Benthic interface studies with landers. Consideration of lander/interface interactions and their design implications

• Published in: Journal of experimental marine biology and ecology 2003-02, Vol.285, p.179-190
• Main Authors: Parker, W.R., Doyle, K., Parker, E.R., Kershaw, P.J., Malcolm, S.J., Lomas, P.
• Format: Article
• Language: English
• Subjects: Artefacts; Benthic interface; Brackish; Computational fluid dynamics; Freshwater; Lander; Marine; Porewater migration; Variable proximity landers
• ISSN: 0022-0981; 1879-1697
• DOI: 10.1016/S0022-0981(02)00526-9

The physical and chemical properties and behaviour of the benthic interface cannot generally be predicted from first principles so must be determined empirically. The physical characteristics of the interface are such that in situ determinations provide the most realistic parameter values and at time and space scales, which describe the full heterogeneity of the interfacial environment. This is especially the case where the interface properties are microbiologically dominated or where the nature of the parameters of interest is such that they are influenced by temporal changes in stress distributions. Part of the problem is the lack of tools capable of providing appropriate measurements at the time and space scales that are most relevant to consideration of sediment–water interface questions. Lander interaction with the substrate derives from its mass, its perturbation of the local boundary hydrodynamics and its role in coupling of hydrodynamic stresses to the sediment/porewater system of the bed. These effects operate on varying time scales largely controlled by sediment properties and structure. The interaction of the lander with the substrate is of fundamental importance to data quality. Issues of local lander context and impact need to be addressed to ensure representative and artefact-free data. Landers provide the best opportunity for process measurements. However, as lander technology moves towards autonomy and longer-term measurement capability, approaches to lander design and deployment need to improve if the results gathered are not to be dominated by experimental artefacts created by the interaction of the lander with large-scale flow structures, the hydrodynamic impact of the proximity of the lander to the sediment–water interface or the loading effect of the lander on the sediment/porewater system. The application of Computational Fluid Dynamics (CFD) or similar techniques will help evaluate lander design and deployment strategies. Appropriate pre-deployment site evaluation plus hydrodynamic analysis of landers are prerequisites for design evolution including consideration of data reliability.