Fragile permafrost ecosystems in Siberian lowland tundra

Did you know?
Permafrost thaw can change the ground surface:
  • Dry areas can become waterlogged.
  • Wet areas can drain
  • Shrubs can invade dry areas
  • Shrubs can be killed by waterlogging which drowns plants
  • Trees fall over when the ground subsides creating a "drunken forest"
  • Buildings also fall down when the ground subsides, roads railway lines and oil pipelines can break and airstrips can be destroyed. See story 5.8
  • Some of the ground disturbance can be huge for example mega thaw slumps over 1 km wide and 100 meter deep.
Some plants and dead matter in soils that are covered by water decompose and release methane - an important greenhouse gas (Methane is much more potent than CO2)
See story 6.5

Get Active!
Decomposition in bottles
Decomposition is when organisms like bacteria and fungi break down dead organic matter (remains of dead plants and animals). When the bacteria break down dead matter, gases and water are released. During decomposition, the release of water causes the organic matter to look more wilted as it loses its water content. Have you seen a fruit go mouldy before? It is usually quite squishy, isn't it? The reason for this is because some of the water has been released due to decomposition of the fruit. Also, the mouldy fruit smells bad because of the gases released by the decomposition process.

Decomposition happens faster where there is lots of oxygen. In aquatic ecosystems, like ponds, there isn't much oxygen in the water. Therefore, in water, decomposition of dead matter happens more slowly than if it were exposed to the air.

The following experiment will test the differences in decomposition due to temperature and moisture. As a control we use inert plastic.
You will need:
Make sure all three of your bottles are clean and the labels are taken off so you can see clearly into the bottles
Label each bottle with a permanent marker, 'plastic control', 'flowers in water' and 'flowers in ice'
In the 'plastic control' bottle, add a piece of plastic – such as a straw or a piece of plastic bag. Then fill the bottle with water to near the top (see the first photos below). Wrap clingfilm around the top of the bottle and use a rubber band to seal it like a bottlecap.
In the 'flowers in water' bottle, add a flower (including its leaves and stem, as seen in diagram below) and fill the bottle with water to near the top (see the first photos below). Seal it with clingfilm and a rubber band wrapped around the top of the bottle.
In the 'flowers in ice' bottle, add a flower (including its leaves and stem, as seen in the diagram below) and fill the bottle with water to near the top (see the first photos below). Make sure there is space at the top of this bottle as the water will expand when it turns into ice. Tightly wrap clingfilm around the top of this bottle and seal it with a rubber band. Put this one in the freezer.
Wait until you see changes happening, check on it in approximately two weeks.
After approximately two weeks, take the 'flower in ice' bottle out of the freezer and compare it to the other two bottles. What happened to each? Write down your observations below.
Take the clingfilm and rubber bands off of all bottles and smell each one. What are the differences?
Day of experiment:
After approximately 2 weeks:
Follow-Up Questions:
What did you see happen in each bottle?
Which bottle's content decomposed the fastest?
Why might the fastest decomposing content be decomposing so quickly compared to the others?
What does the water look like in each bottle?
Open each bottle and smell – which bottle smells the most? Why could this be?