Effect of ocean acidification (OA) on the polychaetes : Spirobranchus triqueter and Spirorbis spirorbis. V. Díaz-Castañeda1, J. Dellile2, F. Gazeau2, E. Cox2, J. P. Gattuso2 1 CICESE, Department of Marine Ecology. Ensenada, Baja California., México. 2LOV CNRS Université Pierre & Marie Curie Paris 6
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RESULTS
INTRODUCTION As a consequence of anthropogenic activities CO2 has increased in the atmosphere, part of this CO2 is absorbed by the oceans causing ocean acidification (Zeebe et al., 2008). According to estimates, CO2 concentration levels will be 500 ppm by 2050 and 800 ppm by 2100 (IPCC, 2007). Ocean acidification (OA) can threaten diverse marine organisms. Many polychaetes form and reside in calcified tubes. Calcareous tube forms occur in the serpulids, sabellids, and cirratulids (Vinn et al. 2008). Among these polychaete members, serpulids are often important components of marine communities in terms of numerical abundance and biomass. Serpulids add structural complexity to the habitat and as filterfeeders link pelagic and benthic food webs (Gosselin & Sewell, 2012; Riedi & Smith, 2014). a)
To collect the second species, S. spirorbis, colonized Posidonia oceanica shoots were collected from the same area (depth of 11 m). Later five shoots were placed per container, for a total of 12 experimental tanks. Organisms were marked with calcein for 48h and acclimated under ambient pHT conditions for 5 days before beginning the experiment at 14-15°C. Staining calcareous structures Fig. 4 Calcein chelates Ca 2+ and Mg 2+, incorporating into growing tubes and setting a mark for later measurements.
S. triqueter The average length ± SD of newly formed tubes within 90 days was 8.49 ± 2.85 mm, 6.26 ± 4.04 mm, and 1.75 ± 1.88 mm for worms exposed to the ambient (8.1), 7.8, and 7.4 treatment. At pHT7.4 the tube growth was significantly affected (one way ANOVA, p
