Assiut university researches
Taxonomical and Ecological Studies on
Freshwater Benthic Invertebrates at Assiut
Governorate, Egypt
‫درا سات ت ص ن ي ف ية وب ي ئ ية ع لى ال قاع يات‬
.‫ م صر‬,‫ال الف قاري ة ل لم ياه ال عذب ة ف ى محاف ظة ا س يوط‬
Fatma El-Zahraa Abd El-Hameed
‫ف اطمة ال زهراء ع بدال حم يد‬
Ahmed Hamed Obuid-Allah, Azhar Hussein Mohamed, Khaleid
Fouad Abd El-Wakeil
‫ خال د ف ؤاد ع بدال وك يل‬،‫ أزهار ح س ين محمد‬،‫أحمد حامد ع ب يدهللا‬
Abstract:
The term benthos comes from the Greek noun meaning
”depths of the sea”. Benthos plays a significant role in
responding to a variety of environmental conditions of rivers
and streams and therefore may be used as bio-indicators for
water quality assessment. These animals are widespread in
their distribution and can live on all bottom types, even on
manmade objects. They can be found in hot springs, small
ponds and large lakes. Some are even found in the soil
beneath puddles. Most benthic species can be found
throughout the year, but the largest numbers occur in spring
just before the reproductive period. On reviewing literature
which have been carried out on the freshwater benthos of
Egypt and to the best of the present author’s knowledge, it
was observed that few studies on the benthos of the Nile
River were done. So, the present work is an attempt to fulfill
this gap. It aims to carry out the following points: 1- A survey
of different benthic taxa inhabiting different habitats of
freshwater at Assiut, Egypt. 2- Study the benthic community
structure in different freshwater habitats at Assiut. 3- Study
the distribution, composition and relative abundance of
benthos under different habitat structure and seasonal
changes. 4- Focus the light on the effects of pollution on the
distribution and abundance of benthos that inhabit freshwater
at Assiut, Egypt. 5- Seasonal determination of some
ecological factors including heavy metals, which may have
influence on freshwater benthic taxa. 6- Deduce some model
equations for the abundance of different benthic groups. To
carry out the above mentioned aims, the following points
were followed: 1-For qualitative study, seasonal sampling of
benthos was carried out from 54 sites at Assiut governorate
during a period of 2 years; from March 2010 until March
2012. 2- For quantitative purposes, monthly sampling of
benthos was carried out, from main nine sites during a period
of one year; from June 2010 until May 2011. 3- During the
period of investigation, air and water temperature, pH,
dissolved oxygen, turbidity, conductivity, water current and
salinity were recorded. Beside, the concentration of heavy
metals (Fe, Mn, Cu, Cd and Pb) in water, sediment and in the
two moll scan species (Lanistes carinatus & Unio
teretiusculus) were determined. The most important results of
the study can be summarized in the following:- 1- The survey
indicated that 98 taxa were recorded from 54 sites during two
years along the River Nile at Assiut, Egypt. 2- The collected
taxa belong to six phyla and 62 families. Fifty benthic taxa
were recorded from the main nine sites during the period of
investigation. In the present investigation, 10 species of
Annelida were recorded which represented 19.08%,
Gastropoda represented 46.05%, Bivalvia
represented18.50%, Insecta represented 15.86% and others
represented 0.50%. 3- The total relative density of all taxa
collected during the period of investigation was (14307)
individuals. The maximum number was recorded during
Spring, while the minimum number was during Winter. 4Statistical results indicated that there were significant
differences between the investigated sites in ecological
factors and relative densities of recorded benthic taxa. 5-The
concentration of iron (Fe), manganese (Mn), copper (Cu),
cadmium (Cd) and lead (Pb), in water, sediment, and in the
two molluscan species: Lanistes carinatus and Unio
teretiusculus were monthly determined at the three sites (1, 5
& 6. The order of heavy metal concentration in water was Fe>
Mn > Pb >Cu> Cd, in sediment was Fe >Mn> Cd>Cu> Pb, in
Lanistes carinatus was Fe>Mn>Cu>Pb>Cd and in Unio
teretiusculus was Mn>Fe>Cu>Cd>Pb. 6-The bioaccumulation
factors (BAF) of metals in Lanistes carinatus body followed
the sequence: Mn>Cu>Fe>Pb>Cd and in Unio teretiusculus
was Mn>Fe>Cu>Pb>Cd, while the bioconcentration factor
(BCF) of metal in Lanistes carinatus Unio teretiusculus body
followed the sequence: Mn>Fe>Cu>Pb>Cd . 7- Statistical
results showed that heavy metal concentrations in water,
sediment and mollusca (Lanistes carinatus & Unio
teretiusculus) have been affected by the interactions between
all the studied factors. The bioaccumulation factors of metals
in the mollusca appeared to be dependent on metals
concentration in the mollusca and sediment and they are
more effective than bioconcentration factors in measuring the
efficiency of the mollusca in accumulating heavy metals.
:‫ال م لخص‬
.”‫ال قاع يات م صط لح ات ى من اال سم ال يون ان ى ب م ع نى”اعماق ال بحار‬
‫ت ل عب ال قاع يات دورا ك ب يرا ف ى اال س تجاب ة ل مجموعة م ت نوعة من‬
‫ اذل ك ي م كن ا س تخدامها ك مؤ شر‬،‫ال ظروف ال ب ي ئ ية ال تى ت ع يش ف يها‬
،‫ ت ن ت شر هذه ال ح يوان ات ع لى ن طاق وا سع‬.‫ح يوى ل ت ق ي يم ن وع ية ال م ياه‬
‫ ح تى ع لى األ ش ياء ال تى ي ص ن عها‬،‫ح يث ت ع يش ع لى جم يع امواع ال قاع‬
‫ك ما ي م كن ال ع ثور ع ل يها ف ى ال ي ناب يع ال حارة وال برك‬.‫االن سان‬
‫ وت تواجد معظم االن واع ال قاع ية ع لى‬.‫ال ص غ يرة وال بح يرات ال ك ب يرة‬
‫مدار ال س نة ل كن ال عدد األك بر م نها ي وجد خ الل ف صل ال رب يع ف ى ف ترة‬
.‫االن جاب‬