Seasonal changes in inorganic nutrient concentration in the alexandria western harbour (Egypt)
Titel:
Seasonal changes in inorganic nutrient concentration in the alexandria western harbour (Egypt)
Auteur:
Okbah, Mohamed Abd Elaziz
Verschenen in:
Chemistry & ecology
Paginering:
Jaargang 20 (2004) nr. 2 pagina's 97-105
Jaar:
2004-04
Inhoud:
Surface and bottom water samples were collected on a monthly basis from six locations in the Alexandria Western Harbour between April 2002 and March 2003. Total nitrogen, ammonia, nitrite, nitrate, total phosphorus, reactive phosphate and silicate were analysed. The average content of total nitrogen ranged from 81.1 to 65.7 µmol l-1 in the surface and bottom waters, respectively, while ammonia ranged from 13.77 to 15.79 µmol l-1 in surface and bottom waters, respectively. Also, the average concentration of nitrite was relatively higher in surface waters than in bottom waters (0.89 and 0.61 µmol l-1, respectively). The results of this study also indicated a considerable temporal variation in nitrate concentrations which ranged from 1.12 to 13.83 µmol l-1. Total phosphorus displayed an irregular pattern throughout the year, ranging from 1.9 to 11.8 µmol l-1 in surface waters and from 1.7 to 9.1 µmol l-1 in bottom waters. The results of PO4-P analysis showed higher values in surface waters (0.28-2.75 µmol l-1) than in bottom waters (0.10-1.70 µmol l-1). The average concentration of silicates was relatively lower in the surface than in the bottom waters (8.97 and 10.1 µmol l-1, respectively). The analysis of variance (ANOVA) among seasons and sites revealed significant differences for ammonia, total nitrogen and phosphate, while nitrate showed no significant differences among stations. Finally, silicate did not show any significant variance among sites and seasons (ANOVA, P > 0.05).
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