A5061559919- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Pleistocene-Era Hominins and Archaeology
- Tree-ring climate responses
- Climate change and permafrost
- Arctic and Antarctic ice dynamics
- Research in Social Sciences
- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Isotope Analysis in Ecology
- Archaeology and ancient environmental studies
- Fire effects on ecosystems
- Marine Biology and Ecology Research
- Peatlands and Wetlands Ecology
- Environmental DNA in Biodiversity Studies
- Geological Studies and Exploration
- Groundwater and Isotope Geochemistry
- Polar Research and Ecology
- Indigenous Studies and Ecology
- Marine and environmental studies
- Geological Formations and Processes Exploration
- Protist diversity and phylogeny
- Atmospheric and Environmental Gas Dynamics
- Marine and coastal plant biology
- Food Industry and Aquatic Biology
University of Helsinki
2015-2025
Geological Survey of Finland
2025
Arctic Research Centre
2023
Aarhus University
2023
Geological Survey of Denmark and Greenland
2018
ECRI Institute
2015-2018
University of Manitoba
2011-2016
Fisheries and Oceans Canada
2011-2014
University of Waterloo
2009-2011
Helsinki University Hospital
2010
Abstract The Younger Dryas (YD) cold reversal interrupts the warming climate of deglaciation with global climatic impacts. sudden cooling is typically linked to an abrupt slowdown Atlantic Meridional Overturning Circulation (AMOC) in response meltwater discharges from ice sheets. However, inconsistencies regarding YD-response European summer temperatures have cast doubt whether concept provides a sufficient explanation. Here we present results high-resolution simulation together new July...
Holocene summer temperature reconstructions from northern Europe based on sedimentary pollen records suggest an onset of peak warmth around 9,000 years ago. However, pollen-based are largely driven by changes in the proportions tree taxa, and thus early-Holocene warming signal may be delayed due to geographical disequilibrium between climate populations. Here we show that quantitative summer-temperature estimates macrofossils aquatic plants many cases ca. 2 °C warmer early (11,700-7,500 ago)...
Reliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible assess past effects environmental variables and land-use change on ecosystems biodiversity, mitigating their in future. We present here most spatially extensive temporally continuous pollen-based plant cover (at a spatial resolution 1° × 1°) over (last 11.7 ka BP) using ‘Regional Estimates VEgetation Abundance from Large Sites’...
Abstract Sea ice is a critical component of the Earth’s Climate System and unique habitat. Sea-ice changes prior to satellite era are poorly documented, proxy methods needed constrain its past variability. Here, we demonstrate potential sedimentary DNA from Polarella glacialis , sea-ice microalga, for tracing conditions. We quantified P. (targeting nuclear ribosomal ITS1 region) in Arctic marine fjord surface sediments sediment core northern Baffin Bay spanning 12,000 years. trap samples...
1 Norway spruce (Picea abies), one of the dominant tree species in Eurasia, has spread slowly westward northern Europe, invading eastern Finland about 6500 calibrated years ago (cal. BP), central Sweden 2700 cal. BP and southern 1000 BP. Its is most recent best constrained invasion a main Europe allows an assessment colonization patterns associated competitive replacement processes. 2 We analysed five selected high-resolution pollen accumulation rate (PAR) -records along 700-km long transect...
Heikkilä, M. & Seppä, H. 2010: Holocene climate dynamics in Latvia, eastern Baltic region: a pollen‐based summer temperature reconstruction and regional comparison. Boreas , Vol. 39, pp. 705–719. 10.1111/j.1502‐3885.2010.00164.x. ISSN 0300‐9483. A ( T ) reveals the history southeastern Latvia contributes to limited understanding of past behaviour sector northern Europe. Notably, steady warming early was interrupted c. 8350–8150 cal. yr BP by well‐known 8.2 ka cold event, recorded as...
Abstract. A synthesis of well-dated high-resolution pollen records suggests a spatial structure in the 8200 cal yr BP event northern Europe. The temperate, thermophilous tree taxa, especially Corylus, Ulmus, and Alnus, decline abruptly between 8300 8000 at most sites located south 61° N, whereas there is no clear change values North-European tree-line region. Pollen-based quantitative temperature reconstructions several other, independent palaeoclimate proxies, such as lacustrine...
Abstract A growing body of evidence implies that the concept 'treeless tundra' in eastern and northern Europe fails to explain rapidity Lateglacial postglacial tree population dynamics region, yet knowledge geographic locations shifting populations is fragmentary. Pollen, stomata plant macrofossil stratigraphies from Lake Kurjanovas poorly studied Baltic region provide improved ranges north‐eastern European trees during subsequent responses abrupt climatic changes Lateglacial/Holocene...
Arctic coastal zones serve as a sensitive filter for terrigenous matter input onto the shelves via river discharge and erosion. This material is further distributed across by ocean currents sea ice. The regions are particularly vulnerable to changes related recent climate change. We compiled pan-Arctic review that looks into changing Holocene sources, transport processes sinks of sediment in Ocean. Existing palaeoceanographic studies demonstrate how warming disappearance ice sheets during...
Abstract To investigate the Holocene climate and treeline dynamics in European Russian Arctic, we analysed sediment pollen, conifer stomata, plant macrofossils from Lake Kharinei, a tundra lake near Pechora area. We present quantitative summer temperature reconstructions Kharinei Tumbulovaty, previously studied same region, using pollen–climate transfer function based on new calibration set northern Russia. Our records suggest that early-Holocene temperatures 11,500 cal yr BP onwards were...
Abstract Aim To assess statistically the relative importance of climate and human impact on forest composition in late Holocene. Location Estonia, boreonemoral Europe. Methods Data (10 most abundant tree shrub taxa) for Holocene (5100–50 calibrated years before 1950) were derived from 18 pollen records then transformed into land‐cover estimates using REVEALS vegetation reconstruction model. Human was quantified with palaeoecological openness, frequencies hemerophilous types (taxa growing...
In order to establish a baseline for proxy-based reconstructions the Young Sound-Tyrolerfjord system (Northeast Greenland), we analysed spatial distribution of primary production and sea ice proxies in surface sediments from fjord, against monitoring data Greenland Ecosystem Monitoring Programme. Clear gradients organic carbon biogenic silica contents reflected marine influence, nutrient availability river-induced turbidity, good agreement with situ measurements. The proxy IP25 was detected...
The biomarker IP25 and fossil diatom assemblages preserved in seafloor sediments are commonly used as proxies for paleo Arctic sea-ice reconstructions, but how their production varies over the seasons is exported to sediment remains unclear. We analysed concentrations from a five-week consecutive series of cores compared results with trap surface samples collected at same site Young Sound fjord, Northeast Greenland. Our aim was investigate dynamics colonization spring sea ice in-situ IP25....
Understanding Holocene climate variability is crucial for predicting future change, which will disproportionally affect high-latitude regions. Summer temperature (Tsummer) reconstructions in regions such as northern Finland are mainly derived from microfossil data. We reconstructed Tsummer spanning the interval 10-1 cal ka BP using branched glycerol dialkyl tetraethers (brGDGTs) lake-sediment record Lake Annan Juomusjärvi (AJU) Finland. The reconstruction shows cool early conditions, ∼2 °C...
Abstract The eastern north coast of Greenland is considered to be highly sensitive the ongoing Arctic warming, but there a general lack data on modern conditions and in particular distribution climate environmental proxies provide baseline context for studies past variability. Here we present detailed investigation 11 biogenic preserved surface sediments from remote High Wandel Sea shelf, entrance Independence, Hagen, Danmark fjords. composition organic matter (organic carbon, C:N ratios, δ...
A long-term perspective is essential for understanding environmental change. To be able to access the past, archives such as marine and lake sediments that store information in form of diverse proxy records are used. Whilst many analytical techniques exist extract stored these records, critical assessment refinement current methods addition developing new crucial improving our understanding. This study aims improve knowledge on diatom species used reconstructing ocean surface conditions,...
Abstract Peatlands, with high spatial variability in ecotypes and microforms, constitute a significant part of the boreal landscape play an important role global carbon (C) cycle. However, effects this peatland heterogeneity within are rarely quantified. Here, we use field‐based measurements, high‐resolution land cover classification, biogeochemical atmospheric models to estimate atmosphere‐ecosystem C fluxes corresponding radiative effect (RE) for (Kaamanen) northern Finland. Our result...
Decreasing sea-ice extent and retreating thinning of Greenland’s glaciers are rapidly changing Arctic coastal environments by warming freshening the sea surface impacting light availability. In fjords, productivity is significantly influenced position glacier termini, present retreat Greenland Ice Sheet will increase number fjords surrounded only land-terminating in future. This most likely affect ecosystem structure marine areas. To predict future cryosphere change its impacts, it...