Decomposition dynamics of two aquatic macrophytes: response of litter interaction with temperature and dissolved oxygen

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ECOLOGY & BIOGEOGRAPHY - ORIGINAL ARTICLE

Decomposition dynamics of two aquatic macrophytes: response of litter interaction with temperature and dissolved oxygen availability Yeda Carolina Paccagnella1 · Irineu Bianchini Jr.1,2   · Marcela Bianchessi da Cunha‑Santino1,2  Received: 11 May 2020 / Revised: 26 July 2020 / Accepted: 29 July 2020 © Botanical Society of Sao Paulo 2020

Abstract The decomposition of a single macrophytes species may not represent entirely the carbon cycling in aquatic ecosystems, as in the freshwater macrophyte-dominant environments several species grow and decay concomitantly. To assess the interaction of the two species in the decomposition process, the temporal variation of particulate organic carbon (POC) of Hedychium coronarium J. König, Typha domingensis Persoon and the mixed sample (50% of each species) was mathematically modeled. Kinetic models were used to verify the temperature and the availability of dissolved oxygen, as regulating factors in decomposition. The aerobic processes favored a faster decay when compared to anaerobic processes. The occurrence of two phases in decomposition was observed: (1) with a rapid mass loss ­(POCLS) and (2) with a slow degradation ­(POCR). During the aerobic decomposition, independently of variation in temperature, the effect was always antagonistic. However, under anaerobic conditions, the three types were observed (antagonistic, additive and synergic). The mixed detritus always displayed the highest Q10 coefficient. Modeling mixed detritus decomposition was a reliable predictive framework of litter decomposition at a ecosystemic scale, improving ecosystem response of carbon cycling feedback under an increasing temperature. Keywords  Aerobic and anaerobic conditions · Hedychium coronarium · Kinetic models · Particulate and dissolved organic carbon · Typha domingensis

1 Introduction Aquatic macrophytes are recognized for their ecosystem services in shallow freshwater systems (O’Hare et al. 2017; Verhofstad and Bakker 2019). Macrophytes play a key role in fundamental ecosystem process, participating in the supporting services, i.e., primary production (Chagas et al. 2012) and decomposition (Swan and Kominoski 2012). The growth of macrophytes culminates in the biomass increasing that represents an important source of carbon * Irineu Bianchini Jr. [email protected] * Marcela Bianchessi da Cunha‑Santino [email protected] 1



Programa de Pós Graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil



Departamento de Hidrobiologia, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil

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for the ecosystem functions (Kazanjian et al. 2018). These plants are very responsive to variation in water temperatures, photosynthetic radiation, current velocity, water level variation, nutrient concentration, and inorganic carbon availability (Naden et al. 2006; Yin et al. 2017; Lauridsen et al. 2019). After the senescence of macrophytes, the detritus decomposition presents important respons