Soil biological characteristics Bacterial numbers
3.1. Soil physical and chemical characteristics
Soil moisture was highly variable among different environments (F = 9.08, P = 0.00004), which can be arranged into a hydrological gradient, with the lowest values in fellfields (6.2–26.4%), intermediate in moss communities (24.1–159.0%) and the highest in wetland soils (60.9–210.7%). Soils from active (2.7–10.6%) and relict (4.1–28.8%) penguin colonies both had very low soil moisture content. The Pearson's correlation matrix indicates a positive relationship of soil moisture with a majority of the investigated characteristics and negative relationship only with AP1903 values, contents of gravel and total P ( Table 2).
Contents of the soil total C also varied significantly (F = 4.35, P = 0.02) from very low values found in soils from fellfields, intermediate in soils from moss communities and the highest in wetland soils. Ornithogenic soils also had very high C contents, with values within the same range as in wetland soils. Distribution of soil total N contents exhibited a very similar pattern. Its contents were the lowest at fellfields and progressively higher in moss communities and wetlands. The highest values were found in soils from active and relict penguin colonies (F = 7.10, P = 0.0003). The data also demonstrate lower values of both C and N in soils from relict colonies compared with those from active colonies. Although the differences were not statistically significant due to very high variability, they indicate loss of C and N in ornithogenic soils with time.