Chersky region

Research objectives

The overall objective of this component of CarboPerm is to characterize and quantify the spatiotemporal variability of CO2 and CH4 fluxes in Arctic permafrost ecosystems, and to analyze causal relationships between recent fluxes and environmental drivers. This goal will be addressed by establishing a carbon cycle observation network in Northeast Siberia covering multiple spatiotemporal scales, and applying a suite of modeling tools to link observed flux patterns to environmental drivers to advance the understanding of the underlying biogeochemical mechanisms.

This main objective is broken up into the three specific research focus areas for this work package of CarboPerm:

  1. Monitor permafrost carbon fluxes with a suite of instruments across multiple spatial scales within the target domain of the Chersky region, and compare findings with observations from the Lena River Delta in order to quantify the spatial variability of CO2 and CH4 fluxes on micro-, meso- and macro-scale.
  2. Collect continuous flux observations in the target region for several entire years to characterize the variability of exchange fluxes across temporal scales, and attribute this variability to environmental conditions and specific seasonal events.
  3. Develop frameworks to determine causal relationships between permafrost carbon fluxes and environmental drivers that are applicable across spatiotemporal scales.

To address the above-mentioned objectives, we set up the following hypotheses:

  1. The spatial variability of CO2 and CH4 fluxes is highest on the micro-scale, and significantly reduced for meso- and macro-scales.
  2. Interannual variability in carbon exchange fluxes can turn terrestrial ecosystems into a net carbon source in individual years, while they are carbon sinks in the long-term average.
  3. Timing of spring thaw and fall re-freeze dominates the interannual variability of carbon fluxes, with non-negligible net flux contributions emitted within the cold seasons.
  4. Thermokarst lakes, which are strong carbon sources, more than compensate the sink strength from terrestrial ecosystems on the regional scale in Northeastern Siberia.

 

 

Study region

Chersky region

The region around Chersky, Northeast Siberia, just south of the arctic tree line, is part of the hypo-arctic tundra zone characterized by dense shrubbery and a high abundance of sphagnum mosses. The major landscape units include forested upland tundra, floodplains with tussock tundra, and thermokarst depressions. The group of the Max-Planck-Institute for Biogeochemistry (MPI-BGC) chose the Chersky region as the focus area for research activities within the context of the CarboPerm project because of the available infrastructure, pre-existing datasets, and a multitude of permafrost landscape units to be sampled within a relatively small domain. All monitoring programs in will be conducted in close cooperation with the Northeast Science Station (NESS) led by Sergey Zimov, which will provide year-round support to maintain the observational network.

Floodplain

Our core site in the Chersky area, a wet tussock grassland located on the flood plain of the Kolyma river (German tower site, 68.61°N, 161.34°E), offers unique conditions to study recent trends in carbon cycle processes in a permafrost ecosystem, and to evaluate the vulnerability of its vast carbon pool to potential future climate change. From previous experiments conducted by the Max-Planck-Institute for Biogeochemistry (MPI-BGC) at that same location, we have gathered a reference database of carbon exchange fluxes monitored by eddy-covariance (EC) systems and soil chambers (SC) for the summer seasons of the years 2002-2005. Fluxes from 2002-2004 represent undisturbed tussock tundra, while in 2005 a drainage ditch ring was installed around the tower that is still in place today, altering the water table and thus modifying the fluxes of CO2 and CH4. This disturbance of the local water regime anticipates the hydrologic changes that are expected for this area with melting of the permafrost under climate change.

Ambarchyk Bay

A second observation site will be established ~100km North of Chersky close to the Arctic Ocean, at the location of the Ambarchyk Bay meteorological observatory (69.62°N, 162.30°E). This site offers favorable conditions for conducting continuous measurements of well calibrated atmospheric mixing ratios of CO2 and CH4. Since the areas influencing such measurements will cover length scales between a few tens of kilometers and several hundreds of kilometers, the atmospheric signals captured at this site will thus contain information that integrate flux emissions from the Arctic Ocean, the ocean shelf, and the coastal permafrost regions. In combination with data from similar observations sites provided by collaborating groups, this site will provide the database for inverse atmospheric modeling studies to constrain regional to pan-arctic scale carbon budgets.

Experiments on recent carbon exchange processes

German tower site

In summer 2013, the MPI-BGC group installed new flux observation systems at the German Tower Site, focusing on flux processes within the area affected by the drainage ring. A nearby location unaffected by the hydrologic disturbance was chosen as a second focus area to provide reference fluxes from an undisturbed ecosystem.

The German Tower Site is equipped with a small infrastructure hub that includes e.g. a winter house, the cabin for the diesel generator, and storage facilities. These structures will support a year-round operation and continuous on-site maintenance of the instrumentation. The actual observation sites are connected to this hub by boardwalks and elevated power lines.

Each of the two focus areas to study recent carbon flux exchange processes between permafrost ecosystems and atmosphere is equipped with the same basic instrumentation setup:

  • One eddy-covariance flux tower (~4.5m) to monitor exchange fluxes of CO2 and CH4
  • A suite of ancillary meteorological sensors (e.g. radiation, wind, temperature, precipitation) and monitoring of soil parameters (e.g. soil temperature profile, soil moisture profile)
  • Ten permanently installed collars (60x60cm) for closed chamber measurements of CO2 and CH4

 

In addition, sampling programs were conducted at each of the focus areas to characterize vegetation communities, general soil properties, microbial community structure and activity, and isotope composition in carbon exchange fluxes.

Tower
Measurements

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News

Our summer school at the Ladoga Lake has just started!!

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News from the summer expedition to the delta!

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In September 2016 our "St. Petersburg summer school" for young scientists will be supported by the DAAD "Go-East Summer Schools" programme.

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Our new bilateral Master's Program CORELIS will start with the first cohort in summer 2016!

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Great photographs from our Summer School at Lake Ladoga available on-line!

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The PhD Meeting in Gülpe was a great success!

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Late summer on Samoylov Island. Read how our six scientists are going!

Scientists from Hamburg are in the Lena River Delta.

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Impressions of the Polar day, the spring flood and the ice breakup. 

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