Abstract
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 334:37-45 (2007) - doi:10.3354/meps334037 Community primary production and calcification in a NW Mediterranean ecosystem dominated by calcareous macroalgae Nathaniel Bensoussan1,*, Jean-Pierre Gattuso2 1Laboratoire Diversité, évolution et écologie fonctionnelle marine, CNRSUniversité de la Méditerranée, Centre dOcéanologie de Marseille, Station Marine dEndoume, rue Batterie des Lions, 13007 Marseille, France 2Laboratoire dOcéanographie de Villefranche, CNRSUniversité de Paris 6, BP 28, 06234 Villefranche-sur-mer Cedex, France *Email: nathaniel.bensoussan@univmed.fr ABSTRACT: The community metabolism of a shallow infralittoral ecosystem dominated by the calcareous macroalgae Corallina elongata was investigated in Marseilles (NW Mediterranean), by monitoring hourly changes of seawater pH and total alkalinity over 6 d in February 2000. Fair weather conditions prevailed over the study period as indicated by oceanographic (temperature, salinity, and current velocity and direction) and meteorological variables, which validated the standing water hypothesis. This temperate ecosystem exhibited high community gross primary production (GPP = 519 ± 106 mmol C m2 d1, n = 6) and also supported high rates of community respiration (R). As a result, the system was slightly autotrophic (net community production, NCP = 20 mmol C m2 d1), with a GPP/R ratio of 1.06. NCP exhibited circadian variations with 2- to 3-fold changes in community respiration, both in the light and in the dark. Rates of net community calcification also exhibited circadian variations, with positive rates (up to 24 mmol CaCO3 m2 h1) for irradiance values >300 W m2 (about 1380 µmol photon m2 s1). Below this irradiance threshold, net community dissolution prevailed. Daily net calcification (G) was on average 8 mmol CaCO3 m2 d1. CO2 fluxes generated by primary production, respiration, and calcification suggest that the study site was a potential atmospheric CO2 sink of 15 mmol CO2 m2 d1 at the time of measurement. KEY WORDS: Ecosystem metabolism · Primary production · Respiration · Calcification · Calcareous macroalgae · Corallina elongata · pH · Total alkalinity · TA Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 334. Online publication date: March 26, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.
Highlights
The coastal zone is characterized by large spatial changes in ecosystem distribution and temporal changes in biological processes, which generate strong gradients of biogeochemical fluxes in space and time
The organic carbon metabolism of seagrass communities has been examined since the introduction of metabolic studies in aquatic ecology, largely through the use of benthic chambers
The present study investigated by Gattuso et al 1998), but comparatively little infor- the winter time community metabolism of a Meditermation is available on temperate systems
Summary
The coastal zone is characterized by large spatial changes in ecosystem distribution and temporal changes in biological processes, which generate strong gradients of biogeochemical fluxes in space and time. Mar Ecol Prog Ser 334: 37–45, 2007 temperate climate regions, as pointed out in recent by 2 mol Both net organic carbon metabolism reviews addressing the European (Gazeau et al 2004) and carbonate dynamics, hereafter collectively reand global (Gattuso et al 1998, Middelburg et al 2005) ferred to as community metabolism, are important to coastal zones. To the best of our knowledge, simultaneous mea- It must, be noted that estimates of CaCO3 production may be biased because a relatively large surements of organic and inorganic carbon metabolism at the ecosystem level have never been conducted in amount of data is available for coral reefs A simple model was derived to predict the effect of the organic
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