Inverse modeling of past lead atmospheric deposition in South Greenland

The aim of this study is to model atmospheric lead fluxes in two different paleoenvironmental records located in southern Greenland. Fifty five sediment samples collected from the Lake Igaliku sedimentary sequence were analyzed for lead and aluminum concentrations, and lead isotopic compositions. The second archive consists in a previously published dataset, obtained from a minerogenic peat deposit, located at Tasiusaq, 16 km northwest from Lake Igaliku. A flux model fitted to both dataset produces similar results, allowing past anthropogenic atmospheric deposition to be reconstructed. This original method can be easily adapted for other studies where natural inputs dominate over discrete a…

Impact of Holocene climate variability on lacustrine records and human settlements in South Greenland

Due to its sensitivity to climate changes, south Greenland is a particularly suitable area to study past global climate changes and their influence on locale Human settlements. A paleohydrological investigation was therefore carried out on two river-fed lakes: Lake Qallimiut and Little Kangerluluup, both located close to the Labrador Sea in the historic farming center of Greenland. Two sediment cores (QAL-2011 and LKG-2011), spanning the last four millennia, were retrieved and showed similar thin laminae, described by high magnetic susceptibility and density, high titanium and TOC / TN atomic ratio, and coarse grain size. They are also characterized either by inverse grading followed by nor…

Sur les traces d'Erik le Rouge (film et conférence)

International audience

An Inverse Modeling Approach to Investigate Past Lead Atmospheric Deposition in Southern Greenland

International audience

Vers l'Amérique : l'implantation médiévale scandinave de la côte sud-ouest du Groenland. Approches historiques et premiers résultats des études paléoenvironnementales

International audience; During the Viking Age (ca AD 800-1100) Scandinavian explorers settled the islands of the western North Atlantic, making the northernmost agricultural area of the medieval period. Expansion to south-west coast of Greenland at the end of the tenth century brought Norse settlers closer to the limits of their European-style agricultural systems. In response to the harsh low arctic climate, the Greenland Norse have adapted their farming strategies and changed their subsistence pattern, giving a more important place to hunting and fishing. This evolution had probably been accelerated by climatic changes of the Little Ice Age. A good knowledge of the Greenland Norse economy…

The history and impacts of farming activities in south Greenland: an insight from lake deposits.

International audience; Agriculture in southern Greenland has a two-phase history: with the Norse, who first settled and farmed the region between 985ad and circa 1450ad, and with the recent reintroduction of sheep farming (1920ad to the present). The agricultural sector in Greenland is expected to grow over the next century as anticipated climate warming extends the length of the growing season and increases productivity. This article presents a synthesis of results from a well-dated 1500-year lake sediment record from Lake Igaliku, south Greenland (61°00′N, 45°26′W, 15m asl) that demonstrates the relative impacts of modern and Norse agricultural activities. Pollen, non-pollen palynomorphs…

Towards America: environmental consequences of the Viking occupation in Greenland.

A 2500 year record of natural and anthropogenic soil erosion in South Greenland

International audience; The environmental impact of the Norse landnám in Greenland has been studied extensively. But to date, no study has quantified the soil erosion that Norse agricultural practices are believed to have caused. To resolve this problem, a high resolution sedimentary record from Lake Igaliku in South Greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use. An accurate chronology allows for the estimation of detritic fluxes and their uncertainties. Land clearance and the introduction of grazing livestock by the Norse around 1010 AD caused an acceleration of soil erosion up to 8 mm/century in 1180 AD which is two-fo…

The impact of Norse occupation in south Greenland: pollen, NPP's and sedimentological analyses from lakes and peat deposits.

Environmental responses of past and recent agropastoral activities on south Greenlandic ecosystems through molecular biomarkers

Paleoenvironmental studies previously performed on Lake Igaliku revealed two agropastoral phases in south Greenland: the Norse settlement from AD 986 to ca. AD 1450 and the recent installation of sheep farmers, since the 1920s. To improve the knowledge of the timing and magnitude of the Greenlandic agropastoral activities, a lipid inventory was realized and compared with biological and geochemical data. During the 12th century, a major increase in deoxycholic acid (DOC) and coprophilous fungal spores revealed a maximum of herbivores. Synchronously, a minimum of the n-C29/ n-C31 alkane ratio and tree and shrub pollen and a maximum of triterpenyl acetates showed a reduction in the tree and s…

Environmental consequences of the Norse occupation in south Greenland: first results of pollen and NPP's data from a peat bog (Qassiarsuk).

Pollen and non-pollen palynomorph evidence of medieval farming activities in southwestern Greenland

International audience; Radiocarbon dating, pollen and non-pollen palynomorph analyses from a lake core were used to establish the timing and effects of farming activities around Lake Igaliku, Eastern Settlement, Greenland. The absence of agro-pastoral impact before the medieval colonization by Europeans provides an opportunity to understand the development of farming activity in a pristine landscape. The results show that the first phase of clearance and grazing pressure, without the expansion of the Norse apophyte (native plant, in habitats created by humans) Rumex acetosa type, could have occurred in the 9–10th century A.D. The presence of Norse settlers and livestock is clearly recorded…

Identification des indices environnementaux d'anthropisation dans la séquence sédimentaire historique du lac d'Igaliko (Groenland)

Long-term dynamics in microbial eukaryotes communities: a palaeolimnological view based on sedimentary DNA

International audience; Assessing the extent to which changes in lacustrine biodiversity are affected by anthropogenic or climatic forces requires extensive palaeolimnological data. We used high-throughput sequencing to generate time-series data encompassing over 2200 years of microbial eukaryotes (protists and Fungi) diversity changes from the sedimentary DNA record of two lakes (Lake Bourget in French Alps and Lake Igaliku in Greenland). From 176 samples, we sequenced a large diversity of microbial eukaryotes, with a total 16 386 operational taxonomic units distributed within 50 phylogenetic groups. Thus, microbial groups, such as Chlorophyta, Dinophyceae, Haptophyceae and Ciliophora, tha…

Contribution to the Holocene North Atlantic wind activity reconstruction from Lake Igaliku, South Greenland

International audience

Vers l'Amérique : l'implantation médiévale scandinave de la côte sud-ouest du Groenland

During the Viking Age (ca AD 800-1100) Scandinavian explorers settled the islands of the western North Atlantic, making the northernmost agricultural area of the medieval period. Expansion to south-west coast of Greenland at the end of the tenth century brought Norse settlers closer to the limits of their European-style agricultural systems. In response to the harsh low arctic climate, the Greenland Norse have adapted their farming strategies and changed their subsistence pattern, giving a more important place to hunting and fishing. This evolution had probably been accelerated by climatic changes of the Little Ice Age. A good knowledge of the Greenland Norse economy by means of historical …

Data from: Long-term dynamics in microbial eukaryotes communities: a paleolimnological view based on sedimentary DNA

Assessing the extent to which changes in lacustrine biodiversity are affected by anthropogenic or climatic forces requires extensive palaeolimnological data. We used high-throughput sequencing to generate time-series data encompassing over 2200 years of microbial eukaryotes (protists and Fungi) diversity changes from the sedimentary DNA record of two lakes (Lake Bourget in French Alps and Lake Igaliku in Greenland). From 176 samples, we sequenced a large diversity of microbial eukaryotes, with a total 16 386 operational taxonomic units distributed within 50 phylogenetic groups. Thus, microbial groups, such as Chlorophyta, Dinophyceae, Haptophyceae and Ciliophora, that were not previously co…