Contribution of humic substances as a sink and source of carbon in tropical floodplain lagoons
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We evaluated the decay of humic (HA) and fulvic acids (FA) in order to discuss the contribution of these substances as a sink and source of carbon in a tropical lagoon.
Materials and methods
Experiments were conducted under aerobic and anaerobic conditions using FA and HA isolated from decomposition of Oxycaryum cubense submitted to 10 and 60 days of degradation. HA and FA were added to water samples from a tropical floodplain oxbow system, the Infernão Lagoon. The mineralization chambers were incubated in the dark at 21.0 °C. The carbon balance, electrical conductivity, pH, and optical density were measured over 95 days.
Results and discussion
The results from the carbon budget were fitted with a first-order kinetics model. The mineralization of refractory fractions predominated for both FA and HA. Overall, although the mineralization pathway yields varied according to the type of resource and oxygen availability, the mineralization half-lives were quite similar (49 to 64 days), suggesting a similar microbial catabolism efficiency during the decay of humic substances. The short-term routes are represented by biochemical oxidations, and the immobilization and labile fractions (varying from 0 to 30%) of FA and HA supported these processes. A yield varying from 61.0 to 91.3% represents a carbon source degradation in the middle term (ca. 2 months) considering the ecosystem.
In tropical floodplain lagoons, there are three carbon routes: (i) the IN1, representing a short-term pathway (hours to days) in the carbon transformation and (ii) IN3, a middle-term carbon source from HA and FA mineralization to the water column and subsequently to the atmosphere. A third route (IN2) supported the heterotrophic metabolism of the lagoon acting as a transitory sink of carbon.
KeywordsAquatic plants Floodplain lagoon Fulvic acid Humic acid Mathematical models Oxycaryum cubense
The authors would like to thank the São Paulo Research Foundation (FAPESP processes n°: 95/0119-8; 2007/08602-9) and the Brazilian National Council for Scientific and Technological Development for the scholarship (CNPq process number 301765/2010-3). We are also indebted to Dr. Osvaldo N. Oliveira Jr. (IFSC-USP) for his critical proofreading of the manuscript.
- Antonio RM, Bianchini I Jr (2002) The effect of temperature on the glucose cycling and oxygen uptake rapes in the Infernão lagoon water, state of São Paulo, Brazil. Acta Sci Biol Sci 24:291–296Google Scholar
- Antonio RM, Bianchini I Jr, Cunha-Santino MB (2002) Test of manometric method to estimate the anaerobic mineralization on sediments in aquatic ecosystem. Acta Limnol Bras 14:59–64 (in Portuguese)Google Scholar
- Berg B, McClaugherty C (2008) Plant litter - decomposition, humus formation, carbon sequestration. Springer, HeidelbergGoogle Scholar
- Bianchini I Jr, Cunha-Santino MB, Bitar AL, Toledo APP (2004) Humification of vascular aquatic plants. In: Martin-Neto L, Milori DMBP, Silva WTL (eds) Humic substances and soil and water environment. EMBRAPA, São Carlos, pp. 82–84Google Scholar
- Chagas GG, Freesz GMA, Suzuki MS (2012) Temporal variations in the primary productivity of Eleocharis acutangula (Cyperaceae) in a tropical wetland environment. Braz. J Bot 35:295–298Google Scholar
- Gasith A, Hoyer AV (1998) Structuring role of submerged macrophytes in lakes: changing influence along lake size and depth gradients. In: Jeppesen E, Sondergaard M, Christoffersen K (eds) The structuring role of submerged macrophytes in lakes. Ecol Stud 131. Springer-Verlag, New York, pp 381–392Google Scholar
- Hammer Ø, Harper DAT, Ryan PD (2001) PAST: paleontological statistics package for education and data analysis. Palaeontol Electr 4:1–9Google Scholar
- Hong YG, Guo J, ZC X, MY X, Sun GP (2007) Humic substances act as electron acceptor and redox mediator for microbial dissimilatory azoreduction by Shewanella decolorationis S12. J Microbiol Biotechnol 17:428–437Google Scholar
- Klavins M, Serzane J (2000) Bioremediation of contaminated soils. In: Wise DL, Trantolo DJ, Cichon EJ, Inyang HI, Stottmeister U (eds) Use of humic substance in remediation of contaminated environments. CRC Press, New York, pp. 217–233Google Scholar
- Konhauser K (2007) Introduction to Geomicrobiology. Blackwell, MaldenGoogle Scholar
- Krusche AV, Mozeto AA (1999) Seasonal hydrochemical variations in an oxbow lake in response to multiple short-time pulses of flooding (Jataí Ecological Station—Mogi-Guaçu River, São Paulo, Luiz Antonio, SP-Brazil). An Acad Bras Ci 71:1–14Google Scholar
- Mitsch WJ, Gosselink JG (1993) Wetlands. Van Nostrand Reinhold, New YorkGoogle Scholar
- Mostofa KMG, Liu C, Feng X, Yoshioka T, Vione D, Pan X, Wu F (2013) Complexation of dissolved organic matter with trace metal ions in natural waters. In: Mostofa KMG, Yoshioka T, Mottaleb A, Vione D (eds) Photobiogeochemistry of organic matter: principles and practices in water environments. Springer-Verlag, Heidelberg, pp. 769–849CrossRefGoogle Scholar
- Nogueira FMB, Esteves FA, Prast A (1996) Nitrogen and phosphorus concentration of different structures of the aquatic macrophytes Eichhornia azurea Kunth and Scirpus cubensis Poepp & Kunth in relation to water level variation in Lagoa Infernão (São Paulo, Brazil). Hydrobiologia 328:199–205CrossRefGoogle Scholar
- Press WH, Teukolsky AS, Vetterling WT, Flannery BP (2007) Numerical recipes in C: the art of scientific computing. Cambridge University, Press New YorkGoogle Scholar
- Reddy KR, DeLaune RD (2008) Biochemistry of wetlands—science and applications. CRC Press, Boca RatonGoogle Scholar
- Schlesinger WH (1997) Biogeochemistry—an analysis of global change. Academic Press, San DiegoGoogle Scholar
- Steinberg CEW, Kamara S, Prokhotskaya VY, Manusadžianas L, Karasyova T, Timofeyev MA, Zhang J, Paul A, Meinelt T, Farjalla VF, Matsuo AYO, Burnison BK, Menzel R (2006) Dissolved humic substances—ecological driving forces from the individual to the ecosystem level? Freshw Biol 51:1189–1210CrossRefGoogle Scholar
- Tamire G, Mengistou S (2014) Biomass and net aboveground primary productivity of macrophytes in relation to physico-chemical factors in the littoral zone of Lake Ziway, Ethiopia. Tropical Ecol 55:313–326Google Scholar
- Thurman EM (1985) Organic geochemistry of natural waters. Kluwer Academic Publishers, Boston, p 497Google Scholar
- Trivinho-Strixino S, Correia LC, Sonoda K (2000) Phytophilous chironomidae (Diptera) and other macroinvertebrates in the ox-bow Infernão Lake (Jatai Ecological Station, Luiz Antonio, SP, Brazil). Braz J Biol 60:527–535Google Scholar