RCAAP Repository
Assessment of mutagenicity and cytotoxicity of Solanum paniculatum L. extracts using in vivo micronucleus test in mice
Solanum paniculatum L. is a plant species widespread throughout tropical America, especially in the Brazilian Savanna region. It is used in Brazil for culinary purposes and in folk medicine to treat liver and gastric dysfunctions, as well as hangovers. Because of the wide use of this plant as a therapeutic resource and food, the present study aimed at evaluating the mutagenic and cytotoxic effects of S. paniculatum ethanolic leaf and fruit extracts using the mouse bone marrow micronucleus test. Our results indicate that neither S. paniculatum ethanolic leaf extract nor its ethanolic fruit extract exhibited mutagenic effect in mice bone marrow; however, at higher doses, both extracts presented cytotoxic activity.
2010
Vieira,PM. Santos,SC. Chen-Chen,L.
Urinary parameters of Trichechus inunguis (Mammalia, Sirenia): reference values for the Amazonian Manatee
The Amazonian manatee, Trichechus inunguis (Natterer 1883) is endemic to the Amazon Basin and is currently considered a vulnerable species. In order to establish normality ranges of urinary parameters to help monitor the health of this species in captivity, chemical urinalyses were performed on twelve males and nine females of various age groups. Urine was collected once a month for twelve months in the tanks just after being drained, by placing stainless steel containers under the genital slit of females and applying abdominal massages to males in order to stimulate urination. Quantitative data of glucose, urea, creatinine, uric acid and amylase levels were obtained using colorimetric spectrophotometry. Dip strips were also useful for routine analyses, despite only providing qualitative results. Normal range to glucose levels, regardless of sex or age class, was 3.0 to 3.6 mg.dL-1, coinciding with qualitative values of glucose measured by dip strips. Statistical differences observed in some parameter levels suggest that some urine parameters analysed must take into consideration the sex and the age class of the animal studied, being these differences less remarkable in creatinine and amylase levels. To this last one, statistical difference was detected only in the calve's urine (7.0 to 11.5 mg.dL-1) compared to other age classes samples (4.1 to 5.3 mg.dL-1). The results presented here may be used as comparative data in future research on urinalysis in related species.
2010
Pantoja,TMA. Rosas,FCW. Da Silva,VMF. Dos Santos,AMF.
Energy metabolism and fasting in male and female insectivorous bats Molossus molossus (Chiroptera: Molossidae)
Metabolic adaptations induced by 24 and 48 hours of fasting were investigated in male and female insectivorous bats (Molossus molossus Pallas, 1766). For this purpose, plasma glucose, non esterified fatty acids (NEFA), glycogen, protein and lipids concentrations in liver and muscles were obtained. Data presented here demonstrate that fed bats showed plasma glucose levels similar to those reported for other mammal species. In response to fasting, glycemia was decreased only in 48 hours fasted females. Plasma NEFA levels were similar in both sexes, and did not exhibit any changes during fasting. Considering the data from energy reserve variations, fed females presented an increased content of liver glycogen as well as higher breast muscle protein and limbs lipids concentrations, compared to fed males. In response to fasting, liver and muscle glycogen levels remained unchanged. Considering protein and lipid reserves, only females showed decreased values following fasting, as seen in breast, limbs and carcass lipids and breast muscle protein reserves, but still fail to keep glucose homeostasis after 48 hours without food. Taken together, our data suggest that the energy metabolism of insectivorous bats may vary according to sexual differences, a pattern that might be associated to different reproduction investments and costs between genders.
2010
Freitas,MB. Goulart,LS. Barros,MS. Morais,DB. Amaral,TS. Matta,SLP.
Biologic aspects of different species of Pachodynerus (Hymenoptera; Vespidae; Eumeninae)
The aim of this study was to compare biological aspects of the Pachodynerus species occurring in the Parque Municipal das Araucárias, Guarapuava, Paraná, Southern Brazil. It was carried from December 2001 to December 2004. Forty one nests belonging to 5 species were collected, of which 17 Pachodynerus guadulpensis, 15 Pachodynerus sp., 1 Pachodynerus argentinus, 1 Pachodynerus ca guadulpensis and 7 Pachodynerus nasidens. The nesting activity of Pachodynerus sp., P. argentinus and P. guadulpensis occurred in similar periods, from December to March, with the exception of P.guadulpensis, that built one nest in October. Pachodynerus ca guadulpensis nested in March and P. nasidens from January to April. The nests of Pachodynerus species present a very similar architecture, comprising a linear series of cylindrical cells that fit perfectly into each other forming a continuous tube. With these results we were able to conclude that, even though Pachodynerus species present common characteristics, such as nest architecture, nesting activities and habitats in which they occur, the used resources, mortality rates, etc., vary among groups of species occurring in different regions.
2010
Buschini,MLT. Buss,CE.
Cytogenetic analysis of the 18S, 5S rDNA and B chromosome of Iheringichthys labrosus (Lütken, 1874) (Siluriformes, Pimelodidae)
Cytogenetic analyses of the location of 18S and 5S ribosomal DNAs, and the base composition of B chromosomes of Iheringichthys labrosus from Tibagi River, Paraná, Brazil, are provided. AgNORs were observed in the terminal position on the long arm of a subtelocentric chromosome pair. CMA3-positive staining was observed in some chromosomes, which besides being associated with NORs, were all DAPI-negative. Chromosome B showed a strong fluorescence with CMA3. The concomitant use of 18S and 5S rDNA probes using the FISH technique revealed 18S ribosomal cistrons in a pair of subtelocentric chromosomes, on the long arm in the terminal position, coinciding with the AgNOR. The 5S sites were found in another subtelocentric pair, on the long arm in the interstitial region, near the centromere. The findings of the present study suggest that, although there are some more conserved cytogenetic characteristics, populations of I. labrosus may show their own characteristics.
2010
Carvalho,RA. Laudicina,A. Giuliano-Caetano,L. Martins-Santos,IC. Dias,AL.
First record of Trichodina heterodentata (Ciliophora: Trichodinidae) from channel catfish, Ictalurus punctatus cultivated in Brazil
This study characterises morphologically Trichodina heterodentata Duncan, 1977 from channel catfish, Ictalurus punctatus (Rafinesque, 1818) in the State of Santa Catarina, Brazil. Body and gill smears were air-dried at room temperature, impregnated with silver nitrate and/or stained with Giemsa. Ten characteristics were selected to compare the present material with other morphological characterisations of T. heterodentata. Prevalence rate was 100%, mean intensity 89,333.70 (3,125 to 299,100 parasites per host). Trichodina heterodentata was considered medium-sized trichodinid with mean body diameter 59.4 ± 8.5 μm, denticulate ring 38.5 ± 4.5 μm, adhesive disc 60.2 ± 6.7 μm diameter and 24.4 ± 1.6 denticles. In relation to previous reports of T. heterodentata this material resembles in 90% of the analysed characters. This work confirms the biometrical variation that exists in the different populations of T. heterodentata. A list of hosts and comparative measurements of T. heterodentata are presented and the channel catfish is considered a new host.
2010
Martins,ML. Marchiori,N. Nunes,G. Rodrigues,MP.
Morphology of the larval shell of three oyster species of the genus Crassostrea Sacco, 1897 (Bivalvia: Ostreidae)
In this study we describe the morphology of the larval shell of three oyster species of Crassostrea genus. Two species, C. rhizophorae and C. brasiliana, are native to the Brazilian coast, and C. gigas is an introduced species. Samples of laboratory reared larvae, obtained through artificial fertilisation, were collected at intervals during the cultivation process for analysis using Scanning Electron Microscopy (SEM). Prodissoconch morphology was observed in relation to the presence, position, form and number of teeth in the three larval stages: D-shaped larva, umbo larva and pediveliger. Characteristic of D-shaped larvae of C. rhizophorae was the total absence of teeth in the provinculum area while C. brasiliana and C. gigas had two anterior and two posterior teeth in each valve. In the umbo larval phase, the three species had the same number of teeth in each valve: two posterior and two anterior teeth in the right valve and three posterior and three anterior in the left valve. In the pediveliger stage the three species could be differentiated by the number of anterior teeth of the right valve: C. rhizophorae had two teeth, C. brasiliana one tooth and C. gigas three teeth.
2010
Christo,SW. Absher,TM. Boehs,G.
Sexual stages of the female portion in the scallop Nodipecten nodosus (Linné, 1758) and astaxanthin quantity in each stage
This work describes the gametogenic cycle of the scallop Nodipecten nodosus kept in a culture system. To this end, during one year, samples were taken from the broodstocks every 30 days to be submitted to macroscopic and microscopic analyses and to measure the amount of astaxanthin. To perform the microscopic evaluation, 5 μ slices from the median portion of the female part of the gonad were submitted to the pattern methodology for histological analyses with paraffin and HE coloration. The remaining portion of the female gonad was lyophilised to extract and quantify the levels of astaxanthin using HPLC. The microscopic analyses revealed four well defined stages for the reproductive cycle. Analyses of data taken throughout the year indicated preferential spawning periods from December to January and from July to September. The astaxanthin analyses showed higher amounts of this carotenoid during the advanced pre-spawning and the initial spawning periods than during gametogenesis, initial pre-spawning, advanced spawning, and the spent stages. According to these results, it was possible to establish a descriptive table of the sexual stages of the female portion of the gonad and the amount of astaxanthin in the sexual stage of the scallop Nodipecten nodosus.
2010
Sühnel,S. Lagreze,F. Bercht,M. Ferreira,JF. Carneiro-Schaefer,AL. Magalhães,ARM. Maraschin,M.
Fish consumption, contaminants and sudden unexpected death in epilepsy: many more benefits than risks
People with epilepsy have an increased risk of dying prematurely and the most common epilepsy-related category of death is sudden unexpected death in epilepsy (SUDEP). SUDEP is mainly a problem for patients with chronic uncontrolled epilepsy. The ultimate goal of research in SUDEP is to develop new methods to prevent it and actions other than medical and surgical therapies that could be very useful. Nutritional aspects, i.e., omega-3 fatty acids deficiency, could have an interesting role in this scenario. Some animal and clinical studies have suggested that omega-3 fatty acids could be useful in the prevention and treatment of epilepsy and hence SUDEP. It has been ascertained that the only foods that provide large amounts of omega-3 are seafood (fish and shellfish); however, some fish are contaminated with methylmercury, which may counteract the positive effects of omega-3 fatty acids. Our update review summarises the knowledge of the role of fish consumption on epilepsy research.
2010
Scorza,FA. Cysneiros,RM. Arida,RM. Terra,VC. Machado,HR. Rabello,GMM. Albuquerque,M. Cavalheiro,EA.
Records on floral biology and visitors of Jacquemontia montana (Moric.) Meisn. (Convolvulaceae) in Mucugê, Bahia
We present the first records on pollination biology of Jacquemontia montana (Moric.) Meisn. (Convolvulaceae), a widespread climber in the Chapada Diamantina. Our objectives were to (1) characterise flower morphology and biology of J. montana; (2) sample flower visitors and (3) make inferences about potential pollinators, based on foraging behaviour. Observations and sampling were performed on two patches from 8:00 AM to 3:30 PM, May 15th to 16th, 2007. The corolla is bowl shaped, pentamerous, gamopetalous, actinomorphic, and yellow, with a mean diameter of 22.43 ± 1.81 mm, the depth being variable during flower phases. Stigma receptivity lasted from 8:00 AM-3:30 PM and pollen viability from 9:00 AM-3:30 PM Pollen. showed great decline in number but not in viability during anthesis. Nectarivorous (Coleoptera, Diptera, Hymenoptera) and herbivorous (Orthoptera) insects were found on the flowers. Both male and female bees (Dialictus spp., Robertson 1902) were the most frequent flower visitor. The bees' behaviour, and time spent on flowers, varied according to the resource gathered (i.e., pollen or nectar). The Dialictus species are likely to be the main pollinator of J. montana, considering the frequency, contact with reproductive parts, and carrying only J. montana pollen spread over the ventral part of the thorax, abdomen and legs. Although not quantified, nectar may still be available in the afternoon, considering the behaviour of bees on flowers during this time. Pollen:ovule ration that was1.200:4, suggests facultative xenogamy.
2010
Silva,FO. Kevan,SD. Roque,N. Viana,BF. Kevan,PG.
Histopathology and the lethal effect of Cry proteins and strains of Bacillus thuringiensis Berliner in Spodoptera frugiperda J.E. Smith Caterpillars (Lepidoptera, Noctuidae)
Among the phytophagous insects which attack crops, the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera, Noctuidae) is particularly harmful in the initial growth phase of rice plants. As a potential means of controlling this pest, and considering that the entomopathogen Bacillus thuringiensis Berliner demonstrates toxicity due to synthesis of the Cry protein, the present study was undertaken to evaluate this toxic effect of B. thuringiensis thuringiensis 407 (pH 408) and B. thuringiensis kurstaki HD-73 on S. frugiperda. The following method was used. Both bacterial strains were evaluated in vitro in 1st instar S. frugiperda caterpillars, by means of histopathological assays. The Cry1Ab and Cry1Ac proteins, codified by the respective strains of B. thuringiensis, were evaluated in vivo by bioassays of 1st instar S. frugiperda caterpillars in order to determine the Mean Lethal Concentration (LC50). The results of the histopathological analysis of the midget of S. frugiperda caterpillars demonstrate that treatment with the B. thuringiensis thuringiensis strain was more efficient, because the degradations of the microvilosities started 9 hours after treatment application (HAT), while in the B. thuringiensis kurstaki the same effect was noticed only after 12 HAT. Toxicity data of the Cry1Ab and Cry1Ac proteins presented for the target-species LC50 levels of 9.29 and 1.79 μg.cm-2 respectively. The strains and proteins synthesised by B. thuringiensis thuringiensis and B. thuringiensis kurstaki are effective in controlling S. frugiperda, and may be used to produce new biopesticides or the genes may be utilised in the genetic transformation of Oryza sativa L.
2010
Knaak,N. Franz,AR. Santos,GF. Fiuza,LM.
Ecohydrology for compensation of Global Change
Water in the XXI century has become the primary factor for sustainable development, eradication of poverty and reversal of ecosystem degradation. Increasing water demand for agriculture and urbanisation, combined with pollution, eutrophication and amplification of the stochastic character of climatic processes, increases water limitations for ecosystems and societies. The transdisciplinary science of Ecohydrology, which has been developed in the framework of the International Hydrological Programme of UNESCO, provides a systemic approach, to regulate hydrology-ecosystem-society interplay towards: 1) slowing down the transfer of water from the atmosphere to the sea, still considered as a priority to reduce the severity of floods and droughts impact; 2) reducing input and regulating the allocation of excess nutrients and pollutants to aquatic ecosystems, toward reversing ecosystems degradation and improvement of human well being; and 3) harmonisation of ecosystem potential with societal needs within the framework of IWRM.
2010
Zalewski,M.
Brazilian Atlantic Forest lato sensu: the most ancient Brazilian forest, and a biodiversity hotspot, is highly threatened by climate change
After 500 years of exploitation and destruction, the Brazilian Atlantic Forest has been reduced to less the 8% of its original cover, and climate change may pose a new threat to the remnants of this biodiversity hotspot. In this study we used modelling techniques to determine present and future geographical distribution of 38 species of trees that are typical of the Brazilian Atlantic Forest (Mata Atlântica), considering two global warming scenarios. The optimistic scenario, based in a 0.5% increase in the concentration of CO2 in the atmosphere, predicts an increase of up to 2 °C in the Earth's average temperature; in the pessimistic scenario, based on a 1% increase in the concentration of CO2 in the atmosphere, temperature increase may reach 4 °C. Using these parameters, the occurrence points of the studied species registered in literature, the Genetic Algorithm for Rule-set Predictions/GARP and Maximum entropy modeling of species geographic distributions/MaxEnt we developed models of present and future possible occurrence of each species, considering Earth's mean temperature by 2050 with the optimistic and the pessimistic scenarios of CO2 emission. The results obtained show an alarming reduction in the area of possible occurrence of the species studied, as well as a shift towards southern areas of Brazil. Using GARP, on average, in the optimistic scenario this reduction is of 25% while in the pessimistic scenario it reaches 50%, and the species that will suffer the worst reduction in their possible area of occurrence are: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis and Vochysia magnifica. Using MaxEnt, on average, in the optimistic scenario the reduction will be of 20% while in the pessimistic scenario it reaches 30%, and the species that will suffer the worst reduction are: Hyeronima alchorneoides, Schefflera angustissima, Andira fraxinifolia and the species of Myrtaceae studied.
2010
Colombo,AF. Joly,CA.
Dissolved nitrogen in rivers: comparing pristine and impacted regions of Brazil
Riverine nitrogen distribution is increasingly controlled by anthropogenic activities in their watersheds, regardless of spatial scale, climate, and geographical zone. Consequently, modelling efforts to predict the export of nitrogen from rivers worldwide have used attributes such as population density, land use, urbanization and sanitation. These models have greatly enhanced our understanding of the sources and fate of nitrogen added to terrestrial systems and transported to rivers and streams, especially for developed countries of the North temperate zone. However, much of the world's population lives in developing countries of the tropics, where the effects of human activities on riverine N exports are still poorly understood. In an effort to close this gap, we compare riverine nitrogen data from 32 Brazilian rivers draining two contrasting regions in this tropical country in terms of economic development - the State of São Paulo and the Amazon. Our data include nitrogen in different dissolved forms, such as Dissolved Inorganic Nitrogen (DIN) and Dissolved Organic Nitrogen (DON). The results show that nitrogen concentrations decreased as river runoff increased in both study areas, and that concentrations were significantly higher in rivers draining the most economically developed region. The relationships between nitrogen concentrations and fluxes with demographic parameters such as population density were also determined and compared to those in temperate systems. In contrast to temperate watersheds, we found that nitrogen fluxes increased only after population densities were higher than 10 individuals per km².
2010
Martinelli,LA Coletta,LD. Ravagnani,EC. Camargo,PB. Ometto,JPHB. Filoso,S. Victoria,RL.
Photosynthetic efficiency of Clusia arrudae leaf tissue with and without Cecidomyiidae galls
Leaf galls induced by a still undescribed new species of Cecidomyiidae (Diptera) are frequent on leaves of Clusia arrudae Planchon & Tirana (Clusiaceae) in the rupestrian fields at 1400 m a.s.l. in Serra do Cipó, Minas Gerais, Brazil. Galls were 7.1 ± 0.7 mm in diameter, one chambered with only one larva inside. Gall tissue is green and soft. Assessments of photosynthetic capacity using chlorophyll-a fluorescence measurements revealed that photosynthetic performance of gall tissue and healthy leaf tissue were rather similar. Hence, the morphological changes due to gall development were not associated with significant changes in the photosynthetic capacity of the tissue.
2010
Fernandes,GW. Coelho,MS. Lüttge,U.
Spectral analysis of flowers used by nectar-feeding birds in an urban area in Southeastern Brazil
The objective of this study was to determine the spectral characteristic of nectar-producing flowers visited by nectarivorous birds in urban areas. This study was carried out in the central area of the city of Taubaté, in the northeast of the State of São Paulo. The sample areas included green areas, such as squares and parks, and the vegetation of streets and avenues. Twelve plant species were recorded with flowers visited by five nectar-feeding birds. The most visited flower species were those that reflected in long wavelengths (>600 nm). The study discussed the birds' detection capability due to the tetrachromatic vision of nectar-feeding birds and the conspicuity of flowers in urban environments. Finally, the study assessed the scarcity of plants attractive to nectar-feeding birds and the need for a management strategy to favour these species and biodiversity in urban areas.
2010
Toledo,MCB. Donatelli,RJ.
Abundance and stratification of soil macroarthropods in a Caatinga Forest in Northeast Brazil
In arid and semiarid environments, seasonality usually exerts a strong influence on the composition and dynamics of the soil community. The soil macroarthropods were studied in a Caatinga forest located in the Reserva Particular do Patrimônio Natural (RPPN) Fazenda Almas, São José dos Cordeiros, Paraíba, Brazil. Samples were collected during the dry and rainy seasons following the method proposed by the Tropical Soil Biology and Fertility Program (TSBF), with minor modifications. At each station, 15 soil blocks (20 × 20 × 30 cm: 12 L) were extracted and divided into three layers: A (0-10 cm), B (10-20 cm), and C (20-30 cm). In the rainy and dry seasons 1,306 ± 543(se) and 458 ± 212 ind.m-2 macroarthropods were found, respectively, with 35 and 18 respective taxa recorded. The abundance of individuals and taxa were significantly higher in the rainy season. Isoptera (57.8%) was the most abundant taxon, followed by Hymenoptera: Formicidae (17.2%), Coleoptera larvae (7.3%), and Araneae (3.5%). In the rainy season, abundance in layer A (576 ± 138 ind.m-2) was significantly higher than that of layer C (117 ± 64 ind.m-2), but was not different from layer B (613 ± 480 ind.m-2). There was also no difference between the layer B and C abundances. In the dry season, abundance in layer B (232 ± 120 ind.m-2) was not significantly different compared to layer A (182 ± 129 ind.m-2), but was significantly higher than abundance in layer C (44 ± 35 ind.m-2). During the rainy season, layer A (34 taxa) was significantly richer in taxa than layers B (19 taxa) and C (11 taxa). On the other hand, during the dry season the richness of layers A (12 taxa) and B (12 taxa) was equal, but significantly higher than that of layer C (6 taxa). Richness of taxa and abundance were positively correlated with soil organic matter and negatively correlated with soil temperature. The community of soil macroarthropods in the area of Caatinga studied has taxonomic and functional structures that are relatively complex and is therefore likely to exert an influence on ecosystem productivity due to its physical effects on soil profile and necromass fragmentation, as occurs in other arid and semiarid ecosystems throughout the world.
2010
Araújo,VFP Bandeira,AG Vasconcellos,A
Nutrient addition does not enhance leaf decomposition in a Southeastern Brazilian stream (Espinhaço mountain range)
A decomposition experiment using eucalyptus leaves was carried out in a Southeastern Brazilian mountain stream located at the transition between the Cerrado and the Atlantic Forest to test whether nutrient addition increases microbial and invertebrate colonisation and accelerates breakdown rates. The results show that none of the tested variables was significantly affected by nutrient addition, despite the average increase in ATP concentrations and invertebrate colonisation observed in the fertilised leaf bags. This could mean that breakdown in the stream was already at its maximum due to the relatively high water temperature and nutrient content, or that the breakdown rate of eucalyptus leaves was too fast to allow the detection of any effects of nutrient addition. Breakdown rates of eucalyptus leaves were much faster than the values reported in literature for most species in Brazilian Cerrado streams, suggesting that the replacement of the natural vegetation by eucalyptus may affect nutrient dynamics in the region.
2010
Abelho,M. Moretti,M. França,J. Callisto,M.
Cladocera of the Lençóis Maranhenses (NE - Brazil): faunal composition and a reappraisal of Sars' Method
We studied the Cladocera of a group of ephemeral interdunal pools in the Lençóis Maranhenses, Maranhão State (NE - Brazil) and recorded 34 species. The fauna was overwhelmingly neotropical, with no evidence of invasive species. Species composition differed in Lagoa da Colher, an acid system. We provide notes on behaviour, morphology and taxonomy of some lesser-known anomopods, with emphasis on the Chydoridae. We figure male Oxyurella longicaudis, Chydorus eurynotus, Disparalona leptorhyncha, Alonella dadayi and A. clathratula. We provide notes on the "Sars' Method", hatching of freshwater crustaceans from dry mud, a simple technique that complements the information of hit-and-run surveys. About half of the total species number (44%) was revived through this method; 18% of species were additional to field-collected samples. The Sars' method also yielded abundant specimens of rare species, useful for identification and studies on behaviour.
2010
Van Damme,K. Dumont,HJ.
Phytoplankton assemblages in a reservoir cascade of a large tropical - subtropical river (SE, Brazil)
The phytoplankton assemblages from eight reservoirs of the Paranapanema River were studied during two consecutive years. Chlorophyceae and Bacillaryophyceae dominated in richness. The observed high number of taxa, 234, reflects the extensive sampling programme and evidences the necessity of considering the whole hydrograph basin to assess the biodiversity status of inland water ecosystems. The dams had a negative effect on phytoplankton richness, with higher number of taxa associate to riverine (non-regulated) stretches. The tributary rivers also exhibited high species richness, showing the importance of considering the lateral dimension, in addition to the longitudinal one, for aquatic biota inventories in large river basins/reservoirs. Richness and diversity were also positively influenced by the connectivity with lateral wetlands (macrophyte-dominated lakes) due to the periphyton influence. The phytoplankton abundance/biomass was not influenced by higher water retention time. Higher values occurred in the middle basin stretches (river-passage reservoirs) due to the increase in the trophic conditions. There was a positive correlation with phosphorus. Poorer light conditions in the cascade do not limit the phytoplankton biomass, with assemblages dominated by species tolerant to turbulent conditions and high mineral turbidity. Bacillariophyceae and Cryptophyceae dominated numerically. The first group (unicellular forms) was prominent in the large and oligotrophic upstream reservoirs. The second was highly abundant in the river-passage (low retention time), and more eutrophic, reservoirs. Cyanophyceae growth is probably controlled by advection processes (wash-out effect). The zooplankton does not control the phytoplankton biomass and the diversity of both groups is positively associated in the cascade. The structure of the phytoplankton assemblages showed to be a good indicator of the operationally distinct reservoirs of the Paranapanema cascade and also reflected the changes in the trophic conditions along the basin.
2010
Nogueira,MG Ferrareze,M Moreira,ML Gouvêa,RM