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In-situ dynamic benthic chamber

Development of an in-situ integrated system for the study
of hydrodynamic, sedimentological, biological and chemical
processes at benthic interface:discrete sensor/environmental
control systems for a modular dynamic benthic chamber.

Outline description It has long been recognised that when considering bed sediment stability for proposed marine or coastal engineering works, dredging activities or spoil ground assessment, etc., the ability to understand erosion/ accretion techniques and related chemical and biological parameters is essential. The collection of sediment for laboratory testing of shear strength, erodability, biological activity, etc., although often used, is losing credibility and frequently produces seriously misleading results. This proposal aims to address these problems with the eventual development of an in-situ dynamic Benthic chamber capable of deployment from virtually any survey vessel. The programme outlined here is unique in that it brings together sedimentalogical, chemical and biological processes in the development of a new "lander" consisting of an in-situ dynamic Benthic chamber with associated probes to enable studies of these inter-related processes to be conducted. The proposed Benthic chamber would consist of an annular flume which is open only at the base such that when deployed on site an area of undisturbed sediment is sealed from the surrounding water. A water injection system would be developed to apply controlled and known shear stresses to the internal water column such that natural bed shear stresses are applied to the sediment being studied. Within the chamber, turbidity and velocity profile sensors, possibly developed or adapted for the purpose, will allow the erosion characteristics of the sediment to be studied. In addition to the erosion aspects, the Benthic chamber would be capable of measuring chemical fluxes across the water/bed interface under natural flow conditions and in particular under erosion conditions. Biological activity is also of prime importance and it is proposed to research a means of measuring oxygen demand by a controlled oxygen balance system to mimic the natural demand under the changing conditions experienced by the sediment under study. The proposal is aimed at research for the development of a remote, in-situ integrated system to promote the study of physical, sedimentalogical, biological and chemical processes at the Benthic interface for a variety of commercial and academic applications. This project will entail the development of discreet sensor and environmental control systems to produce a modular dynamic Benthic chamber. The proposal will require a number of systems to be developed and advanced including a flow induction system, in-situ electrochemistry measurement probes, dissolved oxygen introduction/balancing system and possibly internal lighting and sampling systems. In addition, the internal hydrodynamics, sedimentalogical, biological and chemical processes will require methods of monitoring to be developed as well as control and analysis software. Outline programme (a) Detailed investigations of the state-of-the-art in all aspects of the project with particular attention paid to existing EUROMAR projects, e.g. BIMS. Where appropriate, pursue additional collaboration with related projects to reduce the risk of duplication of effort and resources. (b) Development of software to enable the understanding of the processes measured. (c) Research the development of a vessel operated and/or stand-alone Benthic carousel that will be capable of: - applying artificial current shear stresses to study erosion characteristics - acting as a dynamic Benthic chamber for the in-situ study of chemical fluxes - acting as a respirometer for the estimation of O2/CO2 fluxes. - acting as a chamber for selective biological habitation. (d) Research into and development of probes as necessary for in-situ measurement of: - N02, N03 and CO2 in headspace water. - P04 in pore waters.
Acronym: 
BISCUIT
Project ID: 
1 281
Start date: 
06-03-1995
Project Duration: 
42months
Project costs: 
2 000 000.00€
Technological Area: 
Market Area: 

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