In vitro sensitivity of forest soil enzymes to temperature increase in Western Patagonia

Abstract

Soil enzymes can be sensitive indicators of C changes in forest soils produced by global warming. This study assessed the response to temperature of soil enzymes in forest soils from the fragile cold ecosystems of Western Patagonia (Chile), to be used as indicators of the biological C emissions from the soil under climate change for this Region. Soil from two sites of Nothofagus forest were sampled (0-5 cm), and soil C mineralization (21 days of soil incubation) and the enzyme activities of N-acetyl-β-glucosaminidase (NGA, linked to C and N cycles), β-glucosidase (BG, linked to C cycle), and endo-1,4-β-glucanase (CMCase, linked to C cycle) were measured at 5 °C and 20 o C. Additionally, sensitivity of enzyme activities was measured at 0, 5, 10 and 20 o C during experimental protocol incubation procedure, and energy activation (Ea) and Q 10 parameters were calculated. At both sites, the NGA activity mirrored the microbial activity, when temperature rose from 5 ºC to 20 °C. The NGA showed Ea higher than BG, indicating that the release of N-acetyl-glucosamine was more sensitive to temperature than the release of glucose, related to BG. The results suggest the applicability of NGA as potential indicator to assess effects of global warming in forest soils from Patagonia.

Role of Soil Microbiota Enzymes in Soil Health and Activity Changes Depending on Climate Change and the Type of Soil Ecosystem

“…Soil total nutrients had a greater influence on enzyme K cat than accessible nutrients throughout vegetation succession, with BG being more sensitive to severe temperatures. [197] Ziwuling forest region of the Loess Plateau During extended vegetation succession, total soil nutrients had a greater impact on enzyme K cat than accessible nutrients. The kinetic characteristics of soil enzymes changed dramatically over this succession.…”

Response of Soil Dehydrogenase Activity to Salinity and Cadmium Species

“…Soil enzymes have a key role in nutrient cycling and soil organic matter (SOM) mineralization (Gianfreda 2015), and enzymatic activity can rapidly respond even to small changes in environmental conditions (Dussault et al 2008). Hence, soil enzyme activities are often used as a sensitive indicator of the environmental changes (Machuca et al 2018). Soil dehydrogenase activity (DHA) is considered an indicator of overall soil microbial activity because dehydrogenases occur intracellular in all living microbial cells and do not accumulate extracellularly in the soil (Das and Varma 2011).…”