Fate of Oil Spills in Arctic Marine Environments Leendert Vergeynst 1. Increasing risk for oil spills The Arctic is rich in fossil resources • 13% and 30% of undiscovered oil and gas in the world • ~6% of Earth’s surface area • Mostly offshore (84%) • 87% in 7 Arctic basin provinces Norwegian sea https://geology.com/articles/arctic-oil-and-gas/ AMAP Oil and gas Assessment 2007 High oil and gas prices ~ high risk Gulas et al., 2017, Marine Policy Shipping through the Arctic Pizzolato et al., 2016, Geophysical Research Letters Criteria for shipping routes • Economic ~ fuel costs, distance and shipping time • Technical ~ ice-class ship • Safety ~ weather, complexity, search and rescue • Political ~ policy of Arctic states Tseng and Cullinane, 2018, Maritime Policy and Management Higher risk for oil spills in the Arctic • Sea ice • Heavy weather • Darkness • Unknown sailing routes • Remoteness: Search and Rescue / Oil spill response Exxon Valdez oil spill, Prince William Grounded oil ring due to heavy Sound bay, 1989 weather, Gulf of Alaska, 2012 2. What is petroleum oil? Hydrocarbon: CH (99%) + NOS è10 000s of molecules 3.1. Oil fate in open water Oil weathering: a matter of time < 40% Lee et al., 2015, The Behaviour and Environmental ImpaCts of Crude Oil Released into Aqueous Environments Lee et al., 2015, The Behaviour and Environmental ImpaCts of Crude Oil Released into Aqueous Environments Lee et al., 2015, The Behaviour and Environmental Impacts of Crude Oil Released into Aqueous Environments Wolfe et al., 1994, Environmental Science and Technology 3.2. Oil fate in cold and ice-covered waters AMAP Oil and gas Assessment 2007 Slower weathering in cold and ice- covered water >30% ice coverage è Consequences for oil spill response, biodegradation and toxicity 3.3. Fate of oil in sea ice Oil migration through brine channels Sea ice brine volume ~ Temperature and salinity • > 5%: brine channels are connected è transport of water soluble compounds • >10-15% è brine channels wide enough for oil movement Oil migration through brine channels Faksness and Brandvik, 2008, Cold Regions Science and Technology Bioavailable to sea ice biota? 4. Natural removal processes Lee et al., 2015, The Behaviour and Environmental Impacts of Crude Oil Released into Aqueous Environments Biodegradation is … + O2 + è CO2 + + O2 + è ? Q10 rule of thumb: Rates decrease by factor 2- 3 per 10°C ! Does not consider adaptation to low temperature Three essentials for oil biodegradation 1. Dispersion 2. Adapted microbial community 50-100µm 3. Nutrients N & P Oil ~ CH2 C/N ~ 6.6 Biomass C/P ~ 100 Mimicking oil droplets on oil-coated adsorbents 40-80µm ~ 100 mg oil Seawater Svalbard 2019-20 Cambridge Bay 2019-20 Young Sound 2018 Norway 2019-20 Disko Bay/Vaigat 2019 Godthaab 2016-18 Sea ice Time (days) 0 31 51 63 74 T 50 cm sea ice sea 50 cm M B eawater s SW èQuantitative analysis and fingerprinting of residual oil by GC-MS èMicrobial community profiling by 16S rRNA gene sequencing and quantification C10−27 − alkanes pristane phytane C1 − N C3 − N C4 − N C1 − P 100 75 50 25 0 C2 − P C3 − P C1 − DBT C2 − DBT C3 − DBT C1 − F C2 − F Biodegradation100 of alkanes in cold seawater 75 50 but not in sea ice 25 0 Residual (%) C10−27 − alkanes pristane phytane C1 − N C3 − N 0 20C4 40− N 60 0 20C1 40− P 60 C3 − F C1 − Py C2 − Py BaA C C1 − C 100 100 75 Diesel: 75 Sea ice Top Bottom 50 Seawater 50 Residual 25 25 Middle Seawater 0 0 0 20C2 40− P 60 0 20C3 40− P 60 0 20C1 −40DBT 60 0 20C2 −40DBT 60 0 20C3 −40DBT 60 C1 − F C2 − F 100 Time (days) Time (d) 75 50 25 0 Residual (%) 0 20 40 60 0 20 40 60 C3 − F C1 − Py C2 − Py BaA C C1 − C 100 75 Top Bottom 50 25 Middle Seawater 0 0 20 40 60 0 20 40 60 0 20 40 60 0 20 40 60 0 20 40 60 Time (d) Sea ice vs. seawater: both have oil-degraders Surrounding sea(A) ice SeaSea ice brineice biofilm Sea iceSeawater biofilm biofilm Seawater biofilm Top (T) Middle (M) TopTop (T) (T) Middle Middle (M) (M) Top (T)Bottom (B) MiddleSeawater (M) (SW)Bottom (B) SeaWater (W) 1 75 2 75 3 Oleispira ~ alkanes 4 5 50 Enriched50 Colwellia6 , Peredibacter compared ~ low7 MW hydrocarbons to control 8 25 25 9 Relative abundance (%) abundance Relative Relative abundance (%) Neptunomonas, Arcobacter10 ~ PACs11 12 0 0 0 31 51 63 0 31 51 63 310* 31 51 51 63 63 74 31 51 0* 31 63 51 6331 74 51 63 0* 31 74 51 63 31 74 51 63 0* 31 74 51 63 31 74 51 63 74 31 51 63 74 Time (days) Time (days)Time (days) … but 25-100x higher bacterial abundance in seawater vs. sea ice Oil vs. Control Sea ice biofilm Seawater biofilm 107 106 qPCR: 16S rRNA 105 gene copies / 4 cm2 mesh net 10 103 0 20 40 60 80 0 20 40 60 80 Time (days) C10−27 − alkanes pristane phytane C1 − N C3 − N C4 − N C1 − P 100 75 50 25 0 C2 − P C3 − P C1 − DBT C2 − DBT C3 − DBT C1 − F C2 − F 100 75 Slow biodegradation50 of alkanes 25 during0 summer Residual (%) C10−27 − alkanes pristane phytane C1 − N C3 − N 0 20C4 40− N 60 0 20C1 40− P 60 C3 − F C1 − Py C2 − Py BaA C C1 − C 100 100 Diesel: 75 Spring 75 Sea ice 50 Top Bottom <0 °C 50 Seawater 25 Residual 25 Middle Seawater ~10 µM N 0 0 0 20C2 40− P 60 0 20C3 40− P 60 0 20C1 −40DBT 60 0 20C2 −40DBT 60 0 20C3 −40DBT 60 C1 − F C2 − F 100 Time (d) C10 12 C13 26 pristane phytane 75− − Seawater: 1.00 50 25 Heavy Oil.type Summer 0.75 0 Crude IFO? Residual (%) ~6 °C 0.50 Diesel MGO 0 20 40 60 0 20 40 60 C3 − F C1 − Py C2 − Py BaA C C1 − C Residual TBC 0.2-0.6µM N Residual (%) 0.25 100 0.00 75 Top Bottom 0 30 60 90 0 30 60 90 0 30 60 90 0 30 60 90 50 Time (days) Time (d) 25 Middle Seawater Spring0 Summer 0 20 40 60 0 20 40 60 0 20 40 60 0 20 40 60 0 20 40 60 Seawater Fast biodegradation Biodegradation starts Time (d) (t1/2 ~ 7 days) after 1 month Sea ice No biodegradation Summer vs. spring: oil degraders limited by low nutrients? Spring: ~10µM N Summer: 0.2-0.6µM N Diesel2016.MGO Diesel2017.MGO Crude2017.TBC Heavy2017.IFO 100 Kingdom:Bacteria Bacteroidia Genus:Aurantivirga Campylobacteria Genus:Arcobacter 75 Alphaproteobacteria Family:Micavibrionaceae Alphaproteobacteria Family:Rhodobacteraceae Deltaproteobacteria Family:Bacteriovoracaceae 50 Proteobacteria Class:Gammaproteobacteria Gammaproteobacteria Genus:Colwellia Gammaproteobacteria Genus:Cycloclasticus Gene abundance (%) 25 Gammaproteobacteria Genus:Profundimonas Gammaproteobacteria Family:P13-46 Gammaproteobacteria Genus:Oleispira Gammaproteobacteria Genus:Alkanindiges 0 6 6 6 31 51 63 74 24 24 24 112 112 112 Time (days) 5. Other typical Arctic conditions: need for research 1. Low temperature & sea ice 2. Low nutrients 3. High phytoplankton 4. Glacial suspended sediments 5. Arctic light regime Evaporation Photooxidation Oil-mineral Dispersion Oil-phytoplankton Oil-bacteria è biodegradation Nutrient supply Vergeynst et al., 2018, Science of the Total Environment 6. Oil spill response technologies for the Arctic.