Sediment Chemistry

Where possible sediment chemistry measurements should be made from cores rather than grabs. The first thing that should be measured in the sediments is the vertical profile of redox potential. Separate cores (or sub-cores taken from grabs as appropriate) are then sliced at 1 cm intervals from sediment surface to ~12cm depth for sediment geochemistry. If the redox discontinuity layer is deeper than 12 cm, then slicing should be continued to below its depth.

It is essential that grabs are of good quality for chemical analysis, with as little disturbance as possible. If the samples have been disturbed, the best thing to do is discard the sample and sample again to obtain a good, undisturbed sediment sample. 

 
In Ecasa sediment slices were taken for granulometry, loss on ignition, total organic carbon, total nitrogen and total phosphorus.