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Registro Completo |
Biblioteca(s): |
Embrapa Pantanal. |
Data corrente: |
27/02/1996 |
Data da última atualização: |
27/02/1996 |
Autoria: |
MELACK, J. M. |
Título: |
Temporal variability of phytoplankton in tropical lakes. |
Ano de publicação: |
1979 |
Fonte/Imprenta: |
Oecologia, v.44, n.1, p.1-7, 1979. |
Idioma: |
Inglês |
Conteúdo: |
Temporal variability of ecological systems continues to receive theoretical and empirical attention but remains inadequately documented at low latitudes. Results of my comparati- ve investigation of photosynthetic rates of phytoplankton in 6 equatorial African lakes and similar information from 20 South American, Asian and African lakes studied by others pro- vide the data for an assessment of the range of seasonal variability (expressed as coeffi- cients of variation, CV) among tropical lakes. Sampling intervals varied from 1 week to 3 months and usually spanned at least one year. Within Africa the coefficient of variation ranged from 15% to 61% and among all the lakes the coefficient of variation ranged from 15% to 86%. The Spearman rank correlation coefficient of the CV's of photosynthesis ver- sus latitude is 0.24 and is not significant at the 0.05 level. Coefficients of variation of pho- tosynthetic rates of phytoplankton in a diverse set of 45 temperate and arctic lakes ran- ged from 29% to 155% and were significantly different from the set of 26 tropical lakes by the Mann-Whitney U test. When all 71 lakes are compared, the Spearman rank correla- tion coefficient of CV's of photosynthesis versus latitute is 0.71 and is sifnificant at the 0.0005 level. Three temporal patterns were recognized among tropicl lakes. Most tropical lakes exhibit pronounced seasonal fluctuations that usually correspond with variations in rainfall, river discharges or vertical mixing. A second pattern occurs in lakes with muted fluctuations (coefficient of variation less than 20%) in which diel changes often exceed month to month changes. A third pattern is distinguished by an abrupt change from one persistent algal assemblage (i.e., extant for at least 10 generations) and level of photosyn- thetic activity to another persistent condition. MenosTemporal variability of ecological systems continues to receive theoretical and empirical attention but remains inadequately documented at low latitudes. Results of my comparati- ve investigation of photosynthetic rates of phytoplankton in 6 equatorial African lakes and similar information from 20 South American, Asian and African lakes studied by others pro- vide the data for an assessment of the range of seasonal variability (expressed as coeffi- cients of variation, CV) among tropical lakes. Sampling intervals varied from 1 week to 3 months and usually spanned at least one year. Within Africa the coefficient of variation ranged from 15% to 61% and among all the lakes the coefficient of variation ranged from 15% to 86%. The Spearman rank correlation coefficient of the CV's of photosynthesis ver- sus latitude is 0.24 and is not significant at the 0.05 level. Coefficients of variation of pho- tosynthetic rates of phytoplankton in a diverse set of 45 temperate and arctic lakes ran- ged from 29% to 155% and were significantly different from the set of 26 tropical lakes by the Mann-Whitney U test. When all 71 lakes are compared, the Spearman rank correla- tion coefficient of CV's of photosynthesis versus latitute is 0.71 and is sifnificant at the 0.0005 level. Three temporal patterns were recognized among tropicl lakes. Most tropical lakes exhibit pronounced seasonal fluctuations that usually correspond with variations in rainfall, river discharges or vertical mixing. A second ... Mostrar Tudo |
Palavras-Chave: |
Ecological systems; Lago tropical; Sistema ecologico; Temporal variability; Tropical lakes; Variacao temporal. |
Thesagro: |
Fitoplâncton. |
Thesaurus Nal: |
phytoplankton. |
Categoria do assunto: |
-- |
Marc: |
LEADER 02426naa a2200217 a 4500 001 1787463 005 1996-02-27 008 1979 bl --- 0-- u #d 100 1 $aMELACK, J. M. 245 $aTemporal variability of phytoplankton in tropical lakes. 260 $c1979 520 $aTemporal variability of ecological systems continues to receive theoretical and empirical attention but remains inadequately documented at low latitudes. Results of my comparati- ve investigation of photosynthetic rates of phytoplankton in 6 equatorial African lakes and similar information from 20 South American, Asian and African lakes studied by others pro- vide the data for an assessment of the range of seasonal variability (expressed as coeffi- cients of variation, CV) among tropical lakes. Sampling intervals varied from 1 week to 3 months and usually spanned at least one year. Within Africa the coefficient of variation ranged from 15% to 61% and among all the lakes the coefficient of variation ranged from 15% to 86%. The Spearman rank correlation coefficient of the CV's of photosynthesis ver- sus latitude is 0.24 and is not significant at the 0.05 level. Coefficients of variation of pho- tosynthetic rates of phytoplankton in a diverse set of 45 temperate and arctic lakes ran- ged from 29% to 155% and were significantly different from the set of 26 tropical lakes by the Mann-Whitney U test. When all 71 lakes are compared, the Spearman rank correla- tion coefficient of CV's of photosynthesis versus latitute is 0.71 and is sifnificant at the 0.0005 level. Three temporal patterns were recognized among tropicl lakes. Most tropical lakes exhibit pronounced seasonal fluctuations that usually correspond with variations in rainfall, river discharges or vertical mixing. A second pattern occurs in lakes with muted fluctuations (coefficient of variation less than 20%) in which diel changes often exceed month to month changes. A third pattern is distinguished by an abrupt change from one persistent algal assemblage (i.e., extant for at least 10 generations) and level of photosyn- thetic activity to another persistent condition. 650 $aphytoplankton 650 $aFitoplâncton 653 $aEcological systems 653 $aLago tropical 653 $aSistema ecologico 653 $aTemporal variability 653 $aTropical lakes 653 $aVariacao temporal 773 $tOecologia$gv.44, n.1, p.1-7, 1979.
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Embrapa Pantanal (CPAP) |
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Biblioteca(s): |
Embrapa Cerrados. |
Data corrente: |
30/05/1994 |
Data da última atualização: |
18/01/2019 |
Tipo da produção científica: |
Capítulo em Livro Técnico-Científico |
Autoria: |
REIN, T. A.; SOUZA, P. I. de M. de. |
Título: |
Efeito de niveis de nitrogenio em duas cultivares de trigo irrigado, em latossolo vermelho-escuro argiloso de cerrado. |
Ano de publicação: |
1987 |
Fonte/Imprenta: |
In: EMBRAPA. Centro de Pesquisa Agropecuaria dos Cerrados (Planaltina, DF). Relatorio tecnico anual do Centro de Pesquisa Agropecuaria dos Cerrados 1982/1985. Planaltina, 1987. |
Páginas: |
p.109-111. |
Idioma: |
Português |
Palavras-Chave: |
Variedade Anauac; Variedade Aruana; Variedade BR 12; Wheats. |
Thesagro: |
Adubação; Cerrado; Irrigação; Nitrogênio; Trigo; Triticum Aestivum. |
Thesaurus NAL: |
fertilizer application; irrigation; nitrogen; varieties. |
Categoria do assunto: |
-- |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/128797/1/relatorio-07.pdf
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Marc: |
LEADER 00965naa a2200301 a 4500 001 1548782 005 2019-01-18 008 1987 bl uuuu u00u1 u #d 100 1 $aREIN, T. A. 245 $aEfeito de niveis de nitrogenio em duas cultivares de trigo irrigado, em latossolo vermelho-escuro argiloso de cerrado. 260 $c1987 300 $ap.109-111. 650 $afertilizer application 650 $airrigation 650 $anitrogen 650 $avarieties 650 $aAdubação 650 $aCerrado 650 $aIrrigação 650 $aNitrogênio 650 $aTrigo 650 $aTriticum Aestivum 653 $aVariedade Anauac 653 $aVariedade Aruana 653 $aVariedade BR 12 653 $aWheats 700 1 $aSOUZA, P. I. de M. de 773 $tIn: EMBRAPA. Centro de Pesquisa Agropecuaria dos Cerrados (Planaltina, DF). Relatorio tecnico anual do Centro de Pesquisa Agropecuaria dos Cerrados 1982/1985. Planaltina, 1987.
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