Organic matter cycling in a neotropical reservoir: effects of temperature and experimental conditions

Bottino, F., Calijuri, M. d. C. and Murphy, K. J. (2013) Organic matter cycling in a neotropical reservoir: effects of temperature and experimental conditions. Acta Limnologica Brasiliensia, 25(2), pp. 192-201. (doi: 10.1590/s2179-975x2013000200010)

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Aim: This study reports a comparison between decomposition kinetics of detritus derived from two macrophyte species (Polygonum lapathifolium L.: Polygonaceae; Eichhornia azurea (Sw.) Kunth.: Pontederiaceae) growing in a neotropical reservoir (Brazil), under laboratory and field conditions, in order to assess hypotheses on the main differences in factors affecting organic matter cycling, including the effect of temperature. Methods: Plant and water samples were collected from the reservoir in August 2009. In field incubation mass loss was assessed using a litter bag technique and in the laboratory the decay was followed using a decomposition chamber maintained under controlled conditions (i.e. in the dark, at 15 °C and 25 °C). A kinetic model was adopted to explain and compare the organic matter decay, ANOVA (Repeated Measures) testing was used to describe the differences between the treatments and a linear correlation was used to compare in situ and in vitro experiments. Results: The mass decay was faster in natural conditions with rapid release of the labile-soluble portion. The simulated values of mineralization rates of dissolved organic matter and refractory organic matter were rapid in high temperatures (25 °C). The high Q10 results (mainly for E. azurea), and experimental conditions, and outcomes of ANOVA testing indicate the temperature variation (10 °C) influence the rates of mass decay. Conclusions: The results suggested rapid organic matter cycling in warm months (from October to December) supporting the microbial loop. Although the particulate organic matter losses are high in field conditions the results are of the same magnitude in both conditions suggesting an equivalence of the mass decay kinetic.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Murphy, Dr Kevin and Bottino, Ms Flavia
Authors: Bottino, F., Calijuri, M. d. C., and Murphy, K. J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Acta Limnologica Brasiliensia
Publisher:FapUNIFESP (SciELO)
ISSN (Online):2179-975X
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in Acta Limnologica Brasiliensia 25(2): 192-201
Publisher Policy:Reproduced under a Creative Commons license

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