QUANTITATIVE AND QUALITATIVE VARIABILITY OF EPIPHYTIC ALGAE ON THREE AQUATIC PLANTS IN EUPHRATES RIVER, IRAQ

The epiphytic algae were studied on three aquatic plants (Ceratophyllum demersum, Myriophyllum verticillatum and Potamogeton pectinatus) from seven stations in Euphrates River between Hindia barrage and Al-Kufa city-Iraq, during summer 2004 and spring 2005. A total of (97) species were identified, diatoms were dominant in their species number (73% from the total number), followed by chlorophyta, then cyanophyta and Euglenophyta. Variations were recorded in the species number among the host macrophyte, as well as, among different seasons for each plant. The biomass of epiphytic algae varied among the plant host, diatoms species were dominated and several genera have large number of species as Cymbella, Gomphonema, Nitzschia and Synedra. Most studied stations showed high population density. INTRODUCTION The different types of benthic algae (epilithic, epiphytic and epipelic) play an important role as primary producers in running water, lake and shallow fresh water ecosystems (Nozaki et al. 2003, Simkhada et al. 2006). The term "epiphytic algae" used by Wetzel (1964) refer to the algae attached on the surface of plants, but Allen (1971) used the term "epiphytic periphyton" to describe both the attached algae and bacteria on aquatic plants (Scheldon and Boylen, 1975). Most species of these algae cover wide area and grow in rivers, lakes and reservoir attached on plants and released by current to water flow (Tharb, 1992). The epiphytic algae act as primary producer in the food chain in water ecosystems (Dere et al., 2002), and as natural food to many zooplankton, grazer and fish (Loman, 2001). The density and diversity of these algae influenced by many environmental factors such as temperature, light, location, depth, and macrophyte host, and its abundance and growth phases of host aquatic plant (Scheldon and Boylen, 1975). F. M. HASSAN, M. M. SALAH, J. M. SALMAN 2 The growth of epiphytic algae influenced by nutrient availability in aquatic ecosystem specially nitrogen and phosphorous compounds that reduce the photosynthetic capacity (Limpens et al., 2003). These types of algae act as indicators of the extent of water pollution (Dere et al., 2003). Many subsequent studies had reported variation in epiphytic algae biomass or species composition on different plant host (Kassim et al.,1997; Hadi and Al-Zubadi, 2001; Hawes and Schwarz, 1996; Douglas and Smol, 1995; Blinndow,1987) In Iraq, the epiphytic algae was studied in different aquatic system (Hadi and Al-Saboonchi, 1989; Al-Mousawi et al., 1990; Kassim et al., 2000 and Al-Saadi et al., 2002). This study aims at exploring on the epiphytic algae composition in Euphrates River at its mid region in Iraq between AlHindia dam and Al-Kufa city. MATERIALS & METHODS Three species of aquatic plants were collected from Euphrates River during four seasons (summer 2004, autumn 2004, winter 2005, and spring 2005). These were Ceratophyllum demersum, Myriophyllum verticillatum and Potamogeton pectinatus. The plant parts were placed in polyethylene bags, and then all samples were cut to shall pieces and then kept in 50 ml of distilled water. Separation of epiphytic algae from their host was carried out following the method described by Bell (1976). The epiphytic algae cells were preserved with one ml Lugol's iodine solution, it allowed for sedimentation for about (8-10) days and concentrated to (10) ml for counting (Furet and Beson-Evans, 1982). The diatoms were counted using microtransect method and non diatoms by Haemocytometer method (Martinez et al., 1975). The species diversity was calculated according to Lianso (2002). The identification of algal species followed several references (Desikachary, 1959; Patrick and Reimer, 1966; Prescott, 1973; Hadi, 1984; Al-Handal, 1994). STUDY AREA Seven stations in Euphrates river were selected at mid of Iraq between AlHindia dam and South of Al-Kufa city; about 220 km length (Fig. 1). Some of these stations are covered with dense riverian type vegetations specially stations1, 4, 6 and 7. The stations as the following: 1. St. 1 north of Al-Hindia dam on (1) km before river branched to Al-Hilla river and Al-Hindia river. 2. St. 2 south of Al-Saada town on (0.5) Km. 3. St. 3 before Al-Hindia city on (4) km. 4. St. 4 south Al-Hindia city on (0.5) Km. 5. St.5 in Al-Kifl city. 6. St.6 in Al-Kufa city. 7. St.7 south of Al-Kufa on (15) km in Al-Eysa region. VARIABILITY OF EPIPHYTIC ALGAE IN EUPHRATES RIVER 3 Fig 1: Map of the study area. N