Recolonization of soils by algae in a northcentral Florida pine forest after controlled fire and soil sterilization
Myers, Philip; Edward Davis, Joseph; Steven,
: The Most Probable Numbers method was used to: (1) estimate the depths of soil at which most algae live; (2) determine effects of fire on the abundance of soil algae to a depth of 20 mm; and (3) ascertain recolonization of sterilized soils by algae. Cultures on liquid and solidified media were used to identify the algal taxa in the soils. Genera of the Chlorophyta, particularly Chlamydomonas, Chlorella, Chlorococcum, Klebsormidium, Oocystis, Spongiococcum and Ulothrix dominated the study sites. Abundance of soil algae and genera were greatest in the uppermost 10 mm of the soil profile, but large numbers and most genera of the uppermost half of the cores remained at 20 mm depths. Little to no change in abundance and composition of taxa between burn and control sites occurred before and after the fires. Recolonization of burned plots after moderate and intense heat from fires was rapid. Sterilized soil put back in the burned area recolonized with 3000 cells g-1 soil after one week. Recolonization of burned and sterilized soils was attributed to algal structures capable of withstanding heat and to deposition of airborne propagules. In all the study sites, soil moisture was positively and significantly correlated with abundance of algae. The sparse Cyanobacteria, mainly Oscillatoria, Phormidium, and Synechococcus, were not quantified; their paucity was attributed to the low pH of the soil.