Hannu Nykänen

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I am coordinator in research community UEF Water. My previous work was connected to GHG studies and to processes regulating organic matter degradation and carbon and nitrogen flows in natural and experimental systems. This continues partly al...

Information Publications

My work has been related to emissions of methane, carbon dioxide and nitrous oxide and to processes regulating emissions. Method development related to gas measurement and stable isotope methods (C & N) is also related to my work.
I started in the biogeochemistry research group (now BGC) in 1990. I have studied the greenhouse gas emissions of Finnish naturaql and drained peatlands. I have participated in greenhouse gas balance studies in reservoirs and in projects related to the use of peat and peatlands. I participated in an joint EU project to study greenhouse gas balances in the northern peatlands at Kevo. In 2003, I eventually finalized my PhD thesis about the change in greenhouse balances of natural and drained peatlands. I continued my greenhouse gas balance research on the production of reed canary grass. I have worked as a laboratory manager at the National Institute for Public Health in Kuopio related to the purification of drinking water. I participated in an environmental risk assessment project related to the sudden acidification of a lake with a mining influence. I have been a researcher and teacher at Savonia University of Applied Sciences in Kuopio. In the spring of 2008, I moved to University of Jyväskylä to study lake food webs and biogeochemistry using stable carbon isotopes and carbon dioxide and methane emission measurements. As an academy researcher (2010-2015), I studied the carbon storage in the in oxic and anoxic interfaces. As a spin of from this – application made during unemployment period – I got personal funding to study fish feed production based on methanotrophs and algae. I worked as university researcher stydying sediment gas production and also was a short period resposible of the IRMS system in BGC-group. I started as coordinator in research community UEF Water in autumn 2021.

Research groups

Biogeochemistry research group 01.01.1993 -

Keywords

carbon cycle drained peatlands greenhouse gases lake ecosystems lakes methane sediments stable isotopes

Publications

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Research groups

Keywords

Arctic soil methane sink increases with drier conditions and higher ecosystem respiration

Dynamics and distribution of nitrogen and carbon from fish feed in aquaponic system estimated using stable isotopes and biomass measurements

Nitrogen and carbon dynamics and circulation in the aquaponic system followed using 13C and 15N isotopes

Winter nitrogen cycling in sediments of boreal lakes affected by browning and mining

Lowered nutritional quality of prey decrease the growth and biomolecule content of rainbow trout fry

Lowering water table reduces carbon sink strength and carbon stocks in northern peatlands

Denitrification is the major nitrous acid production pathway in boreal agricultural soils

The influence of lipid content and taxonomic affiliation on methane and carbon dioxide production from phytoplankton biomass in lake sediment

Vertical stratification patterns of methanotrophs and their genetic controllers in water columns of oxygen-stratified boreal lakes

Carbon storage change and δ13C transitions of peat columns in a partially forestry-drained boreal bog

Ecosystem carbon response of an Arctic peatland to simulated permafrost thaw

Ecosystem responses to increased organic carbon concentration: comparing results based on long-term monitoring and whole-lake experimentation

Germinating wheat promotes the emission of atmospherically significant nitrous acid (HONO) gas from soils

Stable Carbon Isotopic Composition Transitions of Peat Columns in a Partially Forestry-Drained Boreal Bog

Vertical stratification of bacteria and archaea in sediments of a small boreal humic lake

Gammaproteobacterial methanotrophs dominate methanotrophy in aerobic and anaerobic layers of boreal lake waters

Novel Autotrophic Organisms Contribute Significantly to the Internal Carbon Cycling Potential of a Boreal Lake

Stable carbon isotopic composition of peat columns, subsoil and vegetation on natural and forestry-drained boreal peatlands

Stable carbon isotopic composition of peat, subsoil and vegetation on natural and forestry-drained boreal peatlands

Abiotic and biotic controls on methane formation down to 2.5 km depth within the Precambrian Fennoscandian Shield

Effects of alternative electron acceptors on the activity and community structure of methane-producing and -consuming microbes in the sediments of two shallow boreal lakes.

The impact of long-term water level draw-down on microbial biomass: A comparative study from two peatland sites with different nutrient status

Whole-Lake Sugar Addition Demonstrates Trophic Transfer of Dissolved Organic Carbon to Top Consumers

CO2 flux determination by closed-chamber methods can be seriously biased by inappropriate application of linear regression

Junttiselän kunnostusmahdollisuudet ja -suositukset

Junttiselän veden happamoituminen keväällä ja sitä säätelevät tekijät

Oxidation, efflux, and isotopic fractionation of methane during autumnal turnover in a polyhumic, boreal lake

Greenhouse gas dynamics of terrestrial and aquatic environments: pristine ecosystems and land-use effects

Greenhouse gas fluxes of coniferous forest floors as affected by wood ash addition

Temporal and seasonal changes in greenhouse gas emissions from a constructed wetland purifying peat mining runoff waters

Reed canary grass cultivation on cut-away peatlands and the ecosystem carbon balance

Annual CO2 exchange and CH4 fluxes on a subarctic palsa mire during climatically different years

Factors controlling large scale variations in methane emissions from wetlands

Fluxes of nitrous oxide and methane from drained peatlands following forest clear-felling in southern Finland

Methane emissions from natural peatlands in the northern boreal zone in Finland, Fennoscandia

Sensitivity of CH4 and N2O Dynamics in Boreal Peatlands to Anthropogenic and Global Changes

Effect of experimental nitrogen load on methane and nitrous oxide fluxes on ombrotrophic boreal peatland

Exchange of CO2, CH4 and N2O between the atmosphere and two northern boreal ponds with catchments dominated by peatlands or forests

Fluxes of CH4, CO2, and N2O in hydroelectric reservoirs Lokka and Porttipahta in the northern boreal zone in Finland

Methane dynamics of a restored cut-away peatland

Predicting variations in methane emissions from boreal peatlands through regression models

The effect of depth and mire gases on the hydraulic conductivity of peat

Vegetation succession controls methane emission from restored cut-away peatland

Carbon balance of a boreal bog during a year with an exceptionally dry summer

Winter CO2, CH4 and N20 fluxes on some natural and drained boreal peatlands