Ett rent hav vår framtid

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1 Ett rent hav vår framtid Marint affald - trusler, udfordringer og løsninger Midtvejskonference Ren Kustlinje Frederikshavn september 2017

2 Spredningen af plast i havet, globale og lokale spredningsveje Göran Broström Institutionen för Marina Vetenskaper Göteborgs Universitet Jon Albretsen, Mats Huserbråten Havforskningsinstituttet Flödeviken

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4 All scales connect!

5 Movements on a rotating Earth

6 The global atmospheric circulation

7 Plastic (bouyant) particles Complex vertical distribution Rise toward the surface Mixed down by turbulence Can accumulate is convergence areas Mid-ocean gyres Local fronts Can often get close to land. Larger particles tend to beach Wave drift (Stokes drift) is often important. Transport particles in the wave direction Langmuir circulation is important. Wind rolls

8 Oceanic plastic particles Cózar, A., Echevarría, F., González-Gordillo, J.I., Irigoien, X., Úbeda, B., Hernández-León, S., Palma, Á.T., Navarro, S., García-de-Lomas, J. & Ruiz, A. (2014) Plastic debris in the open ocean. Proceedings of the National Academy of Sciences 111 (28):

9 Investigating the vertical distribution Reisser, J.W., Slat, B., Noble, K.D., Plessis, K.D., Epp, M., Proietti, M.C., Sonneville, J.d., Becker, T. & Pattiaratchi, C. (2015) The vertical distribution of buoyant plastics at sea: an observational study in the North Atlantic Gyre

10 Plastic plastic particles have a very distinct vertical distribution, which depends on the wind speed Reisser, J.W., Slat, B., Noble, K.D., Plessis, K.D., Epp, M., Proietti, M.C., Sonneville, J.d., Becker, T. & Pattiaratchi, C. (2015) The vertical distribution of buoyant plastics at sea: an observational study in the North Atlantic Gyre

11 1 month drift using mean fields for 2012 Red: Hycom currents Green: ERA Stokes drift Total: black

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13 # particles reaching the SIDS area

14 Stokes (wave) drift Inherent part of surface waves Particle orbitals are not exactly circular Consequence from that waves actually contains momentum Weaker but more persistance as compared to traditional ocean currents May be remotely forced (waves travel great distance quickly) Pushes particles on land!

15 Golden Trader oil spill: Weather situation

16 Wave situation

17 Green: with Stokes drift Red: without Stokes drift

18 New ocean model for Skagerrack Area in-between North Sea and Baltic Sea Does not exist any model focusing on the area Establishment of new ocean model Regional Ocean Model System (ROMS) Used by IMR, MET Norway Collaboration with MET Norway Includes advanced data assimilation i.e. a way to steer the model with observations Presently run for 1 year Trajectory modelling not yet analyzed. Add coastal models to the system Collaboration with IMR

19 Modelled surface salinity

20 Modelled surface salinity & particles

21 Transportveier for plast

22 Work at IMR Jon Albretsen & Mats Huserbråten Focus on transport of particles Regional (Skagerack) Coastal Work on creating regional plastic debris map Hordaland coast Coast on Skgerack Different release scenarios Local sources (rivers) Remote sources

23 1) Spre veldig mange fiktive partikler fra en typisk kilde (her: langs et transekt som representerer innstrømning fra Nordsjøen og Østersjøen/Kattegat) i et realistisk strømfelt med veldig høy oppløsning (her: 160m) 2) Repetere utslippet over en lang tidsperiode og følge bevegelsen til alle partiklene

24 3) Telle opp hvilke partikler som kommer så nærme land at de potensielt kan strande (røde/gule områder definerer hot spots for stranding) 4) Finne opprinnelsen til alle strandede partikler og se hvor de kommer fra (tykkelsen på blå strek angir sannsynlighet for stranding)

25 Spredning hvis partiklene kommer fra elvene i område

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27 Kort fortalt: Detaljerte og realistiske strømmodeller kan brukes til å estimere skjebnen til marint avfall som driver rundt i havet. Mulig anvendelse er å lage plast-kart som fremhever de mest sannsynlige kyststrekningene hvor avfall skylles på land.