Molecular Footprints of Quaternary Climate Fluctuations in the Circumpolar Tundra Shrub Dwarf Birch.

The Arctic tundra biome is undergoing rapid shrub expansion ('shrubification') in response to anthropogenic climate change. During the previous ~2.6 million years, glacial cycles caused substantial shifts in Arctic vegetation, leading to changes in species' distributions, abundance and connectivity, which have left lasting impacts on the genetic structure of modern populations.

Morphological and morphometric investigations on testate amoebae from Mongolia with descriptions of a new genus and four new species.

Testate amoebae are a polyphyletic and highly diverse group of unicellular protists, inhabiting various habitats and successfully used as indicators of property of environmental variables, providing information on hydrology, pH and pollution of ecosystems. However, despite numerous studies, there is still a lack of data regarding their species diversity, geographical distribution and population dynamics in various habitats from previously unexplored or poorly investigated regions such as Mongolia. In this study, we describe the morphology and morphometry of a new genus and four new species: Armatura murmillo gen.

Strengthening potential of recent peat dating.

This study concerned high-resolution age reconstructions of modern organic deposits collected from peatlands distributed in Central Europe. The main focus was on Pb radioisotope as a fundamental geochronometer along with C and Pu radioisotopes used for dating verification. In addition to simple classical models such as CF/CS or CF, the new approach formulated upon the Plum method was implemented.

Ericoid shrub encroachment shifts aboveground-belowground linkages in three peatlands across Europe and Western Siberia.

In northern peatlands, reduction of Sphagnum dominance in favour of vascular vegetation is likely to influence biogeochemical processes. Such vegetation changes occur as the water table lowers and temperatures rise. To test which of these factors has a significant influence on peatland vegetation, we conducted a 3-year manipulative field experiment in Linje mire (northern Poland).

Neodymium isotopes in peat reveal past local environmental disturbances.

Over the past decade, the neodymium (Nd) isotope composition of mineral matter from peat cores has seen increasingly common use as a tracer of dust influx associated with major changes in the Holocene atmospheric circulation. However, the incomplete understanding of the local controls on the sources of the sediment supplied to peatlands remains a key difficulty in the interpretation of the archived Nd isotope signals. Here, we used neodymium isotopes to reconstruct environmental disturbances in peatlands.

Cryogenic mirror position actuator for spectroscopic applications.

We demonstrate a mirror position actuator that operates in a wide temperature range from room temperature to a deep cryogenic regime (10 K). We use a Michelson interferometer to measure the actuator tuning range (and piezoelectric efficiency) in the full temperature range. We demonstrate an unprecedented range of tunability of the mirror position in the cryogenic regime (over 22 μm at 10 K).

Recent climate change has driven divergent hydrological shifts in high-latitude peatlands.

High-latitude peatlands are changing rapidly in response to climate change, including permafrost thaw. Here, we reconstruct hydrological conditions since the seventeenth century using testate amoeba data from 103 high-latitude peat archives. We show that 54% of the peatlands have been drying and 32% have been wetting over this period, illustrating the complex ecohydrological dynamics of high latitude peatlands and their highly uncertain responses to a warming climate.

Fires, vegetation, and human-The history of critical transitions during the last 1000 years in Northeastern Mongolia.

Fires are natural phenomena that impact human behaviors, vegetation, and landscape functions. However, the long-term history of fire, especially in the permafrost marginal zone of Central Asia (Mongolia), is poorly understood. This paper presents the results of radiocarbon and short-lived radionuclides (Pb and Cs) dating, pollen, geochemical, charcoal, and statistical analyses (Kohonen's artificial neural network) of sediment core obtained from Northern Mongolia (the Khentii Mountains region).

The role of Medieval road operation on cultural landscape transformation.

Connecting pathways are essential for cultural and economic exchange. Commonly, historians investigate the role of routes for cultural development, whereas the environmental impacts of historical routes attract less attention. Here, we present a high-resolution reconstruction of the impact of the major trade route via Marchionis in the southern Baltic lowlands on landscape evolution since more than 800 years.

Effects of experimental warming on Betula nana epidermal cell growth tested over its maximum climatological growth range.

Numerous long-term, free-air plant growth facilities currently explore vegetation responses to the ongoing climate change in northern latitudes. Open top chamber (OTC) experiments as well as the experimental set-ups with active warming focus on many facets of plant growth and performance, but information on morphological alterations of plant cells is still scarce. Here we compare the effects of in-situ warming on leaf epidermal cell expansion in dwarf birch, Betula nana in Finland, Greenland, and Poland.

Assessing the responses of micro-eukaryotes to climate changes using high throughput sequencing.

Current projections suggest that climate warming will be accompanied by more frequent and severe drought events. Peatlands store ca. one third of the world's soil organic carbon.

Ultrahigh finesse cavity-enhanced spectroscopy for accurate tests of quantum electrodynamics for molecules.

We report the most accurate, to the best of our knowledge, measurement of the position of the weak quadrupole S(2) 2-0 line in $ {{\rm D}_2} $D. The spectra were collected with a frequency-stabilized cavity ringdown spectrometer (FS-CRDS) with an ultrahigh finesse optical cavity ($ {\cal F} = 637 000 $F=637000) and operating in the frequency-agile, rapid scanning spectroscopy (FARS) mode. Despite working in the Doppler-limited regime, we reached 40 kHz of statistical uncertainty and 161 kHz of absolute accuracy, achieving the highest accuracy for homonuclear isotopologues of molecular hydrogen.

Human-induced fire regime shifts during 19th century industrialization: A robust fire regime reconstruction using northern Polish lake sediments.

Fire regime shifts are driven by climate and natural vegetation changes, but can be strongly affected by human land management. Yet, it is poorly known how humans have influenced fire regimes prior to active wildfire suppression. Among the last 250 years, the human contribution to the global increase in fire occurrence during the mid-19th century is especially unclear, as data sources are limited.

Unveiling tipping points in long-term ecological records from Sphagnum-dominated peatlands.

Unveiling past tipping points is a prerequisite for a better understanding of how individual species and entire ecosystems will respond to future climate change. Such knowledge is key for the implementation of biodiversity conservation. We identify the relationships between peatland vegetation and hydrological conditions over the past 2000 years using plant macrofossils, testate amoebae-based quantitative hydrological reconstructions and Sphagnum-moss functional traits from seven Polish peatland records.

Paleoecological and historical data as an important tool in ecosystem management.

In recent decades, it has been observed that most forest fires in Europe were caused by people. Extreme droughts, which are more often prolonged, can increase the risk of forest fires, not only in southern Europe but also, in Central Europe. Nonetheless, catastrophic fire events are not well recognized in the Central European Lowlands (CEL), where large forest complexes are located.

Predator-prey mass ratio drives microbial activity under dry conditions in peatlands.

Mid- to high-latitude peatlands are a major terrestrial carbon stock but become carbon sources during droughts, which are increasingly frequent as a result of climate warming. A critical question within this context is the sensitivity to drought of peatland microbial food webs. Microbiota drive key ecological and biogeochemical processes, but their response to drought is likely to impact these processes.

Tipping point in plant-fungal interactions under severe drought causes abrupt rise in peatland ecosystem respiration.

Ecosystems are increasingly prone to climate extremes, such as drought, with long-lasting effects on both plant and soil communities and, subsequently, on carbon (C) cycling. However, recent studies underlined the strong variability in ecosystem's response to droughts, raising the issue of nonlinear responses in plant and soil communities. The conundrum is what causes ecosystems to shift in response to drought.

A novel testate amoebae trait-based approach to infer environmental disturbance in Sphagnum peatlands.

Species' functional traits are closely related to ecosystem processes through evolutionary adaptation, and are thus directly connected to environmental changes. Species' traits are not commonly used in palaeoecology, even though they offer powerful advantages in understanding the impact of environmental disturbances in a mechanistic way over time. Here we show that functional traits of testate amoebae (TA), a common group of palaeoecological indicators, can serve as an early warning signal of ecosystem disturbance and help determine thresholds of ecosystem resilience to disturbances in peatlands.

Seasonal changes in Sphagnum peatland testate amoeba communities along a hydrological gradient.

Testate amoebae are an abundant and functionally important group of protists in peatlands, but little is known about the seasonal patterns of their communities. We investigated the relationships between testate amoeba diversity and community structure and water table depth and light conditions (shading vs. insolation) in a Sphagnum peatland in Northern Poland (Linje mire) in spring and summer 2010.