Turbidite sedimentology and history at DSDP Site 89-585

At Site 585 in the East Mariana Basin, a 900-m section of Aptian-Albian to Recent sediments was recovered. The upper 590 m are pelagic components (carbonate, siliceous, and clay); small-scale graded sequences and laminations are common. The underlying sediments are volcaniclastic sandstones with a large proportion of shallow-water carbonate debris; sedimentary structures including complete Bouma sequences, cross-laminae, and scouring are common. These structures indicate that the entire section was deposited by turbidity currents. The change in lithology upward in the section reflects the evolution of the surrounding seamounts, from their growth stages during the middle of the Cretaceous to the later subsidence phases. Several black layers containing pyritized organic debris and associated turbidite structures were cored near the Cenomanian/Turonian boundary; this material has been transported from the flanks of the seamounts where it was deposited within a shallow anoxic zone. Seismic data extends the stratigraphy across the entire Basin, showing the reflectors onlapping the seamounts, and indicating at least 1200 m of sediment at Site 585. The crust is placed at 6900 m after correcting for sediment loading, and the subsidence curve indicates that the Basin has been deeper than 5500 m since before the Aptian.

SIRGAS reference frame realization SIR11P01

To estimate the kinematics of the SIRGAS reference frame, the Deutsches Geodätisches Forschungsinstitut (DGFI) as the IGS Regional Network Associate Analysis Centre for SIRGAS (IGS RNNAC SIR), yearly computes a cumulative (multi-year) solution containing all available weekly solutions delivered by the SIRGAS analysis centres. These cumulative solutions include those models, standards, and strategies widely applied at the time in which they were computed and cover different time spans depending on the availability of the weekly solutions. This data set corresponds to the multi-year solution SIR11P01. It is based on the combination of the weekly normal equations covering the time span from 2000-01-02 (GPS week 1043) to 2011-04-16 (GPS week 1631), when the IGS08 reference frame was introduced. It refers to ITRF2008, epoch 2005.0 and contains 230 stations with 269 occupations. Its precision was estimated to be ±1.0 mm (horizontal) and ±2.4 mm (vertical) for the station positions, and ±0.7 mm/a (horizontal) and ±1.1 mm/a (vertical) for the constant velocities. Computation strategy and results are in detail described in Sánchez and Seitz (2011). The IGS RNAAC SIR computation of the SIRGAS reference frame is possible thanks to the active participation of many Latin American and Caribbean colleagues, who not only make the measurements of the stations available, but also operate SIRGAS analysis centres processing the observational data on a routine basis (more details in http://www.sirgas.org). The achievements of SIRGAS are a consequence of a successful international geodetic cooperation not only following and meeting concrete objectives, but also becoming a permanent and self-sustaining geodetic community to guarantee quality, reliability, and long-term stability of the SIRGAS reference frame. The SIRGAS activities are strongly supported by the International Association of Geodesy (IAG) and the Pan-American Institute for Geography and History (PAIGH). The IGS RNAAC SIR highly appreciates all this support.

Macroinvertebrate abundance and proportion of trait categories in river biotopes across England and Wales

There is a long tradition of river monitoring using macroinvertebrate communities to assess environmental quality in Europe. A promising alternative is the use of species life-history traits. Both methods, however, have relied on the time-consuming identification of taxa. River biotopes, 1-100 m**2 'habitats' with associated species assemblages, have long been seen as a useful and meaningful way of linking the ecology of macroinvertebrates and river hydro-morphology and can be used to assess hydro-morphological degradation in rivers. Taxonomic differences, however, between different rivers had prevented a general test of this concept until now. The species trait approach may overcome this obstacle across broad geographical areas, using biotopes as the hydro-morphological units which have characteristic species trait assemblages. We collected macroinvertebrate data from 512 discrete patches, comprising 13 river biotopes, from seven rivers in England and Wales. The aim was to test whether river biotopes were better predictors of macroinvertebrate trait profiles than taxonomic composition (genera, families, orders) in rivers, independently of the phylogenetic effects and catchment scale characteristics (i.e. hydrology, geography and land cover). We also tested whether species richness and diversity were better related to biotopes than to rivers. River biotopes explained 40% of the variance in macroinvertebrate trait profiles across the rivers, largely independently of catchment characteristics. There was a strong phylogenetic signature, however. River biotopes were about 50% better at predicting macroinvertebrate trait profiles than taxonomic composition across rivers, no matter which taxonomic resolution was used. River biotopes were better than river identity at explaining the variability in taxonomic richness and diversity (40% and <=10%, respectively). Detailed trait-biotope associations agreed with independent a priori predictions relating trait categories to near river bed flows. Hence, species traits provided a much needed mechanistic understanding and predictive ability across a broad geographical area. We show that integration of the multiple biological trait approach with river biotopes at the interface between ecology and hydro-morphology provides a wealth of new information and potential applications for river science and management.

Gene sequences of the lichen Cetraria aculeata

Lichens are symbioses between fungi (mycobionts) and photoautotrophic green algae or cyanobacteria (photobionts). Many lichens occupy large distributional ranges covering several climatic zones. So far, little is known about the large-scale phylogeography of lichen photobionts and their role in shaping the distributional ranges of lichens. We studied south polar, temperate and north polar populations of the widely distributed fruticose lichen Cetraria aculeata. Based on the DNA sequences from three loci for each symbiont, we compared the genetic structure of mycobionts and photobionts. Phylogenetic reconstructions and Bayesian clustering methods divided the mycobiont and photobiont data sets into three groups. An AMOVA shows that the genetic variance of the photobiont is best explained by differentiation between temperate and polar regions and that of the mycobiont by an interaction of climatic and geographical factors. By partialling out the relative contribution of climate, geography and codispersal, we found that the most relevant factors shaping the genetic structure of the photobiont are climate and a history of codispersal. Mycobionts in the temperate region are consistently associated with a specific photobiont lineage. We therefore conclude that a photobiont switch in the past enabled C. aculeata to colonize temperate as well as polar habitats. Rare photobiont switches may increase the geographical range and ecological niche of lichen mycobionts by associating them with locally adapted photobionts in climatically different regions and, together with isolation by distance, may lead to genetic isolation between populations and thus drive the evolution of lichens.

Late Quaternary carbonate and isotope stratigraphy of DSDP Site 90-594 east of South Island, New Zealand

The late Quaternary sequence off eastern South Island, New Zealand, consists of ~100 m of alternating bluish gray pelagic oozes and greenish gray hemipelagic oozes that extend uninterruptedly back to the Brunhes/Matuyama boundary (0.73 m.y.). A very high resolution (~2400 yr.) record of sediment texture, calcium carbonate content, and planktonic and benthic foraminiferal oxygen and carbon isotope composition demonstrates an in-phase cyclical fluctuation between the sedimentary parameters that closely correspond to the pelagic-hemipelagic sedimentation cycles and the isotope composition. Pelagic oozes, formed during interglacial periods of high eustatic sea level, are characterized by calcareous microfossils, relative enrichment in sand and clay sizes, high carbonate contents, reduced delta18O values, and increased delta13C values. Hemipelagic oozes, associated with glacial episodes and lowered eustatic sea level, include common terrigenous material and siliceous microfossils, are enriched in silt sizes, have low carbonate contents, high delta18O values, and low delta13C values. The history of alpine glaciations and associated erosion of the South Island of New Zealand, as expressed by the appearance of hemipelagic oozes, can be correlated directly with the major fluctuations of Northern Hemisphere ice sheets as expressed by the influence of eustatic sea-level changes on the oxygen isotope composition of both planktonic and benthic foraminifers. This high-accumulation-rate record contains conspicuous intervals of highfrequency, high-amplitude isotope variability including the presence of multiple glacial/interglacial intervals within single isotope stages, and offers one of the best sections cored to date for detailed study of the evolution and history of climate change over the last 0.75 m.y.