan, deep sea fish were sampled from depths up to 1.000 m by using the intelligent operative net sampling system IONESS. On-site electrophysiological recordings of resting membrane potentials were performed in freshly isolated skeletal muscles from Sigmops gracile. Experiments were conducted at various extracellular K+ concentrations to derive relative membrane ion permeabilities and estimate intracellular K+ concentrations [K+]i in the muscles studied. With increasing sampling depth, a tendency for depolarized resting membrane potentials was observed. This could be explained by an increase in relative Na+ over K+ resting membrane permeabilities. Fish samples from deeper sites also had larger [K+]i values compared with shallower sites. This study represents a first approach to perform sophisticated physiological live-cell experiments on board a fully operating ship. These data are expected to more realistically reflect the physiological state of biological preparations residing in the deep sea.     

Biology of Pseudopotamilla reniformis (Müller 1771) in the White Sea,with description of asexual reproduction

The tube-dwelling polychaete Pseudopotamilla reniformis (Sabellidae) forms dense and complex aggregations of flexible tubes on hard substrates in the subtidal zone of the White Sea. No sexual reproduction was observed in this study and recruitment appeared to be due to asexual reproduction by architomy in winter, from October to March. The posterior part of the abdomen undergoes spontaneous fission into from 2 to 4 fragments and depending on their position, the fragments regenerate their anterior ends or both anterior and posterior ends. Regeneration in P. reniformis takes place via a combination of epimorphosis (replacement of missing parts by cell proliferation and the growth of new tissue) and morphallaxis (the remodelling of pre-existing structures without cell proliferation). The morphogenetic events during regenerative restoration include de novo formation of branchial crown, formation of thoracic segments and restoration of the posterior end. Asexual reproduction appears to play a crucial role for formation of P. reniformis aggregations and is very important for the population in the White Sea, at the margin of the species’ range.     

Miospore assemblages from the Silurian–Devonian boundary,in borehole A1-61, Ghadamis Basin,Libya

Well preserved and diversified miospore assemblages have been recorded from a relatively continuous sequence in borehole A1-61 which spans the Silurian–Devonian boundary in the northwestern part of the Ghadamis Basin, Libya. The sequence is represented by early Devonian Lochkovian beds of the Tadrart Formation that transgress onto the Silurian Ludlow-Pridoli beds of the upper part of the ‘Alternances Argilo-gréseuses’ Formation. The present work demonstrates a succession of miospore assemblages from closely sampled layers that have been stratigraphically dated as Ludlow–middle Pridoli and early Lochkovian by chitinozoans and acritarchs. Over 80 species of cryptospores and trilete spores have been identified. Modified detailed morphological interpretations are given. The miospore assemblages are correlated with miospore zonation schemes established for the type sequences of the Welsh Borderland, and those previously described from Libya. Early occurrences of some species as Streelispora newportensis on the western Gondwana plate, are put forward by comparison with the Old Red Sandstone continent. Phytogeographic and palaeobotanic implications based on these observations are discussed.     

Impact of resuspension of cohesive sediments at the Oyster Grounds (North Sea) on nutrient exchange across the sediment–water interface

Benthic-pelagic exchange processes are recognised as important nutrient sources in coastal areas, however, the relative impact of diffusion, resuspension and other processes such as bioturbation and bioirrigation are still relatively poorly understood. Experimental ship-based data are presented showing the effects of diffusion and resuspension on cohesive sediments at a temperate shelf location in the North Sea. Measurements of diffusive fluxes in both spring (1.76, 0.51, ?0.91, 17.6 μmol/m²/h) and late summer (8.53, ?0.03, ?1.12, 35.0 μmol/m²/h) for nitrate, nitrite, phosphate and dissolved silicon respectively, provided comparisons for measured resuspension fluxes. Increases in diffusive fluxes of nitrate and dissolved silicon to the water column in late summer coincided with decreases in bottom water oxygen concentrations and increases in temperature. Resuspension experiments using a ship board annular flume and intact box core allowed simultaneous measurement of suspended particulate matter, water velocity and sampling of nutrients in the water column during a step wise increase in bed shear velocity. The resuspension of benthic fluff led to small but significant releases of phosphate and nitrate to the water column with chamber concentration increasing from 0.70–0.76 and 1.84–2.22 μmol/L respectively. Resuspension of the sediment bed increased water column concentrations of dissolved silicon by as much as 125% (7.10–15.9 μmol/L) and nitrate and phosphate concentrations by up to 67% (1.84–3.08 μmol/L) and 66% (0.70–1.15 μmol/L) respectively. Mass balance calculations indicate that processes such as microbial activity or adsorption/desorption other than simple release of pore water nutrients must occur during resuspension to account for the increase. This study shows that resuspension is potentially an important pathway for resupplying the water column with nutrients before and during phytoplankton blooms and should therefore be considered along with diffusive fluxes in future ecosystem models.     

A new species of Fuziidae (Insecta, Blattida) from the Inner Mongolia, China

A new species attributed to the genus Parvifuzia Guo & Ren, 2011, Parvifuzia peregrinasp. n., is described from the Middle Jurassic Jiulongshan Formation of Daohugou Village, Inner Mongolia, China. This new species, with apex of wing almost reaching the end of the abdomen and forewing venation with 30-32 veins at margin, broadens the diversity of Parvifuzia. This new species, with strongly curved cerci, could tightly clasp female and complete copulation more efficiently, same as other members of the family Fuziidae.     

Saurischian (theropod–sauropod) track assemblages from the Jiaguan Formation in the Sichuan Basin,Southwest China: ichnology and indications to differential track preservation

Saurischian (theropod and sauropod) tracks and trackways from the Jiaguan Formation (Lower Cretaceous) of the Sichuan Basin are exposed as natural casts with associated undertrack or transmitted print casts. The theropod tracks (cf. Eubrontes and Grallator) were left by differently sized trackmakers. This is a further example for the occurrence of characteristic Lower Jurassic ichnotaxa in the Cretaceous that obviously had a more extended stratigraphic range in East Asia. The sauropod trackway is tentatively assigned to cf. Brontopodus based on imprint morphology and (nearly wide) gauge. The tracks, however, allow a detailed study of their formation and the taphonomic processes under different substrate conditions. Differential preservation and erosion of primary sedimentary structures, and post-burial deformation structures, give insight into a complex preservational history during a low energy phase interrupting the deposition of a sequence of thick high energy sandstones. This is the sixth report of dinosaur tracks from the Jiaguan Formation and the fifteenth report from the Lower Cretaceous of Sichuan Province. Thus, the tetrapod ichnological record in this region is rapidly becoming of major importance for our knowledge of dinosaur faunas in south-western China.     

Planktic foraminifera from the mid-Cretaceous (Barremian–Early Albian) of the North Sea Basin: Palaeoecological and palaeoceanographic implications

A marine Cretaceous succession (Barremian–Albian) of a cored borehole (BGS 81/40), located in the Central North Sea Basin, has been examined with respect to its planktic and benthic foraminiferal content, as well as for calcareous nannofossils. The distribution patterns of foraminifera and calcareous nannofossils allow for a two fold division of the investigated interval. (1) The Barremian–earliest Aptian interval, which reflects a marine, temporary restricted setting. This is indicated by sporadic occurrences of planktic foraminifera with very rare planispiral forms suggesting short-term connections of the Boreal and Tethyan Realms. The benthic foraminiferal assemblages indicate aerobic, sometimes dysaerobic bottom-water conditions. High abundances of nannoconids in the Barremian suggest enhanced stratification and/or warm, oligotrophic surface water. (2) The late Aptian–early Albian interval, which was characterised by an open-oceanic environment with cool and aerobic surface water conditions. Planktic foraminifera are more abundant and diverse than in the lower interval. Trochospiral hedbergellids dominate the foraminiferal assemblages. The episodic occurrences of planispiral, clavate and trochospiral-flattened planktic morphotypes indicate the existence of a seaway between the Boreal and the Tethyan Realms. Aerobic to dysaerobic bottom-water conditions are suggested by the composition of the benthic foraminiferal assemblages. High abundances of cool-water taxa within the calcareous nannofossil assemblages indicate a cooling trend across the latest Aptian and earliest Albian.     

Climatic and environmental conditions from the Neolithic to the Bronze Age (7000–3000 BP) in the Iberian Peninsula assessed using small-mammal assemblages

We have analyzed the palaeoenvironment and palaeoclimate of the beginning of the Holocene in the Iberian Peninsula on the basis of the small-mammal assemblages from three sites within the geography of the Iberian Peninsula: Mirador (Sierra de Atapuerca, Burgos), Colomera (Sant Esteve de la Sarga, Lleida) and Valdavara-1 (Becerreá, Lugo). These associations reveal that the palaeoenvironment was more humid than today in the sites under study, and the landscape was dominated by woodland and woodland margins in all the studied layers. Further, the climatic conditions were stable, but with winters colder than at present, above all in the Mediterranean area. Finally, our data have been compared with other environmental and climatic proxies, showing that human activities exerted little impact on the palaeoenvironmental conditions that occurred from 7000 to 3000 BP in the Iberian Peninsula.     

Theropod and possible ornithopod track assemblages from the Jurassic–Cretaceous boundary Houcheng Formation,Shangyi, northern Hebei,China

Dinosaur track assemblages from the Houcheng Formation in the small continental Shangyi Basin of northern Hebei Province, China bridge a gap in the record of vertebrates from this unit and enrich our knowledge of ichnofaunas from the Jurassic–Cretaceous boundary. Their stratigraphic position between the Middle Jurassic Yan-Liao Biota and the Lower Cretaceous Jehol Biota gives them a special importance. New discoveries allow a re-assessment of theropod and possible ornithopod tracks that are present with several trackways. Seventy-three footprints were examined and documented. Despite their smaller size, the tridactyl mesaxonic theropod tracks show morphological similarities with the ichnogenus Therangospodus known from the Upper Jurassic deposits of North America, Europe, and Central Asia. The possible ornithopod tracks lack an associated manus imprint, suggesting a bipedal trackmaker. These possible ornithopod tracks from the Houcheng Formation provide evidence for the presence of small basal ornithopods or basal Cerapoda in the Upper Jurassic–Lower Cretaceous in this region. The depositional environment was the margin of an extensive shallow lake with fluctuating water levels under seasonally dry climate.     

Assessment of cetacean–fishery interactions in the marine food web of the Gulf of Taranto (Northern Ionian Sea,Central Mediterranean Sea)

Reviews in Fish Biology and Fisheries - The exploitation of fishery resources acts as a driving force on cetaceans both directly, by determining their fishing mortality or injury as by-catch...     

Development and characterization of microsatellite loci from the Great White Pelican (Pelecanus onocrotalus) and widespread application to other members of the Pelecanidae

We describe the isolation of 10 microsatellite loci from the Great White Pelican using an enrichment protocol. All loci were variable with the number of alleles ranging from 2 to 19, and observed heterozygosity ranging from 0.261 to 0.913. Two loci were out of Hardy–Weinberg equilibrium, although in each case this was restricted to one of the two populations screened. None of the loci were linked. Eight to 10 loci PCR-amplified in three related species: Brown, American White and Pink-backed Pelicans. These loci should prove to be widely applicable to studies of phylogeography and demography in pelicans globally.