UNIVERSITÉ LIBRE DE BRUXELLES Faculté des Sciences Département de Biologie des Organismes Laboratoire de Biologie Marine Temperate and cold water sea urchin species in an acidifying world: coping with change? Ana Isabel DOS RAMOS CATARINO Thèse présentée en vue de l’obtention du titre de Docteur en Sciences Juin 2011 Promoteurs de thèse (ULB) Dr Philippe Dubois Dr Chantal De Ridder UNIVERSITÉ LIBRE DE BRUXELLES Faculté des Sciences Département de Biologie des Organismes Laboratoire de Biologie Marine Temperate and cold water sea urchin species in an acidifying world: coping with change? Ana Isabel DOS RAMOS CATARINO Thèse présentée en vue de l’obtention du titre de Docteur en Sciences Juin 2011 Promoteurs de thèse (ULB) Dr Philippe Dubois Dr Chantal De Ridder Comité de lecture Dr Lei Chou (ULB) Dr Philippe Grosjean (UMons) Dr Guy Josens (ULB) Dr Denis Allemand (Centre Scientifique de Monaco) ACKNOWLEDGMENTS It all started some years ago: the Belgian adventure. Moving to another country, enrolling in changeling projects, meeting new colleagues and friends was a challenging step. It has been a pleasure to meet, to work and to learn from you all. I would like to start by thanking Prof. Michel Jangoux. Your knowledge and experience inspired me to start this adventure. It was still in Portugal that I came across with some of your work and that was how the idea “to leave” and come here was born. Your passion for these interesting little creatures, the echinoderms, has been of great inspiration for my research. I wish to express my sincerest thanks to my supervisor, Philippe Dubois... or should I say, “thankful am I”! During these years you provided encouragement, sound advice and good company. Your guidance, accuracy, knowledge and patience kept me on the right path. You were not only a great advisor, but also a good and supportive friend. Thank you for trusting in me and for always keeping me looking on the bright side of... science ( ♪). I would also like to thank my co-supervisor, Chantal De Ridder. I am grateful for the motivating discussions and collaborations. You always had a positive attitude whenever I came around with questions and it was a pleasure to work together. I am also grateful to Dr. Lei Chou (ULB) and Dr. Philippe Grosjean (UMons), from my graduate committee. Your guidance and advice was precious and helped me structuring my ideas and work. I am also thankful to all the BIANZO, MRAC, Erasme Hospital and Liège University collaborators. Working with you was gratifying and your expertise greatly improved my work. A special acknowledgement to Prof. Luc André and N. Dahkani (Royal Museum for Central Africa), Prof. Philippe Compère (Université de Liège ) and Dr. De Bruyn (Hôpital Erasme). I am grateful to the research groups that hosted me both in Chile and in Croatia. I was warmly welcomed and it was a pleasure to work in these two beautiful places. A special thank you to the INACH (Instituto Antártico Chileno) research group, especially to Dr. Marcelo Gonzalez, Carla, Geraldine and Tania. Also to Emma, Carlos, César and to all the new good friends I made in Punta Arenas. I am grateful to the Laredo personnel, in particular to Dr. Pablo Gallardo. Also, to all the Ruđer Bošković Institute (Croatia) research group a big thank you, especially to Prof. Davorin Medakovic, Dr. Daniel Lyons, Dr. B. Hamer and to sweet Adriana. I am grateful for technical and theoretical advice to Prof Fred Mackenzie (University of Hawaii at Manoa), Dr. Alberto Borges (Université de Liège), Dr. Jerome Harlay (ULB), Dr. Caroline De Bodt (ULB), Dr. Pol Gosselin (UMons), Dr. Bruno Danis (Royal Belgian Institute of Natural Sciences), Prof. Maria Byrne (University of Sydney), Prof. N. Heisler (H- U Berlin), Prof. J. Rohlf (Stony Brooks University), Prof. P. Doncaster (University of Southampton) and Prof. J. H. McDonald (University of Delaware), Dr. N. (Ameziane, Muséum National d’Histoire Naturelle, Paris), Dr. D. Néraudeau (Université de Rennes). Un très grand merci à toute l’équipe de BIOMAR. To Edith and Saloua, Mathieu and Philippe P., Thierry and now also to Jorge, Viviane, a big big THANK YOU! Your work and concern were priceless! Virginie, Laure, Thomas, Marie. It has been a pleasure to collaborate with you. Believe me when I say that I have learned a lot from you. And that it is a great pleasure to see Laure and Marie continuing in the group. I am also grateful to Lindsay and David for their help. Colin, Gauthier, Bea, Catherine, Bruno... It was a pleasure to meet great professionals, always seeking a good opportunity... to have a “scientific” chat! The lab was surely livelier with you. A special acknowledgement to the girls from the Biomineralization- Climate-Change-Ocean-Acidification-PhD-Gang! Claire, Julie, Steph, you were amazing! Thank you ever so much for answering all my questions, for the debates, for the lunch and tea time chats. Of course this thesis would not have been possible without the.... (wait for it).... LEGENDARY Article-Portuguese-Mafia! Caros amigos mafiosos e traficantes de saber, β, Rui, Ju e Super Mário, não há nada melhor do que networking. Se algum dia precisarem seja do que for, seja (a)onde for, basta um email e eu estarei do outro lado para vos fornecer um qualquer “papel” sobre assuntos obscuros, mas de extremo interesse para O bem maior: a Ciência! I am also grateful to the last minute “reviewers” and “advisers” of this thesis! Thank you Bea, Claire, Mathieu, Ju, Namita and Nikos. Finally I am deeply grateful to my friends and family! What would I have done without you?!?!? My friends, B-expats and some other expats all over the world, thank you for your time. I usually don’t blabber much about work (thank God, right?), but the social and human part definitely helped me balancing the other half of my life. Um abraço apertado ao Gang Tuga de Bruxelas e um beijinho às Bioloucas Ju, Joaninha e β. To my Parents and my Brother André! Vocês são pessoas extraordinárias. Além de terem sido em muitos momentos uma ajuda vital, foram os grandes incentivadores desta aventura! Foi o vosso exemplo de perseverança, trabalho árduo e coragem que em muitas ocasiões me serviu de bússola e me guiou. Pai e Mãe, obrigada por todas as oportunidades que me proporcionaram ao longo dos tempos e que me levaram a chegar aqui. Devo-vos tudo e por isso estou profundamente agradecida! To Nikos. Who heroically dealt with my bad moods during the hardest times. Thank you for being by my side, always! I would also like to thank Brussels, yeah... the city! Brussels and I had a tough start. The lack of sun is not something easy to deal with. Still, Brussels has an affectionate and caring side. You won’t find this much diversity and easygoing life in many other places around the world. You need to have a couple of beers with Brussels, date Brussels, fall in love with Brussels, and then this small, intense and crazy city will slowly conquer your heart and eventually will become home. There are not enough words to thank all the people that helped me building this project. To all that believed in me, motivated me, shared their knowledge with me, guided me, listened to me and took care of me: thank you, gracias, dank u wel, obrigada, hvala vam, merci, ευχαριστώ. Summary SUMMARY Anthropogenic carbon dioxide (CO 2) emissions are increasing the atmospheric CO 2 concentration and the oceans are absorbing around 1/3 them. The CO 2 hydrolysis increases + - 2- the H concentration, decreasing the pH, while the proportions of the HCO 3 and CO 3 ions are also affected. This process already led to a decrease of 0.1 pH units in surface seawater. According to "business-as-usual" models, provided by the Intergovernmental Panel on Climate Change (IPCC), the pH is expected to decrease 0.3-0.5 units by 2100 and 0.7-0.8 by 2300. As a result the surface ocean carbonates chemistry will also change: with increasing pCO 2, dissolved inorganic carbon will increase and the equilibrium of the carbonate system – 2– will shift to higher CO 2 and HCO 3 levels, while CO 3 concentration will decrease. Surface seawaters will progressively become less saturated towards calcite and aragonite saturation state and some particular polar and cold water regions could even become completely undersaturated within the next 50 years. Responses of marine organisms to environmental hypercapnia, i.e. to an excess of CO 2 in the aquatic environment, can be extremely variable and the degree of sensitivity varies between species and life stages. Sea urchins are key stone species in many marine ecosystems. They are considered to be particularly vulnerable to ocean acidification effects not only due to the nature of their skeleton (magnesium calcite) whose solubility is similar or higher than that of aragonite, but also because they lack an efficient ion regulatory machinery, being therefore considered poor acid-base regulators. Populations from polar regions are expected to be at an even higher risk since the carbonate chemical changes in surface ocean waters are happening there at a faster rate. The goal of this work was to study the effects of low seawater pH exposure of different life stages of sea urchins, in order to better understand how species from different environments and/or geographic origins would respond and if there would be scope for possible adaptation and/or acclimatization. In a first stage we investigated the effects of ocean acidification on the early stages of an intertidal species from temperate regions, the Atlantic Paracentrotus lividus sea urchin, and of a sub-Antarctic species, Arbacia dufresnei .