Nutrient availability in tropical caves influences the dynamics of microbial biomass

• Published in: MicrobiologyOpen (Weinheim) Vol. 9; no. 7; pp. e1044 - n/a
• Main Authors: Paula, Caio César Pires de, Bichuette, Maria Elina, Seleghim, Mirna Helena Regali
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01-07-2020; John Wiley and Sons Inc; Wiley
• Subjects: Availability; Biomass; Brazil; Carbon; Caves; Creeks & streams; Decomposition; Dry season; Dynamics; Ecological effects; Environmental conditions; Environmental quality; Humidity; Immobilization; microbial parameters; Microorganisms; Nitrogen; Nutrient availability; Nutrient dynamics; Nutrients; Organic matter; Original; Parameter estimation; Precipitation; Rainy season; Respiration; Rivers; State parks; Studies; subterranean environment; Trophic levels; Brazil; microbial parameters; Brazil; organic matter; subterranean environment; decomposition
• ISSN: 2045-8827; 2045-8827
• DOI: 10.1002/mbo3.1044

Few studies have evaluated the trophic level in tropical caves, and none related the microbial biomass dynamics in the immobilization of carbon and nitrogen. Here, four tropical caves of Terra Ronca State Park, Brazil, were studied: Angélica, São Bernardo, Terra Ronca I, and Terra Ronca II caves. Physical, chemical, and microbiological parameters (microbial biomass and respiration) were estimated in the dry and wet seasons. São Bernardo, Terra Ronca I, and Terra Ronca II caves presented higher nitrogen and microbial biomass nitrogen (MBN) values in the wet season than in the dry season. On the other hand, the Angélica cave showed larger amounts of nitrogen and lower MBN values in the dry season. These results indicate that caves can be adjusted in two ecological theories known as “stoichiometric decomposition” and “microbial nitrogen mining”—to the effects of nutrient availability on organic matter decomposition. The caves studied showed different environmental dynamics in relation to organic matter decomposition, which allows them to be considered unique and possess specific characteristics. Microbial biomass dynamics can be an important parameter to evaluate the availability of nutrients and ecological dynamics of the trophic network in subterranean environments.
Microbial biomass shows different decomposition patterns among tropical caves, which could be interpreted by two theories: stoichiometric decomposition and microbial nitrogen mining. Our results indicate that nutrient flow and ecological dynamics, such as microbial parameters related to decomposition processes, cannot be generalized to all subterranean environments.