The use of indices for evaluating the periphytic community in two kinds of substrate in Imboassica Lagoon, Rio de Janeiro, Brazil

Abstract

Biological indices based on the biomass (dry weight, ash content, and chlorophyll-a) of the periphyton in a natural (submersed leaves of Typha domingensis Pers) and in an artificial (plastic hoses) substrate were compared, in experiments performed in summer and winter, in two sampling stations of Imboassica Lagoon, Macaé, Rio de Janeiro. The periphytic community exhibited low biomass at the beginning and end of the experiments, and moderate biomass in the intermediate period of the experiment, whatever the kind of substrate, sampling station, and season. In both seasons, there was a spatial variation regarding the degree of trophy of the periphyton, due to the difference of nutrient availability among the sampling stations. The alternation of inorganic and organic periphyton, as well as of their heterotrophic, heteroautotrophic, auto-heterotrophic and, autotrophic character was due to changes in the abiotic factors of the sampling periods. The Lakatos index proved more sensitive than the Autotrophic Index to variations in the composition of the periphytic community.

Periphyton dry mass, ash content, and chlorophyll content on natural substrata in three water bodies of different trophy

“…A relatively high contribution of inorganic material in the periphyton on reeds in Lake Gardno and in Szczecin Lagoon could be explained by a high concentration of mineral particles in the water column, resulting from sediment resuspension by strong wind mixing in these shallow water bodies, or by high suspended material content in the rivers flowing into them. A similar situation was observed in Imboassica Lagoon in Brazil (Fernandes, Esteves 2003) and in shallow Lake Kis-Balaton and Kiskore Reservoir in Hungary (Kiss et al 2003). Organicinorganic (III) or even organic (IV) status of reed periphyton in Lake Gardno was noted in summer, which is a more stable period, but also in autumn.…”

“…Similarly, the periphyton which developed on the submerged stems of the common reed in oligotrophic Lake Maarsseveen in Holland was of low mass (Meulemans, Heinis 1983), as in eutrophic and shallow Lake Kis-Balaton and Kiskore Reservoir in Hungary (Kiss et al 2003). Periphyton of Typha domingensis in Imboassica Lagoon in Brazil was classified as low to average dry mass (Fernandes, Esteves 2003). Imboassica Lagoon and Szczecin Lagoon share similar conditions.…”

“…The mass of periphytic organic matter can be estimated gravimetrically on the basis of dried and combusted samples, but with this method it is impossible to estimate the proportion of autotrophs, heterotrophs and detritus. A partial solution to this problem can be to use chlorophyll-a content measurements as an indicator of the proportion of autotrophs and ash content analysis as an indicator of the proportion of inorganic matter (Fernandes and Esteves 2003). Determining periphytic biomass is also complicated because of the large diversity of natural substrata.…”

Diatomáceas perifíticas em Polygonum hydropiperoides Michaux, reservatório do Passaúna, Região Metropolitana de Curitiba, Paraná, Brasil

“…Para o Brasil, destaca-se o uso das diatomáceas epilíti-cas como bioindicadoras da qualidade da água (Rodrigues & Lobo 2000, Oliveira et al 2001, Lobo et al 2002Salomoni et al 2006, Hermany et al 2006) e das epifíticas nas contribuições de Souza & Moreira-Filho (1999 a, b) em bancos de macrófi tas da Lagoa Bonita (DF); Rodrigues & Bicudo (2001) em um gradiente lêntico-lótico na divisa entre Paraná e Mato Grosso do Sul; Fernandes & Esteves (2003), na lagoa Imboassica (RJ); Ludwig et al (2004) em lagoas do Sistema Hidrológico do Taim (RS) e Ferrari et al (2007) em igarapés da Amazônia Central.…”

Efeitos da irradiância e da composição espectral da luz sobre o estabelecimento e desenvolvimento de comunidades de macroalgas lóticas em substratos artificiais

“…Exemplos de estudos ecológicos envolvendo a análise de comunidades de produtores associadas a substratos artificiais em ambientes lóticos são relativamente comuns na literatura mundial (Biggs, 1988;Liaw & Maccrimmon, 1978;Leland & Carter, 1985;Clifford et al, 1992;Barbee, 2005). Vários estudos semelhantes são encontrados para rios e riachos brasileiros (Lobo & BuselatoToniolli, 1985;Oliveira et al, 2002;Mendes & Barbosa, 2002;Fernandes & Esteves, 2003;Skinner & Coutinho, 2005;Lobo et al, 2004). Entretanto, a absoluta maioria destas investigações foi dedicada a comunidades perifíticas (sensu Wetzel, 1983), envolvendo a análise dos seus componentes microscópicos.…”