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Do models of organic carbon mineralization extrapolate to warmer tropical sediments?
Author(s) -
Cardoso Simone J.,
Enrich-Prast Alex,
Pace Michael L.,
Roland Fábio
Publication year - 2014
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2014.59.1.0048
Subject(s) - mineralization (soil science) , nitrogen cycle , environmental chemistry , salinity , total organic carbon , sediment , ecosystem , environmental science , nitrogen , oceanography , geology , chemistry , soil science , ecology , soil water , geomorphology , biology , organic chemistry
Freshwater sediments are important sites of organic carbon (OC) burial and mineralization. Previous studies indicate that warming can increase rates of OC mineralization, implying more CO 2 release from sediments and, consequently, less OC burial, but temperatures typical of tropical ecosystems are poorly represented in the models of temperature and OC mineralization. We measured OC mineralization rates in 61 Brazilian tropical systems, including rivers, streams, lakes, coastal lagoons, and reservoirs from different regions (Pantanal, Amazonia, Atlantic Forest, and coastal areas). Oxygen consumption and dissolved inorganic carbon production in sediment core incubations were used for estimating OC mineralization rates. Multiple regression models were used to investigate the importance of temperature and other variables to predict OC mineralization. The average OC mineralization rate for all systems was 1223 ± 950 mg C m ‒2 d ‒1 . Rates increased significantly with increasing temperature and varied across system types and regions. In addition, salinity, total nitrogen, and chlorophyll a were important factors controlling OC mineralization in tropical sediments. The pattern of increasing mineralization with temperature was remarkably consistent with theoretical and empirical expectations. The explanatory power of previous temperature vs. mineralization models is confirmed and enhanced by the addition of the tropical data that substantially extended the temperature range.