Publication Date:
2024-06-12
Description:
This dataset provides counts of diatom valves for the Lateglacial sediment sequence retrieved from Lake Hämelsee (Germany) in 2013. Counts per taxon are presented against both depth (m) and age (cal yr. BP). The diatom data provides information on Lateglacial ecosystem dynamics and the dataset was used to interpret changes in aquatic diversity as well as in palaeolimnological conditions. A total of 78 samples were selected for diatom analysis using 2-5 cm sample intervals throughout the Lateglacial section of the core sequence, with a higher sampling resolution (1 cm intervals) around key transitions. Organic matter was removed from the samples (ca. 0.01 grams dried sediment) by oxidation using 5 ml of H2O2 (30%) and heating in a water bath at 70 °C for 24-28 hrs. Subsequently, a few drops of HCl (50%) were added to remove residual H2O2 and carbonates. Samples were washed by adding distilled water, shaking vigorously, centrifuging at 1200 rpm for 4 minutes, and removing the liquid using a pipette. This process was repeated 5 times, and a few drops of ammonia (NH3) were added to the solution prior to the final wash to prevent clumping of diatoms. Diatom slides were mounted using Naphrax and diatoms were identified using Krammer and Lange-Bertalot (1986–1991) and Camburn and Charles (2000). For several samples the target count sum of 300 diatom valves could not be reached due to low concentrations or poor diatom preservation. Prior to analysis and interpretation, and where possible, neighbouring samples with a low count sum were amalgamated until a count of at least 100 valves was reached; if this was not possible the samples were deleted from our dataset prior to subsequent analysis (note that these samples are still included in the dataset provided here). All analyses were performed in the laboratories of University College London, UK.
Keywords:
Achnanthes sp.; AGE; alkanes; Amphora copulata; Amphora ovalis; Amphora pediculus; Amphora subconstricta; Asterionella formosa; Aulacoseira sp.; Biodiversity; Cavinula cocconeiformis; Chironomidae; Cocconeis neodiminuta; Cocconeis placentula; Cocconeis sp.; Counting valves; Cymbella parva; Cymbella sp.; Denticula kuetzingii; Denticula sp.; Denticula tenuis; DEPTH, sediment/rock; deuterium; Diatoma sp.; diatoms; Diatoms, centrales indeterminata; Diploneis sp.; Discotella stelligera; ecosystem dynamics; Encyonema minutum; Encyonema silesiacum; Epithemia adnata; Epithemia gibba; Epithemia sorex; Epithemia sp.; Epithemia turgida; Eunotia curvata; Eunotia flexuosa; Eunotia rhomboidea; Eunotia sp.; Fallacia pygmaea; Fragilaria recapitellata; Fragilaria sp.; Fragilariforma constricta; Fragilariforma lata; GDGTs; Germany; Gogorevia exilis; Gomphonema brebissonii; Gomphonema clevei; Gomphonema parvulum; Gomphonema sp.; Haemelsee; Haemelsee_Haem13; Halamphora thumensis; Khursevichia jentzschii; Lake Haemelsee, Germany; Lindavia bodanica; LOI; Meridion circulare; Navicula cincta; Navicula exilis; Navicula lanceolata; Navicula radiosa; Navicula sp.; Nepula vitiosa; Niederreiter Piston corer; Nitzschia dissipata; Nitzschia gracilis; Nitzschia lacuum; Nitzschia obtusa var. brevissima; Nitzschia sp.; NPC; Nupela tenuicephala; ORDINAL NUMBER; Pantocsekiella delicatula; Pantocsekiella ocellata; Pediastrum; Placoneis elginensis; Placoneis gastrum; Planothidium joursacense; Platessa conspicua; Pleurosigma sp.; Psammothidium helveticum; Pseudostaurosira brevistriata; Pseudostaurosira robusta; Pseudostaurosira spp.; Sellaphora pupula; Stauroforma exiguiformis; Stauroneis anceps; Stauroneis construens; Stauroneis sp.; Staurosira construens; Staurosirella pinnata; Staurosirella pinnata var. acuminata; Staurosirella pinnata var. intercedens; Staurosirella pinnata var. minutissima; Tabellaria fenestrata; Tabellaria flocculosa; Tabellaria quadriseptata; Tabellaria sp.; XRF
Type:
Dataset
Format:
text/tab-separated-values, 6862 data points
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