Analysis of photosynthetic picoeukaryote community structure along an extended Ellett Line transect in the northern North Atlantic reveals a dominance of novel prymnesiophyte and prasinophyte phylotypes

Photosynthetic picoeukaryotes (PPEs) of a size <3 ??m can contribute significantly to primary production. Here, PPE community structure was analysed along an extended Ellett Line transect, an area in the North Atlantic well studied by physical oceanographers but largely neglected in the field of microalgal ecology. Distribution patterns of specific PPE classes were determined using dot-blot hybridization analysis, while the taxonomic composition of specific PPE classes was revealed by phylogenetic analysis of plastid 16S rRNA gene sequences. In addition, we performed fluorescent in situ hybridization (FISH) analysis of seawater samples collected along the transect to provide a PCR-independent survey of class level PPE distribution patterns. We found the PPE community was dominated by members of the Prymnesiophyceae, Prasinophyceae and Mamiellophyceae. Interestingly, phylogenetic analysis revealed several novel Prymnesiophyceae and Prasinophyceae phylotypes (with only 85-96% identity to neighbouring sequences) within lineages for which cultured counterparts are unknown.     

Analysis of southeast Australian zooplankton observations of 1938-42 using synoptic oceanographic conditions

The research vessel Warreen obtained 1742 planktonic samples along the continental shelf and slope of southeast Australia from 1938-42, representing the earliest spatially and temporally resolved zooplankton data from Australian marine waters. In this paper, Warreen observations along the southeast Australian seaboard from 28°S to 38°S are interpreted based on synoptic meteorological and oceanographic conditions and ocean climatologies. Meteorological conditions are based on the NOAA-CIRES 20th Century Reanalysis Project; oceanographic conditions use Warreen hydrological observations, and the ocean climatology is the CSIRO Atlas of Regional Seas. The Warreen observations were undertaken in waters on average 0.45 °C cooler than the climatological average, and included the longest duration El Niño of the 20th century. In northern New South Wales (NSW), week time-scale events dominate zooplankton response. In August 1940 an unusual winter upwelling event occurred in northern NSW driven by a stronger than average East Australian Current (EAC) and anomalous northerly winds that resulted in high salp and larvacean abundance. In January 1941 a strong upwelling event between 28° and 33°S resulted in a filament of upwelled water being advected south and alongshore, which was low in zooplankton biovolume. In southern NSW a seasonal cycle in physical and planktonic characteristics is observed. In January 1941 the poleward extension of the EAC was strong, advecting more tropical tunicate species southward. Zooplankton abundance and distribution on the continental shelf and slope are more dependent on weekly to monthly timescales on local oceanographic and meteorological conditions than continental-scale interannual trends. The interpretation of historical zooplankton observations of the waters off southeast Australia for the purpose of quantifying anthropogenic impacts will be improved with the use of regional hindcasts of synoptic ocean and atmospheric weather that can explain some of the physically forced natural variability.     

Integration of biochemical, histochemical and toxicogenomic indices for the assessment of health status of mussels from the Tamar Estuary, U.K

The aim of this study was to examine whether a combination of biochemical, histopathological and toxicogenomic data could be used as a valuable tool for the assessment of biological risk associated with pollutants within the Tamar River and Estuary, S.W. England, U.K. Accordingly, biochemical and histopathological biomarkers (protein carbonyls, lipofuscin, neutral lipids, lysosomal stability [N-acetyl-β-hexosaminidase and neutral red], lysosomal volume, ferric reducing antioxidant power [FRAP] and malonaldehyde [MDA]) and gene expression profiles were assessed in 5 sites from the Tamar River and Estuary (Neal Point, Town Quay, Wilcove, Cremyll Ferry and Whitsand; and a reference site, Trebarwith Strand, N. Cornwall). PAHs were measured in mussel tissue and sediment and metals were measured in mussel tissue only. Data from the biomarkers was integrated into a Mussel Expert System (MES) model to produce a simple assessment of mussel stress. Clear gradients of mussel toxicity were identified by the biomarkers (with the exception of neutral lipids) with the highest impacted animals found furthest up the Tamar, whilst the MES was unable to identify a gradient of effect. Gene expression profiles also indicated a gradient of stress with the greatest number of significantly up- or down- regulated genes found at the uppermost 2 sites. The MES did, however, determine that mussels from all sites, except the reference site, were highly stressed; a conclusion that could not be inferred from the biomarker data alone. It is concluded that the MES is a valuable tool that permits integration and interpretation of complex sets of biomarker data by identifying the biological meaning of biomarker changes.     

Primary production and fluxes of organic carbon to the seabed in the Russian Arctic seas as a response to the recent warming

The primary production and fluxes of organic matter to the seabed and their variations were estimated in the Norwegian, Greenland, Barents, Kara, Laptev, East Siberian, and Chukchi seas in 2003–2008 on the basis of satellite and field data. When counting the open water area with the assumptions made for the assessment of the primary production in the regions hidden under clouds, the reliable trends of its variability (increasing) were revealed only in the Greenland, Barents, and Kara seas.     

Estimations of the parameters of the flux of sediments near the west coast of the Bakal’skaya Spit under the conditions of heavy storms in 2007

On the basis of the wind-energy method, we estimate the distributions of the parameters of a longshore flux of sediments formed near the west coast of the Bakal’skaya Spit (in the northwest part of the Crimea) under the conditions of heavy storms whose action caused a significant erosion of the west coast of the spit and retreat of the coastline in January and November 2007. The calculations are carried out by using the actual directions and velocities of the winds recorded in the investigated region. We analyze the trends of changes in the formation of the coastal zone caused by the nonuniform distribution of the intensity of longshore transportation of sediments. In analyzing the causes of formation of gullies in the barrier of the Bakal’skoe Lake and in the narrow distal part of the body of the spit, we make an attempt of interpretation of the quantities characterizing the force of the frontal action of waves. The obtained numerical results are confirmed by the data of field observations.     

Composition and secondary alterations of microfossils in sediments of the Ashadze-1 hydrothermal field (tropical Mid-Atlantic Ridge)

The first thorough analysis of microfossils from ore-bearing sediments of the Ashadze-1 hydrothermal field in the Mid-Atlantic Ridge sampled during cruise 26 of the R/V Professor Logachev in 2005 revealed the substantial influence of hydrothermal processes on the preservation of planktonic calcareous organisms, as well as on the preservation and composition of the benthic foraminifers. From the lateral and vertical distribution patterns and the secondary alterations of the microfossils, it is inferred that the main phase of the hydrothermal mineralization occurred in the Holocene. Heavy metals (Cu, Co, Cr, and Ag) were accumulated by foraminiferal tests and in their enveloping Fe-Mn crusts. The distribution of authigenic minerals replacing foraminiferal tests demonstrates local zoning related to the hydrothermal activity. There are three mineral-geochemical zones defined: the sulfide zone, the zone with an elevated Mg content, and zone of Fe-Mn crusts.     

Overlapping distributions of cryptic Scoloplos cf. armiger species in the western Wadden Sea

Unknowingly lumping cryptic species in biological monitoring studies hinders progress in understanding their functioning in a wide range of research fields including population dynamics, ecophysiology and community ecology. The common polychaete worm Scoloplos cf. armiger is a cryptic species complex comprising entirely different developmental modes: holobenthic and pelago-benthic development. In the northeast Atlantic, three putative species have been described on the basis of molecular data and a breeding study. We report on the development of a fast genotyping assay and on the occurrence and distribution of different molecular types in the western Wadden Sea. The genotyping assay consists of PCR-RFLP analysis by two enzymes of a mitochondrial (cox3-trnQ-nad6) DNA segment. A new, fourth type was observed and this was the only type whose geographical distribution was not uniform but instead skewed toward the eastern part of the study area. All three hitherto known types were also observed and these three displayed a significant difference in depth distribution within the study area. This is the first ecological difference reported for the ‘Subtidal Clade’ (SC) versus the ‘Type Locality Clade’ (TLC). The new type (‘Intertidal Clade 2’) had a similar distribution to what is known as the Intertidal Clade (IC). However, the most striking observation is the large degree of overlap between the depth distributions in the western Wadden Sea, where the clade names ‘Intertidal’ and ‘Subtidal’ do not necessarily reflect local species composition. The necessity to genotype Scoloplos cf. armiger in monitoring programs is emphasized.     

Origin and composition of fluid responsible for metasomatic processes in shear zones of the Bolshie Keivy tectonic nappe,baltic shield: Carbon isotope composition of graphite

Doklady Earth Sciences -