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Details of Award

NERC Reference : NE/E006647/1

Acoustic and optical backscatter from flocculating sediments (FLOCSAM)

Grant Award

Principal Investigator:
Professor CE Vincent, University of Plymouth, Sch of Earth Ocean and Environment
Co-Investigator:
Dr S Bass, University of Plymouth, Sch of Eng, Comp and Math (SECaM)
Science Area:
Marine
Overall Classification:
Marine
ENRIs:
Pollution and Waste
Natural Resource Management
Environmental Risks and Hazards
Science Topics:
Water Quality
Earth Surface Processes
Sediment/Sedimentary Processes
Abstract:
Fine suspended particles exert a profound influence on water quality in estuaries and coastal seas through their propensity to adsorb contaminants such as metals and organic compounds and by acting as a barrier to the penetration of light affecting growth of benthic biota; they impact on sensitive marine ecosystems and influence nutrient cycling and have considerable socio-economic impacts related to dredging and dumping activities around ports and harbours as sediment flocculates due to enhanced settling. Marine scientists, engineers and managers therefore need to be able to measure fine sediment fluxes to assess their impact on the coastal environment. However, fine suspended particles rarely exist in their primary state but form flocs which are typically aggregated, heterogeneous assemblages of mineral grains, biogenic debris, bacteria and organic material. Optical and acoustic instruments are used to measure suspended sediment mass concentrations but with almost no understanding of the effects that flocculation has on the light and sound. Instruments are 'calibrated' against water samples from which sediment mass concentration is measured. We intend to investigate this long-standing and scientifically-challenging problem of how sound and light respond to muddy sediments and develop, through both theory and experiment, algorithms capable of quantitatively inverting backscatter signals from cohesive sediment to predict mass concentration, combining the best features of optical and acoustic sensors. The theoretical results of the study will be tested and evaluated using carefully controlled small-scale (Couette-type tank) and medium-scale (flume) laboratory experiments where a degree of control can be exerted on the flocculation processes, and against a full-scale field campaign at a muddy estuarine site. Both the flume and field trials will use a variety of acoustic (ABS, ADV and ADCP) and optical instruments (OBS, LISST-100 and INSSEV) together with pumped-sampling, velocity and turbulence measurements. The INSSEV (up-graded for this project) will be especially valuable, allowing digital images of individual flocs to be processed and their fall velocity measured.
Period of Award:
1 Apr 2008 - 30 Sep 2012
Value:
£154,212 Split Award
Authorised funds only
NERC Reference:
NE/E006647/1
Grant Stage:
Completed
Scheme:
Standard Grant (FEC)
Grant Status:
Closed
Programme:
Standard Grant

This grant award has a total value of £154,212  

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FDAB - Financial Details (Award breakdown by headings)

DI - Other CostsIndirect - Indirect CostsDA - InvestigatorsDA - Estate CostsDI - StaffDI - EquipmentDI - T&SDA - Other Directly Allocated
£17,845£38,919£13,291£11,699£27,137£23,176£5,011£17,134

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