| Popis: |
Physical and chemical statuses of Mesopotamian Marshes have been studied in the pre- and post-draining processes. It was found that light penetration was ranged between 25 and 155 cm and is mainly affected by the nature of the marsh bottom and boating activity in addition to sedimentation that lead to increase the turbidity. The pH value in the area is generally ranged between 7.1 and 9.18 during 1980, whereas alkalinity had ranged between 68 and 137 mg CaCO3/l, which was mainly bicarbonate alkalinity. In the marshes, water was very hard and was characterized by slightly saline to oligohaline water during 1970–1980, and it is well aerated with high level of oxygen. The main form of inorganic nitrogen was nitrate, and both nitrite and ammonia were also recorded in the environment of the marsh areas. No confidence can be placed in the accuracy of phosphorus measurement as its value is much less than that of the Shatt al-Arab River, whereas silicate value has been varied slightly between 7.7 and 9.8 mg SiO3/l. A clear seasonal variation was evident in southern marshes before draining. Water character after reflooding showed slight value of suspended matter, pH value was 6.6–8, and EC was 1120–2410 μs/cm, and TDS was between 467 and 944 mg/l. All these figures have been recorded in Abu-Zirig Marsh; therefore, the hydrological regime had a clear effect on physicochemical properties of water in the marshes. Electrical conductivity ranged from 910 to 4413 μs/cm in Central Marshes after reflooding. A temporal variation of salinity was observed, and it ranged between 0.8 and 2.25‰ in Central Marshes. Temperature was found to be the main reason of variation in the values of pH, dissolved oxygen, organic matter values, and salinity. Plant nutrient, particularly nitrate, was found to be with much more concentration up to 141 μg/l in comparison to the previously recorded values (24 μg/l). Phosphate levels have also been increased, and the reason might be rainfall and fertilizer. Other parameters such as chloride, sulfate, total hardness, calcium, and magnesium have been also measured in some stations within marshes. |
