بررسی رفتار جهت‌گیری خرچنگ منزوی Diogenes Avarus تحت تاثیر بوی غذا و بوی شکارچی

هدف از این تحقیق بررسی رفتار جهت گیری خرچنگ های منزوی diogenes avarus تحت تاثیر نشانه های شیمیایی غذا و دشمنان بود؛ بنابراین، رفتار جهت گیری نمونه های d. avarus به سوی هدف در حضور آب دریا حاوی نشانه های شیمیایی در غلظت های 1، 2 و 4 گرم بر لیتر در 24 ساعت بوی مواد دفعی شکارچی و 1، 2 و 3 گرم بر لیتر در 24 ساعت بوی غذا در محیط دایره ای موردمطالعه قرار گرفت. نتایج نشان داد که نمونه ها در گروه شاهد دارای جهت گیری یکنواخت بودند (p>0/05). تیمارهای حاوی بوی شکارچی، جهت گیری غیریکنواخت معناداری را به سمت مخالف هدف نشان دادند (0/05>p). در تیمارهای حاوی بوی غذا، با افزایش بوی غذا جهت گیری به سمت هدف نیز به صورت معناداری افزایش یافت (0/05>p). نمونه های d. avarus بر پایه ی برهمکنش بین اطلاعات بینایی و شیمیایی موجود در محیط، به محرک های محیطی پاسخ رفتاری مناسب می دهند.

Adsorption of Cadmium from aqueous solution by the dead algae biomass Scenedesmus sp.: Isotherm, kinetics and thermodynamics studies

Heavy metal pollution has become one of the most serious environmental problems today. Biosorption is usage of biomaterials such as bacteria, fungi, yeast and algae that is regarded as a costeffective biotechnology for the treatment waste containing heavy metals. This study was conducted in order to evaluate the application of nonliving biomass of Scenedesmus sp. algae as biosorbent in eliminating cadmium from synthetic wastewater. In the batch system amount of cadmium absorbed affected by the parameters of concentration, pH, temperature and contact time, were studied in laboratory. The concentration of Cadmium was determined by Atomic absorption spectrometry. Then, the absorption results were described using the Langmuir and Freundlich isotherms and the pseudo first order and Pseudo second order synthetics and thermodynamic equation of absorption. It was found that optimal adsorption (a removal of 98.71 percent) obtained at adsorbent amount of 0.1gr, concentration 40mg/L, pH = 5, temperature 20 deg;C and equilibrium time of 45min. At reviews the correlation coefficient, adsorption kinetics follows the pseudosecondorder model and equilibrium is well described by Freundlich isotherm. According to adsorption thermodynamics, the reaction found to be spontaneous, exothermic and nonrandom. FTIR spectrum revealed that functional groups C = O, OH and NH that they played a major role in the adsorption. The high efficiency (98.71%) of the adsorption process in this study showed that Scenedesmus sp. algae have a good capability in eliminating cadmium and it can be used method for eliminating cadmium from wastewater.