19 Result(s)
within
English
Earth Sciences
Physical Geography
Oliver Heiri
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Article
Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results
Five test runs were performed to assess possible bias when performing the loss on ignition (LOI) method to estimate organic matter and carbonate content of lake sediments. An accurate and stable weight loss wa...
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Article
Effect of low count sums on quantitative environmental reconstructions: an example using subfossil chironomids
The concentrations of chironomid remains in lake sediments are very variable and, therefore, chironomid stratigraphies often include samples with a low number of counts. Thus, the effect of low count sums on r...
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Article
9000 years of chironomid assemblage dynamics in an Alpine lake: long-term trends, sensitivity to disturbance, and resilience of the fauna
Subfossil chironomid analysis was applied to a sediment core from Sägistalsee, a small lake at present-day tree-line elevation in the Swiss Alps. During the whole 9000-year stratigraphy the chironomid fauna wa...
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Article
Within-lake variability of subfossil chironomid assemblages in shallow Norwegian lakes
Subfossil chironomids in the surface sediments of five small and shallow Norwegian lakes were studied to determine the within-lake variability of fossil assemblages, changes in chironomid assemblages with resp...
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Article
Sciaridae in lake sediments: indicators of catchment and stream contribution to fossil insect assemblages
The larval head capsules of Sciaridae (black fungus gnats) are transported into lakes from terrestrial habitats, in most cases via streams or rivers, and preserve well in lake sediments. The abundance of sciar...
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Article
Seasonal temperatures for the past ∼400 years reconstructed from diatom and chironomid assemblages in a high-altitude lake (Lej da la Tscheppa, Switzerland)
We analysed a 42 cm long sediment record from Lej da la Tscheppa, a high-altitude lake (2,616 m a.s.l.) in the Upper Engadine valley (Switzerland) for subfossil diatoms, chironomids and pollen. The chronology ...
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Article
Comparison between chironomid-inferred July temperatures and meteorological data AD 1850–2001 from varved Lake Silvaplana, Switzerland
Inferred temperatures from chironomids preserved in the varved sediment of Lake Silvaplana in the Eastern Swiss Alps were compared with instrumental data obtained from a meteorological station in Sils-Maria, o...
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Article
Open AccessTetraether membrane lipid distributions in water-column particulate matter and sediments: a study of 47 European lakes along a north–south transect
We studied the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) in water-column particulate matter and the top 5 cm of sediment from 47 lakes along a transect from southern Italy to the northern p...
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Article
Open AccessFossil chironomid δ13C as a proxy for past methanogenic contribution to benthic food webs in lakes?
We used a series of experiments to determine whether stable carbon isotope analysis of modern and fossil larval head capsules of chironomids allowed identification of their dietary carbon source. Our main focu...
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Article
Paleotemperature reconstruction in tropical Africa using fossil Chironomidae (Insecta: Diptera)
Fossil assemblages of chironomid larvae (non-biting midges) preserved in lake sediments are well-established paleothermometers in north-temperate and boreal regions, but their potential for temperature reconst...
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Article
Open Access500 years of trophic-state history of a hypertrophic Dutch dike-breach lake
We present a palaeolimnological study encompassing five centuries of trophic-state change of the dike-breach lake De Waay located on the Rhine-Meuse delta (the Netherlands). Diatom-inferred total phosphorus (T...
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Article
Open AccessLate Glacial and Holocene temperature changes at Egelsee, Switzerland, reconstructed using subfossil chironomids
A temperature reconstruction using chironomids was attempted at Egelsee, Switzerland, a site where pollen and macrofossil records showed a correspondence between vegetation and climatic changes inferred by oth...
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Article
Open AccessEfficiency of different mesh sizes for isolating fossil chironomids for stable isotope and radiocarbon analyses
We examined the effects of sieving with different mesh sizes on the efficiency of processing fossil chironomids from lake sediments for isotope analyses. Results obtained for three different sediments indicate...
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Article
Open AccessMidges of the genus Pseudodiamesa Goetghebuer (Diptera, Chironomidae): current knowledge and palaeoecological perspective
Larvae of the genus Pseudodiamesa Goetghebuer, which includes 12 described valid species and is divided by Makarchenko and Makarchenko (1999) into two species groups, Pseudodiamesa branickii group and Pseudodiame...
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Article
Open AccessHow does taxonomic resolution affect chironomid-based temperature reconstruction?
The resolution achievable for chironomid identifications has increased in recent years because of significant improvements in taxonomic literature. However, high taxonomic resolution requires more training for...
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Article
Testing intra-site transfer functions: an example using chironomids and water depth
Most calibration data sets used to infer past environmental conditions from biological proxies are derived from many sites. An alternative strategy is to derive the calibration data set from within a single si...
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Article
Are fossil assemblages in a single sediment core from a small lake representative of total deposition of mite, chironomid, and plant macrofossil remains?
How representative of the whole-lake fossil assemblage are analyses from a single sediment core taken in the centre of a small lake? This question was addressed in five shallow Norwegian lakes that ranged in l...
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Article
Global change revealed by palaeolimnological records from remote lakes: a review
Over recent decades, palaeolimnological records from remote sites have provided convincing evidence for the onset and development of several facets of global environmental change. Remote lakes, defined here as...
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Article
Open AccessAquatic invertebrate mandibles and sclerotized remains in Quaternary lake sediments
Subfossil remains of aquatic invertebrates found in lacustrine sediments are useful paleoenvironmental indicators. Strongly scleroticized chitinous body parts from the exoskeleton or exuviae from invertebrates...
