75 research outputs found
Bottom Melting on the Filchner-Ronne Ice Shelf, Antarctica, Using Different Mesasuring Techniques
Gravel pits support waterbird diversity in an urban landscape
We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space
Near-margin ice thickness from a portable radar: implications for subglacial water routing, Leverett Glacier, Greenland
Ice thickness measurements near the margin of the Greenland Ice Sheet (GrIS) are
relatively sparse, presenting issues for modelling ice flow dynamics, ice sheet change and
subglacial hydrology. We acquired ice thickness data at Leverett Glacier, western
Greenland, using a highly portable, low power commercially-available ice-penetrating
radar operating at 10-80 MHz. Imaging of the bed to depths of 270 m was possible using
this system. Our ice thickness measurements were incorporated into the BedMachine
model of bed elevation created using mass conservation methods. The new data
significantly modified the modelled ice thickness and routing of subglacial water in both
the Leverett and adjacent Russell Glacier. Though changes to the modelled basal
topography and subglacial hydrology are consistent with observations, our new data
unrealistically reduced the overall size of the Leverett hydrological catchment. Additional
ice thickness measurements are therefore required to realistically constrain subglacial
topography and subglacial hydrological routing in this area. Our work has significantly
enhanced our understanding of basal topography and subglacial hydrology of Leverett
Glacier, with implications for glacier dynamics and assessments of water piracy between
catchments in the marginal zone of the GrIS
A lake as a microcosm: reflections on developments in aquatic ecology
In the present study, we aim at relating Forbes' remarkable paper on "The lake as a microcosm", published 125 years ago, to the present status of knowledge in our own research group. Hence, we relate the observations Forbes made to our own microcosm, Lake Krankesjon in southern Sweden, that has been intensively studied by several research groups for more than three decades. Specifically, we focus on the question: Have we made any significant progress or did Forbes and colleagues blaze the trail through the unknown wilderness and we are mainly paving that intellectual road? We conclude that lakes are more isolated than many other biomes, but have, indeed, many extensions, for example, input from the catchment, fishing and fish migration. We also conclude that irrespective of whether lakes should be viewed as microcosms or not, the paper by Forbes has been exceptionally influential and still is, especially since it touches upon almost all aspects of the lake ecosystem, from individual behaviour to food web interactions and environmental issues. Therefore, there is no doubt that even if 125 years have passed, Forbes' paper still is a source of inspiration and deserves to be read. Hence, although aquatic ecology has made considerable progress over the latest century, Forbes might be viewed as one of the major pioneers and visionary scientists of limnology
No more lake balls (Aegagropila linnaei Kützing, Cladophorophyceae, Chlorophyta) in The Netherlands?
Glacio-Kinematic Analysis of ERS-1/2 SAR Data of the Antarctic Ice Shelf Ekströmisen and the Adjoining Inland Ice Sheet
Kartierung von wassergesättigten Firnschichten auf dem Kesselwandferner mit dem EMR-Verfahren
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