Situações de risco e proteção à saúde de adolescentes da Comunidade São Remo

No mundo, um em cada cinco pessoas estão na faixa etária de 10 a 19 anos, sendo que 85% habitam países em desenvolvimento (WHO, 2006). Brasil, 21% do total da população está nesta faixa etária (IBGE, 2002). A adolescência é considerada um dos períodos mais saudáveis da vida humana, porém é reconhecido o aumento dos índices de mortalidade em acidentes, suicídios, violência, complicações na gestação e outras doenças que podem ser prevenidas ou tratadas. O objetivo deste estudo é investigar as situações de risco e de proteção à saúde e à vida, vivenciadas por um grupo de adolescentes de baixa renda. É um estudo descritivo qualitativo, realizado na Comunidade São Remo, município de São Paulo, caracterizada pela pobreza e violência. O método utilizado para a coleta de dados foi o grupo focal. Participaram 20 adolescentes, divididos em dois grupos, um de 12 a 14 anos e outro de 15 a 18 anos, foram realizadas três reuniões com cada grupo. As reuniões foram gravadas, posteriormente transcritas e os conteúdos foram analisado, segundo os propostos de Bardin (1977). Os resultados da pesquisa demonstraram que situações de riscos à saúde estão presentes na fragilidade do suporte familiar, violência física causada por terceiros (com ênfase na violência policial), violência psicológica, situações de exclusão social vivenciadas na escola, uso de drogas e condutas transgressoras. Os fatores de proteção detectados foram: família com ênfase na mãe, religiosidade, professor como referência e projetos futuros. Os resultados demonstram que as situações de risco à saúde são mais evidentes do que de proteção para este grupo de adolescentes de baixa renda.

A comunidade zooplanctônica como bioindicadora do estado trófico de reservatórios da região semiárida tropical

E utrophication in continental aquatic ecosystems and the following deterioration of water quality are some of the greatest problems to be solved in this century. Due to their own peculiarities reservoirs from semi - arid regions constitute a great challenge to water management because of their greater vulnerability to eutrophication process. I dentification of biolo gical community components that may be used as bioindicators is important to allow an early detection of adverse changes, and also to provide subsidies for management and conservation actions. The aim of the present study is to evaluate the potential of zo oplankton community as bioindicator of the trophic state of two reservoirs belonging to the Piranhas - Açu basin, RN, Brazil: Boqueirão de Parelhas and Passagem das Traíras. Monthly sampling s of both systems were carried out in both systems during the period of January to December. Measurements were performed for temperature, pH, dissolved oxygen and water electrical conductivity besides water samples collection for nutrients, suspended solids, chlorophyll - a and zooplankton analyses. T axonomic composition of zooplankton , density and biomass were analysed. Trophic state index, ABC curves , W statistic and the Calanoida: Cyclopoida ratio were also obtained. The results evidenced that Boqueirão de Parelhas reservoir was a mesotrophic sy stem, and Passagem das Traíras r eservoir was eutrophic. In both reservoirs zooplankton community had low species richness, mostly constituted by tolerant species which have wide geographical distribution, as well the dominance of the rotifers Brachionus havanaensis , B. calyciflo rus and Keratella tropica ; of the calanoid copepods Notodiaptomus cearensis and N. iheringi ; cyclopoid copepod Thermocyclops decipiens, and of the cladocerans Ceriodaphnia cornuta and Diaphanosoma spinulosum . Among the biological indices the ABC curves fo r the zooplankton community indicated a moderate dis turbance in both reservoirs, th e Calanoida: Cyclopoida ration indicated not impacted environments , e xcept during the end of the study to the reservoir Passagem das Traíras . It was concluded that the indices used are good indicators of disturbance and alteration in the community, however they are not good indicators for monitoring the trophic state of the studied reservoirs due to the simultaneous occurrence of other factors selecting species, as the c oncentration of ions and high turbidity, which are part of the reservoir characteristics of semiarid.

Usuários de crack, instituições e modos de subjetivação: estudo das práticas e da eficácia terapêutica em uma comunidade terapêutica religiosa (RN)

This anthropological research has as main goal to grasp the meanings and perceptions - mode of subjectivity - of crack users in relation to the proposals of Therapeutic Communities (TC) of religious character. The work emphasizes the analysis of Therapeutic Communities of Rio Grande do Norte state, studying a particular organization, called Anzóis da Dor. I intend to analyze qualitative data, focusing on an analysis of the discursive content of speeches and the observation of social interaction, which results in an ethnographic text characterized by a dense description. In relation to the dissertation’s specific goals, we seek to present a general overview of the emergence and development of Therapeutic Communities – encompassing general and local considerations - and pointing out to the dynamics of religious healing systems of these institutions, besides the principles that guide them. In methodological terms, I conducted the partial mapping of therapeutic communities located in Rio Grande do Norte state; interviews with Therapeutic Communities coordinators, visits, participant observation in one of these institutions as well as some interviews with crack users and people close to these social agents in relation to the Therapeutic Communities and the treatment offered by them

Caracterização da comunidade bentônica do recife raso de Pirangi/RN, Brasil, e avaliação do seu processo de estruturação sob impacto de pisoteio

Despite being areas of socioeconomic and ecological importance, the reef environments in northeastern Brazil have been suffering with cluttered tourism impacts, such as trampling, activity that leads to decrease in abundance of organisms, especially benthic, and loss of biodiversity. The objectives of this study were 1) to characterize the benthic community in the shallow sandstone reef of Pirangi/RN, identifying patterns of zonation, and 2) evaluate its process of structuring under different degrees of impact of trampling, providing information to the proper use of the area. Data on abundance of organisms, the percentage coverage of the substrate and physic-chemical parameters were collected. The formation of two zones on the reef was observed: one that considers submerged areas and ones with shorter time of exposure, lower roughness and higher heterogeneity in the coverage of the substrate, with a predominance of sand, foliose algae, rodolit, being related to organisms such as gastropods, crabs and sea-urchin; the second zone comprises areas with longer time of exposure, greater roughness and predominance of bedrock uncovered, being associated with organisms such as barnacles, gastropods, bivalves and crabs. It is concluded that the studied reef presents its own zonation pattern, influenced by both the time of immersion and the substrate characteristics, such as roughness and type of coverage. To answer the second objective of this study, four experimental blocks were mounted on each of the three areas of different intensities of trampling, containing the following treatments: control (isolated from trampling), shaved isolated, trampling and shaved trampling, with data collection by 11 months. The data in abundance, diversity indices and living coverage of the substrate were compared between areas and treatments. The results showed that at the trampling areas, at the end of the experiment, differences were observed between the intensities of the impact, where higher values of abundance and richness of mobile fauna and richness of live coverage (ANOVA, p <0.05) were found in the area of higher trampling intensity. For fauna withdrawal of trampled scraped treatments, it was observed in the area of greatest impact that the abundance of small benthic invertebrates is more than three times smaller than that at the area of intermediate trampling (ANOVA, p <0.05). Initial isolated areas and final ones differed only as to the percentage of live coverage, with an increase of 35% at the end of this experiment. As for the areas that were completely scraped and isolated at the end of the experiment was observed an increase in the percentage of live coverage of 11.11% compared to the initial amount in the area of intermediate impact and 37.5% in the area with greater impact, indicating recovery of the area. It is suggested that the current use of the reef of Pirangi be reviewed, with a decentralization of trampling, or a decrease in visits, so that it does not occur at high intensities

A biotecnologia na propagação e conservação do umbuzeiro (Spondias tuberosa Arr. Cam.) e percepção sobre sua importância por agricultores da comunidade Malhada Vermelha, Campo Redondo (RN-Brasil)

The umbu tree (Spondias tuberosa Arruda) is a fruit native to the northeast of Brazil with great economic, social and ecological importance for the northeastern semi-arid region. Despite its role, the umbu tree has suffered negative pressure thanks to cluttered extractivism and to negative selection of its fruits, which as the deforestation and the dormancy of seeds contribute to the decrease of its production year after year, making necessary studies that contribute to the improvement of this specie and its conservation. Given the risks to the conservation of the specie and its usefulness to the population, the association between plant biotechnology, for being a tool that can be used to increase its production. and the perception of gathering communities, by valuing the point of view and the knowledge of the population, can facilitate its conservation. This work aimed to develop methods of propagation for umbu tree as well as contribute to its conservation by using biotechnology, with specific objectives to contribute to the conservation of this species; determine concentrations of BAP and ANA in the formation of buds; testing the efficiency of different substrates and concentrations of gibberellic acid on germination in vitro and ex vitro, as well as capture the perception of families in communities that engage in the gathering of umbu. To study the germination, the seeds were inoculated in different substrates (vermiculite, vermiculite + clay, clay, clay + manure and manure + vermiculite) and in different concentrations of gibberellic acid (0 mg, 250 g and 500 mg). For the formation of buds BAP to 0.1 mg-1 was associated with different concentrations of ANA (0.2; 0.4; 0.8mg.L-1). The study of perception was conducted by applying semi-structured questionnaire with Malhada Vermelha community. The experiments resulted in vermiculite and concentration of 500 mg gibberellic acid as the best for germination. The association of 0.1 mg.L-1 of BAP to 0.2 mg.L-1 of ANA provided better formation of buds. As to the application of questionnaires, they revealed that the population understands the decreased amount of umbu plants and umbu fruit in the region, as well as shows concern for its conservation.

Território para viver: dinâmicas territoriais da comunidade quilombola de Acauã, Poço Branco, Rio Grande do Norte

In the late 1980s, the quilombola (or maroon) communities emerged on the Brazilian public scene. They established themselves as new collective subjects and ethnic groups, in a historical moment of sensitive political changes in several social conflicts and struggles, both in Brazil and in Latin America. Because of their socio-cultural and historical singularities, these communities have self-identified in the same collective expression and have organized in search of recognition and respect for their rights. Quilombo communities and other self-labeled as "traditional communities" seek to reaffirm their differences in opposition to a conscious colonizer cultural project and re-signify their memories and traditions, that serve as reference in the construction of alternative production projects and community organization. One of the distinguishing characteristics of this quilombola political emergence process is the territorial nature of the struggles, manifested in at least two directions: on the one hand, the struggle for legal and formal recognition of a given space, i.e., the regularization and titling of occupied territories, considering that the Brazilian Constitution of 1988 recognizes the right of these communities to the final possession of the traditional lands. On the other hand, the struggle for recognition of their territoriality in a broader sense, not necessarily restricted to the demarcated area, but as the recognition of a culture and its own way of life, that originated historically in these territories. The current accomplishments and challenges of the Brazilian quilombola communities are well exemplified by the quilombo of Acauã, in the Poço Branco municipality of Rio Grande do Norte. The last fifteen years have been marked by important changes in this community, which has gained visibility and has emerged as a new political player. Acauã identified itself as quilombola community in 2004, the same year that it formalized its political structure, through the creation of the Association of Residents of Quilombo Acauã (AMQA, in Portuguese). Also in 2004, it requested to the National Institute of Colonization and Land Reform (INCRA, in Portuguese) the opening of the process for regularization and titling of quilombo territory, which is at an advanced stage, but so far without definitive resolution. This study aims to understand the process of territorialization (struggle for territorial claim) played in the last fifteen years by the community of Acauã.

Ecologia trófica de uma comunidade de lagartos da caatinga

The trophic ecology studies issues related to the diet of individuals within a community .The relation between the body size of the predator and the prey size, individual specialization and niche breadth are some of the issues that can be discussed by it .I collected the lizards using pitfall trap, glue and active collecting traps in a fragment of Caatinga. The most common species in this community were Tropidurus hispidus, T. semitaeniatus and Cnemidophorus ocellifer. The visits to the farm also relied on collecting invertebrates at each season to understand how the nutritional resources of lizards were presented in each one of them. I tried to answer some questions : 1) If there was a positive relation between body size of the predator and the size of prey of the community ; 2) If in different seasons the relation of body size of the predator and the maximum and/or minimum size of the prey would be positive ; 3) If species with different foraging strategies have positive relation on the size of the predatorprey relation; 4) If the seasonality would influence on the individual expertise of lizards community and more common species; 5) If the breadth of the niche would be influenced by seasonality ; 6) If more individuals with different morphology between them would present less similar diet. I found that there was indeed a positive relationship between size of prey and predator, but nonexistent related to the minimum size of prey; Among the seasons relative size of predators and prey was different for the maximum and minimum size, but was positively related only to the size of the maximum prey. And comparisons between different foraging strategies had the maximum and minimum line inclination greater than zero and different from each other; individual specialization was not influenced by seasonality and the niche breadth was wider in the dry season only to T. semitaeniatus. At last I didn't find a significant negative relationship between morphological dissimilarity and similarity of diet.

Desempenho zootécnico dos camarões: Litopenaeus vannamei e Macrobrachium rosenbergii em tanques rede e aquicultura familiar na comunidade de Bebida-Velha, RN

The study aims to evaluate the performance and identify lesions of agonistic interactions of Macrobrachium rosenbergii in different densities cages (chapter 1); compare the growth performance of shrimp M. rosenbergii and Litopenaus vannamei cages (chatper 2); in addition the study aimed at identifying the knowledge and practices of a traditional community of farmers Bebida-Velha, in the city of Pureza / RN, practicing rural family and aquaculture, as well as tracing the community socioeconomic profile and evaluate the management that these farmers use in shrimp farming Macrobrachium rosenbergii (chapter 3). To perform the experiments (chapter 1 and 2) shrimp species L. vannamei and M. rosenbergii were weighed on a digital scale and transferred to cultures in cages. The cages had 1m³, with 5mm mesh between us and were closed on top with screen to avoid predators (birds, insects). The animals remained in adaptation for fifteen days before the start of data collection (each experiment). Both experiments lasted seventy days, totaling eighty-five days cultivation. During the cultures, animals were fed pelleted feed for shrimp at 10% of their biomass with 35% crude protein, offered in feed trays twice a day during the hours (7:00 am and 14:00 pm). The remnants in the tray were removed after 2h of permanence to calculate intake. To determine the performance parameters, some samples were taken every 10 days. The results of both experiments were analyzed using the STATISTIC 7.0 (2004). In Chapter 1 experiment were applied5 treatments were applied with 5 replications each: D5 - 5 animals/m2 ; D10 - 10 animals/m2 ; D15 - 15 animals/m2 ; D20 - 20 animals/m2 ; D25 - 25 animals/m2 . To this, were distributed 25 cages randomly in two masonry nurseries. The end of the experiment the lesions were verified and quantified. The chapter 2 experiment began when the shrimp reached the same age (eighty-four days) and was used the density of 25 shrimp / m2 with 4 repetitions. For the realization of chapter 3 were applied semi-structured interviews by direct approach of Bebida Velha of settlers practicing aquaculture activity, tilapia producers and community shrimp. Data were tabulated and analyzed according to the responses obtained by the participants. Therefore, the amount of damage increased with increasing stocking density. The density of 10 freshwater shrimp/m² showed the best conditions for a better performance in cages. It can be concluded that in cages, the cultivation of species of fresh water shrimp M. rosenbergii had better zootechnical indexes than the cultivation of marine shrimp species L. 9 vannamei. It was possible to verify that the activities of which the interviewees practice guarantee a good quality of life and income for them. We find that respondents have traditional and local knowledge, and also may be interested in the cultivation of the species M. rosenbergii.

Mapeamento cromossômico de DNAs repetitivos com fins biotecnológicos em peixes marinhos e interesse comercial - Rachycentridae e Lutjanidae

The Rachycentron canadum species, commonly known as beijupirá or cobia is the only representative of Rachycentridae family which has been increasingly used in marine fish farming, in intensive cultivation. As advantageous features it has easy adaptation, prolific behavior, early growth in captivity and high commercial value. Additionally, specie of Lutjanidae family (Lutjanus synagris, Lutjanus jocu, Lutjanus analis, Lutjanus alexandrei and Ocyurus chrysurus) represents an important fisheries resource in all areas of its occurrence. In Brazil, the commercial exploitation of Lutjanidae which begun in the 60's and 80's, already has showed a decline in catch volumes. This fact suggests that the snappers must have a conservative management. Despite the economic potential, little is known about the genetic and cytogenetic characteristics of these species, especially with respect to repetitive DNA analysis, which represents the major part of the eukaryotes genome, playing important evolutionary roles in the fish genome. Cytogenetic data is increasingly being used in population studies and biotechnological purposes in fishes. The cytogenetical analyzes were performed using classical methods such as Giemsa staining, C-banding and Ag-NORs, fluorochromes base-specific staining (DAPI and MM) and physical mapping of repetitive sequences among which, telomeric sequences, transposons (Tol2), retrotransposons (Rex1 and Rex3), repetitive DNA (microsatellites and Cot-1) and transcriptionally active regions of the 18S and 5S ribosomal genes and histone (H3 and H2BA) by in situ hybridization with fluorescent probes (FISH). The chromosomal patterns obtained contributed to the organization of repetitive sequences in the genome of the species, as well as karyotypical differentiation. Unusual patterns of histone sequences expansion depict the first occurrence in marine fishes. The obtained data provided subsides to the genetic knowledge of the important fisheries resource represented by the species here analyzed, seeking the marine pisciculture improvement.

Adição de policloreto de alumínio e remoção de peixes bentívoros como técnicas de restauração de lagos rasos do semiárido brasileiro

Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

Adição de policloreto de alumínio e remoção de peixes bentívoros como técnicas de restauração de lagos rasos do semiárido brasileiro

Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

O turismo de base comunitária como vetor de etnodesenvolvimento: a comunidade Mebêngôkre-Kayapó na Terra Indígena Las Casas - PA

This study aims to analyze the contribution that the future implementation of community-based tourism can provide to Mebengokre-Kayapo, people of the village Tekrejarôti, they re-inhabiting the indigenous land Las Casas, located in southern of Pará, taking into consideration that tourism is as vector of ethnodevelopment, and it can also contribute to the conservation of Sociobiodiversity and local culture through experiences that will enable the realization of acquaintanceship, where there will be sharing of the daily activities of the customs of the local people, and cultural changes, which is the aim between visitors and the community, where these ones can promote the knowledge of non-indigenous people, and to consolidate the ethnic and cultural identity thereof too. Thus, this study guided by the participatory action research, it was used data obtained in 2012, that were results from the application of interviews with the community to make the diagnosis of tourism potential. It is an exploratory and descriptive research about the topic. The field research combined with participant observation, workshops and interviews contributed to it was possible to conduct a depth analysis about the environment studied. This research has the intention to obtain concrete results in the implementation and/or promotion of a cultural practice and environmentally sustainable ruled in organizational processes that permeates the guidelines of community-based tourism, however this depends on the conditions of human and forest resources, and infrastructure conditions in the community, providing in the short and medium terms, social activities and culturally positive for the culture of this people, and providing to long term, environmental and economic landmarks. As result, it was possible to identify that the community with its cultural events, parties and ceremonies being allied to their way of life and taken from their criteria, it is able to work with the tourism within their land and it can makes the tourism, a cultural affirmation opportunity and income generation. But, it concludes that for tourism to become ,in fact, there are required to be carried out some measures, that meets the new Regulatory Instruction IN 3/2015, this IN states that for the community to work with tourism in their land, it is necessary to be prepared a visitation plan that fits the established requirements. This research is constituted as an important tool in building this visitation plan, given that it was done from the community demand and it was conducted in a participatory manner, valuing the horizontal dialogue and the autonomy of this people.

O turismo de base comunitária como vetor de etnodesenvolvimento: a comunidade Mebêngôkre-Kayapó na Terra Indígena Las Casas - PA

This study aims to analyze the contribution that the future implementation of community-based tourism can provide to Mebengokre-Kayapo, people of the village Tekrejarôti, they re-inhabiting the indigenous land Las Casas, located in southern of Pará, taking into consideration that tourism is as vector of ethnodevelopment, and it can also contribute to the conservation of Sociobiodiversity and local culture through experiences that will enable the realization of acquaintanceship, where there will be sharing of the daily activities of the customs of the local people, and cultural changes, which is the aim between visitors and the community, where these ones can promote the knowledge of non-indigenous people, and to consolidate the ethnic and cultural identity thereof too. Thus, this study guided by the participatory action research, it was used data obtained in 2012, that were results from the application of interviews with the community to make the diagnosis of tourism potential. It is an exploratory and descriptive research about the topic. The field research combined with participant observation, workshops and interviews contributed to it was possible to conduct a depth analysis about the environment studied. This research has the intention to obtain concrete results in the implementation and/or promotion of a cultural practice and environmentally sustainable ruled in organizational processes that permeates the guidelines of community-based tourism, however this depends on the conditions of human and forest resources, and infrastructure conditions in the community, providing in the short and medium terms, social activities and culturally positive for the culture of this people, and providing to long term, environmental and economic landmarks. As result, it was possible to identify that the community with its cultural events, parties and ceremonies being allied to their way of life and taken from their criteria, it is able to work with the tourism within their land and it can makes the tourism, a cultural affirmation opportunity and income generation. But, it concludes that for tourism to become ,in fact, there are required to be carried out some measures, that meets the new Regulatory Instruction IN 3/2015, this IN states that for the community to work with tourism in their land, it is necessary to be prepared a visitation plan that fits the established requirements. This research is constituted as an important tool in building this visitation plan, given that it was done from the community demand and it was conducted in a participatory manner, valuing the horizontal dialogue and the autonomy of this people.

Causas e consequências da onivoria de peixes em ecossistemas aquáticos

Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.

Causas e consequências da onivoria de peixes em ecossistemas aquáticos

Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.