Recruitment patterns of Serpula vermicularis L. (Polychaeta, Serpulidae) in Loch Creran, Scotland

This study aimed to contribute to conservation management of reefs of Serpula vermicularis by increasing understanding of the factors influencing larval settlement. The study was carried out in Loch Creran, which supports the most extensive known development of S. vermicularis reefs in the world. Settlement plates were deployed to examine the influence of season, depth, reef density, substrate type and orientation. Monthly deployment of plates revealed settlement of S. vermicularis to occur predominantly from mid-June to mid-October, peaking in late August to early September. Settlement of Pomatoceros spp. peaked much earlier, in late May to early June. Deployment of plates at different depths revealed a marked reduction in S. vermicularis settlement intensity between 6 and 12 m. As this corresponds with the deeper limit of the peripheral fringe of serpulid reefs in the loch, it is suggested that this limit is imposed by a depth-correlated settlement response, rather than reduction in available substrata. Comparisons of various substrata showed a preference by S. vermicularis larvae for a slate over a scallop substrate and no evidence of enhanced recruitment to occupied or unoccupied tubes of S. vermicularis, suggesting that gregarious attraction is unlikely to be a factor causing reef formation. Settlement onto the upper side of a horizontal scallop substrate was found to be insignificant in comparison with the underside or a vertically orientated scallop. Evidence for the role of light in controlling the depth and substrate-orientation preferences of S. vermicularis larvae is discussed. Based on the results of this study, recommendations are made regarding remediation of areas suffering reef damage.     

Effects of pulsed nutrient inputs on phytoplankton assemblage structure and blooms in an enclosed coastal area

The response of phytoplankton assemblage structure to terrestrial nutrient inputs was examined for the Gulf of Kalloni in the Northern Aegean Sea, a productive semi-enclosed coastal marine ecosystem. The study was focused on a typical annual cycle, and emphasis was placed on the comparative analysis between blooms developing after significant nutrient inputs from the watershed, and naturally occurring blooms. Baseline information was collected on a monthly basis from a network of stations located in the oligotrophic open sea and the interior and more productive part of the embayment. Intensive sampling was also carried out along a gradient in the vicinity of a river which was the most important source of freshwater and nutrient input for the Gulf. Phytoplankton assemblage structure was analyzed from 188 samples using diversity indices (Shannon and Average Taxonomic Distinctness), multivariate plotting methods (NMDS), multivariate statistics (PERMANOVA), and canonical correspondence analysis (CCA). Three characteristic assemblages were recognized: (1) an autumn assemblage developed under nutrient depleted conditions, having low diversity due to the dominance of two small diatoms, (2) a winter bloom of the potentially toxic species Pseudo-nitzschia calliantha occurring immediately after a nutrient peak and characterized by very low diversity, and (3) a naturally occurring early summer bloom of centric diatoms with relatively high diversity. The results of the study support the view that moderate nutrient inputs may have a beneficial effect on the functioning of coastal ecosystems, stimulating the taxonomic diversity through the growth of different taxonomic groups and taxa. On the other hand, a sudden pulse of high nutrient concentrations may greatly affect the natural succession of organisms, have a negative effect on the diversity through the dominance of a single species, and can increase the possibility of a harmful algal bloom development.     

Kinematic structure and mesoscale variability of the rim current near the coast of Crimea (according to the data of instrumental measurements in September 2008)

By using the results of processing of the instrumental data with high space resolution obtained in September 2008, we analyze the structure of the Rim Current in the upper 100-m layer near the coast of Crimea. We determine the statistical characteristics of the mesoscale fluctuations of currents according to the data of 1165 vertical probes. It is shown that the kinetic energy of intense mesoscale perturbations observed in the vicinity of the Rim Current is of the same order of magnitude as the kinetic energy of the mean current.     

Evolution of deep-water stratigraphic architecture, Magallanes Basin, Chile

The ˜4000 m thick and ∼20 Myr deep-water sedimentary fill of the Upper Cretaceous Magallanes Basin was deposited in three major phases, each with contrasting stratigraphic architecture: (1) the oldest deep-water formation (Punta Barrosa Formation) comprises tabular to slightly lenticular packages of interbedded sandy turbidites, slurry-flow deposits, and siltstone that are interpreted to record lobe deposition in an unconfined to weakly ponded setting; (2) the overlying, 2500 m thick and shale-dominated Cerro Toro Formation includes a succession of stacked conglomeratic and sandstone channel-fill deposits with associated finer-grained overbank deposits interpreted to record deposition in a foredeep-axial channel-levee system; (3) the final phase of deep-water sedimentation is characterized by sandstone-rich successions of highly variable thickness and cross-sectional geometry and mudstone-rich mass transport deposits (MTDs) that are interpreted to record deposition at the base-of-slope and lower slope segments of a prograding delta-fed slope system. The deep-water formations are capped by shallow-marine and deltaic deposits of the Dorotea Formation.These architectural changes are associated with the combined influences of tectonically driven changes and intrinsic evolution, including: (1) the variability of amount and type of source material, (2) variations in basin shape through time, and (3) evolution of the fill as a function of prograding systems filling the deep-water accommodation. While the expression of these controls in the stratigraphic architecture of other deep-water successions might differ in detail, the controls themselves are common to all deep-water basins. Information about source material and basin shape is contained within the detrital record and, when integrated and analyzed within the context of stratigraphic patterns, attains a more robust linkage of processes to products than stratigraphic characterization alone.     

Ionospheric response to submarine earthquake of March 11, 2011, in Japan according to GPS observations

Using available Russian and international Global Positioning System (GPS) network data, we studied the ionospheric response to the M = 8.9 submarine earthquake of March 11, 2011, on the northeastern coast of Honshu Island, Japan, both near and far (about 2000 km away) from the epicenter. In the region over the epicenter, 8.7 min after the event, we detected a characteristic signal of the total electron content (TEC) variations consisting of compression and rarefaction phases and a linear transition zone in between, i.e., in the form of an N-type wave with a steep leading front indicating a rapid uplift of the water surface and, correspondingly, the bottom of the ocean. The shape of the signal can be used for early tsunami warning; i.e., it may indicate the tsunamigenic character of a submarine earthquake. We monitored the subsequent evolution of the ionospheric response as far as 2000 km from the epicenter. It was shown that, besides the wellknown ionospheric N-type wave response to the earthquake, there is also a response in the form of an inverted N-wave, both nearby and far from the epicenter. We detected two more types of ionospheric responses far from the epicenter: a solitary-like wave and an internal gravity wave (IGW). The detected signals have been interpreted.     

Assessment of the effectiveness of POLYMODE data assimilation by a numerical barotropic model for synoptic motions

This paper considers the results of numerical experiments involving POLYMODE data assimilation by a barotropic model for synoptic ocean dynamics. The model's response the data assimilation for various space-time discretenesses of assimilation is studied. Results derived from the application of optimal interpolation algorithms and modified optimal filtration algorithms are compared. Qualitative similarity to the calculations carried out through the simulation modelling technique is noted. Optimal assimilation algorithms are determined, depending on the space-time discreteness used. An optimal sampling discreteness for the POLYMODE conditions is suggested.Translated by Vladimir A. Puchkin.     

A stratigraphic and tectonofacies framework of the “calcari aLucina” in the Apennine Chain,Italy

The Apennine Chain provides the first example of stratigraphic (time) and synsedimentary tectonic (space) distribution of the calcari aLucina Miocene equivalents of modern cold-vent carbonates. Chemosynthetic faunal assemblages and related carbonate deposits are found at different stratigraphic levels, with peaks during Langhian-Serravallian and late Tortonian-early Messinian times. A general increase in frequency and volume occurs with time. A genetic link between venting and the Messinian Evaporite event is difficult to demonstrate. However,Lucina limestones are limited to preevaporitic times, and their maximum abundance is reached just before the onset of the Messinian Evaporite accumulation.Lucina limestones occur in almost all tectofacies of the orogen, from backland to foreland.     

Heated diver decompression shelter: The “womb concept”

A hybrid thermal protection method using waste heat from a surface-mounted outboard motor is shown to create a warm “micro-climate” environment for divers. The effects of surface heater capacities, water flow rates, shelter volume and shelter insulation on micro-climate temperatures are characterized. During long, cold-water decompression stops this method offers a reliable, low-cost alternative to surface-supplied hot water suits or diver-carried heating systems. An added bonus for divers using closed-circuit breathing apparatus is prolonged durations of their carbon dioxide scrubbers when surrounded by the warm water “micro-climate”. Closed-circuit and open-circuit options of this diver decompression shelter concept are evaluated.