A SEMI-QUANTITATIVE METHOD TO STUDY MICROBIAL FUNCTIONAL ACTIVITY DISTRIBUTION ALONG POSIDONIA SOIL PROFILES. (E)
Among the services of the P. oceanica meadows a growing importance is currently paid to its role as global carbon sink. The sequestration capacity and stability of its C stocks are link to the microbial activity within the highly organic soils (known as mat). Ecoplates (Biolog) is a semi-quantitative tool for the assessment of microbial functional activity that generates profiles of carbon sources utilization. In this study aerobic and anaerobic carbon utilization in a healthy meadow are compared, drawing the depth spatial expression of communities’ activity down the mat. The carbon utilization was measured over eleven days and the average well color development (AWCD), the Shannon-Weaver diversity index (H’), the hierarchical cluster analysis (HCA) of the carbon sources, and the kinetics of AWCD of each layer were calculated. Both metabolisms showed consumption at all depths but with different intensity. Color observations showed that three types of carbon sources were mainly consumed and three others presented a low consumption or no consumption at all. HCA confirmed the observations. The kinetics was similar at all the layers. The results suggest a pronounced stratification of microbial activity, controlled by oxygen availability and a low degradation of carboxylic acids, amines and miscellaneous C-compounds. Despite of the higher aerobic metabolism in the top 40 cm, the overall anaerobic metabolism largely dominated the environment of the Posidonia mate. This is a key factor to explain the extremely high efficience of P. oceanica as a long term C sink.
Piñeiro-Juncal, N., University of Santiago de Compostela, Spain, email@example.com
Mateo, M. A., Centro de Estudios Avanzados de Blanes (CSIC), Spain
Martínez-Cortizas, A., University of Santiago de Compostela, Spain
Location: 306 B
Presentation is given by student: Yes