A Simulation Model of a Deep Meiobenthic Compartment: A Preliminary Approach

Abstract

Abstract. On the basis of data obtained during the ECOMARGE programme and during an annual survey of a deep station (910 m), a first attempt at modelling the carbon flux through a simplified benthic system is presented. Three compartments are simulated: organic matter, bacteria, nematodes. Several hypotheses are proposed by the present simulation: constant or seasonal input of organic matter, intra‐compartmental control or lack thereof. The pulses related to the seasonal input of organic matter and to the internal kinetics of the system are described. Nine to 11 mg C · m‐2· d‐1 are necessary to equilibrate the carbon budget of this simplified deep‐sea benthic system.SummaryA simulation model is used to estimate the importance of energy transfers which could equilibrate the needs of a deep nematode community in the course of time.The observed values for the compartments are obtained from the annual survey of a deep station (910m) of the ECOMARGE programme. Surface sediment organic matter concentrations ranged from 0.50 % to 0.56 % sediment dry weight (or 67,000 mg C · m‐2 to 75,000 mg C · m‐2, respectively), for a mean near‐bottom flux input of 33g C · m‐2· a‐1 (90mg · m‐2· d‐1). The mean organismal biomass approximated to 30 mg C · m‐2 for the bacteria and 37 mg C · m‐2 for the meiofauna.In the simulations, when 9–11% of the input flux are used by the system (9–10 mg C · m‐2· d‐1), the meiofauna compartment is maintained close to the osberved level, while bacterial biomass (9 mg C · m‐2) is lower than the observed value. At lower rates (<8%), the meiobenthic compartment disappears, at higher rates (> 12%) the simulated biomasses show unrealistic values. With a seasonal input flux, the periods of the meiofauna biomass pulses correspond well with the observed data. The mean time lag between the maximum values of the organic matter input and the simulated maximum biomass is 60 days, slightly smaller than the observed value.