English
norskBlar i forfatter "Rouillard, Alexandra"
Viser treff 1-10 av 10
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A 2-million-year-old ecosystem in Greenland uncovered by environmental DNA
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-07)Late Pliocene and Early Pleistocene epochs 3.6 to 0.8 million years ago had climates resembling those forecasted under future warming. Palaeoclimatic records show strong polar amplification with mean annual temperatures of 11–19 °C above contemporary values. The biological communities inhabiting the Arctic during this time remain poorly known because fossils are rare. Here we report an ancient ... -
Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-08)Understanding patterns of colonisation is important for explaining both the distribution of single species and anticipating how ecosystems may respond to global warming. Insular flora may be especially vulnerable because oceans represent severe dispersal barriers. Here we analyse two lake sediment cores from Iceland for ancient sedimentary DNA to infer patterns of colonisation and Holocene vegetation ... -
A complete Holocene lake sediment ancient DNA record reveals long-standing high Arctic plant diversity hotspot in northern Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-09)Arctic hotspots, local areas of high biodiversity, are potential key sites for conservation of Arctic biodiversity. However, there is a need for improved understanding of their long-term resilience. The Arctic hotspot of Ringhorndalen has the highest registered diversity of vascular plants in the Svalbard archipelago, including several remarkable and isolated plant populations located far north of ... -
Glacier response to the Little Ice Age during the Neoglacial cooling in Greenland
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-04)In the Northern Hemisphere, an insolation driven Early to Middle Holocene Thermal Maximum was followed by a Neoglacial cooling that culminated during the Little Ice Age (LIA). Here, we review the glacier response to this Neoglacial cooling in Greenland. Changes in the ice margins of outlet glaciers from the Greenland Ice Sheet as well as local glaciers and ice caps are synthesized Greenland-wide. ... -
Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-13)The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original ... -
Late Quaternary dynamics of Arctic biota from ancient environmental genomics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-20)During the last glacial–interglacial cycle, Arctic biotas experienced substantial climatic changes, yet the nature, extent and rate of their responses are not fully understood1,2,3,4,5,6,7,8. Here we report a large-scale environmental DNA metagenomic study of ancient plant and mammal communities, analysing 535 permafrost and lake sediment samples from across the Arctic spanning the past 50,000 years. ... -
Postglacial relative sea level change and glacier activity in the early and late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard
(Journal article; Peer reviewed, 2019-05-01)Sediment cores from Kløverbladvatna, a threshold lake in Wahlenbergfjorden, Nordaustlandet, Svalbard were used to reconstruct Holocene glacier fluctuations. Meltwater from Etonbreen spills over a threshold to the lake, only when the glacier is significantly larger than at present. Lithological logging, loss-on-ignition, ITRAX scanning and radiocarbon dating of the cores show that Kløverbladvatna ... -
The sedimentary ancient DNA workflow
(Chapter; Bokkapittel, 2023)Sedimentary ancient DNA (sedaDNA) is continuing to revolutionise our understanding of past biological and geological processes by retrieving and analysing the ancient DNA preserved in lake, cave, open terrestrial, midden, permafrozen, and marine environments (Crump, 2021). The study of sedaDNA began in the late 1990s (Coolen and Overmann, 1998) with the first reports of extinct animal sedaDNA in ... -
Unique stable isotope signatures of large cyclonic events as a tracer of soil moisture dynamics in the semiarid subtropics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-09)Evaporative flux from soils in arid and semi-arid climates can be very high and may substantially reduce soil moisture retained between infrequent rainfall events. Direct measurement of the evaporative losses from soils is technically challenging. However, environmental tracers such as water stable hydrogen and oxygen isotope composition can be used to calculate evaporation rates if the initial ... -
Wood Jams Or Beaver Dams? Pliocene Life, Sediment And Landscape Interactions In The Canadian High Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-28)During the mid-Pliocene (Zanclean, ca. ~ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–228C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative ...
