Trial No. 1 - Hexagenia culture

This post describes the first application trial using a batch of synthediment(TM) I developed for a government toxicity laboratory.  The director of the tox lab provided specifications of the natural sediment currently used to culture hexagenia in their laboratory.  Their field-collected sediment (from a northern-climate pond/lake) is heavy in the silt fraction and averages about 3.6% total organic carbon.  The challenge with this batch, and all batches of synthediment(TM), is finding a suitable surrogate material for the silt fraction particle size.  Sand and clay components are easy to replicate geochemically; natural silts on the other hand are a mixture of large clay clusters and weathered sand particles.  I'm not aware of one single material composed of such a mixture of geochemical components.

For this batch of synthediment(TM), some of the silt phase included a low-density silica-based material which gave the final dry-solids product an almost fluffy texture.  I was concerned that the solids would float upon hydration, but apparently that did not occur.  I received a photo (below) from the toxicity lab showing the hydrated synthediment(TM) solids (grey material on the left) side-by-side with their natural sediment (reddish-brown material on the right), being prepared for an hexagenia culture trial. 

The texture appears to be replicated rather well.  The coloring is definitely off, very likely due to a greater proportion of iron oxides in the natural sediment than in the synthediment(TM) batch.  This can be addressed very easily in future batches.  The grey color of the synthediment(TM) batch is due primarily to all 16 components in this batch being colored either white or black (with the exception of the minor component of dark brown peat powder).

At last report, overlying water and hexagenia larvae were added to the tanks sometime during the last week of February.  We'll have an update on the progress soon..