ALBERT

Description: Stratigraphy, sedimentology and paleoecology of Mesozoic continental sequences in the Depressao periferica, Rio Grande do Sui, Brazil, are subject of a DFG (German Research Foundation) research project. Results of the first two years period of activities in which the Geologicai-Paleontological Institutes of the Universities of Kiel and Frankfurt/M. in collaboration with the Departamento de Geociencias, University of Santa Maria in Camobi, RS, were involved are reported here. A second phase of field activities is planned for the time period from fall 1993 to the spring of 1995. The stratigraphic boundaries of the investigation are the underlying sediments of the Permian Passa Dais-Series and the overlying basalts of the Serra Geral Formation, covering the time span of 235 Ma to 133 Ma. A subordinate, chronostratigraphic system encompassing the sediments of this time period has yet to be established and extensive hiatuses are to be expected. Correlations with the lschigualasto Formation in NW-Argentina support the assumption that the upper Santa Maria Formation (Aiemoa member) falls in the mid Carnian. This is the only reasonable certain chronostratigraphic date from the Mesozoic of the Depressao periferica established at the present time. The classical tetrapod sites of the Triassic Santa Maria Formation all fall within the Alemoa-Member, the sediments of which were deposited under in part evaporitic conditions on playa mud flats. Evidence points to isochronic sedimentation and discounts the possibility of a diachronic genesis. The Santa Maria Formation and the underlying Sanga do Cabral Formation are placed together in the Rio do Rasta Subgroup as a genetic unit in accordance with the original definition, which conflicts with present day usage of the names. The Rio do Rasto Subgroup pinches out west of Sao Francisco do Assis and east of the Taquarl river. The entire Rio do Rasto Formation is enclosed in eolic sediments, indicating an extensive sedimentation complex arising from a persistently subsiding playa areal within the Botucatu desert. Beyond the range of the Rio do Rasto Subgroup, it is difficult or impossible to distinguish between the eolic sediments of the older, underlying Rosario do Sui Formation and the overlying, younger Botucatu Sandstone Member. As such, the entire paleogeographically and genetically uniform sedimentation complex is compiled together under the term Botucatu Group. The Sanga do Cabral Formation is characterized by an abundance of detritic micas (muscovite and biotite). K/ Ar dating have indicated a preliminary age for muscovite of 418 ± 8 Ma and 423.5 ± 9.7 Ma. Presumably, they originated from volcanites, subvolcanites and pyroclastics of the Camaqua Group (Brasiliano molasse). As such, the Precambrian/ lower Paleozoic Escudo Sui in Rio Grande do Sui was exposed and eroded to the level found today at the time of deposition of the Sanga do Cabral Formation.

Description: research

Description: Kohlenstoff-Umsatz und -Bilanz des Bodens eines Buchenwald- Ökosystems auf Kalkgestein. Ziel der Arbeit war die Beantwortung der Frage, ob sich der C-Speicher Boden eines Kalkbuchenwald-Ökosystems im Zustand des Fließgleichgewichtes oder in einem auf- bzw. abbauenden Ungleichgewichtszustand befindet. Dazu wurden die CO2 -Abgaberaten des Bodens ,als Outputgröße mit einem Absaugverfahren, einer modifizierten Glockenme- thode und einem Partialdruck-Gradienten-Rechenansatz be- stimmt und dem C-Eintrag gegenübergestellt. Die CO2 Abgaberaten des Bodens schwankten zwischen 20 (Winter) und 300 mg CO2 .m-2.h-1 (Sommer). Die Beziehung zwischen der Höhe der C02 -Abgaberate, der Temperatur und dem Wassergehalt des Bodens ließ sich in einer multiplen line- 2 aren Regressionsgleichung darstellen (r ≈0.80). Einem C-Eintrag von 282 g.m-2 .a-1standen C-Verluste von )06 g.m- .a- gegenüber. Der Differenzbetrag wurde auf die Wurzelatmung der Bäume zurückgeführt. Die C-Bilanz des Bo-dens erscheint somit ausgeglichen. Die rechnerischen Antei- le des Streufalles, der Wurzelstreu und der Wurzelatmung an der Gesamt-C02 -Abgabe des Bodens liegen bei 61, 31 und 8%. Durch Messungen der C02 -Konzentrationen der Gasphase im Solum und anstehenden Gesteinsverband konnten wertvolle Erkenntnisse über die ökologischen Eigenschaften des Standortes gewonnen werden. So liegen die CO2 Konzentrationen im Waldboden mit max. 0.8 Val. %deutlich unter den Werten ackerbaulich genutzter Standorte. Die gegen Ende des Untersuchungszeitraumes in 100 - 250 cm Tiefe des aufgelockerten Kalksteinverbandes gemessenen C02 Partialdrücke stimmen mit den anhand von Sicker- und Quell wasseranalysen errechneten Gleichgewichts-C02 Partialdrücken überein.

Description: thesis

Description: Due to the remoteness and di culty to access the snow covered polar regions, ski-equipped aircraft are an indispensable tool for polar research. The Alfred Wegener Institute has a long tradition in airborne polar science – starting with the aircraft Polar1 and Polar2 in 1983. In 2007 the rst Basler BT-67 (Polar5) and in 2011 the second Basler BT-67 (Polar6) were brought into service and replaced Polar2 and Polar4. They carry a variety of scienti c equipment for investigation of the lithosphere, atmosphere and cryosphere and all their interactions. Beside being deployed for science missions, the aircraft are also part of the Dronning Maud Land Air Network (DROMLAN), a logistical partnership to transport equipment and personnel to various stations in Dronning Maud Land, Antarctica.

Description: Soil porosity is the fraction of total volume occupied by pores or voids measured at matric potential 0. To measure soil porosity, soil samples were taken from each plot using sample rings with an internal diameter of 57 mm and height of 40.5 mm (inner volume of Vs=100 cm**3). The samples were placed on a sand bed box with water level set to allow saturation of the samples with water. After 48 h the samples were weighed (ms), oven dried at 105 °C and weighed again to determine the dry weight (md). We calculated soil porosity (n [%]) using the density of water (pw=1 g cm**-3), n=100 * (mw-md) / (pw*Vs). To account for the spatial variation of soil properties, three replicates were taken per plot, approximately 2, 3 and 4 weeks after the flood that occurred at the field site during June 2013. Data are the average soil porosity values per plot. All data where measured in the main experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown in the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, or 4 functional groups). Plots were maintained by bi-annual weeding and mowing.

Description: This data set contains measurements of soil bulk density in different depth layers. Data presented here is from the Main Experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained in general by bi-annual weeding and mowing. Since 2010, plot size was reduced to 5 x 6 m and plots were weeded three times per year. Soil bulk density was determined in spring from undisturbed soil samples to a depth of 30 cm. Three soil cores per plot were taken with a split tube sampler with an inner diameter of 4.8 cm and separated in depth increments of five cm. The bulk material was passed through a sieve with 2 mm mesh size, dried to constant weight at 40 °C and subsequently weighed to calculate the density. Paired sampling was chosen to avoid additional spatial variability (Lal et al., 2000), which means that three of the five sampling locations of 2002 bulk density measurement, that were in the core area of the plots, were chosen for the repeated sampling. The spatial distance of the paired soil samples were less than 30 cm.

Description: This data set contains measurements of soil bulk density in different depth layers. Data presented here is from the Main Experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained in general by bi-annual weeding and mowing. Since 2010, plot size was reduced to 5 x 6 m and plots were weeded three times per year. Soil bulk density was determined in spring from undisturbed soil samples to a depth of 100 cm. Soil cores were taken with a metal bulk density ring of ten cm height and partly pooled to obtain depth increments with a resolution of ten cm from ground level to 40 cm depth and 20 cm from 40 cm to 100 cm depth. The bulk material was passed through a sieve with 2 mm mesh size, dried to constant weight at 105 °C and subsequently weighed to calculate the density. In 2002, bulk density was measured at 27 locations before plot establishment. Two of them are now reference plots and thus not included in this data set. The chosen plots represented a spatial gradient across the field site and resulted in average soil bulk density estimations at the beginning of the experiment.