ارزيابي شرايط تروفي تالاب چغاخور

چكيده انگليسي :

88 Trophic Status Assessment of Choghakhor Wetland Ali Reza Esmaeli Ofogh Email A esmaeliofogh@in iut ac ir Date of Submission 22 2 2012 Department of Natural Resources Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Eisa Ebrahimi E ebrahimi@cc iut ac irAbstractWetlands are known as kidney of the earth functioning ecologically environmentally and productively in theaspects of flood storage climate regulation pollution control soil erosion reduction landscaping andmaintenance of biological diversity and productivity Eutorphication is increase of primarily productivity inwater ecosystems as result of increase of nutrients especially phosphorus and nitrogen in ecosystems Eutorphication lead to decrease of water quality and occurrence of algal blooms In addition eutorphicationaffect biodiversity With increase of human activity such as development of agriculture and increase ofwastewater release to aquatic ecosystems assessment of trophic status seemed to be very necessary Choghakhor wetland is important ecosystems because is located in Iran s central plateau and has a highbiodiversity The aim of this research was the assessment of trophic status and change in throughout the year Sampling is carried out from May to March 2010 in eight stages with time interval of 45 days In order toassessment of trophic status in Choghakhor s wetland 10 station selected and physico chemical parameters temperature dissolved oxygen pH alkalinity depth Secchi disk depth and nutrients as well as biologicalparameters chlorophyll a and macrophytes coverage were measured in throughout the year In addition phytoplankton species diversity and density were determined in order to assessment of trophic status changeeffect on structure diversity and density of phytoplankton assemblage Results showed there was notsignificance difference between stations in all stages P 0 05 With respect to Redfield index and high positivecorrelation between chlorophyll a and total phosphorus probably phosphorus is limiting factor in thisecosystem This ecosystem classified as shallow ecosystems because the mean depth is lower than two meters Shallow aquatic ecosystems are very dynamics and recycling of nutrients which lost in sediments is fastercompared to deep ecosystems The nutrients released from sediment had key role in trophic state compared toexternal nutrient loading Based on pearson s correlation there were significant correlation between chlorophylla with total phosphorus r 0 679 total nitrogen r 0 448 temperature r 0 338 macrophytes coverage r 0 324 Secchi disk depth r 0 201 as well as thermal stratification To determine of trophic state threecommon indices of trophic classification for lakes that suggested with OECD as well as Carlson s and TRIXindices were applied According to Carlson index and OECD classification for lakes the Choghakhor wetlandcategorized as eutrophic Our finding showed that TRIX index there is not suitable index for assessment oftrophic state in this wetland In this research the dominant phytoplankton assemblage was green algae Chlorophyta while diatoms Bacillariophyta were rich in number of species 17 genus This study illustratedthat the phytoplankton assemblages are not suitable criteria for monitoring of trophic states based on Margalef srichness index in the Choghakhor wetland Key wordsChoghakhor Wetland Eutrophication Carlson Index TRIX Index Redfield Index Trophicstate

اسماعيلي افق، علي رضا

ارزيابي شرايط تروفي تالاب چغاخور

يوتريفيكاسيون , شاخص TSI , شاخص TRIX , وضعيت تروفي , شاخص Redfield