Cellulolytic and fermentative guilds in eutrophic soils of the Florida Everglades

Abstract

The northern Florida Everglades has been subject to eutrophication in recent years, resulting in well-documented changes in microbial ecology and a shift in the dominant plant species. This study investigated effects of plant quality and eutrophication on activities and composition of cellulolytic and fermentative guilds in soils. Most probable numbers of cellulolytic bacteria in eutrophic (F1) and transition (F4) soils were 10-fold higher than in oligotrophic soils (U3). Higher potential methanogenesis was observed from cellulose in microcosms with soils from F1 and F4, compared to U3 soils. Nutrient status of soil, rather than plant type, was the major factor controlling methanogenesis rates, although numbers of fermentative bacteria were higher in microcosms supplemented with ground cattail (dominant in F1 and F4) than with sawgrass (dominant component of soil in U3), regardless of soil origin. DNA sequence analysis indicated Clostridium assemblage composition correlates with soil nutrient status.