7 resultados para Bee

em Publishing Network for Geoscientific


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Wild bee species abundance based on combined flight traps (yellow funnels with perspex windows) placed at ecotones between semi-natural habitats and agricultural fields. Design: six agricultural dominated landscapes of 4x4 km with one trap per square km in Saxony-Anhalt (Germany), activity of traps in late spring-early summer (three sampling rounds) and late summer (three sampling rounds).

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Wild bee species abundance based on combined flight traps (yellow funnels with perspex windows) placed at ecotones between semi-natural habitats and agricultural fields. Design: six agricultural dominated landscapes of 4x4 km with one trap per square km in Saxony-Anhalt (Germany), activity of traps in late spring-early summer (three sampling rounds) and late summer (three sampling rounds).

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Wild bee species abundance based on combined flight traps (yellow funnels with perspex windows) placed at ecotones between semi-natural habitats and agricultural fields. Design: six agricultural dominated landscapes of 4x4 km with one trap per square km in Saxony-Anhalt (Germany), activity of traps in late spring-early summer (three sampling rounds) and late summer (three sampling rounds).

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In 2001 we started as part of the EU FP5 project Greenveins monitoring of insect communities in the normal landscape of Saxony-Anhalt (Germany), which is dominated by agricultural use. We selected four landscape sites of 4x4 km and recorded insects using combined flight traps, combining the ideas of window and yellow pan traps (see Duelli et al., 1999). Traps consist of a yellow funnel (25 cm diameter) filled with water (preserving agent added) and two perspex windows mounted in a way that they are crossed in the center. Within each square km of a site one trap was placed at ecotones between semi-natural habitats and agricultural fields (16 traps per site). Traps were operated in late spring-early summer (three sampling rounds) and late summer (three sampling rounds). Follow-up sampling started in 2010 as long-term monitoring within the TERENO project (www.tereno.net), contributing to the LTER network (Long-Term Ecosystem Research) in Germany (www.lter-d.de) and internationally as well (www.lter-europe.net). Metadata about the sites and related activities and data sets can be found in the DEIMS Repository for Research Sites and Datasets (https://data.lter-europe.net/deims/). In 2010 another two landscapes were added and yearly sampled in the same way. Due to long processing time of trapped insects data of follow-up years will be available about 18 months after trapping.

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Wild bee species abundance based on combined flight traps (yellow funnels with perspex windows) placed at ecotones between semi-natural habitats and agricultural fields. Design: six agricultural dominated landscapes of 4x4 km with one trap per square km in Saxony-Anhalt (Germany), activity of traps in late spring-early summer (three sampling rounds) and late summer (three sampling rounds).

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Wild bee species abundance based on combined flight traps (yellow funnels with perspex windows) placed at ecotones between semi-natural habitats and agricultural fields. Design: six agricultural dominated landscapes of 4x4 km with one trap per square km in Saxony-Anhalt (Germany), activity of traps in late spring-early summer (three sampling rounds) and late summer (three sampling rounds).

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We determined changes in equatorial Pacific phosphorus (µmol P/g) and barite (BaSO4; wt%) concentrations at high resolution (2 cm) across the Paleocene/Eocene (P/E) boundary in sediments from Ocean Drilling Program (ODP) Leg 199 Site 1221 (153.40 to 154.80 meters below seafloor [mbsf]). Oxide-associated, authigenic, and organic P sequentially extracted from bulk sediment were used to distinguish reactive P from detrital P. We separated barite from bulk sediment and compared its morphology with that of modern unaltered biogenic barite to check for diagenesis. On a CaCO3-free basis, reactive P concentrations are relatively constant and high (323 µmol P/g or ~1 wt%). Barite concentrations range from 0.05 to 5.6 wt%, calculated on a CaCO3-free basis, and show significant variability over this time interval. Shipboard measurements of P and Ba in bulk sediments are systematically lower (by ~25%) than shore-based concentrations and likely indicate problems with shipboard standard calibrations. The presence of Mn oxides and the size, crystal morphology, and sulfur isotopes of barite imply deposition in sulfate-rich pore fluids. Relatively constant reactive P, organic C, and biogenic silica concentrations calculated on a CaCO3-free basis indicate generally little variation in organic C, reactive P, and biogenic opal burial across the P/E boundary, whereas variable barite concentrations indicate significant changes in export productivity. Low barite Ba/reactive P ratios before and immediately after the Benthic Extinction Event (BEE) may indicate efficient nutrient burial, and, if nutrient burial and organic C burial are linked, high relative organic C burial that could temporarily drawdown CO2 at this site. This interpretation requires postdepositional oxidation of organic C because organic C to reactive P ratios are low throughout the section. After the BEE, higher barite Ba/reactive P ratios combined with higher barite Ba concentrations may imply that higher export productivity was coupled with unchanged reactive P burial, indicating efficient nutrient and possibly also organic C recycling in the water column. If the nutrient recycling is decoupled from organic C, the high export production could be indicative of drawdown of CO2. However, the observation that organic C burial is not high where barite burial is high may imply that either C sequestration was restricted to the deep ocean and thus occurred only on timescales of the deep ocean mixing or that postdepositional oxidation (burn down) of organic matter affected the sediments. The decoupling of barite and opal may result from low opal preservation or production that is not diatom based.