Mesopo. Environ. j Vol.3, No.2:1-10, 2017 ISSN 2410-2598 Mesopotemia Environmental journal journal homepage:www.bumej.com A quantitative study of attached algae on two substrates (natural and artificial) in a lotic ecosystem Fikrat M. Hassan Jinan S. Z. Al-Hasaniy Rawaa N. Q. Al- Aeady Department of Biology, College of Science for Women, University of Baghdad, Iraq. Corresponding author: fikrat@csw.uobaghdad.edu.iq To cite this article: Hassan, F. .M., and Al-Hasaniy, J S. Z. and Al-Aeady, R. . Q. A quantitative study of Attached Algae on Two substrates (Natural and Artificial) in A Lotic Ecosystem Mesop. Environ. j., 2017, Vol. 3, No.2, pp. 1-10 . Received Date: 3/1/2017 Accepted Date: 5/1/2017 Publishing Date: 1/3/2017 This work is licensed under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International License. Abstract: The attached algae have a big role in lotic ecosystems. This study conducted to explain the different quantity of the attached algae on different substrates. Two macrophytes were selected as a natural substrate ( Certophyllum demersum and Hydrilla verticillata) and artificial substrates and sampling taken monthly, from March 2013 to December 2013 from Tigris river within Al-Jadria campus of the University of Baghdad in the center of Baghdad city. Four biodiversity indices (Shannon-Weaver, richness, evenness and similarity) were calculated. The study showed a variation in the total number of attached algae on different substrates. The higher number of total algae was recorded on artificial substrates (26.68x10 4 individual/g WW) which represented as 44%. While the lowest number of benthic algae (8.76 x10 4 individual/g WW) was on H. verticllata and expressed as 23%. Also, different index values recorded on various substrates. Keywords: Benthic algae, Artificial substrate, Natural substrate, Lotic ecosystem . Introduction Many authors were emphasized the importance of submerged macrophytes in aquatic ecosystems due to their roles as primary producers, a good habitat for other organisms as algae and its role in nutrient cycling [1, 2, 3]. The C. demersum is a dominant species in different aquatic ecosystems in Iraq [4]. While H. verticillata is recorded as introduced species for the first time by Alwan [5]) in Abu-Ziirig marsh (southern Iraq), then registered in the northern Iraqi rivers (the little Zab river) by Al-Mandeel [6]. Algae group occurrence in different habitats. In an aquatic ecosystem found as plankton or periphyton. [1]. Wetzel [7] referred to algae grown on the macrophytes surface as periphyton. Graham et al. [8] stated that the periphyton algae attached to the different substrate include biotic or non-biotic material. The benthic algae have a significant role in the