degradation at the land-ocean interface George Tanski, Michael - PowerPoint PPT Presentation

Permafrost carbon release and degradation at the land-ocean interface George Tanski, Michael Fritz, Justine Ramage, Christian Knoblauch, Nicole Couture, and Hugues Lantuit Herschel Island, Yukon, Canada

Background of northern landmass of global coasts km of coastline (Gt C org. ) Global carbon storage in soils TARNOCAI et al. 2009 George Tanski 1

Background of the coast are unlithified Erosion rates up to Herschel Island, Yukon Coast, Canada George Tanski 2

Background of the coast are unlithified Erosion rates up to Komakuk Beach, Yukon Coast, Canada George Tanski 3

Background of the coast are unlithified Erosion rates up to Herschel Island, Yukon, Canada Photo: J. WOLTER George Tanski 4

Topic I release... Dissolved organic carbon (DOC) OC ≤ 0.45 µm Particulate organic carbon (POC) Sediments George Tanski 5

Topic I: Release of DOC from ground ice Herschel Island Roland Bay Canada Study sites Kay Point Beaufort Sea (Arctic Ocean) Unglaciated Glaciated George Tanski 6

Topic I: Release of DOC from ground ice River discharge ** DOC: 1.3 Gg yr -1 POC: 2.1 Gg yr -1 Sediment: 127.0 Gg yr -1 Coastal erosion * DOC: ? SOC: 0.04 Gg yr -1 Sediment: 2.66 Gg yr -1 * MACDONALD et al. 1998 1 Gg = 10 12 g = 10 9 kg = 10 6 t ** COUTURE 2010 George Tanski 7

Topic I: Release of DOC from ground ice Ground ice content and types along the Yukon Coastal Plain • 37% ground ice C: 26% A+B: 11% After COUTURE 2010 A) Ice wedges B) Massive ice beds C) Pore/Non-massive intrasedimental ice George Tanski 8

Topic I: Release of DOC from ground ice Ground ice content and types along the Yukon Coastal Plain • 37% ground ice C: 26% A+B: 11% After COUTURE 2010 A) Ice wedges B) Massive ice beds A) B) C) C) Pore/Non-massive intrasedimental ice George Tanski 9

Topic I: Release of DOC from ground ice Calculation of DOC flux • n DOC storage = θj ∗ ρ ∗ DOCconc.j j=1 n DOC flux = lj ∗ hj ∗ Rj ∗ DOC storage j j=1 Modified, after COUTURE 2010 George Tanski 10

Topic I: Release of DOC from ground ice River discharge * DOC: 1.3 Gg yr -1 POC: 2.1 Gg yr -1 Sediment: 127.0 Gg yr -1 Coastal erosion ** DOC: 0.09 -3 Gg yr -1 SOC: 0.04 Gg yr -1 Sediment: 2.66 Gg yr -1 * MACDONALD et al. 1998 1 Gg = 10 12 g = 10 9 kg = 10 6 t ** COUTURE 2010 George Tanski 11

Topic I: Conclusion Low dissolved organic carbon fluxes from eroding permafrost coasts • Western part and Herschel Island are hotspots • Mostly fluxes from ice thrust moraine ridges and lacustrine deposits • Mostly as POC  DOC/POC ratio of ~1:1000 • OC input from the Mackenzie dominates the Beaufort Sea • But: High bioavailabilty of DOC assumed • Recent studies show high bioavailabilty • e.g. VONK et al. 2013  DOC loss > 34.0 ± 0.8% within two weeks • e.g. HOOD et al. 2009  45% of DOC terr. bioavailable • George Tanski 12

Topic II release... Dissolved organic carbon (DOC) OC ≤ 0.45 µm Particulate organic carbon (POC) Nutrients (NH 4 , NO 2 , NO 3 ) Sediments George Tanski 13

Topic II: Degradation of organic matter Herschel Island Slump D Canada Study site Beaufort Sea (Arctic Ocean) Unglaciated Glaciated George Tanski 14

Topic II: Degradation of organic matter Retrogressive thaw slump: „Slump D“ George Tanski 15

Topic II: Degradation of organic matter Evolution of „Slump D“ George Tanski 16

Topic II: Degradation of organic matter Vegetation classification of „Slump D“ based on NDVI George Tanski 17

Topic II: Degradation of organic matter DOC Surface/10cm depth 30cm depth George Tanski 18

Topic II: Degradation of organic matter DON Surface/10cm depth 30cm depth George Tanski 19

Topic II: Degradation of organic matter NH 4 Surface/10cm depth 30cm depth George Tanski 20

Topic II: Conclusion DOC conc. gradient from permafrost headwall to slump deposits •  Degradation of DOC right after thawing High ammonium conc. directly after thawing •  Indicator for quick depletion of organic material Strong degradtion of organic material at the land-ocean interface • George Tanski 21

Outlook and open questions What are the degradation mechanisms? What are the degradation patterns of POC ? What happens with permafrost carbon after transport into the ocean? What are possible impacts on nearshore marine nearshore ecosystem ? How is OC incorporated into local food webs ? George Tanski 22

PYRN PYRN celebratesf its 10 th anniversary • Just released its long-term strategy until 2018 • Is seeking to increase the network • More involvement of east asian partners planned • @ICOP 2016 big young researcher workshop planned • ICOP 2016 chance to be part of the new Executive Committee • You can apply for travel funding! • George Tanski 23

PYRN Improvement of the network • Census preparation in progress • Meet us at the poster session ! • Find us online or on facebook! • George Tanski 24

Thank you very much for the attention! Herschel Island, Yukon, Canada