A. Migne et D. Davoult, CARBON-DIOXIDE PRODUCTION AND METABOLIC PARAMETERS IN THE OPHIURID OPHIOTHRIX FRAGILIS, Marine Biology, 127(4), 1997, pp. 699-704
As part of the evaluation of fluxes between the water column and a ric
h benthic community of the Dover Strait (Eastern English Channel), lab
oratory measurements of oxygen consumption were carried out on a commo
n ophiurid, Ophiothrix fragilis (Abildgaard), from February 1993 to Fe
bruary 1995. The mean O-2-consumption rate was evaluated at 0.31 mg O-
2 g(-1) h(-1); (ash-free dry weight). Simultaneous measurements of O-2
consumption and CO2 production using the pH-alkalinity method reveale
d an average respiratory quotient of 0.69 proved suitable for converti
ng oxygen demand to carbon flux. A seasonal trend in respiration data
was demonstrated by sinusoidal curves fitted to O-2-uptake and CO2-rel
ease data as a function of time. The influence on respiration rate of
two seasonal parameters (temperature and food availability) is discuss
ed; linear regression indicated a highly significant relationship betw
een O-2 consumption (or CO2 production) and temperature; both O-2-cons
umption and CO2-production rates decreased with starvation. The averag
e O:N ratio was estimated at 8.46, close to the theoretical value when
proteins constitute the catabolic substrate. The annual carbon respir
ed by the O. fragilis community examined and the estimated annual prim
ary production by phytoplankton indicate that the respiration of the O
. fragilis community could supply 35% of phytoplankton carbon requirem
ents.