A5089539714- Marine and coastal ecosystems
- Atmospheric and Environmental Gas Dynamics
- Soil and Water Nutrient Dynamics
- Hydrology and Watershed Management Studies
- Arctic and Antarctic ice dynamics
- Aquatic Ecosystems and Phytoplankton Dynamics
- Fish Ecology and Management Studies
- Microbial Community Ecology and Physiology
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Wastewater Treatment and Nitrogen Removal
- Groundwater and Isotope Geochemistry
- Peatlands and Wetlands Ecology
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Climate variability and models
- Microplastics and Plastic Pollution
- Climate change and permafrost
- Phosphorus and nutrient management
- Oceanographic and Atmospheric Processes
- Atmospheric chemistry and aerosols
- Recycling and Waste Management Techniques
- Isotope Analysis in Ecology
- Research in Social Sciences
- Constructed Wetlands for Wastewater Treatment
University of Helsinki
2013-2025
Ministry of Water Resources of the People's Republic of China
2024
Inner Mongolia Agricultural University
2024
Chinese Academy of Sciences
2019
LAM Foundation
2010-2014
University of Lapland
2011
Lapland University of Applied Sciences
2008
[1] Measurements of the energy balance components a small boreal lake (area 0.041 km2, mean depth 2.5 m) in southern Finland were performed during four open water periods (April–October) 2005–2008. Turbulent fluxes sensible and latent heat acquired using eddy covariance technique accompanied by net radiation storage measurements. In April was near isothermal, whereas May development thermocline enabled dark color sheltered location. The continued to deepen until September down 3.5 m...
We studied methanotrophic activity in the water column relation to heterotrophic bacterial production and efflux of methane (CH4) from lake surface a small, stratified, humic, boreal (Valkea-Kotinen, southern Finland). During summer winter stratification, highest activities were metalimnion, where oxygen concentration was <6 mmol m−3. an incomplete spring turnover stratification period, 3-5 times more CH4 consumed by methanotrophs than released atmosphere. The effluxes (1.2–5.1 m−2 d−1)...
[1] Significant amounts of terrestrial carbon are processed in lakes and emitted into the atmosphere as CO2. However, due to lack appropriate measurements absolute role landscape sinks or sources CO2 is still uncertain. We conducted first long-term, ecosystem-level flux with eddy covariance technique a boreal lake within natural-state catchment covering 5 years. The aim was reveal natural level between its regional cycling. On average, ca 10% net ecosystem production surrounding old-growth...
Long‐term measurements of sensible and latent heat carbon dioxide fluxes were performed over a boreal lake in southern Finland using the direct micrometeorological eddy covariance (EC) technique. The water column was sampled weekly for dissolved dioxide, CO 2 flux estimated also applying concentration gradient method. Temperature oxygen profiles measured twice week. covered one full open‐water period from April to November 2003, it is longest continuous record ever by EC. H positive, that...
We studied CO 2 and CH 4 fluxes from two boreal lakes with differing trophic status (chlorophyll a 17.8 vs. 48.7 mg m −2 ) water color (100 20 Pt L −1 throughout an open‐water period when summer precipitation doubled, using both floating chambers concentration gradients. Fluxes measured in were higher, but irrespective of the method, heterotrophic annual sources carbon gases to atmosphere. However, flux 6.85 (chambers) or 5.43 mol (gradients), humic lake had notably higher emissions than...
We studied the concentrations and diffusive fluxes of carbon dioxide (CO 2 ) methane (CH 4 in 12 lakes a size range 0.004–35 km mean total organic (TOC) 6–25 mg L −1 , located southern boreal area Finland. TOC, mainly originating from catchment, was best predictor areal CO effluxes whole lake‐area range, but among with an < 1 having anoxic hypolimnion during summer, were also related to lake index turbulence. The concentration CH lakes' pelagic zones more closely lake‐size‐related water...
Abstract Winter is a long period of the annual cycle many lakes in northern hemisphere. Low irradiance, ice, and snow cover cause poor light penetration into water column these lakes. Therefore, lakes, respiration often exceeds primary production leading to low dissolved oxygen concentrations. This study aimed quantify under‐ice metabolic processes during winter an arid zone lake with little cover. was carried out mid‐latitude Inner Mongolia, China. The receives relatively high incoming...
Inland waters transport and emit into the atmosphere large amounts of carbon (C), which originates from terrestrial ecosystems. The effect land cover land-use practises on C export ecosystems to inland is not fully understood, especially in heterogeneous landscapes under human influence. We sampled for dissolved species five tributaries with well-determined subcatchments (total size 174.5 km(2)), as well various points two draining a boreal lake southern Finland over full year. Our aim was...
To improve the understanding of seasonal evolution mass and heat budget ice-covered lakes in cold arid climate zone, in-situ observations were collected during two winters (2016–2017 2017–2018) Lake Wuliangsuhai, Inner Mongolia, China. The mean snow thickness was 5.2 1.6 cm these winters, due to low winter precipitation. ice 50.9 36.1 cm, growth rate 3.6 2.1 mm day−1 at lower boundary ice. Analyses balance data from revealed that surface governed by solar radiation terrestrial radiation. net...
Abstract Interaction of under‐ice physical, chemical, and biological processes with lake ice/snow cover is examined to better understand how changing winter climate may affect ecosystems. We derived dissolved oxygen (DO) dynamics from high‐frequency observations modified a widely used metabolism model by including the effect freezing thawing on DO concentration. Estimates were produced for production respiration in shallow Mongolian Plateau three winters. Diel, synoptic, seasonal variations...
During the last few decades organic matter concentrations and water colour values have increased in a large number of lakes rivers Eurasia North America. The upward shift colour, often called browning, shortage mobile cations been linked to recovery catchments from acid deposition precipitation. Here, long-term chemistry responses 33 boreal forest atmospheric catchment scale drivers were studied small drainage basin southern Finland. longest data series cover four starting 1979, thus include...
Constructed wetlands provide cost-efficient nutrient removal, with minimal input of human labor and energy, their number is globally increasing. However, in northern latitudes, are rarely utilized, because removal efficiency has been questioned due to the cold climate. Here, we studied retention nitrogen a boreal constructed wetland (4-ha) receiving treated nitrogen-rich wastewater. On yearly basis, most inorganic nutrients were retained by wetland. The highest was found during ice-free...
Spectral albedo and light transmittance through snow, ice, water were measured in Lake Wuliangsuhai (40°36′–41°30′N, 108°43′–108°70′E), Inner Mongolia, China, during winter 2016. Data on the weather, structure of lake geochemistry also collected 60-day field program. The study is shallow (mean depth 1.0–1.5 m) with a large wetland area. Compared polar lakes, solar elevation higher, snow accumulation much lower, ice has more sediment. was all congelation mean thickness 36.6 cm, corresponding...
We have constructed a system based on commercially available inexpensive NDIR CO 2 sensors to continuously monitor concentrations in water bodies. Here we demonstrate its use boreal humic lake. With the system, collect high frequency data with 10‐min time resolution for determination of consumption and production. modify computational methods commonly used forest ecology enable characterization aquatic primary To advantages method, present results against observations from long‐term...
Hulun Lake is the largest lake in northeastern China, and its basin located China Mongolia. This research aims to analyze dynamic changes water volume of estimate groundwater recharge during past 60 years. Multi-source data were used, water-level-data-interpolation extrapolation, water-balance equations, other methods applied. The proportion contribution each component quantity last years was accurately calculated. Evaporation loss main Lake. In years, average annual runoff into about 1.202...
Key Points First gas exchange measurements with eddy covariance technique over river Measured transfer velocity was clearly higher than modeled Results suggest that emissions from large rivers are likely underestimated
C cycling and dissolved organic (DOC) inputs to boreal aquatic systems probably will change substantially with climate change. DOC concentrations already are increasing in surface waters. Terrestrial is a major source of freshwater ecosystems, but the interface between these 2 riparian zone, has not been studied often. To improve our understanding importance terrestrial from surrounding forests, we followed changes concentration along continuum precipitation, throughfall, soil water, ground...
AbstractAbstractWeather-induced episodic mixing events in lake ecosystems are often unpredictable, and their impacts therefore poorly known. The can be short-lived, including changes water temperature stratification, but long-lasting effects on the lake’s biology may also occur. In this study we used automated quality monitoring (AWQM) data from 8 boreal lakes to examine how weather-induced influenced thermal structure, hypolimnetic dissolved oxygen (DO), fluorometric chlorophyll estimates...
Abstract The pH value of lake water varies with the environment, which has an effect on form phosphorus in sediment, and then release sediment phosphorus. sediments was analyzed using field sampling. environmental conditions values 4.0, 7.0 10.0 were simulated indoors to estimate effects from content change various forms studied. results showed that Wuliangsuhai Lake, Ca-P accounted for 54.3%, largest portion TP. Phosphorus favored under acidic alkaline conditions, condition more favorable....
The numerous water bodies and their riparian zones in the boreal zone are crucial to lateral carbon transport can thus be very significant for cycle on landscape level. Therefore, we installed automatic measurement systems with Vaisala CARBOCAP CO 2 probes (Vaisala Oyj, Vantaa, Finland) soil matrix around a small headwater lake, lake itself, outflowing brook followed seasonal diurnal variation concentration as well rain event‐driven changes this natural‐state soil–lake–brook continuum...