SciELO - Scientific Electronic Library Online

vol.71 issue1Development of a benthic multimetric index for biomonitoring of a neotropical watershedPerformance of Azolla caroliniana Willd. and Salvinia auriculata Aubl. on fish farming effluent author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand




Related links


Brazilian Journal of Biology

Print version ISSN 1519-6984

Braz. J. Biol. vol.71 no.1 São Carlos Feb. 2011 



Oxygen uptake from aquatic macrophyte decomposition from Piraju Reservoir (Piraju, SP, Brazil)


Consumo de oxigênio da decomposição de macrófitas aquáticas do reservatório da usina hidrelétrica Piraju (Piraju, SP, Brasil)



Bianchini Jr., I.I, II, *; Cunha-Santino, MB.I, II, *; Panhota, RS.I

IPrograma de Pós-graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos - UFSCar, Rod. Washington Luiz, Km 235, CP 676, CEP 13565-905, São Carlos, SP, Brazil
IIDepartamento de Hidrobiologia, Universidade Federal de São Carlos - UFSCar, Rod. Washington Luiz, Km 235, CP 676, CEP 13565-905, São Carlos, SP, Brazil




The kinetics of oxygen consumption related to mineralisation of 18 taxa of aquatic macrophytes (Cyperus sp, Azolla caroliniana, Echinodorus macrophyllus, Eichhornia azurea, Eichhornia crassipes, Eleocharis sp1, Eleocharis sp2, Hetereanthera multiflora, Hydrocotyle raniculoides, Ludwigia sp, Myriophyllum aquaticum, Nymphaea elegans, Oxycaryum cubense, Ricciocarpus natans, Rynchospora corymbosa, Salvinia auriculata, Typha domingensis and Utricularia foliosa) from the reservoir of Piraju Hydroelectric Power Plant (São Paulo state, Brazil) were described. For each species, two incubations were prepared with ca. 300.0 mg of plant (DW) and 1.0 L of reservoir water sample. The incubations were maintained in the dark and at 20 ºC. Periodically the dissolved oxygen (DO) concentrations were measured; the accumulated DO values were fitted to 1st order kinetic model and the results showed that: i) high oxygen consumption was observed for Ludwigia sp (533 mg g-1 DW), while the lowest was registered for Eleocharis sp1 (205 mg g-1 DW) mineralisation; ii) the higher deoxygenation rate constants were verified in the mineralisation of A. caroliniana (0.052 day-1), H. raniculoides (0.050 day-1) and U. foliosa (0.049 day-1). The oxygen consumption rate constants of Ludwigia sp and Eleocharis sp2 mineralisation (0.027 day-1) were the lowest. The half-time of oxygen consumption varied from 9 to 26 days. In the short term, the detritus of E. macrophyllus, H. raniculoides, Ludwigia sp, N. elegans and U. foliosa were the critical resources to the reservoir oxygen demand; while in the long term, A. caroliniana, H. multiflora and T. domingensis were the resources that can potentially contribute to the benthic oxygen demand of this reservoir.

Keywords: aquatic macrophytes, oxygen consumption, decomposition, detritus, Piraju Hydroelectric Power Plant, kinetic.


Neste estudo foram descritas as cinéticas dos consumos de oxigênio dissolvido (OD) das mineralizações de 18 espécies de macrófitas aquáticas (Cyperus sp, Azolla caroliniana, Echinodorus macrophyllus, Eichhornia azurea, Eichhornia crassipes, Eleocharis sp1, Eleocharis sp2, Hetereanthera multiflora, Hydrocotyle raniculoides, Ludwigia sp., Myriophyllum aquaticum, Nymphaea elegans, Oxycaryum cubense, Ricciocarpus natans, Rynchospora corymbosa, Salvinia auriculata, Typha domingensis e Utricularia foliosa) do reservatório da Usina Hidrelétrica Piraju (São Paulo, Brasil). Para cada planta, duas incubações foram preparadas, com ca. 300,0 mg de planta (PS) em 1,0 L de água do reservatório. As incubações foram mantidas no escuro a 20 ºC. Periodicamente, as concentrações de oxigênio dissolvido (OD) foram determinadas; os consumos acumulados de OD foram ajustados a um modelo cinético de 1ª ordem e os resultados indicaram que: i) o consumo mais elevado foi observado na mineralização de Ludwigia sp (533 mg g-1 PS), enquanto que o menor foi registrado para os detritos de Eleocharis sp1 (205 mg g-1 PS); ii) os maiores coeficientes de desoxigenação foram verificados nas mineralizações de A. caroliniana (0,052 dia-1), H. raniculoides (0,050 dia-1) e U. foliosa (0,049 dia-1). Os coeficientes de desoxigenação das mineralizações de Ludwigia sp e Eleocharis sp2 foram os mais baixos (0,027 dia-1). Os tempos de meia-vida dos consumos de oxigênio variaram entre 9 e 26 dias. A curto prazo, os detritos de E. macrophyllus, H. raniculoides, Ludwigia sp, N. elegans e U. foliosa representam os recursos mais críticos para a demanda de oxigênio, enquanto que a longo prazo, A. caroliniana, H. multiflora e T. domingensis são os recursos que potencialmente mais podem contribuir para as demandas bentônicas do reservatório.

Palavras-chave: macrófitas aquáticas, consumo de oxigênio, decomposição, detritos, Usina Hidrelétrica Piraju, cinética.



1. Introduction

Macrophytes in tropical regions continuously supply the food webs of different types of aquatic environments, mainly in the littoral zones (Wetzel, 1990; Camargo and Esteves, 1995). Depending on the amount of plant detritus, decomposition may contribute to water fertilisation and raise the oxygen demands (Bianchini Jr.  et al., 2008). This may endanger the long-term health of the aquatic ecosystem, and also the water multipurpose uses and the power generation equipment (Tundisi and Matsumura-Tundisi, 2003). However, such intensive development of aquatic macrophytes depends on conditions such as absence of strong winds, low water turbulence, and availability of propagules or other sources of dispersion, that occur simultaneously with typical nutrient increases within the filling phase of the reservoir (Agostinho  et al., 1999). Several species grow in natural and man-made freshwater ecosystems in tropical regions, and an excess presence is usually noted for Eichhornia crassipes, Egeria spp, Eleocharis sp, Ludwigia spp, Oxycaryum cubense, Pistia stratiotes, Salvinia spp and Typha domingenseis (Bini  et al., 1999; Tanaka  et al., 2002; Marcondes  et al., 2003; Thomaz. et al., 2005, 2006; Bianchini Jr.  et al., 2006a; Camargo  et al., 2006; Martins  et al., 2008).

The tissues of the macrophytes are composed of particulate organic matter (POM), soluble organic (in the form of dissolved organic matter, DOM) and inorganic compounds (Little, 1979; Henry-Silva  et al., 2001). During decomposition, the POM and DOM are processed at different rates and in general, the detritus in the sediments show the predominance of structural compounds as cellulose and lignin. Processes related to decomposition (e.g. leaching, comminution and catabolism; Swift  et al., 1979) are regulated by biotic (e.g. types of organisms), abiotic (e.g. quality and size of detritus, temperature, pH, redox potential; Wetzel, 1990; Enríquez  et al., 1993; Hohmann and Neely, 1993; Gessner, 2000) and catabolism occurs by specific metabolic pathways and produce different intermediates that interact with other compounds and biota (Steinberg, 2003). The prevalence and characteristics of microbial catabolic often results from oxygen availability. Aerobic mineralisation generates more stable products and tends to transfer carbon for the growth of microorganisms (Davis and Cornwell, 2008). However, other factors change the respiratory coefficients of metabolic processes (e.g. presence of alternative electron receptors, and aliphatic amino acids) and generate interference in the degradation of organic substances and dissolved oxygen availability (Dilly, 2001). The knowledge of events related to decomposition of macrophytes is important for understanding the role of these organisms in the functioning of biogeochemical cycles within aquatic ecosystems.

The aim of this study was to describe the oxygen uptake and mineralised carbon formations resulting from the decomposition of eighteen taxa of aquatic macrophytes from the reservoir of the Hydroelectric Power Plant (HPP) Piraju (Piraju, São Paulo state, Brazil). The effects of decomposition of these organisms in this environment are also discussed, using two kinetic models for the comparisons of mineralisation parameters.


2. Material and Methods

2.1. Study area

Water samples and aquatic macrophytes were collected in the reservoir of the HPP Piraju. This reservoir was formed in September, 2002 and is located at Alto Paranapanema in the southeast of São Paulo state, Brazil (parallels between 23K 257.468 UTM 7.450.796 and 22J 666.086 UTM 7.339.238). It is the second of a cascade of reservoirs from upstream-downstream in the Paranapanema River; it is located between Jurumirim and Paranapanema reservoirs. At 531.5 m above sea level, the reservoir presents the following characteristics: i) area: 17.1 km2; ii) length: 16.2 km; iii) total cumulative volume: 105.6 × 106 m3; iv) mean residence time: 5.7 days; v) mean depth: 6.96 m; and vi) maximum depth: 25.2 m (ANEEL, 2005). The main tributary of the reservoir is the Paranapanema River and some small tributaries (i.e. Mina d'água, Virado, Bananeira, São Bartolomeu, Monte Alegre, Brejão, Douradinho and Santa Lúcia streams). According to the classification proposed by Straškraba (1999), this reservoir is small (area between 1 and 100 km2) and Class A (mean residence time less than 15 days). It is an oligo-mesotrophic system (sensu. Vollenweider, 1968) under low anthropogenic pressures (UFSCar/CBA, 2008). In Piraju Reservoir, the appearance of macrophytes is restricted to littoral regions, with the predominance of Eichhornia azurea and Typha domingensis (UFSCar/CBA, 2008). The sampling of macrophytes occurred from August, 2003 to May, 2004. In 2004, the water from the reservoir had a high concentration of dissolved oxygen (average: 7.8 ± 2.1 mg L-1). pH, total solids and electrical conductivity were 6.92 ± 0.20, 0.172 ± 0.267 mg L-1 and 41.0 ± 6.7 μS cm-1, respectively. Secchi depth disappearance was 2.1 ± 0.8 m. Dissolved inorganic carbon varied from 3.7 (August) to 8.9 mg L-1 (May), with a mean value of 5.7 ± 1.2 mg L-1. Total-P and total-N were, respectively, 14.5 and 533 μg L-1, and considering N forms, the organic fraction predominated (ca. 76%). On average, 8.7% of the sediments were organic (UFSCar/CBA, 2008).

2.2. Mineralisation experiment design

Samples of aquatic macrophytes (n = 18 taxa) were collected in the Piraju reservoir: Azolla caroliniana Willd., Cyperus sp, Echinodorus macrophyllus (Kunth) Micheli, Eichhornia azurea (Sw.) Kunth, Eichhornia crassipes (Mart.) Solms, Eleocharis sp1, Eleocharis sp2, Heteranthera multiflora (Griseb.) Horn, Hydrocotyle ranunculoides L. f., Ludwigia sp, Myriophyllum aquaticum (Vell.) Verdec, Nymphaea elegans Hook, Oxycaryum cubense (Poepp. & Kunth) Lye, Ricciocarpus natans (L.) Corda, Rhynchospora corymbosa (L.) Britt., Salvinia auriculata Aubl., Utricularia foliosa L.and Typha domingensis Pers. The plants were washed, dried at 40 °C and grounded. After plant fragments preparation, reservoir water samples (ca. 10 L) were collected (22K 065.839 UTM 7.438.694 in May, 2004) with a Van Dorn bottle and equivalent aliquots of water (from the surface, middle and bottom) were mixed. In the laboratory, water samples were filtered (cellulose ester membrane, Millipore 0.45 μm) and submitted to aeration (24 hours). For each taxon, incubations (n = 2) were prepared with ca. 300.0 mg of plant (DW) in 1.0 L reservoir water (Bianchini Jr.  et al., 2003). Two control incubations (with only water reservoir) were also prepared. The incubations were maintained in the dark under controlled temperature (20 ± 0.6 ºC). Periodically, during 85 days DO concentrations were recorded by the polarographic method (oximeter YSI model 58). In order to maintain the solutions under aerobic conditions, they were oxygenated during 1 hour, with clean filtered air to keep the dissolved oxygen near saturation. When the dissolved oxygen concentrations were near 2.0 mg L-1, the solutions where oxygenated again, until the oxygen reached the saturation value; this procedure avoided anaerobiosis of the solutions. After measurements, the bottles were closed to prevent oxygen diffusion (Cunha-Santino and Bianchini Jr., 2003a).

After 85 days, the incubation contents (particulate and dissolved fractions) were fractionated with cellulose ester membrane (Millipore, 0.22 μm) in order to calculate the mass balance. After being dried (at 40 ºC), the fractions of particulate organic carbon (POC) were estimated from remaining detritus masses (ash free basis), by multiplication of the factor 0.47 (Westlake, 1965; Wetzel and Likens, 1979). The concentrations of dissolved organic carbon (DOC) were determined by combustion and non-dispersive infrared detection (TOC Analyzer, Shimadzu model 5000A). Based on the differences between initial and final carbon contents (Equation 1), the yields of mineralised carbon (MC) were evaluated.

where: MC = mineralised carbon; TOC = total organic carbon (initial content of organic carbon); POC = particulate organic carbon; DOC = dissolved organic carbon.

2.3. Kinetic parameters

For representations of mineralisation kinetics, the temporal variations of accumulated oxygen consumption (OC) were fitted to the first order model (Equation 2), as usually used in BOD tests (Borsuk and Stow, 2000; Davis and Cornwell, 2008). For the fittings and the coefficient estimations, a nonlinear regression method was used, using the iterative algorithm of Levenberg-Marquardt (Press  et al., 1993). The mineralisation coefficient (kM) was determined according to Equation 3 (Xie  et al., 2004).

where: OC = cumulative oxygen consumption; OCMAX = maximum amount of consumed oxygen (mg g-1 DW); kd = deoxygenation rate constant (day-1); t = time (day).

where: kM = mineralisation rate constant (day-1); ROC = remaining organic carbon (final amount of detritus organic carbon: POC + DOC).

The times of half-life (t½) from oxygen consumption (t½-kd) and decrease of mass owing to macrophyte decomposition (t½-kM) were calculated according to Equation 4,

The stoichiometric relationship associated with oxygen consumption and mineralised carbon (O/C) were estimated from the ratio OCMAX:MC (Bianchini Jr.  et al., 2006b). The frequency distributions of the following parameters were considered: OCMAX, kd, t½-kd, O/C, ROC, MC, kM and t½-kM. These parameters were also submitted to the normality test (Shapiro and Wilk, 1965) with a significant level of 0.05.


3. Results

The oxygen uptakes involved in the mineralisation of aquatic macrophytes are presented in Table 1; by difference, the effects of DOC oxidation from reservoir water samples (control flasks) were neutralised. The oxygen consumptions were more pronounced in the mineralisation of Ludwigia sp and E. macrophyllus (533 and 489 mg g-1 DW, respectively), the lowest oxygen consumption occurred in the mineralisation of Eleocharis sp1 (205 mg g-1 DW) and E. azurea (206 mg g-1 DW). The kinetics of the higher and lowest oxygen consumptions are shown in Figure 1a; thus, all the other kinetics were included among these two curves. The normal distributions (at 0.05 level) were only verified for the following parameters: OCMAX, t½-kd, O/C and t½-kM (Figures 1 and 2). The slope derived from MC and OCMAX refers to the total O/C stoichiometric relationship. Comparing the results, it is possible to note that this value is equivalent to the O/C average value registered in Table 1.

The distributions also show that the macrophytes detritus are mainly refractory resources (Figures 1e and 2a) and that oxygen consumption and decrease in mass were not linked processes; thus, on average, the oxygen consumption was 5.3-fold fast (Figures 1c and 2b). The changes in OCMAX, kd, kM and MC consequently promoted changes in the O/C values (Figures 1b,c, 2a,b); but without strong variation (range: 1.06-2.07; Table 1 and Figure 2d).

The highest amount of MC was observed in the mineralisation of N. elegans (73%) and lowest in S. auriculata (33%). In the experimental period (85 days), on average, 54% of carbon was not oxidized. The mineralisation coefficients ranged from 0.005 (E. azurea, O. cubense, R. corymbosa and S. auriculata) to 0.015 day-1 (N. elegans). The average value (0.008 day-1) is equivalent to a half-time of 90 days (Table 1).


4. Discussion

The oxygen consumption patterns recorded in this experiment were similar to those obtained in related experiments (e.g. Brum  et al., 1999; Farjalla  et al., 1999; Bitar and Bianchini Jr., 2002). The decomposition experiment with aquatic macrophytes from Óleo Lagoon (São Paulo, Brazil) recorded the lowest value of OCMAX (165 mg g-1  DW) in the mineralisation Salvinia auriculata and the highest (700 mg g-1 DW) of Egeria najas (Bianchini Jr.  et al., 2008). The results were analogous, still, to those obtained in an experiment that tested the size of the detritus (from Scirpus cubensis) as a determinant of mineralisation, in this case the values of OCMAX ranged between 143 and 203 mg g-1 DW (Bianchini Jr. and Cunha-Santino, 2006). According to the low values of errors and high correlation coefficients (r2) (Table 1), the selected model (Equation 2) was appropriate for the descriptions of the aerobic mineralisation kinetics.

The temporal variations of oxygen consumption were similar to those obtained from mineralisation experiments that tested resources other than aquatic macrophytes (e.g. leaves, branches, barks, litter, sediments, phytoplankton, DOM, humic substances, sugars, polyphenolic compounds and amino acids; Almazan and Boyd, 1978; Antonio  et al., 1999; Borsuk and Stow, 2000; Bitar and Bianchini Jr., 2002; Cunha-Santino  et al., 2002, 2008; Cunha-Santino and Bianchini Jr., 2003b, 2004). Initially, consumption tended to be high, and after, there was a gradual decrease in the rates of oxygen uptake. Considering that these resources are heterogeneous from the structural point of view (Silva  et al., 1994; Henry-Silva  et al., 2001), in the beginning of the experiment, the oxidation of labile fraction with high oxygen demands prevailed due to substances derived from the cytoplasmatic content of the macrophyte tissues (Nelson  et al., 1990). Thus, oxygen consumption has been frequently associated with the increments of microbial respiration rates when decomposing the detritus that are rich in nutrients and with the low content of recalcitrant structures (Gessner, 2000; Komínková  et al., 2000).

The oxidation of nitrogen compounds (e.g. nitrification) may also have contributed to the oxygen uptake, especially from the second week (USEPA, 1985; Davis and Cornwell, 2008). Moreover, it is assumed that decreases in oxygen consumption rates were mainly related to the mineralisation of refractory fractions. However, other factors may have occurred: i) the photo-oxidation of humic compounds (Cooper  et al., 1989); ii) the hydroxylation of aromatic organic compounds (Dagley, 1971); iii) mechanical agitation during sample homogenisation (Cunha-Santino and Bianchini Jr., 2003a); and iv) the chemical and biochemical reactions for the formation of hydrogen peroxide (Mopper and Zika, 1987), e.g. amino acid degradation (Rose, 1976). Affecting these values, other oxidations not directly related to carbon mineralisation must be included (e.g. sulfur oxidizing processes; Wetzel, 2001).

According to the deoxygenation rate (kd) it was estimated that the half-time of oxygen consumption ranged between 9 and 26 days (mineralisations of R. natans and Eleocharis sp1 e Ludwigia sp, respectively). The mean values of kd and OCMAX obtained from other mineralisation experiments of aquatic plants (Cunha and Bianchini Jr., 1998; Lemos and Bianchini Jr., 1998; Brum  et al., 1999; Farjalla  et al., 1999; Bitar and Bianchini Jr., 2002) were respectively 0.18 day-1 and 229 mg g-1 (DW). The kd mean value corresponds to a half-time of 4 days. These results indicate that, on average, the processes of mineralisation of the detritus of aquatic macrophytes from the HPP Piraju reservoir were 4.7 times slower than that showed in other studies. By contrast, the mean value of OCMAX achieved in the present experiment was 43% higher than the average consumption of related studies. Besides the effect of the chemical structure of detritus composition, the diversity and number of microorganisms are considered factors responsible for low values of kd, referring to the Piraju Reservoir. The predominance of the meso-oligotrophic conditions implies that it is possible that the microflora used as inoculum were not adapted to the high amount of detritus as used in this experiment.

Comparing the OCMAX with CM, there was a direct relationship between these processes (r2: 0.73) a slope value of 1.5, corresponding to the total stoichiometric coefficient of O/C (Table 1). Thus, this experiment showed that for the oxidation of each atom of carbon, on average 1.5 atoms of oxygen were required; this number corresponds to 56% of the theoretical value (2.67), considering as a reference the oxidation of glucose (Davis and Cornwell, 2008). The stoichiometric relationships are valid for carbon compounds mineralised in the short term, i.e. the labile organic forms, in view of the experiment's duration (85 days) and the differences between mean half-time processes of oxygen consumption and carbon mineralisation. The values of O/C were higher in mineralisation and Ludwigia sp and H. multiflora (2.07 and 2.06, respectively) and the lowest value was observed for Eleocharis sp1 (1.06). Once kM values were derived from MC, the mineralisation coefficients (Equation 3) were also directly related to OCMAX (r2: 0.70); on the other hand, no relationship was found between the values of OCMAX and kd. The magnitude of kd was primarily related to the quality and quantity of labile compounds, considering that the values of kd vary basically as a function of temperature, types of microorganisms and the resource quality (Davis and Cornwell, 2008) and that the incubations were maintained under the same experimental conditions (temperature and inoculums).

Comparing the values of kM with the kd, the processes of decarboxylation were slower (ca. 5.3 times), the mineralisation of N. elegans showed the lowest value of the ratio kd:kM (2.6) and R. natans the highest (11.5). Among other factors (e.g. detritus structural heterogeneity), it is possible that the lack of synchronisation between oxidative processes and decarboxylation results in the underestimation of mineralisation net rates. Considering that the growth of microorganisms tends to conserve carbon in organic form, it interferes, in this manner, in the precise recording of organic compounds circulation. In this case, even considering that the oxygen uptake and the carbon mineralisation processes are coupled, experiments have shown that decarboxylation is processed by different routes, with specific rates and individual stoichiometric relationships that normally do not contribute to the experimental acquisition of theoretical stoichiometry values used to make the connection between these processes (Cunha-Santino and Bianchini Jr., 2002). The variations in the stoichiometric coefficients were related to the chemical compositions of detritus, with the predominance of catabolic routes and with the densities of the main microorganisms involved (Cunha-Santino and Bianchini Jr., 2002). Several organic compounds are used by microorganisms as an energy source, the catabolism of these substances leads to the production of intermediate compounds that are also used in the reactions of biosynthesis and energy acquisition. Thus, the stoichiometric coefficients were related to the metabolic pathways of degradation via the organic compounds that are processed. Hence, the set of predominate metabolic pathways resulting from the specific action of the organisms community altered the values of the stoichiometric relationships.

With regard to the decomposition of aquatic macrophytes in the reservoir of the HPP Piraju, it is possible to infer from the results that: i) in the short term, the resources that showed the lowest mineralisation coefficient (i.e. Cyperus sp, E. azurea, E. crassipes, Eleocharis spp, M. aquaticum, O. cubense, R. corymbosa, S. auriculata) probably served primarily for the humification or other forms of refractory organic matter, to the detriment of microbial catabolic processes (respiration). Regarding the decomposition of these plants, these results suggest that those with the lowest values of kM contributed potentially to the organic matter formation in the reservoir sediments; ii) by presenting high mineralisation rates and values of O/C, E. macrophyllus, H. raniculoides, Ludwigia sp, N. elegans and U. foliosa were characterised as resources that generate high oxygen deficits in the short and medium term, depending on the form in which these plants were incorporated into the detritus chain; and iii) by presenting low values of kM and high O/C, the mineralisation of A. caroliniana, H. multiflora and T. domingensis possibly promotes low demands for oxygen in the long-term, and so it is possible that these species are the main sources of detritus responsible for the occurrence of benthonic oxygen demand in the Piraju reservoir.

Acknowledgements - The authors thank the Companhia Brasileira de Alumínio (CBA-Votorantim) for support for the field sampling and for the concession of limnological data from the Piraju reservoir. We also thank CNPq (processes: 300959/2004-4 and 150169/2004-3) for scholarships.



Agência Nacional de Energia Elétrica - ANEEL, 2005. Atlas de energia elétrica. Brasília: ANEEL. 243 p.         [ Links ]

AGOSTINHO, AA., MIRANDA, LE., BINI, LM., GOMES, LC., THOMAZ, SM. and SUZUKI, HI., 1999. Patterns of colonization in Neotropical reservoirs, and prognoses on aging. In TUNDISI, JG. and STRAŠKRABA M., Ed. Theoretical reservoir ecology and its applications. São Carlos: Brazilian Academy of Science/IIE/Backhuys. p. 227-265.         [ Links ]

ALMAZAN, G. and BOYD, CE., 1978. Effects of nitrogen levels on rates of oxygen consumption during decay of aquatic plants. Aquatic Botany, vol. 5, p. 119-126.         [ Links ]

ANTONIO, RM., BITAR, AL. and BIANCHINI Jr., I., 1999. Consumo de oxigênio na mineralização de folhas, galhos, cascas e serapilheira. Acta Limnologica Brasiliensia, vol. 11, no. 2, p. 65-78.         [ Links ]

BIANCHINI Jr., I., BITAR, AL. and CUNHA-SANTINO MB., 2006a. Crescimento de Egeria najas Planchon da lagoa do óleo em condições laboratoriais. In SANTOS, JE., PIRES, JSR. and MOSCHINI, LE., ed. Estudos integrados em ecossistemas - Estação Ecológica de Jataí. São Carlos: FAPESP/EdUFSCar. p. 99-111.         [ Links ]

BIANCHINI Jr., I., BITAR, AL., VERANI, JR. and PERET, AC., 2003. Experimento de mineralização aeróbia para ambientes aquáticos: determinação do número de réplicas. Acta Scientiarum Biological Sciences, vol. 25, no. 2, p. 245-252.         [ Links ]

BIANCHINI Jr., I. and CUNHA-SANTINO, MB., 2006. The effect of particles size on mineralization of Oxycaryum cubense (Poepp. & Kunth) Lye. Brazilian Journal of Biology, vol. 66, no. 2B, p. 641-650.         [ Links ]

BIANCHINI Jr., I., CUNHA-SANTINO, MB. and PERET, AM., 2006b. A mesocosm study of aerobic mineralization of seven aquatic macrophytes. Aquatic Botany, vol. 85, no. 2, p. 163-167.         [ Links ]

-, 2008. Oxygen demand during mineralization of aquatic macrophytes from an oxbow lake. Brazilian Journal of Biology, vol. 68, no. 1, p.61-67.         [ Links ]

BINI, LM., THOMAZ, SM., MURPHY, KJ. and CAMARGO, AFM., 1999. Aquatic macrophyte distribution in relation to water and sediment conditions in the Itaipu Reservoir Brazil. Hydrobiologia, vol. 415, p. 147-154.         [ Links ]

BITAR, AL. and BIANCHINI Jr., I., 2002. Mineralization assays of some organic resources of aquatic systems. Brazilian Journal of Biology, vol. 62, no. 4A, p. 557-564.         [ Links ]

BORSUK, ME. and STOW, CA. 2000. Bayesian parameter estimation in a mixed-order model of BOD decay. Water Research, vol. 34, no. 6, p. 1830-1836.         [ Links ]

BRUM, PR., FARJALLA, VF., GONÇALVES Jr., JF., SANTOS, AM., PÔRTO, MT., VIEIRA, EDR., FERREIRA, FM. and BIANCHINI JR., I., 1999. Aspects of uptake of dissolved oxygen in Cabiúnas and Imboassica lagoons (Macaé, RJ). Brazilian Achieves of Biology and Technology, vol. 42, no. 4, p. 433-440.         [ Links ]

CAMARGO, AFM. and ESTEVES, FA., 1995. Biomass and productivity of aquatic macrophytes in Brazilian lacustrine ecosystems. In TUNDISI, JG., BICUDO, CEM. and MATSUMURA-TUNDISI, T., Eds. Limnology in Brazil. Rio de Janeiro: ABC/SBL, p. 137-149.         [ Links ]

CAMARGO, AFM., PEZZATO, MM., HENRY-SILVA, GG. and ASSUMPÇÃO, AM., 2006. Primary production of Utricularia foliosa, Egeria densa and Cabomba furcata from rivers of the coastal plain of the State of São Paulo, Brazil. Hydrobiologia, vol. 570, no 1, p. 35-39.         [ Links ]

COOPER, WJ., ZIKA, RG., PETASNE, RJ. and FISCHER, AM., 1989. Sunlight-induced photochemistry of humic substances in natural waters: major reactive species. In SUFFET, IH. and MACCARTHY, P., Ed. Aquatic humic substances: influences on fate and treatment of pollutants. Washington: ACS. p. 333-362.         [ Links ]

CUNHA, MB. and BIANCHINI Jr., I., 1998. Mineralização aeróbia de Cabomba piauhyensis e Scirpus cubensis. Acta Limnologica Brasiliensia, vol. 10, no. 1, p. 81-91.         [ Links ]

CUNHA-SANTINO, MB. and BIANCHINI Jr., I., 2002. Estequiometria da decomposição aeróbia de galhos, cascas serapilheira e folhas. In ESPÍNDOLA, ELG., MAUAD, FF., SCHALCH, V., ROCHA, O., FELICIDADE, N. and RIETZLER, AC., Ed. Recursos hidroenergéticos: usos, impactos e planejamento integrado. São Carlos: Rima. p. 43-56.         [ Links ]

-, 2003a. Effect of initial concentration of dissolved oxygen in aeration coefficient for long-term experiments. Acta Scientiarum Biological Sciences, vol. 25, no. 2, p. 253-256.         [ Links ]

-, 2003b. Oxygen consumption during mineralization of organic compounds in water samples from a small sub-tropical reservoir (Brazil). Brazilian Achieves of Biology and Technology, vol. 46, no. 4, p. 723-729.         [ Links ]

-, 2004. Oxygen uptake during mineralization of humic substances from Infernão Lagoon (São Paulo, Brazil). Brazilian Journal of Biology, vol. 64, no. 3B, p. 583-590.         [ Links ]

CUNHA-SANTINO, MB., BIANCHINI Jr., I. and SERRANO, LEF., 2002. Aerobic and anaerobic degradation of tannic acid on water samples from Monjolinho Reservoir (São Carlos, SP - Brazil). Brazilian Journal of Biology, vol. 64, no. 2, p. 585-590.         [ Links ]

CUNHA-SANTINO, MB., GOUVÊA, SP., BIANCHINI Jr., I. and VIEIRA, AAH., 2008. Oxygen uptake during mineralization of photosynthesized carbon from phytoplankton of the Barra Bonita Reservoir: a mesocosm study. Brazilian Journal of Biology, vol. 68, no. 1, p. 123-130.         [ Links ]

DAGLEY, S., 1971. Catabolism of aromatic compounds by micro-organisms. In ROSE, AH. and WILKINSON, JF., ed. Advances in Microbial Physiology. New York: Academic Press. vol. 6, p. 1-46.         [ Links ]

DAVIS, ML. and CORNWELL, DA., 2008. Introduction to environmental engineering. 4th ed. Singapore: McGraw-Hill. 1008 p.         [ Links ]

DILLY, O., 2001. Microbial respiratory quotient during basal metabolism and after glucose amendment in soils and litter. Soil Biology and Biochemistry, vol. 33, no. 1, p. 117-127.         [ Links ]

ENRÍQUEZ, S., DUARTE, CM. and SAND-JENSEN, K., 1993. Patterns in decomposition rates among photosynthetic organisms: the importance of detritus C:N:P content. Oecologia, vol. 94, p. 457-471.         [ Links ]

FARJALLA, VF., MARINHO, CC. and ESTEVES, FA., 1999. The uptake of oxygen in the initial stages of decomposition of aquatic macrophytes and detritus from terrestrial vegetation in a tropical coastal lagoon. Acta Limnologica Brasiliensia, vol. 11, no. 2, p. 185-193.         [ Links ]

GESSNER, MO., 2000. Breakdown and nutrient dynamics of submerged Phragmites shoots in the littoral zone of temperate hardwater lake. Aquatic Botany, vol. 66, p. 9-20.         [ Links ]

HENRY-SILVA, GG., PEZZATO, MM., BENASSI, RF. and CAMARGO, AFM., 2001. Chemical composition of five species of aquatic macrophytes from lotic ecosystems of southem coast of the state of São Paulo (Brazil). Acta Limnologica Brasiliensia, vol. 13, no. 1, p. 11-17.         [ Links ]

HOHMANN, J. and NEELY, RK., 1993. Decomposition of Sparganium eurycarpum under controlled pH and nitrogen regimes. Aquatic Botany, vol. 46, no. 1, p. 17-33.         [ Links ]

KOMÍNKOVÁ, D., KUEHN, KA., BÜRSING, N., STEINER, D. and GESSNER, MO., 2000. Microbial biomass, growth, and respiration associated with submerged litter of Phragmites australis decomposing in a littoral reed stand of large lake. Aquatic Microbial Ecology, vol. 22, no. 3, p. 271-282.         [ Links ]

LEMOS, RMA. and BIANCHINI Jr., I., 1998. Estudo sobre a decomposição de Scirpus cubensis (CYPERACEAE) da lagoa do Infernão (SP) - Efeito do teor de nitrogênio e da quantidade de matéria orgânica. In Anais do VIII Seminário Regional de Ecologia. São Carlos: PPGERN/UFSCar. vol. 3, p. 1271-1287.         [ Links ]

LITTLE, ECS., 1979. Handbook of utilization of aquatic plants. Rome: FAO Fisheries. 176 p. Technical Paper, no. 187.         [ Links ]

MARCONDES, DAS., MUSTAFÁ, AL., and TANAKA, RH., 2003. Estudos para manejo integrado de plantas aquáticas no reservatório de Jupiá. In THOMAZ, SM. and BINI, LM., Ed.. Ecologia e manejo de macrófitas aquáticas. Maringá: EDUEM. p. 299-317.         [ Links ]

MARTINS, D., COSTA, NV., TERRA, MA. and MARCHI, SR., 2008. Caracterização da comunidade de plantas aquáticas de dezoito reservatórios pertencentes a cinco bacias hidrográficas do estado de São Paulo. Planta Daninha, vol. 26, no. 1, p. 17-32.         [ Links ]

MOPPER, K. and ZIKA, RG. 1987. Natural Photosensitizers in Sea Water: Riboflavin and Its Breakdown Products. In ZIKA, RG. and COOPER, WJ., Ed. Photochemistry of environmental aquatic systems. Washington: ACS. p. 174-190.         [ Links ]

NELSON, JW., KADLEC, JA. and MURKIN, HRO. 1990. Seasonal comparisons of weight loss for two types of Typha glauca Godr. leaf litter. Aquatic Botany, vol. 37, no. 4, p. 299-314.         [ Links ]

PRESS, WH., TEUKOLSKY, SA., VETTERLING, WT. and FLANNERY, BP., 1993. Numerical recipes in C: the art of scientific computing. New York: Cambridge University Press. 994 p.         [ Links ]

ROSE, AH., 1976. Chemical microbiology - An introduction to microbial physiology. London: Butterworths. 469 p.         [ Links ]

SHAPIRO, SS. and WILK MB., 1965. An analysis of variance test for normality (complete samples). Biometrika, vol. 52, no. 3-4, p. 591-611.         [ Links ]

SILVA, CJ., NOGUEIRA, F. and ESTEVES, FA., 1994. Composição química das principais espécies de macrófitas aquáticas do lago Recreio, Pantanal Matogrossense (MT). Revista Brasileira de Biologia = Brazilian Journal of Biology, vol. 54, no. 4, p. 617-622.         [ Links ]

STEINBERG, CEW., 2003. Ecology of humic substances in freshwaters. Berlin: Springer. 440 p.         [ Links ]

STRAŠKRABA, M., 1999. Retention time as a key variable of reservoir limnology. In TUNDISI, JG. and STRAŠKRABA, M., Ed. Theoretical reservoir ecology and its applications. São Carlos: International Institute of Ecology, Brazilian Academy of Sciences and Backhuys Publishers. p. 385-410.         [ Links ]

SWIFT, MJ., HEAL, DW. and ANDERSON, JM., 1979. Studies in ecology. Decomposition in terrestrial ecosystems. Oxford: Blackwell. 371 p.         [ Links ]

TANAKA, RH., CARDOSO, LR., MARTINS, D., MARCONDES, DAS. and MUSTAFÁ AL., 2002. Ocorrência de plantas aquáticas nos reservatórios da Companhia Energética de São Paulo. Planta Daninha, vol. 20, p. 99-111.         [ Links ]

THOMAZ, SM., PAGIORO, TA., BINI, LM. and MURPHY, KJ., 2006. Effect of reservoir drawdown on biomass of three species of aquatic macrophytes in a large sub-tropical reservoir (Itaipu, Brazil). Hydrobiologia, vol. 570, no. 1, p. 53-59.         [ Links ]

THOMAZ, SM., PAGIORO, TA., BINI, LM. and ROBERTO, MC., 2005. Ocorrência e distribuição de macrófitas aquáticas em reservatórios. In RODRIGUES L., THOMAZ SM., GOMES, LC. and AGOSTINHO, AA., Ed. Biocenoses em reservatórios: padrões espaciais e temporais. São Carlos: Rima. p. 281-292.         [ Links ]

TUNDISI, JG. and MATSUMURA-TUNDISI, T., 2003. Integration of research and management in optimizing multiple uses of reservoirs: the experience in South America and Brazilian case studies. Hydrobiologia, vol. 500, no. 1-3, p. 231-242.         [ Links ]

United States Environmental Protection Agency - USEPA, 1985. Rates, constants, and kinetics formulations in surface water quality modeling. 2nd ed. Athens: U.S. Government Printing Office. 455 p. EPA/600/3-85/040.         [ Links ]

Universidade Federal de São Carlos - UFSCar/CBA, 2008. Plano de controle ambiental UHE Piraju: monitoramento da qualidade de águas superficiais e monitoramento e controle das macrófitas aquáticas e de florações de algas. São Carlos: UFSCar. Relatório Técnico, ago/2003 - ago/2007.         [ Links ]

VOLLENWEIDER, RA., 1968. Scientific fundamentals of the eutrophication of lakes and flowing waters, with particular reference to nitrogen and phosphorous as factors in eutrophication. Paris: Organization for Economic Cooperation and Development. 192 p. DAS/CSI/68.27.         [ Links ]

WESTLAKE, DF., 1965. Some basic data for investigations of the productivity of aquatic macrophytes. Memorie dell Instituto Italiano di Idrobiologia Dott Marco de Marchi, vol. 18, p. 229-248.         [ Links ]

WETZEL, RG., 1990. Detritus, macrophytes and nutrient cycling in lakes. Memorie dell Instituto Italiano di Idrobiologia Dott Marco de Marchi, vol. 47, p. 233-249.         [ Links ]

-, 2001. Limnology. Lake and river ecosystems. 3rd ed. New York: Academic Press. 1006 p.         [ Links ]

WETZEL, RG. and LIKENS, GE., 1979. Limnological Analyses. Philadelphia: Saunders. 357 p.         [ Links ]

XIE, YH., YU, D. and REN, B., 2004. Effects of nitrogen and phosphorus availability on the decomposition of aquatic plants. Aquatic Botany, vol. 80, no. 1, p. 29-37.         [ Links ]



Received May 21, 2010
Accepted June 24, 2010
Distributed February 28, 2011



* e-mail:,

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License