Material aderido à macrófitas aquáticas submersas enraizadas com arquiteturas de ramo distintas e em diferentes tipos de água
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Data
2018-02-15
Autores
Silveira, Aline Flores [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Uma forma de compreender e caracterizar a importância ecológica das macrófitas aquáticas é através do delineamento das diferenças morfológicas das plantas e da quantificação de sua complexidade. As macrófitas podem atuar como estruturas retentoras de partículas em suspensão controlando a quantidade de material em suspensão na água, além de servirem como substrato para a colonização e crescimento do perifíton. Neste estudo foram utilizadas duas macrófitas aquáticas: Cabomba furcata Schult. & Schult. e Egeria densa Planch, encontradas na Bacia Hidrográfica do Rio Itanhaém. O objetivo geral foi avaliar se a capacidade de retenção de material varia entre macrófitas aquáticas com arquitetura de ramo distintas e se há variação na capacidade de retenção de material de C. furcata em rios com características limnológicas distintas. A coleta foi realizada em duas áreas no Rio Branco (A e B) e uma área no Rio Preto (C). Amostras de água e sedimento foram coletadas para análises limnológicas. Ramos de C. furcata e E.densa no Rio Branco e ramos de C. furcata no rio Preto foram coletados para a descrição de sua arquitetura e para a quantificação do material aderido. Em laboratório foram realizadas análises das variáveis limnológicas e do conteúdo de nitrogênio e fósforo total na biomassa das macrófitas e no material aderido. Para a caracterização ambiental das áreas de coleta, foram comparados os resultados das variáveis limnológicas medidas em cada área estudada. Para testar a diferença significativa entre as áreas A e C, foi aplicado o teste-t (p<0,05) às variáveis limnológicas. O teste Mann-Whitney foi aplicado às variáveis de C. furcata, E. densa e às variáveis do material aderido coletadas no Rio Branco. O mesmo teste foi utilizado para a comparação entre C. furcata e material aderido em rios distintos. Os valores das variáveis limnológicas do Rio Branco foram similares nas áreas A e B. A quantidade de material em suspensão na água foi maior (p<0,001) no Rio Branco quando comparado ao Rio Preto. Porém, a matéria orgânica contida no sedimento do Rio Branco foi menor (p: 0,005) do que a contida no sedimento do Rio Preto. Por outro lado, os teores de nitrogênio e fósforo total da água e do sedimento não apresentaram diferença significativa. C. furcata e E.densa apresentaram diferenças na arquitetura do ramo (p<0,05), indicando uma maior complexidade do ramo para C. furcata. C. furcata de rios distintos apresentou pequenas variações na sua morfologia. Apesar da C. furcata apresentar maior área total do ramo do que E. densa, a quantidade de material aderido por ramo de C. furcata foi menor (p: 0,001). A quantidade de material aderido à C. furcata no Rio Branco foi menor (p:0,0251) do que à C. furcata no Rio Preto. De modo geral, a quantidade de material aderido às macrófitas em ambientes lóticos pode ser positiva, negativa ou neutra às macrófitas e pode estar associada à complexidade da arquitetura do ramo desses organismos. Todavia, neste estudo a relação entre as espécies de macrófitas aquáticas avaliadas e o material aderido é neutra. Desta maneira, essas espécies podem ser consideradas apenas como um substrato para o acúmulo de material aderido, pois não foram encontradas relações positivas ou negativas com esse material.
One way to understand and characterize the ecological importance of aquatic macrophytes is to delineate the morphological differences of plants and quantify its complexity. Aquatic macrophytes can act as suspended particulate retentive structures by controlling the amount of suspended material on the water and serve as a substrate for the colonization and growth of the periphyton. Two aquatic macrophytes were used in this study: Cabomba furcata Schult. & Schult. and Egeria densa Planch, bouth are found in the Itanhaém River Basin. The aim of this research was to evaluate if the retention capacity of material varies between aquatic macrophytes with different branch architecture and if there is variation in the material retention capacity of Cabomba furcata in rivers with different limnological characteristics. The sample were collected in two areas in Branco River (A and B) and one area in Preto River (C). Water and sediment samples were collected for limnological analysis. C. furcata and E. densa branches were collected in Branco River for the description of the branch architecture and for the quantification of the attached material. In the same way, branches of C. furcata were collected in Preto River for the same purpose. In laboratory, analyzes of the limnological variables, the nitrogen and total phosphorus content in the macrophytes biomass and the attached material were performed. For the environmental characterization of the study areas, the results of the limnological variables measured in each studied area were compared. To test the significant difference between areas A and C, the t-test (p <0.05) was applied to the limnological variables. The Mann-Witney test was used for the variables of C. furcata, E. densa and attached material collected in Rio Branco. The same test was applied for the comparison between C. furcata and attached material from different rivers. The values of the limnological variables of Branco River were similar in areas A and B. The amount of suspended material in water was higher (p <0.001) in Branco River when compared to Preto River. However, the organic matter contained in Branco River sediment was lower (p: 0.005) than the one contained in Preto River sediment. On the other hand, nitrogen and total phosphorus contents of water and sediment did not present a significant difference. C. furcata and E. densa presented differences in the branch architecture (p <0.05), indicating a greater branch complexity for C. furcata. C. furcata of distinct rivers showed small variations in its morphology. Although C. furcata had a larger branch total area than E. densa, the amount of attached material per branch of C. furcata was lower (p: 0.001). The amount of attached material to C. furcata in Branco River was lower. In general, the amount of attached material on the macrophytes in lotic environments may be positive, negative or neutral to the macrophytes and may be associated with the complexity of the macrophytes architecture. However, in this study, the relationship between the species of aquatic macrophytes evaluated and the attached material is neutral, so that these species can only be considered as a substrate for the accumulation of attached material, not having a positive or negative relation with this material.
One way to understand and characterize the ecological importance of aquatic macrophytes is to delineate the morphological differences of plants and quantify its complexity. Aquatic macrophytes can act as suspended particulate retentive structures by controlling the amount of suspended material on the water and serve as a substrate for the colonization and growth of the periphyton. Two aquatic macrophytes were used in this study: Cabomba furcata Schult. & Schult. and Egeria densa Planch, bouth are found in the Itanhaém River Basin. The aim of this research was to evaluate if the retention capacity of material varies between aquatic macrophytes with different branch architecture and if there is variation in the material retention capacity of Cabomba furcata in rivers with different limnological characteristics. The sample were collected in two areas in Branco River (A and B) and one area in Preto River (C). Water and sediment samples were collected for limnological analysis. C. furcata and E. densa branches were collected in Branco River for the description of the branch architecture and for the quantification of the attached material. In the same way, branches of C. furcata were collected in Preto River for the same purpose. In laboratory, analyzes of the limnological variables, the nitrogen and total phosphorus content in the macrophytes biomass and the attached material were performed. For the environmental characterization of the study areas, the results of the limnological variables measured in each studied area were compared. To test the significant difference between areas A and C, the t-test (p <0.05) was applied to the limnological variables. The Mann-Witney test was used for the variables of C. furcata, E. densa and attached material collected in Rio Branco. The same test was applied for the comparison between C. furcata and attached material from different rivers. The values of the limnological variables of Branco River were similar in areas A and B. The amount of suspended material in water was higher (p <0.001) in Branco River when compared to Preto River. However, the organic matter contained in Branco River sediment was lower (p: 0.005) than the one contained in Preto River sediment. On the other hand, nitrogen and total phosphorus contents of water and sediment did not present a significant difference. C. furcata and E. densa presented differences in the branch architecture (p <0.05), indicating a greater branch complexity for C. furcata. C. furcata of distinct rivers showed small variations in its morphology. Although C. furcata had a larger branch total area than E. densa, the amount of attached material per branch of C. furcata was lower (p: 0.001). The amount of attached material to C. furcata in Branco River was lower. In general, the amount of attached material on the macrophytes in lotic environments may be positive, negative or neutral to the macrophytes and may be associated with the complexity of the macrophytes architecture. However, in this study, the relationship between the species of aquatic macrophytes evaluated and the attached material is neutral, so that these species can only be considered as a substrate for the accumulation of attached material, not having a positive or negative relation with this material.
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Palavras-chave
Complexidade do ramo, Cabomba furcata, Egeria densa, Água branca, Água preta, Branch complexity, White water, Black water