Tuesday 4 August 2015

Deployment of sediment trap in Lurefjorden

The weather was not particularly inviting to start with
Today the McLane Time Series Sediment Trap was deployed, to a depth of 450 m. This trap, with a honeycombed structure to slow the settling of material, will allow any jellyfish particulate matter to be quantified using isotope signature analysis, and also determine overall particle flux. The trap consists of a funnel to catch the particulates, as well as a series of sample bottles to contain the material, which will be changed every 14 days. After a year, the attached KumQuat acoustic release transducer will be triggered which releases the weighted trap, which then floats to the surface to be collected.  

The chain link weight to keep the trap on the sea floor for a year. Attached to the weight is the battery-powered acoustic release transducer, which when triggered will separate from the weight and float to the surface. Pictured: Andrew Sweetman.
McLane Time Series Sediment Trap, with sample bottles at the bottom. A programmed computer on-board switches the sample bottle every 14 days. 

Lowering the sediment trap into the water. The top is honeycombed in order to slow the deposition of sediment. 
Lowering the floats into the water, which are attached to the sediment trap. Pictured: Andrew Sweetman, Graihagh Hardinge and Leon Pedersen. 

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