Nature and environmental significance of microbialites in Quaternary reefs: the Tahiti paradox

IODP Expedition 310 Reconstructs Sea Level, Climatic and Environmental chagnes in the South Pacific during the Last Deglaciation

“…they provide paleowater depth estimates based on their comparison with modern counterparts. Coral assemblages are dominated by Porites, Pocillopora, Acropora, and Montipora genera, which form distinctive assemblages that are indicative of a range of modern reef environments, from the upper to middle reef slope to deep reef slope (0-30 m deep; Sugihara et al, 2006), in agreement with earlier studies on Tahiti Camoin et al, 1999;Cabioch et al, 1999a) and other Indo-Pacific reef sites (Camoin et al, , 2004Cabioch et al, 1999b;Sagawa et al, 2001). …”

“…To investigate the geomicrobiology processes on the Tahiti fore-reef slopes to study potential modern counterparts of the microbialites that characterize the last deglacial reef sequence drilled in Papeete (Camoin and Montaggioni, 1994;Camoin et al, 1999). The objectives are to 1) identify the microbial communities that are involved in their formation and 2) to have a better understanding of the environmental significance of those microbial fabrics.…”

“…Preliminary sedimentological and chronological results on the dredged samples have confirmed the significance of these features as unique archives of abrupt global sea level rise and climate change . Based on the results of previous drillings on the Papeete reef (Bard et al, 1996;Camoin et al, 1999 ;Cabioch et al, 1999a) and of the SISMITA cruise (Camoin et al, 2003), we drilled a transect of holes in three areas around Tahiti-offshore Faaa, Tiarei, and Maraa ( Figs. 1 and 2).…”

Irradiance Regulation of Photosynthesis and Respiration in Modern Marine Microbialites Built by Benthic Cyanobacteria in a Tropical Lagoon (New Caledonia)

“…Marine microbialites have been abundantly reported in the fossil record: in the Precambrian, which bears the earliest microfossils at the Earth's surface [43], and throughout the Phanerozoic until Quaternary times [13,14]. Based on the similarities between the microfossils included in Precambrian stromatolites and cyanobacteria, it has been suggested that oxygenic photosynthesis was carried out by cyanobacteria 3.5 billion years ago [24].…”

Defining organominerals: Comment on ‘Defining biominerals and organominerals: Direct and indirect indicators of life’ by Perry et al. (2007, Sedimentary Geology, 201, 157–179)

“…Thereafter, examples of organominerals and organomineralization processes have been documented, and the former papers cited, in mainstream scientific literature, beginning with our own work on carbonate organomineral formation in modern and recent microbialites and ooids (Défarge et al, 1996;Reitner et al, 1997;Arp et al, 1999;Trichet et al, 2001;Arp et al, 2003;Gautret et al, 2004;Gautret and Trichet, 2005), ancient microbialite analogues (Camoin et al, 1999;Tribovillard et al, 1999Tribovillard et al, , 2000, mud mounds (Neuweiler et al, 1999), encrusting sponge cements (Russo et al, 2006), housing tubes of worms (Fischer et al, 2000), coral EPS (Reitner, 2005), decaying sponge tissues (Delecat et al, 2001), and during laboratory experiments with microbialite-, ooid-and meteorite-extracted organic matter (Reitner, 2004). Organominerals and organomineralization processes have also been brought up in a discussion, involving one of us, about the origin of lower Paleozoic carbonate mud (Pratt, 2001;Arp et al, 2002).…”