Effects of water exchange and vegetation on the macroinvertebrate fauna composition of shallow land-uplift bays in the Baltic Sea

Shallow bays with soft sediment bottoms are common habitats along the Swedish and Finnish Baltic Sea coastline. These bays undergo a process of geomorphometric evolution with the natural isostatic land-uplift process, whereby open bays and sounds decrease in depth and are gradually isolated from the sea, forming bays with narrow openings. This study tested the relationship between the morphometric isolation of the bays from the sea and the macroinvertebrate fauna community of these bays. Additionally, we tested the specific role of the submerged vegetation as an indicator of the macroinvertebrate fauna community. We chose two environmental factors for the analyses, water exchange of the bays and the taxon richness of the macroflora in the bays. We found a hierarchical relationship between water exchange, flora taxon richness, and fauna biomass and taxon richness using structural equation modelling: decreased biomass and taxon richness of fauna were related to decreased flora taxon richness, which in turn was related to decreased water exchange. Using multivariate redundancy analysis, the two environmental factors included in the model were found to explain 47.7% of the variation in the fauna taxon composition and 57.5% of the variation in the functional feeding groups of the fauna. Along the morphometric isolation gradient of the bays, the fauna assemblages changed from a community dominated by gastropods, bivalves, and crustaceans, to a community mainly consisting of a few insect taxa. Moreover, the proportion of predators, gathering collectors, and shredders increased while that of filtering collectors and scrapers decreased. Our results indicate that the density and taxon richness of macroinvertebrate fauna are higher in less morphometrically isolated bays than in more isolated bays in the Baltic Sea. Furthermore, we suggest that the taxon richness of macroflora can serve as an indicator of the fauna community.     

Feeding habits of Solea senegalensis in earthen ponds in Sado estuary

The senegale sole, Solea senegalensis Kaup, 1858, is a commercially valuable fish and it is beginning to be cultured in a semi-intensive way in fish farms in southern European countries. The present study was initiated to investigate the diet of S. senegalensis under semi-extensive conditions. The feeding habits of sole were studied in two earthen ponds of a fish farm in the Sado estuary. In one earthen pond, artificial fish ration was given. S. senegalensis feeds on few prey items, its diet is mainly composed of insect larvae (Chironomus salinarus) and polychaeta (Hediste diversicolor). The diet composition of this species suggests feeding specialization, by consuming mainly annelids and insect larvae and by avoiding other items, extremely abundant in the environment, such as gastropods. In the water reservoir where ration was given, some fish consumed simultaneously benthic organism together with ration. However, benthic organisms seem to be the most important component of S. senegalensis diet.     

Models of the flexure-controlled strength,stiffness and cyclic deformation capacity of rectangular RC columns with smooth bars,including lap-splicing and FRP jackets

Cyclic tests of single concrete columns with smooth (plain) bars are not representative of building columns with lap splices at floor levels and story-long starter bars. Column specimens with fixity at top and bottom resemble building columns best, but few of those tested so far had smooth bars and even then without bar lap-splicing at floor level or FRP jackets at column ends. Empirical models based on single-column tests, especially the numerous ones with cantilever-type specimens, cannot be readily extended to columns with smooth bars in real-life buildings. Physical models of the Strut-and-Tie type are developed and are validated or calibrated through comparisons with laboratory tests. Their scope includes anchorage and splicing of bars with either 180° hooks or straight ends. Once validated, they are adapted to real-life multistory rectangular RC columns with smooth bars, in order to obtain the column properties of interest: the chord rotation at yielding and the cyclic ultimate chord rotation, with or without FRP jacketing. Different expressions apply to the top and bottom end of a column in a story, but a single one is used to estimate the column’s effective stiffness. Empirical alternatives fitted to the single-element test results have slightly less scatter than physical models, but caution is needed for their application to columns of real buildings. Simulations of the 3D seismic response of a plan wise asymmetric full size building, tested pseudo-dynamically before or after retrofitting all columns with FRPs or just two of them with RC jackets, provide certain confidence in the extension of the physical models for the estimation of the stiffness and ultimate deformation of columns with smooth bars in real-life buildings.     

An Early Pleistocene interglacial deposit at Pingorsuit,North-West Greenland

At the Pingorsuit Glacier in North-West Greenland, an organic-rich deposit that had recently emerged from the retreating ice cap was discovered at an elevation of 480 m above sea level. This paper reports on macrofossil analyses of a coarse detritus gyttja and peaty soil, which occurred beneath a thin cover of till and glacifluvial deposits. The sediments contained remains of vascular plants, mosses, beetles, caddisflies, midges, bryozoans, sponges and other invertebrates. The flora includes black spruce, tree birch, boreal shrubs and wetland and aquatic taxa, which shows that mires, lakes and ponds were present in the area. We describe a new extinct waterwort species Elatine odgaardii. The fossils were deposited in a boreal environment with a mean July air temperature that was at least 9 °C higher than at present. The fossil assemblages show strong similarities with others from Greenland that have been assigned an Early Pleistocene age, and we suggest a similar age for the sediments found at the margin of the Pingorsuit Glacier. At the Pingorsuit Glacier in North-West Greenland, an organic-rich deposit was discovered at an elevation of 480 m above sea level. The sediments contained remains of vascular plants, mosses, beetles, caddisflies, midges, bryozoans, sponges and other invertebrates. The fossils were deposited in a boreal environment with a mean July air temperature that was at least 9 °C higher than at present.     

From land to sea: provenance,composition, and preservation of organic matter in a marine sediment record from the North-East Greenland shelf spanning the Younger Dryas–Holocene

The organic matter content of marine sediments is often used to infer past changes in ocean conditions. However, the organic carbon pool preserved in coastal sediments is a complex mixture derived from different sources and may not reflect in situ processes. In this study, we combine taxonomic identification of reworked palynomorphs with pyrolysis organic geochemistry and reflected-light organic petrographic microscopy to investigate the provenance, composition and preservation of organic matter in a marine sediment core retrieved from the NE Greenland shelf. Our study reveals continuous yet variable input of land-derived organic carbon to the marine environment throughout the late Younger Dryas–Holocene, with the highest input of inert carbon in the late Younger Dryas. Although the sediments contain some recent marine palynomorphs, there is no other evidence of fresh marine organic carbon. In contrast, our results indicate that these shelf sediments represent a significant sink of recycled organic carbon. The results of pyrolysis geochemistry revealed that ~90% of the total organic carbon in the sediments is inert. The organic petrography analyses revealed that >70–84% of the organic carbon in the sediment core is terrigenous. Reworked dinoflagellate cysts showed a continuous provenance of Cretaceous land-derived material, most likely from the nearby Clavering Island. Our study points to the importance of constraining the organic matter origin, composition and preservation in marine sediments to achieve more accurate palaeoenvironmental reconstructions based on organic proxies.     

Fish assemblages of small estuaries of the Portuguese coast: A functional approach

The importance of estuaries for coastal environments is widely acknowledged but their role, structure and ecological status have been the focus of recent scientific efforts mainly concerning large estuarine areas. In this work we used fish assemblages to establish, for the first time, the functional and ecological role of five small estuarine systems along the Portuguese south and southwest coasts. Our results showed that, at a functional approach, fish communities did not differ between estuaries, and that all systems presented a seasonal pattern in diversity values, ecological and feeding guilds. These small estuaries contribute to the support of coastal fish populations by providing temporary habitats to the critical life stages of marine species, shelter and feeding grounds, and should be considered in an ecological and conservation perspective.     

Geochemical controls on leaching of lignite-fired combustion by-products from Greece

The mobility of inorganic pollutants is of key concern for a range of industrial and engineering applications of fly ash produced during the combustion of lignite in power generation. This paper investigates the role that the geochemical features of lignite, the ash composition and the partitioning of elements during combustion play in determining leaching properties of lignite fired by-products. The work is based on surveys on three lignite-fired power plants in Greece. Calcium-rich ashes show a high abatement potential for SO₂ and other gaseous pollutants. For most elements, the concentrations in the parent lignite and the ashes follow the same trend. Relative enrichments in Cd, Co, Cr, Cu, Mo, Ni, Pb, U, V, W, Zn fingerprint the regional and local geological settings of the lignite basins. The total and leachable concentrations of highly volatile elements are strongly influenced by the interaction with ubiquitous free lime. A broad array of elements is highly insoluble in alkaline ash, while a few oxyanionic-forming elements display substantial mobility. Their mode of occurrence in the parent lignite plays a primary role in the leaching of combustion ashes. The outcomes of this study may assist in addressing the impact of co-firing high ash or high Ca alternative fuels on the leaching properties of combustion by-products.     

Elemental abundances in the Milky Way stellar disk(s), bulge,and halo

We present a review of elemental abundances in the Milky Way stellar disk, bulge, and halo with a focus on data derived from high-resolution stellar spectra. These data are fundamental in disentangling the formation history and subsequent evolution of the Milky Way. Information from such data is still limited and confined to narrowly defined stellar samples. The astrometric Gaia satellite will soon be launched by the European Space Agency. Its final data set will revolutionize information on the motions of a billion stars in the Milky Way. This will be complemented by several ground-based observational campaigns, in particular spectroscopic follow-up to study elemental abundances in the stars in detail. Our review shows the very rich and intriguing picture built from rather small and local samples. The Gaia data deserve to be complemented by data of the same high quality that have been collected for the solar neighborhood.     

High resolution spectroscopy in the far UV: Observations of the interstellar medium by IMAPS on ORFEUS-SPAS

The Interstellar Medium Absorption Profile Spectrograph (IMAPS) is an objectivegrating, echelle spectrograph built to observe the spectra of bright, hot stars over the spectral region 950–1150Å, below the wavelength coverage of HST. This instrument has a high wavelength resolving power, making it especially well suited for studies of interstellar absorption lines. Following a series of sounding rocket flights in the 1980's, IMAPS flew on its first Shuttle-launched orbital mission in September 1993, as a partner in the ORFEUS-SPAS program sponsored by the US and German Space Agencies, NASA and DARA.On ORFEUS-SPAS, IMAPS spent one day of orbital time observing the spectra of 10 O- and early B-type stars. In addition to outlining how IMAPS works, we document some special problems that had an influence on the data, and we explain the specific steps in data reduction that were employed to overcome them. This discussion serves as a basic source of information for people who may use archival data from this flight, as well as those who are interested in some specific properties of the data that will be presented in forthcoming research papers.IMAPS is scheduled to fly once again on ORFEUS-SPAS in late 1996. On this flight, 50% of the observing time available for IMAPS and two other spectrographs on the mission will be available to guest observers.