مقايسه توانايي دو گونه صدف دو كفه اي Corbigula fluminea و Anodonta cygnea در فيلتراسيون جلبك Chlorella spp (راهكارهاي جهت كنترل بيولوژيكي اكوسيستم هاي آبي)

The Comparison between Anodonta Cygnea & Corbigula Flumineaʹs (Uniondale) Capability in Filter Feeding of Chlorella spp.(The strategies for biological control of the water of ecosystems)

The generation of sewages from agricultural & industrial activities, causes ecological quality derangement of the water of ecosystems. Among them, in many of ecosystems, Enrichment caused danger for ecosystem. To introduce a biological control method was the main objective of the present research experiments. In this study filtration rates of two species of (Asian clam) Corbicula Fluminea and (The Swan mussel) Anodonta Cygnea utilizing Chlorella spp in a closed system was experimented. In these studies three treatments of algas (5x 104, lxlO and 2x 105 cell in per milliliter) which already were cultured in mono Xenic and Guillard media were used. Surrounding water of mussels in the recipient was sampled in 30 min period of time and then, current water was remained during intervals of 120 min between two stagnant sampling times (30 min). For Each treatment there was a triplicate repetition and two repetitions for whole experiments. Results show that in each treatment, filtration rates decreased at the end of the experiment compared to the start stage. However, the result for Corbigula fluminea differences was insignificant. The maximum filtration rate was observed in the first treatment (low concentration) 3.56 (a=0.7) ml. min "ʹ.gr ʹAFDW. In Anadonta Cygnea case filtration rate in three treatments was closed to one another and in second treatment (medium concentration) was more and eventually average of three replicates in low concentration had partial significant differences with medium concentration. (t=3.19, p<0.05, mcan50000=5.29± 0.56, mean 100000=5.89±0.32) But filtration rates in high concentration of alga had no significant difference with those in medium concentrations. (t-0.2, p>0.05, mean 200000=5.86±0.16, mean 100000=5.89±0.32) J.Env. Sci. Tech., Vol 12, No.4, Winter 2011 Comparison between filtration rate values of C. Fhnninea and A. cygnea suggest that the lather has better clearance capacity. In first treatment, filtration rate of Chlorella spp was in the case of C.Fluminea 3.56 ml.min "ʹ.gr "ʹ(AFDW) and in the case of A. cygnea 5.29 ml.min ~ .gr ʹ(AFDW). In medium concentration C. Fluminea filtred 3.44 ml.min"1.gr"1 (AFDW) compared to 5.89 ml.min"1.gr"1 (AFDW) of A. Cygnea but in high concentration C. Fluminea filtered 2.95 ml.min"1.gr"1 (AFDW) compared to 5.86 ml.min"1.gr1 (AFDW) of A. Cygnea. Key Words: filtration rate, Chlorella spp, Anodonta cygnea, Corbicula fluminea