ﮐﺎرﺑﺮد اﯾﺰوﺗﻮپﻫﺎي ﭘﺎﯾﺪار ﻧﯿﺘﺮوژن )15δN( و ﮐﺮﺑﻦ )13δC( در ﺑﺮرﺳﯽ ﭘﻮﯾﺎﯾﯽ ﻣﺎﻫﯿﺎن ﺧﻠﯿﺞ ﮔﺮﮔﺎن در اﺳﺘﺎن ﮔﻠﺴﺘﺎن

Application of Stable Isotopes of carbon (13δC) and nitrogen (15δN) in assessment of Gorgan Bay Fish dynamic in Golestan Province

ﺧﻠﯿﺞ ﮔﺮﮔﺎن و ﺳﻮاﺣﻞ ﺟﻨﻮبﺷﺮﻗﯽ درﯾﺎي ﺧﺰر در اﺳﺘﺎن ﮔﻠﺴﺘﺎن از ﻣﻨﺎﻃﻖ ﻣﻬﻢ زﯾﺴﺘﯽ و ﺷﯿﻼﺗﯽ ﻣﯽﺑﺎﺷﻨﺪ، درﺣﺎﻟﯽ ﮐﻪ در ﺳﺎﻟﯿﺎن اﺧﯿﺮ ﺑﻪ ﺷﺪت آﻟﻮده ﺷﺪهاﻧﺪ. در ﭘﮋوﻫﺶ ﺣﺎﺿﺮ، ﭘﻮﯾﺎﯾﯽ ﻣﺎﻫﯿﺎن ﺑﺎ اﺳﺘﻔﺎده از اﯾﺰوﺗﻮپﻫﺎي ﭘﺎﯾﺪار ﻧﯿﺘﺮوژن و ﮐﺮﺑﻦ، ﺟﻬﺖ ﺗﻌﯿﯿﻦ رژﯾﻢ ﻏﺬاﯾﯽ و ﺟﺎﯾﮕﺎه ﺗﺮوﻓﯽ آنﻫﺎ، ارزﯾﺎﺑﯽ ﮔﺮدﯾﺪ ﮐﻪ ﻣﯽﺗﻮاﻧﺪ ﺷﺮاﯾﻂ زﯾﺴﺘﯽ اﮐﻮﺳﯿﺴﺘﻢ را ﺑﻪﺧﻮﺑﯽ ﺗﺮﺳﯿﻢ ﻧﻤﺎﯾﺪ. ﺑﺮ اﯾﻦ اﺳﺎس در ﺷﻬﺮﯾﻮر- ﻣﻬﺮ ﺳﺎل 1394 در 5 اﯾﺴﺘﮕﺎه اﮐﻮﻟﻮژﯾﮏ، ﻧﻤﻮﻧﻪﺑﺮداري از ﭘﺮﯾﻔﯿﺘﻮنﻫﺎ، ﻣﺎﮐﺮوﻓﯿﺖﻫﺎ، ﺑﺰرگﺑﯽﻣﻬﺮﮔﺎن ﮐﻔﺰي و ﻣﺎﻫﯽﻫﺎ ﺻﻮرت ﮔﺮﻓﺖ و ﮔﻮﻧﻪﻫﺎي ﻏﺎﻟﺐ ﺗﺤﺖ آﻧﺎﻟﯿﺰﻫﺎي اﯾﺰوﺗﻮﭘﯽ ﺑﺎ اﺳﺘﻔﺎده از دﺳﺘﮕﺎه EA-IRMS ﻗﺮار ﮔﺮﻓﺘﻨﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از اﯾﺰوﺗﻮپ ﻧﯿﺘﺮوژن- 15 و اﯾﺰوﺗﻮپ ﮐﺮﺑﻦ- 13 ﻧﺸﺎندﻫﻨﺪه ﻋﺪم وﺟﻮد ﺗﻌﺎدل درﺷﺮاﯾﻂ اﮐﻮﺳﯿﺴﺘﻢ ﺑﻮده ﮐﻪ ﻣﻮﺟﺐ ﺗﻐﯿﯿﺮ رژﯾﻢ ﻏﺬاﯾﯽ ﻣﻮﺟﻮدات و ﮐﺎﻫﺶ راﻧﺪﻣﺎن ﺷﺒﮑﻪ ﻏﺬاﯾﯽ ﺷﺪه اﺳﺖ. ﻣﻬﻤﺘﺮﯾﻦ ﻋﻮاﻣﻞ ﻓﺸﺎر ﺑﺮ اﮐﻮﺳﯿﺴﺘﻢ ﻧﯿﺰ، ﺑﺴﺘﻪ ﺑﻮدن ﮐﺎﻧﺎل-ﻫﺎي اﺻﻠﯽ درﯾﺎ ﺑﻪ ﺧﻠﯿﺞ، ورود آﻻﯾﻨﺪهﻫﺎي ﻣﺨﺘﻠﻒ ﺑﻪ اﮐﻮﺳﯿﺴﺘﻢ و ﻓﯿﺰﯾﻮﮔﺮاﻓﯽ ﺿﻌﯿﻒ ﺧﻠﯿﺞ ﮔﺮﮔﺎن ﺗﻌﯿﯿﻦ ﮔﺮدﯾﺪ.

Gorgan Bay and the southeastern coasts of the Caspian Sea in the Golestan Province are important biological and fisheries areas., while in recent years, they have been heavily contaminated. In present study, the dynamic of fishes, using stable nitrogen and carbon isotopes was evaluated to determine the diet and its trophic status, which can accurately chart the ecosystem's biological conditions. Accordingly, in September-October 2015 at 5 ecological stations, sampling of prephytones, macrophytes, macro invertebrates and fish, were taken and dominant species were subjected to isotope analyzes using the EA-IRMS device. The results of the nitrogen-15 and carbon-13 isotopes indicate an imbalance in ecosystem conditions that alters the diet of the organisms and reduces the efficiency of the food web. The main factors of pressure on the ecosystem, the closure of the main channels of the sea to the bay, the entry of various pollutants into the ecosystem and weak physiography of Gorgan Bay, were determined.