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| Nuccio, C; Melillo, C; Massi, L; Innamorati, M. |
| The Orbetello lagoon consists of two coastal ponds, Laguna di Ponente and Laguna di Levante, characterized by high nutrient concentrations, very poor exchanges with the sea and subjected to recurrent eutrophication crisis mainly in the past decades. To assess its current trophic status, from 1995 to 2001 the temporal evolution and spatial distribution of environmental factors, phytoplankton biomass and composition have been investigated. In this paper, the mean annual cycles of phytoplankton abundance, community structure and diversity are discussed. The seasonal cycles of micro- and nanophytoplankton densities are characterized by high frequency oscillations with fast increasing and decreasing blooms, but generally the lowest densities occur in winter,... |
| Tipo: Text |
Palavras-chave: Communauté phytoplanctonique; Diversité du phytoplancton; Lagune d'Orbetello; Taux N/P; Phytoplankton community structure; Phytoplankton diversity; Orbetello Lagoon; N/P ratio. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00322/43281/43016.pdf |
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| Ridame, C; Moutin, T; Guieu, C. |
| A Saharan soil, considered as a proxy for Saharan aerosols, was used to perform radio-labelled phosphate adsorption experiments using (33)PO(4)(3-): leached particles were exposed to poisoned western Mediterranean seawater for varying lengths of time. The measured adsorption capacity of Saharan dust for phosphate was 0.13 mumol g(-1). Considering this value and an annual Saharan dust deposition of 12.5 t km(-2) year(-1), we show that Saharan particles do not represent a significant sink for seawater phosphate in the western Mediterranean Sea. This result is in agreement with that determined from a similar approach conducted in the eastern basin. As a consequence, the unusual NIP ratio measured in the whole Mediterranean Sea (up to 29) cannot be explained... |
| Tipo: Text |
Palavras-chave: Poussières sahariennes; Adsorption; Phosphate; Rapport N/P; Méditerranée; Saharan dust; Adsorption; Phosphate; N/P ratio; Mediterranean Sea. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00321/43254/42985.pdf |
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| Jauffrais, Thierry; Sechet, Veronique; Herrenknecht, Christine; Truquet, Philippe; Savar, Veronique; Tillmann, Urban; Hess, Philipp. |
| Azadinium spinosum, a small dinoflagellate isolated from the North Sea, is a producer of azaspiracids (AZAs), a group of biotoxins associated with human illness following ingestion of contaminated shellfish. Using batch and continuous cultures of A. spinosum, the present study investigated the effects of different environmental and nutritional factors (salinity, temperature, photon flux density, aeration, culture media, nitrogen sources, phosphate source, and N/P ratios) on growth, maximum cell concentration, and AZA cell quota. Azadinium spinosum grew in a wide range of conditions; from 10 ̊C to 26 ̊C and salinities from 30 to 40, under irradiances ranging from 50 μmol m−2 s−1 to 250 μmol m−2 s−1, with or without aeration. Growth and maximum cell... |
| Tipo: Text |
Palavras-chave: AZA; Chemostat; Dinophyceae; Nutrients; N/P ratio; Photobioreactor. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00149/26054/24411.pdf |
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| Ferreira,Eric Victor de Oliveira; Novais,Roberto Ferreira; Médice,Bruna Maximiano; Barros,Nairam Félix de; Silva,Ivo Ribeiro. |
| The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in the nutrient solution. In addition, a field experiment was carried out in a completely randomized design in a 2 × 2 × 2 × 3 factorial arrangement, consisting of two seasons, two regions, two young clones (approximately two years old), and three positions of crown leaf sampling. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Eucalyptus; N/P ratio; Nutritional diagnosis; Plant analysis; Soil fertility evaluation; Chlorophyll meter. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000401127 |
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