Efficient separation of subfossil Chironomidae from lake sediments

Walker, Ian R.; Paterson, C. G.

doi:10.1007/bf00032107

Cited by 49 publications

(30 citation statements)

References 9 publications

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“…The sub-samples were sieved using 233 µm and 85 µm sieve, respectively (WALKER & PATERSON, 1985). The fraction retained on the sieve was manually sorted at 7-40 magnifications in a counting tray.…”

Section: Methodsmentioning

confidence: 99%

Subfossil chironomids (Diptera, Chironomidae) in three Tatra Mountain lakes (Slovakia) on an acidification gradient

Kubovčík

Bitušík

2006

Biologia

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Three lakes were studied in the High Tatra Mountains at altitudes from 2000 to 2157 m a.s.l., which represent three categories of acidity status recognised in the Tatra lakes in the 1980s: non-acidified, acidified, and strongly acidified. Subfossil chironomid remains from dated sediment cores covering ca. throughout 200 years were analysed. The chironomid thanatocoenoses of all cores layers reflected ultra-oligotrophic non-acidified conditions in Ľadové pleso. Nevertheless, the finding of the acid-tolerant species Zalutschia tatrica in littoral samples in 1980s indicates that the littoral zone was more influenced by acidification than deeper areas of the lake. Three stages of lake developmental history can be distinguished in the acidified lake Vyšné Wahlenbergovo pleso based on the chironomid subfossil record: the pre-acidification stage before the 1920s, the anthropogenic acidification stage between the 1920-1980s, and the recovery of the lake from the end of the 1980s. The period of acidification was accompanied by a decline in chironomid numbers, while chironomid fauna composition was unchanged during the whole investigated history of the lake. None of the chironomid taxa present prior to the acidification period disappeared during the peak of acidification. The most apparent change in the sediment record taken from the strongly acidified lake Starolesnianske pleso was recognised in the layers corresponding to the period 1960-1980. It is characterised by the disappearance of the dominant acid-sensitive Tanytarsus lugens group and the dominance of acidtolerant Tanytarsus gregarius group. The most recent chironomid assemblage probably benefits from the amount of food resources as a result of increased lake productivity induced by acidification.

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Section: Methodsmentioning

confidence: 99%

Subfossil chironomids (Diptera, Chironomidae) in three Tatra Mountain lakes (Slovakia) on an acidification gradient

Kubovčík

Bitušík

2006

Biologia

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“…Fossil diatom assemblages were analysed quantitatively in aqueous suspensions of undigested sediment (Kling 1998). Sample processing for fossil midge analysis followed standard techniques (Walker & Patterson 1985), using a 100 µm sieve to extract fossils from the sediment matrix.…”

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confidence: 99%

History and timing of human impact on Lake Victoria, East Africa

Verschuren

Johnson

Kling

et al. 2002

Proc. R. Soc. Lond. B

348

261

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Lake Victoria, the largest tropical lake in the world, suffers from severe eutrophication and the probable extinction of up to half of its 500+ species of endemic cichlid fishes. The continuing degradation of Lake Victoria's ecological functions has serious long-term consequences for the ecosystem services it provides, and may threaten social welfare in the countries bordering its shores. Evaluation of recent ecological changes in the context of aquatic food-web alterations, catchment disturbance and natural ecosystem variability has been hampered by the scarcity of historical monitoring data. Here, we present highresolution palaeolimnological data, which show that increases in phytoplankton production developed from the 1930s onwards, which parallels human-population growth and agricultural activity in the Lake Victoria drainage basin. Dominance of bloom-forming cyanobacteria since the late 1980s coincided with a relative decline in diatom growth, which can be attributed to the seasonal depletion of dissolved silica resulting from 50 years of enhanced diatom growth and burial. Eutrophication-induced loss of deep-water oxygen started in the early 1960s, and may have contributed to the 1980s collapse of indigenous fish stocks by eliminating suitable habitat for certain deep-water cichlids. Conservation of Lake Victoria as a functioning ecosystem is contingent upon large-scale implementation of improved land-use practices.

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“…Previous studies have examined the effect of different mesh sizes on chironomid sample processing. However, these studies mainly examined the effect of mesh size on the representativeness of chironomid assemblages identified and enumerated under the light microscope (Walker and Paterson 1985;Verschuren and Eggermont 2007) and no studies are available that document the effects of the mesh size used during sieving on the sorting time of chironomid samples. In this study we assess the effect of mesh size on fossil chironomid sample mass and processing time, with the aim of providing a recommendation for the most time-efficient mesh size to be used to concentrate fossil chironomids for stable isotope analyses and AMS radiocarbon dating.…”

Section: Introductionmentioning

confidence: 99%

“…The choice of the commonly used ~100 µm mesh size for sieving sediments is based on the observation by Walker and Paterson (1985) that most head capsules are larger than 100 µm in diameter and thus retained on a 100 µm sieve. Even the sorting of 50-100 head capsules per sample commonly used in palaeoecological analyses can take an analyst several hours for sediments with large amounts of obscuring debris.…”

Section: Introductionmentioning

confidence: 99%

Stable carbon isotopes of invertebrate remains: do they reveal past methane release from lakes?

Hardenbroek

2012

Quaternary International

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Efficient separation of subfossil Chironomidae from lake sediments

Cited by 49 publications

References 9 publications

Subfossil chironomids (Diptera, Chironomidae) in three Tatra Mountain lakes (Slovakia) on an acidification gradient

Subfossil chironomids (Diptera, Chironomidae) in three Tatra Mountain lakes (Slovakia) on an acidification gradient

History and timing of human impact on Lake Victoria, East Africa

Stable carbon isotopes of invertebrate remains: do they reveal past methane release from lakes?

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