ALBERT

Beschreibung: Mg/Ca and stable oxygen isotope compositions (d18O) of planktic foraminifera tests are commonly used as proxies to reconstruct past ocean conditions including variations in the vertical water column structure. Accurate proxy calibrations require thorough regional studies, since parameters such as calcification depth and temperature of planktic foraminifera depend on local environmental conditions. Here we present radiocarbon-dated, modern surface sediment samples and water column data (temperature, salinity, and seawater d18O) from the Western Pacific Warm Pool. Seawater d18O (d18OSW) and salinity are used to calculate individual regressions for western Pacific surface and thermocline waters (d18OSW = 0.37 × S-12.4 and d18OSW = 0.33 × S-11.0). We combine shell d18O and Mg/Ca with water column data to estimate calcification depths of several planktic foraminifera and establish regional Mg/Ca-temperature calibrations. Globigerinoides ruber, Globigerinoides elongatus, and Globigerinoides sacculifer reflect mixed layer conditions. Pulleniatina obliquiloculata and Neogloboquadrina dutertrei and Globorotalia tumida preserve upper and lower thermocline conditions, respectively. Our multispecies Mg/Ca-temperature calibration (Mg/Ca = 0.26exp0.097*T) matches published regressions. Assuming the same temperature sensitivity in all species, we propose species-specific calibrations that can be used to reconstruct upper water column temperatures. The Mg/Ca temperature dependencies of G. ruber, G. elongatus, and G. tumida are similar to published equations. However, our data imply that calcification temperatures of G. sacculifer, P. obliquiloculata, and N. dutertrei are exceptionally warm in the western tropical Pacific and thus underestimated by previously published calibrations. Regional Mg/Ca-temperature relations are best described by Mg/Ca = 0.24exp0.097*T for G. sacculifer and by Mg/Ca = 0.21exp0.097*T for P. obliquiloculata and N. dutertrei.

Beschreibung: Surface and thermocline conditions of the Western Pacific Warm Pool (WPWP) reflect changes in regional and basin scale ocean and atmosphere circulations and in turn may affect climate globally. Previous studies suggest that a range of factors influences the WPWP on different timescales, however the precise forcings and mechanisms are unclear. Combining surface and thermocline records from sediment cores offshore Papua New Guinea we explore the influence of local and remote processes on the WPWP in response to astronomical forcing and changing glacial-interglacial boundary conditions over the past 110 kyr. We find that thermocline temperatures change with variations in Earth's obliquity with higher temperatures coinciding with high obliquity, which is attributed to variations in subduction and advection of the South Pacific Tropical Water. In contrast, rainfall variations associated with meridional migrations of the Intertropical Convergence Zone are primarily driven by changes in insolation due to precession. Records of bulk sedimentary Ti/Ca and foraminiferal Nd/Ca indicate an additional influence of obliquity, which, however, cannot unambiguously be related to changes in precipitation. Finally, our results suggest a thermocline deepening during the Last Glacial Maximum (LGM). A compilation of available proxy records illustrates a dipole-like pattern of LGM thermocline depth anomalies with a shoaling (deepening) in the northern (southern) WPWP. A comparison of the proxy compilation with an ensemble of Paleoclimate Model Intercomparison Project (PMIP) climate model simulations reveals that the spatial pattern of LGM thermocline depth anomalies is mainly attributable to a contraction of the Pacific Walker circulation on its western side.

Beschreibung: Strong earthquakes cause large changes in the station positions and velocities of the geodetic reference stations; i.e., the global ITRF (International Terrestrial Reference Frame) and its regional densifications like SIRGAS (Sistema de Referencia Geocéntrico para Las Américas) in Latin America and the Caribbean. To ensure the long-term stability of the geodetic reference frames, the transformation of station positions between different epochs requires the computation of reliable continuous surface deformation (or velocity) models. This data set contains the new continental continuous crustal deformation model VEMOS2015 (Velocity Model for SIRGAS 2015) for Latin America and the Caribbean inferred from GNSS (GPS+GLONASS) measurements gained after the strong earthquakes occurred in 2010 in Chile and Mexico. It is based on a multi-year velocity solution for a network of 456 continuously operating GNSS stations covering a five years period from March 14, 2010 to April 11, 2015. VEMOS2015 is computed using the least square collocation (LSC) approach with empirically determined covariance functions.

Beschreibung: We provide a present-day surface-kinematics model for the Alpine region and surroundings based on a high-level data analysis of a network of about 300 continuously operating GNSS (GPS+GLONASS) stations with observations collected over 12.4 years. Based on the network station velocities, a continuous kinematic field is derived using a geodetic least-squares collocation approach with empirically determined covariance functions. Main results are (1) a deformation model, (2) a continuous surface-kinematic (velocity) field, and (3) a strain field consistently assessed for the entire Alpine mountain belt. The core contribution of this work is the homogeneous analysis of a large number of freely available data from GNSS stations located in the Alpine region, using unified processing standards and a common reference frame for the complete time-span covered by the observations. The GNSS network solution refers to the reference frame IGb08, epoch 2010.0. The mean precision of the station positions at the reference epoch is ±1.1 mm in N and E and ±2.3 mm in height. The mean precision of the station velocities is ±0.2 mm/a in N and E and ±0.4 mm/a in the height. The averaged accuracy of the horizontal and vertical deformation models inferred from the pointwise station velocities are ±0.2 mm/a and ±0.3 mm/a, respectively. The deformation model as well as the continuous velocity and strain fields are given in a grid of 25 km x 25 km covering the region between longitudes 4°E and 16°E and latitudes 43°N and 49°N.

Beschreibung: We performed the field-work during the dry (March 2014) and reainy season (May and June 2014) at the species type locality: Cerro Socopó, located at central-west region between Falcón, Lara and Zulia states, Venezuela. Socopó is a small and isolated mountain (1.571 m) belonging to the Ziruma mountains, and represents a relict of tropical mountain forest surrounded by semi-arid vegetation and grassland. This area is home to 312 species of vertebrates, including endangered and endemic amphibians species like Mannophryne lamarcai, Leptodactylus magistris and Dendropsophus amicorum. These forest and species are severely threatened by cattle ranch and illegal timber extraction, with forest formations only above 1000 meters. Despite this, no legal protected figure has been established in the area. We identified a 2.5 km secondary road transect within the study area based on the following criteria: 1) it cover different habitat types (streams and lagoons); and 2) it within the altitudinal gradient described for the specie (1,040 to 1,363 m). We identified three sampling points throughout the transect located in the vicinity of wetland habits: socopo1, socopo2 and socopo4. We did two types of recordings: 1) high quality recordings to characterize the advertisement call for M. lamarcai, non described to date (socopo4), and 2) recordings in different sampling points to evaluate call detectors performance in different acoustic scenarios (in all three localities).

Beschreibung: The phylogenetic composition of the heterotrophic microbial community is depth stratified in the oceanic water column down to abyssopelagic layers. In the layers below the euphotic zone, it has been suggested that heterotrophic microbes rely largely on solubilized particulate organic matter as a carbon and energy source rather than on dissolved organic matter. To decipher whether changes in the phylogenetic composition with depth are reflected in changes in the bacterial and archaeal transporter proteins, we generated an extensive metaproteomic and metagenomic dataset of microbial communities collected from 100- to 5,000-m depth in the Atlantic Ocean.