Physiologia Plantarum 133: 1–3. 2008 Copyright ª Physiologia Plantarum 2008, ISSN 0031-9317 EDITORIAL Inorganic carbon utilisation by freshwater and marine photosynthetic microorganisms Francisco JL Gordillo Departamento de Ecologı´a, Facultad de Ciencias, Universidad de Ma ´ laga, Bulevar Louis Pasteur s/n, E-29010 Ma ´ laga, Spain e-mail: gordillo@uma.es doi: 10.1111/j.1399-3054.2008.01095.x The collection of peer-reviewed articles in this issue represent some of the contributions presented at the VIth International Symposium on Inorganic Carbon Utilisation by Aquatic Photosynthetic Organisms (CCM6) held at the Rectorate Building of the University of Malaga in Malaga, Spain, on 16–20 July 2007. Articles in this special issue contain original research or current reviews and represent the latest advances in our knowledge of the CO 2 - concentrating mechanisms (CCMs) in aquatic photosyn- thetic organisms. The symposium was sponsored by the Universidad de Ma ´laga, the Instituto Espan ˜ol de Oceanografı ´a and the Consejo Superior de Investigaciones Cientı ´ficas. Addi- tional support was obtained from the Malaga City Council, the Fundacio ´ n General Universidad de Ma ´laga, the Spanish Ministry of Education and Science and the regional government Junta de Andalucı ´a, whose gener- ous contributions we greatly acknowledge. Francisco JL Gordillo (Universidad de Ma ´laga, Spain), Xavier Niell (Universidad de Ma ´ laga, Spain), Jesus Mercado (Instituto Espan ˜ ol de Oceanografı ´a, Spain) and Emma Huertas (Consejo Superior de Investigaciones Cientı ´ficas, Spain) were in charge of the local organisation, kindly assisted by John Raven (University of Dundee, Scotland, UK). The local organisers are indebted to George Espie (University of Toronto, Canada) and Brian Colman (York University, Canada) for their continuous support and for contributing with their organisational experience gained in previous editions of the CCM symposia series. They also contrib- uted by being part of the International Advisory Commit- tee from whom we received further organisational and scientific advice. Also in this committee were Philippe Tortell (University of British Columbia, Canada), Dean Price (Australian National University, Australia), Murray Badger (Australian National University, Australia), Mario Giordano (Universita ` Politecnica della Marche, Italy), John Raven (University of Dundee, Scotland, UK), James Moroney (Louisiana State University, USA), Martin Spalding (Iowa State University, USA), Aaron Kaplan (Hebrew University of Jerusalem, Israel) and Hideya Fukuzawa (Kyoto University, Japan). The VIth edition of the CCM symposia was the first one held in Europe after five former editions that started in 1984 at the Asilomar Conference Center in California, USA. The following meetings were held at Queen’s University in Kingston, Canada, 1991, the University of British Colum- bia in Vancouver, Canada, 1997, Palm Cove Resort, Queensland, Australia, 2001, and Manoir Saint-Sauver, Saint-Sauver, Quebec, Canada, 2004. The present issue is the sixth volume of contributed articles arising from these meetings (Colman 1991, 1998, Colman and Espie 2005, Lucas and Berry 1985, Price and Badger 2002). Taken together, these six volumes represent the milestones of the scientific progress of our understanding of the carbon acquisition, transport and concentration mechanisms (CCMs) in aquatic photosynthetic organisms. The complexity of the CCMs found in aquatic photosynthetic organisms is particularly revealed when compared with other resource acquisition systems. In the review by Raven et al. (2008), the polyphyletic origin of CCMs, their regulatory factors as well as the interference of other processes of the C assimilation pathway appear as responsible for such complexity. For the past two decades, the major advances in our understanding of algal CCMs have come from intensive laboratory stud- ies of model organisms, in particular the chlorophyte Chlamydomonas reinhardtii for the eukaryotic systems and several members of the cyanobacterial genus Synechococcus for the prokaryotic CCMs. These advan- ces have been greatly enhanced by knowledge of the genomes of these model organisms and the associated powerful proteomic tools. New insight in the CCMs of C. reinhardtii is reported in this issue by Ynalvez et al. (2008) who identify and characterise two new carbonic anhydrases (CAs) in addition to the six known previously. They are b-type CAs and have been designated as CAH7 and CAH8. They are expressed constitutively and at least CAH8 seems to be localised in the periplasmic space. Physiol. Plant. 133, 2008 1