Our Winograsky columns have come a long way from our previous post two weeks ago. To review what a Winogradsky column is and our goals for them please see: Adventures with Winogradskies.

After 4 weeks:

Green layers have started to develop on the top of some of the tubes and to a less visible extent on some of the larger containers.

In some tubes we are starting to see defined layers. Layers seem to vary between tubes containing seawater from different sample locations as well as between tubes with water from the same location.

Unfortunately, our tiny microcentrifuge tubes haven’t changed much in the past two weeks.

4 Weeks vs. 1.5 Weeks:

Definitive layers are less visible in our large containers (perhaps due to their non-cylindrical shape?), but there is significant visible growth compared to the containers at 1.5 weeks. Additionally, upon closer inspection both red and green splotches can be found in the container.

Simulating Soil Conditions – 4 weeks:

At first glance, the container that we covered to simulate soil conditions looks similar to the uncovered columns. However, there is a small white strip at the top of sediment that we don’t see in the uncovered columns. There also appears to be a biofilm growing along the sides of the container.

As well as the beginning of a layer floating on the top of the seawater in the container.

Experimental tubes at 3 weeks (where we added either Potassium Nitrate or Ammonium Acetate):

From left to right: Ammonium Acetate Added, Potassium Nitrate Added, Nothing Added

We decided to keep one vial where Ammonium Acetate was added and one vial where Potassium Nitrate was added in complete darkness.

From left to right: Dark Potassium Nitrate Added, Light Potassium Nitrate Added, Light Nothing Added

Notice the difference in the amount of bubbles between the vials under different light and chemical conditions. All three of these vials have seawater from the same location.