Manganese is a metallic nutrient that is essential for
plant life. (Incitec Pivot, 2003) It is used in metabolic processes, carbon
dioxide absorption and electron transport in photosynthesis, and the synthesis
of chlorophyll (Hong, Ketterings, McBride, 2010, Spectrum Analytic Inc, 2013).
In our research, we learned that when large populations of bacteria are present in aqueous soil conditions, almost all manganese is reduced to manganese oxide (He, Zhang, Jin, Zhu, Liu, 2008). However, the solubility of all forms of manganese depends on the amount of acidity in the soil. As pH decreases, it is easier for the ionic bond in manganese to dissociate, producing Mn+2. This process makes the manganese more available to plants to use as nutrients for their metabolic purposes. However, unusually low pH can yield a toxic amount of manganese in the soil. Manganese toxicity can be the cause of unusually short roots, necrotic lesions, and chlorosis in plants.
During the E.S.S.R.E. 2013 Biota Survey (E.S.S.R.E., 2013), anomalous amounts of
manganese were observed in Sites 1 and 2.
The soil in these areas was extremely acidic, yet lower levels of
manganese were found. However, in Site 4, a microclimate in close proximity to
the other sites, an expected relationship between manganese and pH was present
creating an anomaly.
One of the possible reasons such drastic differences were observed between
adjacent sites was the moisture present in Site 4. One of the dominant
differing features in Site 4 is the stream running through it, as opposed to the
drier and steeper environments in Sites 1 and 2. In our investigation, we tested
the samples in Site 4 for moisture and bacteria in an attempt to explain
anomalous differences in manganese content between sites.