Annual and short-term variability in primary productivity by phytoplankton and correlated abiotic factors in the Jurumirim Reservoir (São Paulo, Brazil)

Abstract

ABSTRACTthe annual variability of the photosynthetic production (PP) by phytoplankton in the lacustrine zone of the Jurumirim reservoir (São Paulo, Brazil) was evaluated in a three-year study to identify recurrent patterns and their causes. Variability in PP was measured daily during two periods of the year (the dry and rainy seasons). An analysis of the PP data failed to identify a recurrent pattern, since the PP values showed no correlation with hydrological factors (rainfall, water level and discharge, and washout) nor, apparently, with the water's nutritional conditions. A principal component analysis revealed that the PP and assimilation ratio were higher when the Po 4 3-and n-nh 4 + contents were low and the z eu /z miX ratios were at their highest. Areal primary productivity can be predicted based on the ratio between the maximum volumetric productivity and the coefficient of vertical extinction of light. however, the biomass integrated for z eu was a poor predictor of areal primary productivity. no correlation was found between water temperature and areal and maximum volumetric productivity. thus, the three-year PP study indicated that the variability pattern is typically chaotic. As for the short-term measurements, the PP was found to be higher in the dry season than in the rainy, although both seasons showed an areal PP variability of 35 to 40%. this pattern was attributed to the daily variation in the nutritional conditions and the magnitude of light penetrating through the water, combined with the mixing of phytoplanktonic cells. A comment about the relationship between primary production by phytoplankton and fish yield is also briefly discussed here.Keywords: primary productivity, phytoplankton, variability, reservoir, light, nutrients. RESUMOVariabilidade anual e de curto prazo na produtividade primária pelo fitoplâncton e fatores abióticos correlatos na Represa de Jurumirim (São Paulo, Brasil)A variabilidade anual da produção fotossintética (PP) pelo fitoplâncton na zona da barragem da represa de Jurumirim (São Paulo, Brasil) foi medida após um estudo no período de três anos sucessivos, com o objetivo de identificar padrões recorrentes e suas causas. medidas da variabilidade da PP em escala diária foram obtidas em dois períodos do ano (estações seca e chuvosa). nenhum padrão recorrente foi verificado nos dados de PP, visto não haver relação de sua variabilidade com nenhum fator hidrológico (precipitação, nível e vazão de água e washout) nem, aparentemente, com as condições nutritivas da água. A análise de componentes principais revelou que a PP e a taxa de assimilação foram mais elevadas na época do ano em que o conteúdo de Po 4 3-e n-nh 4 + foi mais baixo e quando as razões z eu /z miX foram mais elevadas. A produtividade primária/área pode ser estimada pela razão entre a produtividade volumétrica máxima e o coeficiente de extinção vertical da luz. entretanto, a biomassa integrada na z eu foi um pobre preditor da produtividade primária/área. nenhuma correlação foi encontrada entre a temperatura d...

Phytoplankton assemblages in lateral lagoons of a large tropical reservoir

“…Positive correlation among phytoplankton assemblages and nutrient concentration during the high water period was also observed by other authors in the upper Paraná River basin (Train and Rodrigues, 1998;Rodrigues and Bicudo, 2001) and in the Paranapanema River Basin (Nogueira, 2000;Bittencourt-Oliveira, 2002;Henry et al, 2006a;Ferrareze and Nogueira, 2006;Bicudo et al, 2006;Nogueira et al, 2010).…”

“…This structural characteristic seems to be a consistent pattern for the phytoplankton assemblages in the floodplain lagoons of the high Paraná River basin (Rodrigues and Bicudo, 2001). High richness of Bacillaryophyceae and Chlorophyceae has also been observed for three lateral lagoons of the upper Paranapanema River basin (Jurimirim reservoir tail zone) (Henry et al, 2006a), and for the Paranapanema River reservoir cascade (Nogueira et al, 2010). Another factor influencing the high richness of Zygnemaphyceae in the lateral lagoons is the contribution of the periphyton assemblages, due to the high abundance of different species of aquatic macrophytes, microhabitats highly propitious for the development of attached algae (Tundisi and Matsumura-Tundisi, 2008).…”

Ecological Features of Large Neotropical Reservoirs and Its Relation to Health of Cage Reared Fish

“…Lastly, it was studied Chavantes reservoir, that is also a storage plant in Paranapanema River, operating since 1970 in its middle stretch at 474 m above sea level. This reservoir area is 400 km 2 , total volume of 8,800 x 10 6 m 3 , maximum depth 80 m, residence time 281 days, mean outflow 322 m 3 s -1 , and seasonal water level oscillation is more than 3 m (Nogueira et al, 2006). The three reservoirs are in a region with annual precipitation above 1,500 mm, and with a rainy season from September to February and dry season from March to August.…”

“…Various studies in hydrographic sub-basins of Tietê and Paranapanema Rivers show that this index usually varies. As an example, the index varies between oligotrophic to mesotrophic state for upper and middle Paranapanema stretches (Nogueira et al 2006), and also between oligotrophic to eutrophic for Tietê River (Barbosa et al 1999;Moretto et al, 2008;Tundisi & Straškraba, 1999). These variations are mainly due to anthropogenic actions, such as occupation of lands for agriculture, livestock, increasing urbanization due to growth of human population, and emissions of organic wastes (Tundisi, 2005).…”

Dinâmica do fitoplâncton e assimilação de nitrato, amônio e ureia em reservatórios subtropicais com diferentes graus de trofia

“…Em reservatórios tropicais, diversos fatores como a RSFA disponível (HENRY et al, 2006;CUNHA & CALIJURI, 2011), o TDH (BEAVER et al 2013, temperatura (MCCARTHY et al, 2009), períodos de estratificação e de mistura da coluna de água (CALIJURI et al, 2002), parecem ser importantes para regular a comunidade fitoplanctônica. Especialmente em ambientes com maior estado trófico (HUSZAR et al, 2006 Não houve variação significativa entre as profundidades para a maioria das variáveis, apenas para RSFA e para a assimilação de ureia.…”