There are many lessons to be taken from this photograph. For starters your lighting is spectacular. The side lighting really brings out the texture in the wood and the ducks. Your slightly dark exposure also helps enhance the contrast and the texture of the photograph. In my opinion, this is the most visually impressive component of the photograph.
Secondly, your composition is great. You’ve added depth as a primary element by using the piece of wood as part of your foreground which leads your viewer’s eye to the background. In this sense, the piece of wood acts to the photographs leading line.
Most importantly, this photograph has achieved what the assignment asked of you. You’ve very successfully controlled the colors of the photograph without oversimplifying the composition of the photograph. What I mean by this is that color control is very easy if you’re shooting macro photograph. However, your composition is wide enough that there is complexity in your composition. This is impressive because finding simplicity in our chaotic surrounding is no easy task.