scholarly journals Identifying Drivers Behind Spatial Variability of Methane Concentrations in East Siberian Ponds

2021 ◽  
Vol 9 ◽  
Author(s):  
Zoé Rehder ◽  
Anna Zaplavnova ◽  
Lars Kutzbach
Keyword(s):  
Surface Water ◽  
Spatial Variability ◽  
Water Depth ◽  
Methane Emissions ◽  
The Arctic ◽  
Lena River ◽  
Small Water ◽  
Important Region ◽  
Ice Wedge ◽  
Methane Concentrations

Waterbody methane emissions per area are negatively correlated with the size of the emitting waterbody. Thus, ponds, defined here as having an area smaller than 8 · 104m2, contribute out of proportion to the aquatic methane budget compared to the total area they cover and compared to other waterbodies. However, methane concentrations in and methane emissions from ponds show more spatial variability than larger waterbodies. We need to better understand this variability to improve upscaling estimates of freshwater methane emissions. In this regard, the Arctic permafrost landscape is an important region, which, besides carbon-rich soils, features a high pond density and is exposed to above-average climatic warming. We studied 41 polygonal-tundra ponds in the Lena River Delta, northeast Siberia. We collected water samples at different locations and depths in each pond and determined methane concentrations using gas chromatography. Additionally, we collected information on the key properties of the ponds to identify drivers of surface water methane concentrations. The ponds can be categorized into three geomorphological types with distinct differences in drivers of methane concentrations: polygonal-center ponds, ice-wedge ponds and larger merged polygonal ponds. All ponds are supersaturated in methane, but ice-wedge ponds exhibit the highest surface water concentrations. We find that ice-wedge ponds feature a strong stratification due to consistently low bottom temperatures. This causes surface concentrations to mainly depend on wind speed and on the amount of methane that has accumulated in the hypolimnion. In polygonal-center ponds, high methane surface concentrations are mostly determined by a small water depth. Apart from the influence of water depth on mixing speed, water depth controls the overgrown fraction, the fraction of the pond covered by vascular plants. The plants provide labile substrate to the methane-producing microbes. This link can also be seen in merged polygonal ponds, which furthermore show the strongest dependence on area as well as an anticorrelation to energy input indicating that stratification influences the surface water methane concentrations in larger ponds. Overall, our findings underpin the strong variability of methane concentrations in ponds. No single driver could explain a significant part of the variability over all pond types suggesting that more complex upscaling methods such as process-based modeling are needed.

Sensitivity of pond methane emissions in the Lena River Delta to climate changes in new model MeEP

2021 ◽  
Author(s):  
Zoé Rehder ◽  
Thomas Kleinen ◽  
Lars Kutzbach ◽  
Victor Stepanenko ◽  
Victor Brovkin
Keyword(s):  
Spatial Variability ◽  
Model Performance ◽  
Methane Emissions ◽  
River Delta ◽  
Lena River ◽  
Methane Fluxes ◽  
Eddy Covariance Measurements ◽  
Ice Wedge ◽  
Set Up ◽  
Lena River Delta

<p>Permafrost ponds are a steady source of methane. However, it is difficult to assess the sensitivity of pond methane emissions to ongoing warming and climate-change-induced drainage, because pond methane emissions show large temporal and spatial variability already on local scale.<br>We study this sensitivity on the landscape level with a new process-based model for Methane Emissions from Ponds (MeEP model), which simulates the three main pathways of methane emissions (diffusion, plant-mediated transport and ebullition) as well as the temperature profile of the water column and the surrounding soils. The model was set up for the polygonal tundra in the Lena River Delta. Due to a temporal resolution of one hour, it is capable of capturing the diurnal, day-to-day and seasonal variability in methane fluxes. MeEP also considers one of the main drivers of spatial variability - ground heterogeneity. Depending on where ponds form in the polygonal tundra, they can be classified as ice-wedge, polygonal-centre or merged-polygonal ponds. In MeEP, each of these pond types is simulated separately and the representation of these ponds was informed by dedicated measurements.<br>The model performance is validated against eddy-covariance measurements of methane fluxes and against in-situ measurements of the aqueous methane concentration, both obtained on Samoylov Island.  We will present results regarding the sensitivity of modeled methane emissions from ponds to warming and drainage on the landscape scale.</p>

Vegetation height and other controls of spatial variability in methane emissions from the Arctic coastal tundra at Barrow, Alaska

2010 ◽  
Vol 115 ◽  
Author(s):  
Joseph C. von Fischer ◽  
Robert C. Rhew ◽  
Gregory M. Ames ◽  
Bailey K. Fosdick ◽  
Paul E. von Fischer
Keyword(s):  
Spatial Variability ◽  
Methane Emissions ◽  
The Arctic ◽  
Vegetation Height

scholarly journals Methane dynamics in three different Siberian water bodies under winter and summer conditions

2021 ◽  
Vol 18 (6) ◽  
pp. 2047-2061
Author(s):  
Ingeborg Bussmann ◽  
Irina Fedorova ◽  
Bennet Juhls ◽  
Pier Paul Overduin ◽  
Matthias Winkel
Keyword(s):  
Water Column ◽  
Methane Concentration ◽  
Ice Cores ◽  
Ice Cover ◽  
Arctic Lakes ◽  
Water Bodies ◽  
The Arctic ◽  
Late Winter ◽  
Lena River ◽  
Methane Concentrations

Abstract. Arctic regions and their water bodies are affected by a rapidly warming climate. Arctic lakes and small ponds are known to act as an important source of atmospheric methane. However, not much is known about other types of water bodies in permafrost regions, which include major rivers and coastal bays as a transition type between freshwater and marine environments. We monitored dissolved methane concentrations in three different water bodies (Lena River, Tiksi Bay, and Lake Golzovoye, Siberia, Russia) over a period of 2 years. Sampling was carried out under ice cover (April) and in open water (July–August). The methane oxidation (MOX) rate and the fractional turnover rate (k′) in water and melted ice samples from the late winter of 2017 was determined with the radiotracer method. In the Lena River winter methane concentrations were a quarter of the summer concentrations (8 nmol L−1 vs. 31 nmol L−1), and mean winter MOX rate was low (0.023 nmol L−1 d−1). In contrast, Tiksi Bay winter methane concentrations were 10 times higher than in summer (103 nmol L−1 vs. 13 nmol L−1). Winter MOX rates showed a median of 0.305 nmol L−1 d−1. In Lake Golzovoye, median methane concentrations in winter were 40 times higher than in summer (1957 nmol L−1 vs. 49 nmol L−1). However, MOX was much higher in the lake (2.95 nmol L−1 d−1) than in either the river or bay. The temperature had a strong influence on the MOX (Q10=2.72±0.69). In summer water temperatures ranged from 7–14 ∘C and in winter from −0.7 to 1.3 ∘C. In the ice cores a median methane concentration of 9 nM was observed, with no gradient between the ice surface and the bottom layer at the ice–water interface. MOX in the (melted) ice cores was mostly below the detection limit. Comparing methane concentrations in the ice with the underlaying water column revealed methane concentration in the water column 100–1000 times higher. The winter situation seemed to favor a methane accumulation under ice, especially in the lake with a stagnant water body. While on the other hand, in the Lena River with its flowing water, no methane accumulation under ice was observed. In a changing, warming Arctic, a shorter ice cover period is predicted. With respect to our study this would imply a shortened time for methane to accumulate below the ice and a shorter time for the less efficient winter MOX. Especially for lakes, an extended time of ice-free conditions could reduce the methane flux from the Arctic water bodies.

scholarly journals Fate of terrigenous organic matter across the Laptev Sea from the mouth of the Lena River to the deep sea of the Arctic interior

2016 ◽  
Author(s):  
Lisa Bröder ◽  
Tommaso Tesi ◽  
Joan A. Salvadó ◽  
Igor P. Semiletov ◽  
Oleg V. Dudarev ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Depth ◽  
Deep Sea ◽  
River Mouth ◽  
The Arctic ◽  
Laptev Sea ◽  
Climate Feedbacks ◽  
Lena River ◽  
Lignin Phenols ◽  
Future Work

Abstract. Ongoing global warming in high latitudes may cause an increasing supply of permafrost-derived organic carbon through both river discharge and coastal erosion to the Arctic shelves. Here it can be either buried in sediments, transported to the deep sea or degraded to CO2 and outgassed, potentially constituting a positive feedback to climate change. This study aims to assess the fate of terrestrial organic carbon (TerrOC) in the Arctic marine environment by exploring how it changes in concentration, composition and degradation status across the wide Laptev Sea shelf. We analyzed a suite of terrestrial biomarkers as well as source-diagnostic bulk carbon isotopes (δ13C, Δ14C) in surface sediments from a Laptev Sea transect spanning more than 800 km from the Lena River mouth (~ 10 m water depth) across the shelf to the slope and rise (2000–3000 m water depth). These data provide a broad view on different TerrOC pools and their behavior during cross-shelf transport. The concentrations of lignin phenols, cutin acids and high-molecular weight (HMW) wax lipids (tracers of vascular plants) decrease by 89–99 % along the transect. Molecular-based degradation proxies for TerrOC (e.g., the carbon preference index of HMW lipids, the HMW acids/alkanes ratio and the acid/aldehyde ratio of lignin phenols) display a trend to more degraded TerrOC with increasing distance from the coast. We infer that the degree of degradation of permafrost-derived TerrOC is a function of the time spent under oxic conditions during protracted cross-shelf transport. Future work should therefore seek to constrain cross-shelf transport times in order to compute a TerrOC degradation rate and thereby help to quantify potential carbon-climate feedbacks.

Drivers of methane variability in Arctic ponds

2020 ◽  
Author(s):  
Zoé Rehder ◽  
Anna Zaplavnova ◽  
Lars Kutzbach
Keyword(s):  
Vegetation Cover ◽  
Meteorological Data ◽  
Chemical Properties ◽  
Methane Emissions ◽  
Spatiotemporal Variability ◽  
Permafrost Degradation ◽  
Lena River ◽  
Arctic Ponds ◽  
Physical And Chemical ◽  
Methane Concentrations

<p>Arctic ponds are significant sources of methane, but their overall contribution to pan-Arctic methane emissions is still uncertain. Ponds come in different sizes and shapes, which are associated with different stages of permafrost degradation. Methane concentrations and fluxes show large spatiotemporal variability. To better understand this variability, as a first step towards upscaling pond methane emissions, we studied 41 ponds in the Lena River Delta, northeast Siberia. We collected water samples at different locations and depths in each pond and determined methane concentrations using gas chromatography. Additionally, we collected information on the geomorphology, vegetation cover as well as on key physical and chemical properties of the ponds and combined them with meteorological data.</p><p>The ponds are divided into three geomorphological types with distinct differences in methane concentrations: water-filled degraded polygon centers, water-filled interpolygonal troughs and larger collapsed and merged polygons. These ponds exhibit mean surface methane concentrations (with standard deviation) of 1.2 ± 1.3 μmol L-1, 4.3 ± 4.9 μmol L-1 and 0.9 ± 0.7 μmol L-1 respectively, while mean bottom methane concentrations amount to 102.6 ± 145.4 μmol L-1, 263.3 ± 275.6 μmol L-1 and 17.0 ± 34.1 μmol L-1. Using principle components and multiple linear regressions, we show that a large portion of spatial variability can be explained by the ponds’ shape and vegetation. Merged ponds have the least relative vegetation cover, and they also tend to be better mixed, both of which explains the lowest methane concentrations and the lowest variability in these ponds. Vegetation covers larger fractions in polygon centers and troughs, leading to a larger methane variability. Finally, troughs, as they are underlain by ice wedges, exhibit more pronounced stratification and the highest methane concentrations. More results will be presented at the conference.</p>

scholarly journals Methane oxidation in the waters of a humics-rich boreal lake stimulated by photosynthesis, nitrite, Fe(III) and humics

2021 ◽  
Author(s):  
Sigrid van Grinsven ◽  
Kirsten Oswald ◽  
Bernhard Wehrli ◽  
Corinne Jegge ◽  
Jakob Zopfi ◽  
...  
Keyword(s):  
Surface Water ◽  
Methane Oxidation ◽  
Bottom Water ◽  
Water Concentration ◽  
Eutrophic Lake ◽  
Methane Emissions ◽  
Boreal Lakes ◽  
Boreal Lake ◽  
Methane Concentrations

Abstract. Small boreal lakes are known to contribute significantly to global methane emissions. Lake Lovojärvi is a eutrophic lake in Southern Finland with bottom water methane concentrations up to 2 mM. However, the surface water concentration, and thus the diffusive emission potential, was low (

scholarly journals Fate of terrigenous organic matter across the Laptev Sea from the mouth of the Lena River to the deep sea of the Arctic interior

2016 ◽  
Vol 13 (17) ◽  
pp. 5003-5019 ◽  
Author(s):  
Lisa Bröder ◽  
Tommaso Tesi ◽  
Joan A. Salvadó ◽  
Igor P. Semiletov ◽  
Oleg V. Dudarev ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Depth ◽  
Deep Sea ◽  
River Mouth ◽  
The Arctic ◽  
Laptev Sea ◽  
Climate Feedbacks ◽  
Lena River ◽  
Lignin Phenols ◽  
Future Work

Abstract. Ongoing global warming in high latitudes may cause an increasing supply of permafrost-derived organic carbon through both river discharge and coastal erosion to the Arctic shelves. Mobilized permafrost carbon can be either buried in sediments, transported to the deep sea or degraded to CO2 and outgassed, potentially constituting a positive feedback to climate change. This study aims to assess the fate of terrigenous organic carbon (TerrOC) in the Arctic marine environment by exploring how it changes in concentration, composition and degradation status across the wide Laptev Sea shelf. We analyzed a suite of terrestrial biomarkers as well as source-diagnostic bulk carbon isotopes (δ13C, Δ14C) in surface sediments from a Laptev Sea transect spanning more than 800 km from the Lena River mouth (< 10 m water depth) across the shelf to the slope and rise (2000–3000 m water depth). These data provide a broad view on different TerrOC pools and their behavior during cross-shelf transport. The concentrations of lignin phenols, cutin acids and high-molecular-weight (HMW) wax lipids (tracers of vascular plants) decrease by 89–99 % along the transect. Molecular-based degradation proxies for TerrOC (e.g., the carbon preference index of HMW lipids, the HMW acids ∕ alkanes ratio and the acid ∕ aldehyde ratio of lignin phenols) display a trend to more degraded TerrOC with increasing distance from the coast. We infer that the degree of degradation of permafrost-derived TerrOC is a function of the time spent under oxic conditions during protracted cross-shelf transport. Future work should therefore seek to constrain cross-shelf transport times in order to compute a TerrOC degradation rate and thereby help to quantify potential carbon–climate feedbacks.

The Northern Sea Route as a Tool of Arctic Development

2019 ◽  
pp. 21-44
Author(s):  
Ju.V. Zvorykina ◽  
K.S. Teteryatnikov
Keyword(s):  
Economic Development ◽  
Oil And Gas ◽  
The Arctic ◽  
Arctic Zone ◽  
Investment Projects ◽  
Northern Sea Route ◽  
Important Region ◽  
Socio Economic Development ◽  
Asian Pacific ◽  
Simplified Procedure

The article is devoted to the analysis of the role of the Northern Sea Route (NSR) in the socio-economic development of the Arctic zone of Russia. The authors believe that climate change, gradually leading to the melting of polar ice, opens up new opportunities for the development of Arctic resources and navigation in the seas of the Arctic Ocean. Of particular interest to the NSR are non-Arctic countries, critically dependent on the supply of foreign mineral and carbon resources, as well as on the export of their goods to Europe. Among them, China stands out, considering the NSR as the Arctic Blue Economic Corridor as part of the global Silk Road system. The NSR is intended to become an essential tool for further development of the Arctic zone of Russia. Development of port infrastructure and creation of a modern ocean and maritime fleet will accelerate the pace of socio-economic development of this strategically important region. To do this, it is necessary to adopt a federal law on special system of preferences for investors, including foreign ones, implementing their projects in the Arctic. Among such preferences there are preferential profit tax rates, reduction in Mineral Extraction Tax (MET) rates, a declarative procedure for VAT refunds, a simplified procedure for granting land plots and unchanged conditions for the implementation of investment projects. In addition, it is important to make the NSR safe and profitable both in terms of quality of service and of price for the shippers. In particular, the payment for icebreakers’ escort of vessels should be competitive and reasonable. The largest Russian private and state-owned companies should be involved into Arctic projects. It is important to synchronize the Arctic oil and gas projects with nuclear and LNG icebreakers’ construction, as well as with the launch of two logistics hubs in Murmansk and Kamchatka. In this case, year-round NSR navigation will be organized, which will ensure the high competitiveness of Russian products supplied to the Asian Pacific markets.

scholarly journals Microplastics distribution in the Eurasian Arctic is affected by Atlantic waters and Siberian rivers

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Evgeniy Yakushev ◽  
Anna Gebruk ◽  
Alexander Osadchiev ◽  
Svetlana Pakhomova ◽  
Amy Lusher ◽  
...  
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Water Masses ◽  
The Arctic ◽  
Plastic Pollution ◽  
Siberian River ◽  
Highest Weight ◽  
Surface Samples ◽  
Atlantic Origin ◽  
Type Size

AbstractPlastic pollution is globally recognised as a threat to marine ecosystems, habitats, and wildlife, and it has now reached remote locations such as the Arctic Ocean. Nevertheless, the distribution of microplastics in the Eurasian Arctic is particularly underreported. Here we present analyses of 60 subsurface pump water samples and 48 surface neuston net samples from the Eurasian Arctic with the goal to quantify and classify microplastics in relation to oceanographic conditions. In our study area, we found on average 0.004 items of microplastics per m3 in the surface samples, and 0.8 items per m3 in the subsurface samples. Microplastic characteristics differ significantly between Atlantic surface water, Polar surface water and discharge plumes of the Great Siberian Rivers, allowing identification of two sources of microplastic pollution (p < 0.05 for surface area, morphology, and polymer types). The highest weight concentration of microplastics was observed within surface waters of Atlantic origin. Siberian river discharge was identified as the second largest source. We conclude that these water masses govern the distribution of microplastics in the Eurasian Arctic. The microplastics properties (i.e. abundance, polymer type, size, weight concentrations) can be used for identification of the water masses.

Sign in / Sign up

Export Citation Format

Share Document