Q: Why are these wetlands nutrient poor?

• Sarracenia flava
• Sarracenia purpurea

A: In wetlands such as isolated ponds where the water is not flushed by streams, chemicals released by decaying plant matter can become concentrated. Acidic compounds such as tannins accumulate and increase the acidity of the water. When the water becomes acidic, two things happen.

First, many microorganisms which aid in decomposition cannot survive in the highly acidic waters. As a result, when plants die they do not rot--they just become waterlogged. With little decomposition, there are few nutrients for plants.

Second, when the soil is very acidic, it is difficult for a plant to assimilate nutrients (which is why there are special fertilizers available for people who grow acid-loving plants).

Both of these factors--decreased decomposition and the difficulty of obtaining nutrients from acid water--contribute to making wetlands nutrient-poor settings. Bog-water is sometimes so rich in tannins it is darker than well-brewed tea, but it is actually quite clean and odorless.

Page citations: Crum, H., & Planisek, S. 1992; Johnson, C.W. 1985; Juniper, B.E., et al. 1989.