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Registro Completo |
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Biblioteca(s): |
Embrapa Pantanal. |
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Data corrente: |
03/04/1995 |
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Data da última atualização: |
04/04/2017 |
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Autoria: |
HILL, W. R.; BOSTON, H. L.; STEINMAN, A. D. |
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Título: |
Grazers and nutrients simultaneously limit lotic primary productivity. |
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Ano de publicação: |
1992 |
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Fonte/Imprenta: |
Canadian Journal of Fisheries & Aquatic Science, v.49, n.3, p.504-512, 1992. |
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Idioma: |
Inglês |
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Conteúdo: |
Nitrate and phosphate were added to two of four flow throught channels in a second-order stream in eastern Tennessee to raise nutrient concentrations to 3-4 times-background, while two of four sets of colonized ceramic tiles in each channel were raised above the substratum to exclude grazing snails (Rlimia clavaeformis). Snail grazing maintained a thin layer of peruphyton dominated by Stigeoclonium basal cells, regardless of nutrient regime. Although nutrient effects on peruphyton ash-free mass were statistically insignificant, nutrient additions significantly increased chlorophyll a, especially where snails were excluded. Snail grazing maintained a thin layer of periphyton dominated by Stigeoclonium basal cells, regardless of nutrient regime. Althought nutrient effects on periphyton ash-free dry mass were statiscally insignificant, nutrient additions significantly increased chlorophyll a, specially where exclused. Snail densites were 89% higher nutrient-enriched channels. Photosynthesis-irradiance data suggested that nutrient enrichment increased self-shading in the peruphyton. Areal-specific productivity was simultaneously limited by grazing and low nutrient concentrations: snail exclusion and nutrient enrichment both increased productivity > 2 times. The negative effects of snails on areal-specific producitivity was due (1) reduction in biomass by cropping and (2) depression of chlorophyll-specific productivity. The means by which Elimia depresses chlorophyll-specific productivity is unclear, but the depression is clearly disadvantageous to food-limited grazers. Because Elimia was the dominant invertebrate, our resultas indicate that low nutrient concentrations limit secondaryas well as primary production in autumn. MenosNitrate and phosphate were added to two of four flow throught channels in a second-order stream in eastern Tennessee to raise nutrient concentrations to 3-4 times-background, while two of four sets of colonized ceramic tiles in each channel were raised above the substratum to exclude grazing snails (Rlimia clavaeformis). Snail grazing maintained a thin layer of peruphyton dominated by Stigeoclonium basal cells, regardless of nutrient regime. Although nutrient effects on peruphyton ash-free mass were statistically insignificant, nutrient additions significantly increased chlorophyll a, especially where snails were excluded. Snail grazing maintained a thin layer of periphyton dominated by Stigeoclonium basal cells, regardless of nutrient regime. Althought nutrient effects on periphyton ash-free dry mass were statiscally insignificant, nutrient additions significantly increased chlorophyll a, specially where exclused. Snail densites were 89% higher nutrient-enriched channels. Photosynthesis-irradiance data suggested that nutrient enrichment increased self-shading in the peruphyton. Areal-specific productivity was simultaneously limited by grazing and low nutrient concentrations: snail exclusion and nutrient enrichment both increased productivity > 2 times. The negative effects of snails on areal-specific producitivity was due (1) reduction in biomass by cropping and (2) depression of chlorophyll-specific productivity. The means by which Elimia depresses chlorophyll-specific pro... Mostrar Tudo |
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Palavras-Chave: |
Ecossistem. |
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Thesagro: |
Biomassa; Ecossistema. |
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Thesaurus Nal: |
biomass; periphyton. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02311naa a2200205 a 4500
001 1783992
005 2017-04-04
008 1992 bl --- 0-- u #d
100 1 $aHILL, W. R.
245 $aGrazers and nutrients simultaneously limit lotic primary productivity.
260 $c1992
520 $aNitrate and phosphate were added to two of four flow throught channels in a second-order stream in eastern Tennessee to raise nutrient concentrations to 3-4 times-background, while two of four sets of colonized ceramic tiles in each channel were raised above the substratum to exclude grazing snails (Rlimia clavaeformis). Snail grazing maintained a thin layer of peruphyton dominated by Stigeoclonium basal cells, regardless of nutrient regime. Although nutrient effects on peruphyton ash-free mass were statistically insignificant, nutrient additions significantly increased chlorophyll a, especially where snails were excluded. Snail grazing maintained a thin layer of periphyton dominated by Stigeoclonium basal cells, regardless of nutrient regime. Althought nutrient effects on periphyton ash-free dry mass were statiscally insignificant, nutrient additions significantly increased chlorophyll a, specially where exclused. Snail densites were 89% higher nutrient-enriched channels. Photosynthesis-irradiance data suggested that nutrient enrichment increased self-shading in the peruphyton. Areal-specific productivity was simultaneously limited by grazing and low nutrient concentrations: snail exclusion and nutrient enrichment both increased productivity > 2 times. The negative effects of snails on areal-specific producitivity was due (1) reduction in biomass by cropping and (2) depression of chlorophyll-specific productivity. The means by which Elimia depresses chlorophyll-specific productivity is unclear, but the depression is clearly disadvantageous to food-limited grazers. Because Elimia was the dominant invertebrate, our resultas indicate that low nutrient concentrations limit secondaryas well as primary production in autumn.
650 $abiomass
650 $aperiphyton
650 $aBiomassa
650 $aEcossistema
653 $aEcossistem
700 1 $aBOSTON, H. L.
700 1 $aSTEINMAN, A. D.
773 $tCanadian Journal of Fisheries & Aquatic Science$gv.49, n.3, p.504-512, 1992.
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Registro original: |
Embrapa Pantanal (CPAP) |
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Registro |
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Registro Completo
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Biblioteca(s): |
Embrapa Amazônia Oriental. |
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Data corrente: |
09/02/2023 |
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Data da última atualização: |
24/03/2023 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
B - 2 |
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Autoria: |
RIBEIRO, L. B.; MOTA, D. M. da. |
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Afiliação: |
LAIANE BEZERRA RIBEIRO; DALVA MARIA DA MOTA, CPATU. |
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Título: |
O trabalho em vilas rurais sob influência da dendeicultura no nordeste parense. |
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Ano de publicação: |
2021 |
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Fonte/Imprenta: |
Revista de Administração e Negócios da Amazônia, v. 13, n. 4, p. 11-25, 2021. Especial. |
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Idioma: |
Português |
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Conteúdo: |
O objetivo deste artigo é analisar as atividades realizadas pelos moradores de vilas rurais sob influência da dendeicultura no Nordeste Paraense. A expansão desse cultivo tem transformado não só a paisagem, mas também a dinâmica social, cuja face mais visível são as vilas rurais, lugares de residência de grupos que trabalham na dendeicultura na condição de assalariados e de integrados. A pesquisa foi conduzida no âmbito do projeto AFInS1, e a metodologia constou de observações e entrevistas com atores-chave residentes em 346 vilas rurais em 22 municípios. Os principais resultados mostram a predominância de quatro tipo de vilas e a inquestionável importância da agricultura e do assalariamento. |
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Palavras-Chave: |
Dendeicultura. |
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Thesagro: |
Comunidade Rural; Dendê; Elaeis Guineensis; Trabalho. |
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Categoria do assunto: |
B Sociologia Rural |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/doc/1151634/1/Vilas-Rurais-RARA.pdf
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Marc: |
LEADER 01315naa a2200193 a 4500
001 2151634
005 2023-03-24
008 2021 bl uuuu u00u1 u #d
100 1 $aRIBEIRO, L. B.
245 $aO trabalho em vilas rurais sob influência da dendeicultura no nordeste parense.$h[electronic resource]
260 $c2021
520 $aO objetivo deste artigo é analisar as atividades realizadas pelos moradores de vilas rurais sob influência da dendeicultura no Nordeste Paraense. A expansão desse cultivo tem transformado não só a paisagem, mas também a dinâmica social, cuja face mais visível são as vilas rurais, lugares de residência de grupos que trabalham na dendeicultura na condição de assalariados e de integrados. A pesquisa foi conduzida no âmbito do projeto AFInS1, e a metodologia constou de observações e entrevistas com atores-chave residentes em 346 vilas rurais em 22 municípios. Os principais resultados mostram a predominância de quatro tipo de vilas e a inquestionável importância da agricultura e do assalariamento.
650 $aComunidade Rural
650 $aDendê
650 $aElaeis Guineensis
650 $aTrabalho
653 $aDendeicultura
700 1 $aMOTA, D. M. da
773 $tRevista de Administração e Negócios da Amazônia$gv. 13, n. 4, p. 11-25, 2021. Especial.
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Embrapa Amazônia Oriental (CPATU) |
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