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Berlin Brandenburg

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  • 1
    Language: English
    In: Plant and Soil, 1 June 2012, Vol.355(1/2), pp.407-416
    Description: Background and aims Environmental factors such as climate and atmospheric CO2 control inputs of plant-derived matter into soils, which then determines properties and decomposition of soil organic matter. We studied how dissolved organic matter (DOM) in forest floors responded to six years of litter fall manipulation at a spruce site. Methods Experimental treatments included (i) ambient litter fall, as well as (ii) reduction or (iii) increase of litter fall, each by 80%. Results Reduced litter input did not change fluxes of dissolved organic carbon (DOC), which suggests that much of the mobile DOM in forest floors is not from recent litter but older, partly degraded material. Litter addition increased DOC fluxes over 6 years by 68% (Oi), 23% (Oe) and 12% (Oa). This was mainly due to excessive DOM production in Oi horizons, while net DOM production in Oe and Oa horizons decreased. Upon litter addition, aromaticity and molecule complexity of DOM released from the Oi horizon increased, but decreased for DOM leaving Oa horizons. The results suggest that DOM production by lignin degradation was enhanced in Oi but reduced in Oe and Oa horizons upon litter addition. Conclusions Recent litter is not an important source for DOM entering mineral soils, but increased litter input changes organic matter decomposition, thus affecting fluxes and properties of DOM within forest floors.
    Keywords: Biological sciences -- Biology -- Botany ; Applied sciences -- Materials science -- Materials ; Biological sciences -- Agriculture -- Agricultural sciences ; Biological sciences -- Agriculture -- Agricultural sciences ; Biological sciences -- Agriculture -- Agricultural sciences ; Biological sciences -- Agriculture -- Agricultural sciences ; Biological sciences -- Agriculture -- Agricultural sciences ; Biological sciences -- Agriculture -- Agricultural sciences ; Physical sciences -- Chemistry -- Chemical compounds ; Biological sciences -- Agriculture -- Agricultural sciences
    ISSN: 0032079X
    E-ISSN: 15735036
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  • 2
    Language: English
    In: Plant and Soil, 2012, Vol.355(1), pp.407-416
    Keywords: Litter manipulation ; Dissolved organic matter ; Field experiment ; Soil organic matter
    ISSN: 0032-079X
    E-ISSN: 1573-5036
    Source: Springer Science & Business Media B.V.
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  • 3
    Language: English
    In: Journal of Hydrology, 2010, Vol.393(3), pp.174-185
    Description: This study conducts a broad sensitivity analysis, taking into account the influence of initial soil moisture content in two soil layers, layer depths, event properties, and two infiltration models. A distributed hydrology and soil erosion model (LISEM) is used. Using the terrain data from the Catsop research catchment and two different rainfall events, the sensitivity of discharge is investigated for a range of pre-event soil moisture contents (0.1–0.40 cm cm ) in two-layers for a two-layer Green–Ampt as well as Richards infiltration model. The sensitivity of the predicted discharge to the initial condition of soil moisture appears to depend highly on all factors: infiltration model, event properties, topsoil/subsoil depth configuration and the level of the initial condition itself. There are interaction effects between all the factors. However, the effect of the different infiltration models is most pronounced. The Green–Ampt model shows less sensitivity to moisture content variation of both top and subsoil. Top/subsoil depth configuration rarely influences the results of the Green–Ampt model. The Richards model shows a highly variable discharge – initial soil moisture relation with changing rainfall intensity and topsoil/subsoil depth configurations. Two methods of sensitivity analysis, relative sensitivity and One factor-At-a Time sensitivity, have been used. The two methods gave comparable results. Depending on the other parameter values, 1% changes in topsoil moisture content resulted into 0.8–1.81% and 0.03–3.5% changes in total discharge predicted by the Green–Ampt and Richards models, respectively.
    Keywords: Soil Moisture ; Infiltration ; Rainfall-Runoff ; Sensitivity Analysis ; Lisem ; Geography
    ISSN: 0022-1694
    E-ISSN: 1879-2707
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  • 4
    In: Freshwater Biology, July 2014, Vol.59(7), pp.1522-1531
    Description: The distance–decay relationship has been claimed to be a predictor for biological diversity because it unites several ecological phenomena such as dispersal ability and environmental structure. The effect of long‐term disturbances on distance decay, however, has been widely overlooked, especially for microorganisms. We examine the effect of eutrophication on the distance–decay relationship in communities of attached diatoms in three peatland areas: mesotrophic, eutrophic and hypertrophic. The study follows a spatially explicit sampling scheme, collecting evenly spaced samples along 6‐km sampling tracks. The three areas shared 24% of the total number of species, but the different nutrient levels in the three areas are reflected by the prominence of low profile and planktonic diatom species. Our study demonstrates that eutrophication can affect distance–decay relationships by decreasing turnover rates in microorganisms. Diatom communities are shown to be constrained by both environmental and spatial features, whose relative importance depends on the degree of eutrophication. Under eutrophic conditions, species are filtered from the regional species pool and community structure responds strongly to environmental factors (water chemistry variables and depth), while in mesotrophic environments, purely spatial processes play a prominent role in structuring diatom communities. These findings reveal that homogenisation of communities triggered by environmental disturbance is an ecological phenomenon of importance in the microbial world.
    Keywords: Beta Diversity ; Diatoms ; Distance Decay ; Microorganisms ; Turnover
    ISSN: 0046-5070
    E-ISSN: 1365-2427
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  • 5
    In: Significance, October 2013, Vol.10(5), pp.40-42
    Description: Where does a seagull spend its day? Overcrowded diagrams don't help you to see it. More cunning designs show it all clearly. and describe how visualising the geography of time and movement supports the study of animal ecology.
    Keywords: Gulls;
    ISSN: 1740-9705
    E-ISSN: 1740-9713
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  • 6
    Language: English
    In: Current Biology, 22 January 2018, Vol.28(2), pp.275-279.e2
    Description: Compass orientation is central to the control of animal movement from the scale of local food-caching movements around a familiar area in parids [ ] and corvids [ ] to the first autumn vector navigation of songbirds embarking on long-distance migration [ ]. In the study of diurnal birds, where the homing pigeon, , has been the main model, a time-compensated sun compass [ ] is central to the two-step map-and-compass process of navigation from unfamiliar places, as well as guiding movement via a representation of familiar area landmarks [ ]. However, its use by an actively navigating wild bird is yet to be shown. By phase shifting an animal’s endogenous clock, known as clock-shifting [ ], sun-compass use can be demonstrated when the animal incorrectly consults the sun’s azimuthal position while homing after experimental displacement [ ]. By applying clock-shift techniques at the nest of a wild bird during natural incubation, we show here that an oceanic navigator—the Manx shearwater, —incorporates information from a time-compensated sun compass during homeward guidance to the breeding colony after displacement. Consistently with homing pigeons navigating within their familiar area [ ], we find that the effect of clock shift, while statistically robust, is partial in nature, possibly indicating the incorporation of guidance from landmarks into movement decisions. Padget et al. show that a wild bird makes use of a time-compensated sun compass during active navigation. By measuring the minute-by-minute orientation of GPS-tracked Manx shearwaters homing under clock shift from distant release sites, the authors demonstrate that a sun compass is fundamental even once visual landmarks are available.
    Keywords: Bird Navigation ; Compass Orientation ; Sun Compass ; Shearwater ; Seabird ; Clock Shift ; Biology
    ISSN: 0960-9822
    E-ISSN: 1879-0445
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  • 7
    Language: English
    In: PLoS ONE, 01 January 2014, Vol.9(10), p.e109486
    Description: This study describes in vivo cell turnover (the balance between cell proliferation and cell loss) in eight marine sponge species from tropical coral reef, mangrove and temperate Mediterranean reef ecosystems. Cell proliferation was determined through the incorporation of 5-bromo-2'-deoxyuridine...
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 8
    Language: English
    In: Freshwater Biology, 2014, Vol.59, pp.1522-5070
    Description: The distance–decay relationship has been claimed to be a predictor for biological diversity because it unites several ecological phenomena such as dispersal ability and environmental structure. The effect of long-term disturbances on distance decay, however, has been widely overlooked, especially for...
    Keywords: Beta Diversity ; Diatoms ; Distance Decay ; Microorganisms ; Turnover
    ISSN: 0046-5070
    Source: NARCIS (National Academic Research and Collaborations Information System)
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  • 9
    In: Proceedings of the Royal Society B, 2010, Vol.277(1687), pp.1505-1511
    Description: Numerous animals move vast distances through media with stochastic dynamic properties. Avian migrants must cope with variable wind speeds and directions en route , which potentially jeopardize fine-tuned migration routes and itineraries. We show how unpredictable winds affect flight times and the use of an intermediate staging site by red knots ( Calidris canutus canutus ) migrating from west Africa to the central north Siberian breeding areas via the German Wadden Sea. A dynamic migration model incorporating wind conditions during flight shows that flight durations between Mauritania and the Wadden Sea vary between 2 and 8 days. The number of birds counted at the only known intermediate staging site on the French Atlantic coast was strongly positively correlated with simulated flight times. In addition, particularly light-weight birds occurred at this location. These independent results support the idea that stochastic wind conditions are the main driver of the use of this intermediate stopover site as an emergency staging area. Because of the ubiquity of stochastically varying media, we expect such emergency habitats to exist in many other migratory systems, both airborne and oceanic. Our model provides a tool to quantify the effect of winds and currents en route .
    Keywords: Research articles
    ISSN: 0962-8452
    E-ISSN: 1471-2945
    E-ISSN: 14712954
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  • 10
    Language: English
    In: The Journal of experimental biology, September 2006, Vol.209(Pt 18), pp.3489-98
    Description: During non-migratory flight, gulls (Larids) use a wide variety of flight strategies. We investigate the extent to which the energy balance of a bird explains flight strategy selection. We develop a model based on optimal foraging and aerodynamic theories, to calculate the ground speeds and airspeeds at which a gull is expected to flap or soar during foraging flight. The model results are compared with observed flight speeds, directions, and flight strategies of two species of gulls, the black-headed gull Larus ridibundus and the lesser black-backed gull Larus fuscus. The observations were made using a tracking radar over land in The Netherlands. The model suggests that, especially at combinations of low ground speed (approximately 5-10 m s(-1)), high air speed (approximately 20-25 m s(-1)) and low ground and air speed, gulls should favor soaring flight. At intermediate ground and air speeds the predicted net energy gain is similar for soaring and flapping. Hence the ratio of flapping to soaring may be higher than for other air and ground speed combinations. This range of speeds is broadest for black-headed gulls. The model results are supported by the observations. For example, flapping is more prevalent at speeds where the predicted net energy gain is similar for both strategies. Interestingly, combinations of air speed and flight speed that, according to the model, would result in a loss of net energy gain, were not observed. Additional factors that may influence flight strategy selection are also briefly discussed.
    Keywords: Flight, Animal ; Charadriiformes -- Physiology
    ISSN: 0022-0949
    E-ISSN: 14779145
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