Spatio-Temporal Variations of Microphytobenthos in the Botafogo and Siri estuaries (norteast - Brazil)

Variações espaço-temporais da biomassa do microfitobentos foram investigadas nos estuários dos rios Botafogo e Siri em Pernambuco, Brasil. As amostragens foram realizadas em baixa-mar (bimestralmente) de fevereiro a dezembro de 2003. Em cada estuário foram determinadas três estações de amostragem no médio- e no infralitoral. Fortes variações espaciais e temporais foram verificadas nas concentrações tanto de clorofila-a como de feopigmentos. No estuário do Botafogo, a clorofila-a teve 34% do total da sua variação explicada pela análise de regressão múltipla (MRA) baseada nas concentrações de nitrogênio e de fósforo, enquanto no estuário do Siri somente 16% dessa variação foi explicada pela MRA baseada na concentração de nitrogênio. Feopigmentos apresentou 39% de sua variação total explicada pela MRA baseada na concentração de nitrogênio e na salinidade no estuário do Botafogo; enquanto no Siri a MRA explicou 58% da variação total baseada somente na concentração de nitrogênio. Nitrogênio foi discriminado como o fator mais importante para explicar as variações do microfitobentos no estuário do rio Botafogo. Os resultados do presente trabalho ressaltam o papel dos nutrientes e sugerem que ambos estuários apresentam evidências de eutrofização.Spatio-temporal variations of microphytobenthic biomass were investigated in the Botafogo and Siri estuaries, Pernambuco - Brazil. Samples were taken during low water (bi-monthly) from February to December, 2003. Three sampling stations were located in each estuary, in both midlittoral and sublittoral areas. Clear spatial and temporal variations were found for both chlorophyll-a and phaeopigment concentrations. In Botafogo, chlorophyll-a had 34% of total variation explained by MRA from nitrogen and phosphorus concentrations, while only 16% of total variation was thus explained from nitrogen concentration in the Siri estuary. Phaeopigments had 39% of total variation explained by MRA from nitrogen concentration and salinity in the Botafogo estuary and 58% of total variation was similarly explained from nitrogen concentration in the Siri estuary. Nitrogen was discriminated by the b coefficients as the most important factor in the explanation of the microphytobenthic pigments variations in the Botafogo estuary. The data of this study emphasize the role of nutrients and suggest that both estuaries show evidence of eutrophication

Response of estuarine meiofauna assemblage to effects of fertilizer enrichment used in the sugar cane monoculture. Pernambuco, Brazil

A aplicação in situ de fertilizantes inorgânicos foi utilizada para simular a eutrofização associada ao cultivo da cana-de-açúcar. A estrutura da associação de meiofauna foi analisada com o objetivo de avaliar este impacto. O experimento de enriquecimento do sedimento foi desenvolvido em nove áreas quadrangulares de 4m² distribuídas de forma aleatória no mediolitoral da área estuarina. Três áreas foram enriquecidas com alta concentração (375 g/m²) de NPK (Nitrogênio-Fósforo-Potássio), três com baixa concentração (187,5 g/m²) e as demais tratadas como controle. Os fertilizantes foram aplicados semanalmente. Os parâmetros físico-químicos do sedimento e a meiofauna bentônica foram coletados após três a quatro semanas da aplicação dos fertilizantes. Obedecendo este intervalo foram realizadas 6 amostragens subseqüentes. As amostras foram triadas e a meiofauna contada e identificada em nível de grande grupo. As respostas da meiofauna variaram de acordo com a área: enquanto a área Controle manteve sua abundância total durante todo o experimento, as áreas tratadas apresentaram forte queda nas densidades totais. A ordenação MDS e a análise ANOSIM evidenciaram mudanças significativas na estrutura da associação de meiofauna entre as áreas e também ao longo do experimento nas áreas tratadas.In situ application of inorganic fertilizer was used to simulate environmental eutrophication associated with the sugar cane monoculture. Meiofauna community structure is herein used to assess this experimental impact. Nine quadrangular areas (4m² each) were randomly defined in the midlittoral estuarine area. Three of these areas received a high dose of sugar cane fertilizer (375 g/m² Nitrogen-Phosphorus-Potassium), three areas received a low dose of the fertilizer (187.5 g/m²) and the other three areas represented the control. The fertilizer was applied every week. Environmental parameters and meiofauna were sampled using three-to-four week intervals. Six samplings were subsequently performed maintaining this interval. Meiofauna was counted and identified to major taxonomic groups. Meiofauna community structure varied throughout the experimental areas. Control areas maintained their abundance values during the study period, but within the enriched areas meiofauna abundance decreased greatly. MDS and ANOSIM analysis showed significant variation in the meiofauna community structure among experimental areas and also along the experimental period in the enriched areas

Benthic estuarine communities in Brazil: moving forward to long term studies to assess climate change impacts

Abstract Estuaries are unique coastal ecosystems that sustain and provide essential ecological services for mankind. Estuarine ecosystems include a variety of habitats with their own sediment-fauna dynamics, all of them globally undergoing alteration or threatened by human activities. Mangrove forests, saltmarshes, tidal flats and other confined estuarine systems are under increasing stress due to human activities leading to habitat and species loss. Combined changes in estuarine hydromorphology and in climate pose severe threats to estuarine ecosystems on a global scale. The ReBentos network is the first integrated attempt in Brazil to monitor estuarine changes in the long term to detect and assess the effects of global warming. This paper is an initial effort of ReBentos to review current knowledge on benthic estuarine ecology in Brazil. We herein present and synthesize all published work on Brazilian estuaries that has focused on the description of benthic communities and related ecological processes. We then use current data on Brazilian estuaries and present recommendations for future studies to address climate change effects, suggesting trends for possible future research and stressing the need for long-term datasets and international partnerships

The construction of an eletrical currente source and of a probe for conductivity measurement by a four point probe method

Submitted by Franciele Moreira ([email protected]) on 2018-07-05T17:03:34Z No. of bitstreams: 2 Artigo - Olacir Alves Araújo - 2003.pdf: 132947 bytes, checksum: 58e7f708ae3756e361dbd625d0b61df2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2018-07-06T13:46:35Z (GMT) No. of bitstreams: 2 Artigo - Olacir Alves Araújo - 2003.pdf: 132947 bytes, checksum: 58e7f708ae3756e361dbd625d0b61df2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-07-06T13:46:35Z (GMT). No. of bitstreams: 2 Artigo - Olacir Alves Araújo - 2003.pdf: 132947 bytes, checksum: 58e7f708ae3756e361dbd625d0b61df2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2003This paper describes the construction of an eletrical current source and of a probe to be used in the measurement of eletrical conductivity through a four-point probe method. These pieces of equipments can be obtained at the low price of US$ 50.00 and are adequate for eletrical conductivity measurements in the semiconductor range, that is from 10-1 to 10-6 S cm-1

New records confirming the occurrence of the ghost shrimps Biffarius biformis (Biffar, 1970) and B. fragilis (Biffar, 1971) (Decapoda, Callianassidae) in Brazil and the southwestern Atlantic

Previous records of the callianassid ghost shrimps Biffarius biformis (Biffar, 1971) and Biffarius fragilis (Biffar, 1970) from Pernambuco, northeastern Brazil, were considered as doubtful, because their original record (Carvalho et al. 1997) in a conference abstract cannot be considered as a valid publication. The original material examined by Carvalho et al. (1997) combined with the more recently collected material of B. biformis and B. fragilis, confirm the presence of these two species in Brazil and the southwestern Atlantic. Taxonomic and ecological remarks, as well as illustrations, are provided for both species