There are only two nature miracles in Mark's gospel. They are:
Mark 4:35-41 - Jesus calms the storms.
Mark 6:45-56 - Jesus walks on water.
My first observation is that they concern water or the sea. This is important, because the sea in the ancient near east was considered a frightful thing. If you have ever been out in the sea, you will understand. So, by the fact that Jesus calms the sea and storm, Mark is showing that he is the Lord over creation and symbolically chaos. This is what we see in the Old Testament as well. In Genesis 1, God is hovering over the water and creates a garden paradise instead of a sea. We also see this in the crossing of the Red Sea with Moses. We can even say that this is what happened with Joshua as the Israelites were entering into the Promised Land.
Also it is interesting to note that at the end of the Bible in the book or Revelation. The author in Revelation 21 states that there is no more sea.
So, Mark points to the fact that Jesus is the conquerer of the sea, the one who brings peace and order.
I will include a link on how to read the bible in a a literary way.