Other occasionally common aquatic macrophytes, especially in the more brackish sites, are Naias minor, N. Often, however, the focus for conservation is on the surrounding vegetation or on extent of water of value for birds; in fact it is the quality of the aquatic environment that underpins the conservational value.
In the Nile system, Aulacoseira granulata is usually the common plantkonic diatom. Other fish species have been introduced recently to North African freshwaters and these include the common carp Cyprinus carpiopike Esox esoxblack bass Sander luciopercarainbow trout Onchorynchus mykissand tench Tinca tinca.
Many organisms typically show adaptations to strong seasonal changes and fluctuating conditions, including receding water levels and water quality variations similar to those described elsewhere for desert river systems and temporary waters.
The trend in availability of phytoplanktons related to the seasonal changes is comparable to that in European lakes with early and late summer peaks. Birds Main migration routes are through Morocco, Tunisia, and eastern Egypt, and lakes on these routes are important habitats for these birds.
Sites such as Merja Zerga, Ichkeul, Burrulus, Manzala are important resting areas for migrating birds. Superimposed on these factors are an array of disturbance activities caused by people, and so many lakes today are modified systems where typically nutrient enrichment and salinity changes have occurred as a result of agriculture and development generally.
Amphibians and Reptiles The turtle Mauremys leprosa is very common in different water bodies in North Africa but Emys orbicularis is very rare and limited to the Rif and the Atlas mountain areas.
Phytoplankton was scarce in acidic Megene Chitane but some Cyclotella pseudostelligera and several acidophilous diatom species were recorded. Fisheries Barbel Barbus callensis, B. Bufo bongersmai is more frequent in the desertic and arid areas South west of Morocco and south of Algeria. Rotifers seem to dominate where organic pollution is high, such as in Lake Manzala Egyptbut elsewhere crustaceans such as Daphnia magna, Ceriodaphnia dubia, Moina micrura, Dunhevidea crassa, Chydorus sphaericus, Alona esteparica, Alona quadrangula, Leidigia ciliata, Dipatomus cyaneus admotus, Metadiaptomus chevreuxi, Hemidiaptomus maroccanus, Mixodiaptomus laciniatus atlantis, and Diacyclops bicuspidatus are common.
Crustaceans showing summer dormancy are the Notostracha Triops concriformis mauritanicas, Lepidurus apusAnostraca Chirocephalus diaphanousConchostracha Cyzicus sp. These fish are found in a variety of habitats, including oasis and delta lakes.
Flower, in Encyclopedia of Inland WatersThe Biota of North African Lakes Water quality and its availability as well as geography play important roles in influencing the occurrences and abundances of aquatic animals and plants in North African lakes.
Pleurodeles waltli is common in dayas types 3 and 4. Green algae tend to be the most diverse group in all lakes except enriched lakes, where blue-greens cyanophytes can dominate, making the open water highly turbid and green. Isoetes velata and I.
For diatoms, Cyclotella species such as C. Fish aquaculture is frequently developed for mullet and for Tilapia in the Nile delta lakes.Whole Effluent Toxicity (WET) testing uses fathead minnows and Ceriodaphnia dubia to measure if a discharge is or may be toxic.
Ceriodaphnia dubia exhibited a 7 day no observable effect concentration (NOEC) of 1 mg l − 1 and S. capricornutum exhibited a 96 h NOEC of 29 mg l − 1 to an insoluble, anionic styrene–acrylic dispersion polymer with a molecular weight of 50–60 kDa used in floor finishes.
Ceriodaphnia dubia longevity and reproduction did not differ much among the three water types in the ﬁrst set of tests, but both longevity and reproduction were strongly affected by the ﬁltering and food-addition treatments in the second (R2,by regression analysis).
The increase in predictability of lifetime reproduction ofC. A model for Ceriodaphnia dubia reproductive toxicity outcomes is presented.
This model assumes that the number of young is a Poisson‐distributed random variable and that the mean number of young can be modeled using an exponential term involving a polynomial in the test concentrations.Risk Analysis, 29, 2, (), ().
Wiley. Article Statistical analysis of the Ceriodaphnia toxicity test: Sample size determination for reproductive effects. Consequently, the aim of this study was to estimate the effects of nine selected EGEs on the reproduction of Ceriodaphnia dubia since this freshwater crustacean is commonly used for assessing the chronic toxicity of single chemicals and effluents (e.g., Chemical analysis.Download