Published online by Cambridge University Press: 11 May 2009
A biometrical study was conducted on two common cnidarians: Alcyonium digitatum (Octocorallia) and Urticina felina (Hexacorallia). The aim was to relate both the carbon and the nitrogen content of these species to a simple and rapid measurement. As the simplest measurement that can be done on A. digitatum is a measurement of size, relationships were determined between the height of a colony and its organic carbon (OC=0.0002 H2.0254, n=104, γ2=0·923) and nitrogen (N=0.00004 H2.0283, n=104, γ2=0.928) content. As no constant size could be determined on sea anemones, linear relationships were established between dry weight (DW) and organic carbon (OC=0.419 DW, n=65, r=0.995) and nitrogen (N=0.095 DW, n=65, r=0.997) content in U. felina. All these relationships were highly significant (P<0.1%) and appeared useful to express biomass of the two species in terms of carbon or nitrogen and then to consider dynamic processes such as respiration or excretion as fluxes of carbon and nitrogen.