Embed Size (px)
Citation preview
TEAM
Treibhausgasdynamik & Klimawirksamkeit
wiedervernässter Moore
Torsten Sachs1,2, Pia Gottschalk1, Christian Wille1, Franziska Koebsch31GFZ - German Research Centre for Geosciences, Potsdam, Germany2Technische Universität Braunschweig, Germany3Landscape Ecology, University of Rostock, Germany
[email protected] 225. September 2018
Wetlands as carbon sink…
• Wetlands can be found in 175 countries• Cover only 3% of the land surface but store >500 Gt C in peat• Twice as much C as in entire forest biomass
Slide: Modified from Joosten
[email protected] 325. September 2018
… or source
• Drained peatlands on 0.4% of the land surface emit 5 % of the anthropogenic CO2 worldwide: Nr. 1. Indonesia, Nr. 2. EU, ….
• In Germany: ~ 5 % of national emissions• In Mecklenburg-Vorpommern: ~ 30 % of state-wide emissions
Slide: Modified from Joosten
[email protected] 425. September 2018
Agriculture on peatlands
• Peatlands used for agriculture in Germany emit almost twice as much CO2 as the 7th dirtiest power plant in the world
Slide: Modified from Joosten
[email protected] 525. September 2018
Foto: Sabine Wichmann
• German peatland agriculture causes 3,6 Billion € in climate damage per year…
… with the help of 300 Million € inEU-subsidies
Agriculture on peatlands
Slide: Modified from Joosten
[email protected] 725. September 2018
Solution: re-wetting?
• Objectives: Protecting… … biodiversity … climate … soils … water
[email protected] 825. September 2018
• Fen in a river valley mire system, drainage began early 1700s, re-wetting 2000• Peat depth up to 10 m, MAT 8.7 °C, mean annual precipitation: 584 mm
Polder Zarnekow, Peenetal (DE-Zrk)
Map: Bennet Juhls
[email protected] 1025. September 2018
Degradation classes (Schumann & Joosten)
Source: Timmermann et al. 2009, modified
[email protected] 1325. September 2018
Polder Zarnekow throughout the years
2013 2014 2015
2016 2017 2018
[email protected] 1425. September 2018
Note the water level fluctuations! (not obviously related to precipitation…)
Weather at Zarnekow
[email protected] 1525. September 2018
• All years were warmer than the long-term average:
• 2017 was much wetter than average,2014, 2016, and 2018 much drier:
Meteorology and climate at Zarnekow
[email protected] 1625. September 2018
• 2D wind speed & direction Gill WindSonic• 3D sonic anemometer Gill HS-50• Closed path H2O/CO2/CH4 Los Gatos FGGA-EP• Enclosed H2O/CO2 LI-7200• Open path CH4 LI-7700• Temperature / humidity Vaisala HMP155• Pressure Young Model 61302V• 4 component radiation Kipp & Zonen CNR4• PAR LI-190SL• Precipitation Young 52203 tipping bucket• Water temperatures• Sediment temperatures UMS Th3• Heat flux plates Hukseflux HFP01SC• O2 sensors
Instrumentation
[email protected] 1725. September 2018
Footprint – what do we “see”?
• Two main surface types Open water Emergent vegetation (Typha latifolia)
• Surface type fractions based on Göckede et al. (2004)• Source area based on Kormann & Meixner (2001)• Footprint climatology based on Chen et al. (2011)
• Peak contribution 18 m from the tower mainly from the open water area
• Open water covered on average 62.5% of source area
Franz et al. (2016) Biogeosciences
[email protected] 1825. September 2018
Large CO2 loss July/ Aug 2018 vs. damped CO2 loss in wet 2017
Significant CO2 uptake in 2018 compared to previous years
Monthly ecosystem respiration (CO2 loss)
[email protected] 1925. September 2018
• Much more photosynthesis in 2018, followed by dry year 2016 Does temporal drying enhance vegetation growth and thus CO2 uptake?
• Respiration also clearly increased in dry years 2016/2018, lowest in wet 2017 High water level supresses respiration (known, that‘s why we re-wet)
Annual cumulative photosynthesis & respiration
[email protected] 2025. September 2018
Annual total fluxes
• Unclear trends: Slowly decreasing CH4 source? Transition from CO2 source to sink?
[email protected] 2125. September 2018
Summary and to do list
• Substantial and slowly decreasing CH4 and CO2 source First CO2 sink year in 2018
• Increasing respiration, unclear trend in photosynthesis May depend on re-analysis of suspicious 2015 data Dry years appear to enhance photosynthesis
• Climate impact dominated by CH4 release
• To do: 2015 data possibly biased towards respiration re-analysis to verify/falsify unusal Sept flux
Involve hydrologists (lateral transport) (continued) biogeochemical and micro-biological
investigations - why are CH4 oxidizers missing? Investigate spatial representativeness
based on aircraft and UAV measurements
