{"refrec":{"BRefID":9367,"RR":"<b>Longhurst, A.R.</b> (1989). Pelagic ecology: definition of pathways for material and energy flux, <b><i>in</i></b>: Denis, M. (Ed.) <i>Océanologie: actualité et prospective.</i> pp. 263-288","BEntID":9367,"PublicFlag":1,"CheckedFlag":0,"wosflag":null,"vabbflag":null,"RefStringPartII":", <b><i>in</i></b>: Denis, M. (Ed.) <i>Océanologie: actualité et prospective.</i> pp. 263-288","DocTypID":17,"DocType":"Book chapters","MarineFlag":1,"FreshFlag":0,"BrackishFlag":0,"TerrestrialFlag":0,"Authorstring":"Longhurst, A.R.","OrigTitleTranslFlag":0,"Authorstringtrunc":"Longhurst, A.R.","Englishabstract":"Perhaps the first priority task for marine ecologists in the coming decades is to quantify the global oceanic carbon cycle, a task already begun by geochemists. But models of carbon flux designed by ecologists are usually anthropocentric, treating shunts to ahiotic sinks as irrelevant, with emphasis being placed on flux leading to top predators. This is not the correct approach when quantifying global carbon flux, since very small proportions of total carbon flowing through ecosystems passes above the primary herbivore level, the majority passing directly from protozoa and algae to the interior of the ocean. The simple models used by geochemists to quantify this flux ignore major uncertainties concerning ecological processes, as do the classic particle size distribution models of ecologists. A generalised prey/predator ratio is often assumed to have been quantified, but this can easily be shown to be false: protists and metazoa have quite different prey/predator size relationships. The effects of viscosity are quite different for small and large biota, and there may be discontinuities across the range of Reynolds numbers encountered in the pelagos that will affect the distribution of biomass between size classes of biota. The dispersion of the autotrophic function among protists is far wider than usualy assumed and it remains quite impracticahle to trace pathways for energy flux within the protist microcosm, though this is where most carbon flux to oceanic reservoirs occurs. Models to simulate carbon flux in the ocean, required to quantify global carbon flux, are largely inadequate as presently formulated. What is urgently needed is better quantification of the roles of different trophic groups of protists in the pelagic ecosystem.","AbstractOtherLang":"La recherche prioritaire des océanographes-biologistes, dans les prochaines décennies, sera probablement de quantifier le flux global de carbone dans l'océan; tache déjà entreprise par les géochimistes. Les modèles d'échanges de carbone proposés par les écologistes sont généralement anthropocentriques, traîtant les liens avec les systèmes abiotiques comme dénués de tout intérêt. En revanche, une importance plus grande est attribuée à I'analyse des flux de matières organiques vers les grands prédateurs. Cette approche est peu satisfaisante dans la mesure ou seule une petite fraction du carbone total impliqué dans chaque écosysteme se retrouve au-delà du niveau des herbivores primaires. En réalité, la plus grande partie du carbone passe directement des algues et protozoaires aux profondeurs des océans. De leur coté, les modèles simples utilisés par les géochimistes tendent à ignorer les principales incertitudes concernant les processus biologiques, au même titre que les modeles écologiques basés sur la distribution des tailles des particules. Par exemple, I'utilisation d'un rapport moyen entre la taille des prédateurs et celle des proies dans I'estimation d'une composante liée au réseau trophique est souvent incorrecte. Cette relation prédateur-proie est, en effet, tres différente chez les protistes et les métazoaires. De plus, les effets de la viscosité affectent différemment les organismes pélagiques selon leur taille, entraînant des discontinuités dans la gamme des nombres de Reynolds observée au sein du pelagos et modifiant la distribution de la biomasse entre les classes de taille des organismes. La fonction autotrophique parmi les protistes s'avère plus répandue qu'on ne l'aurait supposé et les échanges d'énergie entre ces organismes sont encore impossibles à définir précisément bien que ce microcosme renferme la presque totalité du carbone qui s'accumulera dans les profondeurs océaniques. Les modèles simulant le flux de carbone dans les océans, indispensables pour évaluer les échanges du carbone au sens global, sont encore peu efficaces. Une meilleure évaluation du rôle des différents groupes trophiques au sein des protistes dans l'écosystème pélagique est nécessaire.","BibLvlCode":"AM","StandardTitle":"Pelagic ecology: definition of pathways for material and energy flux","OrigTitleLangCode":"en","OrigTitleLangCodeExtended":"eng","OrigTitleLangID":15,"DateLastModified":{"date":"2024-12-10 01:33:17.368041","timezone_type":1,"timezone":"+01:00"},"UserAccessRight":null,"UserAccID":null,"AuthorKeywords":null,"OtherDescriptors":null,"Notes":null,"AnaPub":1989,"MonPub":null,"DateUpdate":"2001-05-18","DateCreate":"2001-05-18","SecASFANote":null,"ConfID":null,"PeerRev":null,"VlizCoreFlag":1,"WoScode":null,"VABBcode":null,"OpenAcc":0},"refs":null,"anarec":{"AnaID":9367,"PubliDate":1989,"Pagination":"263-288","XtraPublOfAnaID":null,"ISBN":"2-907752-00-6","Volume":null,"Issue":null,"BRefMon":9352,"BRefMonRR":"<b>Denis, M. (Ed.)</b> (1989). Océanologie: Actualité et prospective. Centre d' Océanologie: Marseille. 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