Contributions made by citizen scientists were equally based on incidental observations as on standardized surveys. In general, the contribution of citizen scientists greatly enhances research capacity, providing an increased workforce over extensive spatial and intensive temporal scales at comparatively moderate costs. This review is a first attempt to explore the extensive literature on volunteer participation in marine research. Accessibility can be a challenge for marine research, and it could thus be expected that projects with volunteer participants will be concentrated in particular habitats, most likely beaches and nearshore, shallowwater environments. Marine research topics supported by volunteers Main topics and taxa Of the 227 publications analyzed, 84.6% were dedicated to, or at least included, the study of fauna. Projects addressing taxa of commercial importance were considered in 56 publications in our database, including mainly bony fishes, but also other taxa. A comparatively large proportion of initiatives dealt with emblematic species.

Sellanes, J., Quiroga, E., and Neira, C. 2008. Megafauna community structure and trophic relationships at the recently discovered Concepción Methane Seep Area, Chile, ∼36°S. – ICES Journal of Marine Science, 65: 1102–1111. The fauna, community composition, and trophic support of the newly discovered Concepción Methane Seep Area (CMSA) are compared with those at a nearby non-seep control. The assemblage of chemosymbiotic bivalves is defined by eight species, including the families Lucinidae, Thyasiridae, Solemyidae, and Vesicomyidae. Seep polychaetes are represented by Lamellibrachia sp. and two commensal species of the vesicomyid Calyptogena gallardoi. Although taxonomic analysis is still under way, most of the chemosymbiotic species seem to be endemics. The CMSA is a hotspot for non-seep benthic megafauna too; 101 taxa were present, but most of them are colonists or vagrants (i.e. not endemics of methane seeps). Isotope analysis supported the belief that non-symbiont-bearing species utilize photosynthetically fixed carbon, because they were isotopically distinct from the chemosymbiotic bivalve species present. It is our opinion that, at this site, which underlies one of the most productive coastal upwelling regions of the world, spatial heterogeneity and the availability of hard substratum, generated by the presence of authigenic carbonate crusts, are more important factors in attracting non-seep fauna than the availability of locally produced chemosynthetic food.