Sand, at a glance…

Two weeks ago, we tuned into our bacteria cultures to observe what was happening. Upon looking at the few we had begun using, s. Pasturii was the bacteria strain that was yielding the most promising calcification. Looking in on the s. Pasturii samples a week later, in both the Jove and Malta media, we can see that the bacteria seem to be splitting even after being incased in calcium – which creates the barbell shapes present.

The s. Pasturii in the Jove media seems to be thriving the most post precipitate and yielding an average size of precipitate ranging from 10 micrometers to 33 micrometers.

Looking at the sand, we are looking not only at particle size but also the size of gapping between sand when lightly packed. the four sands that we tested were pool filter sand, play sand, coarse sand, and black sand from a sand blaster.

Pool Filter Sand

Play Sand

Coarse Sand

Black Sand 

After lightly packing the sand under a slide cover we attempted to observe the gap sizes, so that once we introduce the bacteria to the sand, we know that the gap sizes are roughly as big as the gaps in sand particles.

Pool Filter Sand (approx. 42um – 300um)

Play Sand (approx. 80um – 250um) 

Coarse Sand (approx. 4um – 350um)

*grain sizes are much larger and inconsistent compared to the play sand

Black Sand – Photo not possible 

Looking at the different sands in comparison, the pool filter sand seems to have particles that are much more rounded with smooth surfaces, the play and coarse sand are similar but the coarse sand might be a bit too inconsistent on its own without being sifted, were the play sand is on the smaller side of inconsistency and it seems like the really really small particles present may aid us in getting a solid calcified chunk of material.

The next week…

We decided to look a little closer at two other precipitations, one done without heat or stirring*, and then a sample from using Whiffin media – in effort to find samples closer to our sand gap size.

Slow Precipitate

*this info may have to be adjusted after double checking the label in the lab

Whiffin Media

 – The first sample in this section yielded results similar to the other examples of precipitate, but the Whiffin sample (while still having a fairly small grain size) presents a better ability to clump after precipitation giving us larger grains closer to the sizes of our sand gaps.

About the author: Emma Whitlock

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