2. Why Spring ? It is the first important biological event after shipwreck Bloom of phytoplankton in the area Spawning of many species of fishes and shellfish of commercial interest Effects on plankton ---- effects on food web

3. Source of Data Instituto Español de Oceanografia Core Project: Studies on Times Series of Oceanographic Data –Starting in 1988 in A Coruna –Several localities of study in the N-NW Coast of Spain Pelacus Cruises –Cover the area from Portugal to France OmexII Satellite Data –For the area in front of Rias Bajas Satellite chlorophyll IEO –Gijon Radial

4. NG SG WBB EBB Area of study

5. Have effects on phytoplankton been observed after the Prestige oil spill during spring? Effects on biomass (chlorophyll-a) Effects on physiology (primary production) Effects of taxonomic groups Effects on main phytoplankton species

6. Effects on biomass (chlorophyll-a)

8. Effects on primary production

10. Effects on diatoms

12. Effects on dinoflagellates

14. Main phytoplankton species

15. Effects on biomass during Pelacus Cruises Bf: 1999-2002 Af: 2003

16. Effects on primary production OMEX II Box Area

17. Radial Gijon. Instituto Español de Oceanografia

18. Final Remarks No effects on phytoplankton at several levels Differences are the result of natural variabiliy of ecosystem

19. Why effects have not been observed?

20. Low solubility of Prestige fuel Low concetrations in water Low concentations in plankton Low aromatic content High density--sinking Pristane/Phytane ratio no Prestige

21. Plankton mechanisms remove oil from surface waters Zooplankton: grazing on oil particles –Fecal pellets sinking to bottom Diatoms: adsorption on silica wall –eventual sinking to bottom Detritus and clay particles: adsorption –Aggregates and eventual sinking

22. A Coruna Zooplankton: oil in the gut content

23. CONCLUSIONS No effects have been observed on phytoplankton during spring blooms for biomass, production and community structure We can not ascertain whether or not oil has affected phytoplankton –Large variability caused by meso and large-scale processes masks any effect –Effects reduced or short-lived. No effect on spring bloom

24. Acknowledgements Technical assistance –Teodoro Patrocinio Ibarrola –Jorge Lorenzo Salamanca –Leticia Viesca Lombardia Crew of R/V –IEO (Lura, Rioja, Navaz) –IFREMER (Thalassa) Projects –CICYT Aes: Reconocimiento Oceanografico en la é poca de floraci ó n primaveral en Galicia y Cant á brico –IEO: Studies on Time Series of Oceanographic Data –EU: Pelasses and Sardyn