... And A Couple Weeks Later!

March 14th — So a couple weeks later from the results described in my last post, some more changes can be seen in the columns (fig. 1). As before, Columns A (Potting Soil + Tap Water, far left) and B (Potting Soil + Thames Water, middle left), still appear as they did initially. I'd guess that the color from the soil has steeped into the water, giving it that tea-color, however no growth has been observed either in the soil layer, in the water column, or in the sediment at the surface.

Fig. 1 All four columns a month on. Columns A (far left) and B (middle left) show little change from before. The most change has been seen in Column C (middle right), with minimal change in Column D (far right).

The most obvious difference between the results seen in this post and last post is the change in the color of Column C (Thames Mud + Tap Water), which has gone from black and opaque to more like Column D (Thames Mud + Thames Water). There is a dusting of dark in the water above the mud line (fig. 2), as was observed in Column D last time, which makes me wonder if all the coloration (microbial growth?) has either settled to just above the mud, or has dispersed throughout the water column. Now that the water is transparent, filamentous growth can be seen at the base of the biofilm at the surface, which is just as robust as it was the last time. There seems to be little change in Column D, except for maybe a decline in the filamentous growth at the surface of the water. I'll keep my eyes on these guys and keep you updated!!!

(a) (b)

Fig. 2 - Here you can really clearly see the change in Column C. (a) The water in Column C (second from right) is fairly transparent. It's easy to see the filamentous growth extending into the water from the biofilm layer. (b) In this photo from last month you can see how dark the water in Column C is compared with Column D.