scholarly journals Variability in methane emissions from West Siberia's shallow boreal lakes on a regional scale and its environmental controls

2017 ◽  
Vol 14 (15) ◽  
pp. 3715-3742 ◽  
Author(s):  
Aleksandr F. Sabrekov ◽  
Benjamin R. K. Runkle ◽  
Mikhail V. Glagolev ◽  
Irina E. Terentieva ◽  
Victor M. Stepanenko ◽  
...  
Keyword(s):  
Pore Space ◽  
Regional Scale ◽  
Methane Emissions ◽  
Southern Taiga ◽  
Boreal Lakes ◽  
Middle Taiga ◽  
Taiga Zone ◽  
Power Law Distribution ◽  
Small Lakes ◽  
Environmental Controls

Abstract. Small lakes represent an important source of atmospheric CH4 from northern wetlands. However, spatiotemporal variations in flux magnitudes and the lack of knowledge about their main environmental controls contribute large uncertainty into the global CH4 budget. In this study, we measured methane fluxes from small lakes using chambers and bubble traps. Field investigations were carried out in July–August 2014 within the West Siberian middle and southern taiga zones. The average and median of measured methane chamber fluxes were 0.32 and 0.30 mgCH4 m−2 h−1 for middle taiga lakes and 8.6 and 4.1 mgCH4 m−2 h−1 for southern taiga lakes, respectively. Pronounced flux variability was found during measurements on individual lakes, between individual lakes and between zones. To analyze these differences and the influences of environmental controls, we developed a new dynamic process-based model. It shows good performance with emission rates from the southern taiga lakes and poor performance for individual lakes in the middle taiga region. The model shows that, in addition to well-known controls such as temperature, pH and lake depth, there are significant variations in the maximal methane production potential between these climatic zones. In addition, the model shows that variations in gas-filled pore space in lake sediments are capable of controlling the total methane emissions from individual lakes. The CH4 emissions exhibited distinct zonal differences not only in absolute values but also in their probability density functions: the middle taiga lake fluxes were best described by a lognormal distribution while the southern taiga lakes followed a power-law distribution. The latter suggests applicability of self-organized criticality theory for methane emissions from the southern taiga zone, which could help to explain the strong variability within individual lakes.

scholarly journals Variability in methane emissions from West Siberia's shallow boreal lakes

2016 ◽  
Author(s):  
Aleksandr F. Sabrekov ◽  
Benjamin R. K. Runkle ◽  
Mikhail V. Glagolev ◽  
Irina E. Terentieva ◽  
Victor M. Stepanenko ◽  
...  
Keyword(s):  
Pore Space ◽  
Temporal Variations ◽  
Methane Emissions ◽  
Boreal Lakes ◽  
Middle Taiga ◽  
Taiga Zone ◽  
Power Law Distribution ◽  
Small Lakes ◽  
The South ◽  
Environmental Controls

Abstract. Small lakes represent an important source of atmospheric CH4 from northern wetlands. However, spatio-temporal variations in flux magnitudes and the lack of knowledge about their main environmental controls contribute large uncertainty into the global CH4 budget. In this study, we measured methane fluxes from small lakes using chambers and bubble traps. Field investigations were carried out in July–August 2014 within the West Siberian middle and south taiga zones. The average and median of measured methane chamber fluxes were 0.32 and 0.30 mgCH4 m−2 h−1 for middle taiga lakes and 8.6 and 4.1 mgCH4 m−2 h−1 for south taiga lakes, respectively. Pronounced flux variability was found during measurements on individual lakes, between individual lakes and between zones. To analyze these differences and the influences of environmental controls we developed a new dynamic process-based model. It shows good performance with emission rates from the south taiga lakes and poor performance for individual lakes in the middle taiga region. The model shows that, besides well-known controls such as temperature, pH and lake depth, there are significant variations in the maximal methane production potential between these climatic zones. In addition, the model shows that variations of gas-filled pore space in lake sediments are capable to control the total methane emissions from individual lakes. The CH4 emissions exhibited distinct zonal differences not only in absolute values but also in their probability density functions: the middle taiga lake fluxes were best described by a lognormal distribution while the south taiga lakes followed a power law distribution. The latter suggests applicability of self-organized criticality theory for methane emissions from the south taiga zone, which could help to explain the strong variability within individual lakes.

scholarly journals Persistence of the Swiss Needle Cast Outbreak in Oregon Coastal Douglas-Fir and New Insights from Research and Monitoring

2021 ◽  
Author(s):  
David C Shaw ◽  
Gabriela Ritóková ◽  
Yung-Hsiang Lan ◽  
Doug B Mainwaring ◽  
Andrew Russo ◽  
...  
Keyword(s):  
Climate Change ◽  
Regional Scale ◽  
Emerging Diseases ◽  
Douglas Fir ◽  
Landscape Patterns ◽  
Needle Cast ◽  
Plantation Management ◽  
Environmental Controls ◽  
Swiss Needle Cast ◽  
Improvement Programs

Abstract Swiss needle cast (SNC), caused by Nothophaeocryptopus gaeumannii, is a foliage disease of Douglas-fir (Pseudotsuga menziesii), that reduces growth in native stands and exotic plantations worldwide. An outbreak of SNC began in coastal Oregon in the mid-1990s and has persisted since that time. Here we review the current state of knowledge after 24 years of research and monitoring, with a focus on Oregon, although the disease is significant in coastal Washington and has recently emerged in southwestern British Columbia. We present new insights into SNC distribution, landscape patterns, disease epidemiology and ecology, host-pathogen interactions, trophic and hydrologic influences, and the challenges of Douglas-fir plantation management in the presence of the disease. In Oregon, the SNC outbreak has remained geographically contained but has intensified. Finally, we consider the implications of climate change and other recently emerged foliage diseases on the future of Douglas-fir plantation management. Study Implications: Douglas-fir tree growers need to consider Swiss needle cast (SNC) and other emerging foliage diseases as SNC has not abated over the past 24 years, and along with other emerging diseases, it continues to pose a threat to Douglas-fir plantation productivity. Douglas-fir management in western Oregon remains important, such that a knowledge of disease impacts and effective silvicultural responses is key. Managers should carefully consider whether alternative species may be ecologically or economically beneficial in some situations while tree improvement programs must continue to breed for tolerance to SNC. Research shows that regional scale foliage disease outbreaks can result in trophic cascades and hydrologic changes that affects more than just the trees. The environmental controls on the SNC epidemic imply that climate change could strongly influence future directions of the outbreak, with the greatest threats to trees at higher elevations.

scholarly journals The Multiscale Monitoring of Peatland Ecosystem Carbon Cycling in the Middle Taiga Zone of Western Siberia: The Mukhrino Bog Case Study

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 824
Author(s):  
Egor Dyukarev ◽  
Evgeny Zarov ◽  
Pavel Alekseychik ◽  
Jelmer Nijp ◽  
Nina Filippova ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Western Siberia ◽  
Carbon Accumulation ◽  
Middle Taiga ◽  
Taiga Zone ◽  
Field Station ◽  
Moss Species ◽  
Chamber Method ◽  
The Impact

The peatlands of the West Siberian Lowlands, comprising the largest pristine peatland area of the world, have not previously been covered by continuous measurement and monitoring programs. The response of peatlands to climate change occurs over several decades. This paper summarizes the results of peatland carbon balance studies collected over ten years at the Mukhrino field station (Mukhrino FS, MFS) operating in the Middle Taiga Zone of Western Siberia. A multiscale approach was applied for the investigations of peatland carbon cycling. Carbon dioxide fluxes at the local scale studied using the chamber method showed net accumulation with rates from 110, to 57.8 gC m−2 at the Sphagnum hollow site. Net CO2 fluxes at the pine-dwarf shrubs-Sphagnum ridge varied from negative (−32.1 gC m−2 in 2019) to positive (13.4 gC m−2 in 2017). The cumulative May-August net ecosystem exchange (NEE) from eddy-covariance (EC) measurements at the ecosystem scale was −202 gC m−2 in 2015, due to the impact of photosynthesis of pine trees which was not registered by the chamber method. The net annual accumulation of carbon in the live part of mosses was estimated at 24–190 gC m−2 depending on the Sphagnum moss species. Long-term carbon accumulation rates obtained by radiocarbon analysis ranged from 28.5 to 57.2 gC m−2 yr−1, with local extremes of up to 176.2 gC m−2 yr−1. The obtained estimates of various carbon fluxes using EC and chamber methods, the accounting for Sphagnum growth and decomposition, and long-term peat accumulation provided information about the functioning of the peatland ecosystems at different spatial and temporal scales. Multiscale carbon flux monitoring reveals useful new information for forecasting the response of northern peatland carbon cycles to climatic changes.

scholarly journals Methane emissions from global rice fields: Magnitude, spatiotemporal patterns, and environmental controls

2016 ◽  
Vol 30 (9) ◽  
pp. 1246-1263 ◽  
Author(s):  
Bowen Zhang ◽  
Hanqin Tian ◽  
Wei Ren ◽  
Bo Tao ◽  
Chaoqun Lu ◽  
...  
Keyword(s):  
Methane Emissions ◽  
Rice Fields ◽  
Spatiotemporal Patterns ◽  
Environmental Controls

scholarly journals Growth and Development of Introduced Larix Mill. Species in the Taiga Zone (Karelia)

2021 ◽  
pp. 61-83
Author(s):  
Ivan T. Kishchenko
Keyword(s):  
Plant Communities ◽  
Growth And Development ◽  
Growing Season ◽  
Botanical Garden ◽  
Larix Sibirica ◽  
Middle Taiga ◽  
Taiga Zone ◽  
State University ◽  
Residential Landscaping ◽  
Phenological Phases

The study reports results of research carried out from April to October during 1988–2016 at the Botanical Garden of Petrozavodsk State University (South Karelia, middle taiga subzones). Three introduced species of the genus Larix (Larix sibirica Ledeb., L. leptolepis (Sieb. et Zucc.) Gord, and L. dahurica Turcz. ex Trautv.) were studied. The growth of shoots and needles in different species begins, reaches its culmination, and ends almost simultaneously, differing by no more than one week across the species. L. sibirica shows the highest growth rate. The timing of growth, culmination, and the dynamics of growth of shoots and needles are largely determined by variations in precipitation, temperature, and humidity. The direction and strength of such an effect may vary from year to year. The dates of phenological phases of the Larix species studied here are chiefly determined by the air temperature in the current growing season and the dates of formation of wintering buds in the previous growing season. Bud swelling and opening begins almost simultaneously in the studied species. Most of the other phenological phases begin and end earliest in L. sibirica and latest in L. leptolepis. All the studied species, primarily L. sibirica, are promising for residential landscaping and creation of artificial plant communities in Karelia

scholarly journals PSI-1 Effects of source and level of inclusion of engineered biocarbon in a total mixed beef cattle diet on in vitro methane emissions and fermentation parameters

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 290-291
Author(s):  
Paul Tamayao ◽  
Kim Ominski ◽  
Gabriel Ribeiro ◽  
Emma McGeough
Keyword(s):  
Fixed Effects ◽  
Pore Space ◽  
Block Design ◽  
In Vitro Study ◽  
Methane Emissions ◽  
Gas Production ◽  
Feed Digestibility ◽  
Fermentation Parameters ◽  
Barley Silage

Abstract This in vitro study evaluated seven different engineered biocarbon products supplied at three levels (0.5, 1.5 and 2.5 mg/ml inoculum) to determine their effects on total gas, methane production, and fermentation parameters when added to a barley silage-based diet. The biocarbon sources were derived from either coconut (CP001 and CP014) or pine (CP002, CP015, CP016, CP023, CP024) and differed in their physical properties and chemical composition. The coconut biocarbon sources were lower in pore space, particle size distribution and surface area but higher in bulk density than the pine products. The control consisted of only the barley-silage diet. The in vitro batch culture jars were incubated for 24 h at 39°C at the above inclusion levels in 0.5 g of diet. Gas samples were collected at 3, 6, 9, 12, 18 and 24 h and DM disappearance, pH, VFA and ammonia concentrations post incubation were measured. Data were analysed using the PROC MIXED in SAS as a randomized complete block design with treatment and rate as fixed effects and run and replicate as random effects. Total gas production was not affected by source of biocarbon (P = 0.85) and inclusion rate (P = 0.91). Cumulative methane (ml/g DM) had no response to biocarbon addition (P = 0.40) at any inclusion level (P = 0.48). Additionally, concentration of total VFA was not affected by treatment (P = 0.31) or inclusion rates (P = 0.25). NH3-N concentrations responded quadratically (P < 0.001) to all types of biocarbon. Higher inclusion rates of biocarbon linearly (P < 0.002) decreased feed digestibility, particularly the coconut-based biocarbon sources CP001 and CP014. In conclusion, supplementation of biocarbon to a TMR diet did not reduce methane emissions, but at higher levels of inclusion diet digestibility was negatively affected.

scholarly journals Decreased Snow Cover Stimulates Under-Ice Primary Producers but Impairs Methanotrophic Capacity

mSphere ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Sarahi L. Garcia ◽  
Anna J. Szekely ◽  
Christoffer Bergvall ◽  
Martha Schattenhofer ◽  
Sari Peura
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Water Column ◽  
Relative Abundance ◽  
Heterotrophic Bacteria ◽  
Methane Emissions ◽  
Boreal Lakes ◽  
Climate Change Scenarios ◽  
Primary Producers ◽  
Microbial Composition

ABSTRACT Climate change scenarios anticipate decreased spring snow cover in boreal and subarctic regions. Forest lakes are abundant in these regions and substantial contributors of methane emissions. To investigate the effect of reduced snow cover, we experimentally removed snow from an anoxic frozen lake. We observed that the removal of snow increased light penetration through the ice, increasing water temperature and modifying microbial composition in the different depths. Chlorophyll a and b concentrations increased in the upper water column, suggesting activation of algal primary producers. At the same time, Chlorobiaceae, one of the key photosynthetic bacterial families in anoxic lakes, shifted to lower depths. Moreover, a decrease in the relative abundance of methanotrophs within the bacterial family Methylococcaceae was detected, concurrent with an increase in methane concentration in the water column. These results indicate that decreased snow cover impacts both primary production and methane production and/or consumption, which may ultimately lead to increased methane emissions after spring ice off. IMPORTANCE Small lakes are an important source of greenhouse gases in the boreal zone. These lakes are severely impacted by the winter season, when ice and snow cover obstruct gas exchange between the lake and the atmosphere and diminish light availability in the water column. Currently, climate change is resulting in reduced spring snow cover. A short-term removal of the snow from the ice stimulated algal primary producers and subsequently heterotrophic bacteria. Concurrently, the relative abundance of methanotrophic bacteria decreased and methane concentrations increased. Our results increase the general knowledge of microbial life under ice and, specifically, the understanding of the potential impact of climate change on boreal lakes.

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