ماهي آب شيرين، منبع غذايي مورد استفاده توسط ساكنان محوطه ي عصر آهن گوهر تپه مازندران

Fresh Water Fish, Food Resource Used by the Inhabitants of the Gowhar Tepe Site, Mazandaran

آناليز ايزوتوپ هاي پايدار جهت بازسازي و تفسير رژيم هاي غذايي گذشتگان، رويِ كربن و نيتروژنِ موجود در عناصر اسكلتي (اعم از استخوان و دندان) تمركز يافته و پيش بيني هاي صحيحي را از اين موضوع مهم (ديرينه تغذيه شناسي) به دست مي دهد؛ زيرا به طور طبيعي اين نسبت ها بين طبقات معينِ انواع مواد غذايي فرق مي كند. ماهي آب شيرين، نقش مهمي در رژيم غذايي گذشتگان داشته و مدارك مربوط به مصرف آن با شيوه هاي گوناگوني قابل بازيافت است. يكي از اين موارد، آناليز ايزوتوپي است. تنوع ايزوتوپي كربن در محيط هاي آب شيرين بسيار گسترده است. اين تنوع بر موجوداتِ زنده ي چنين اكوسيستم هايي حكم فرما است، حتي اگر اين اكوسيستم ها از نظر جغرافيايي به هم نزديك باشد. اما گوناگوني سطوح ايزوتوپ نيتروژن 15 در تمام جهان، براي ماهي آب شيرين تقريباً يكسان است. شايان ذكر است كه هم پوشاني در سطوح ايزوتوپي كربن 13 بين ماهي آب شيرين و منابع خشكي (زميني) وجود دارد. آناليز ايزوتوپ هاي پايدار كربن و نيتروژن در تفسير رژيم هاي غذايي كاربرد دارد؛ چراكه تفاوت هاي ايزوتوپي موجود در مواد غذايي به استخوان هاي افرادي كه اين غذاها را مصرف مي كنند، منتقل شده و بررسي نسبت ايزوتوپ هاي اين عناصر در استخوان ها، مي تواند نوع غذايي را كه افراد مصرف مي كردند، مشخص نمايد. اين مقاله با استفاده از آناليز ايزوتوپ هاي پايدار كربن و نيتروژنِ كلاژن دنداني 12 اسكلت انساني، مربوط به قبرستان عصر آهنِ محوطه ي باستاني گوهرتپه در شرق استان مازندران، واقع در ساحل جنوبي درياي خزر، فرض وجود ماهي آب شيرين را در رژيم غذايي ساكنان محوطه ي گوهرتپه بررسي كرده و تا حدودي فرضيه ي مصرف ماهي آب شيرين در رژيم غذايي ساكنين گوهرتپه را تاييد كرد؛ هرچند اثبات بهتر اين موضوع، به آناليز ايزوتوپي موجودات زنده در محيط هاي آب شيرين آن منطقه، وابسته است.

The analysis of stable isotopes concentrated on carbon and nitrogen in skeletal elements (such as bone and teeth)، to reconstruct and interpret of past diets and provides accurate predictions too excellent results of this important issue، because these ratios are normally different be-tween certain categories of food. Freshwater fish have played an important role in human diet over time. Evidence of fish consumption is inferred mainly from the study of food remains، and weapons and tools، and indirectly from the pattern of wear on tools، iconography، artifacts، and fish vertebrae used for necklaces and also isotopic analysis is one of these. Carbon isotopic var-iation is widespread and different in freshwater environments. This diversity is dominant on the Organisms that live in these ecosystems، even if these ecosystems are geographically close to each other and not far together. Nevertheless، δ15N variation in the whole world، for freshwater fish is identical and similar. The stable nitrogen isotopes in terrestrial plants and animals are depleted relative to fish from fresh or marine water habitats. But، this variation in δ13C is widespread and different. It is noteworthy that there is an overlap of the isotopic 13C levels be-tween freshwater fish and Terrestrial resources. Stable isotopic analysis of carbon and nitrogen in bone and tooth collagen is now a well-established technique and a reliable method for the reconstruction of ancient human diet، because isotopic composition of carbon and nitrogen in the human body tissues reflects the consumed food. Also this analysis has become a valuable tool in studies of ecosystem function and animal ecology. In terrestrial، freshwater and marine ecosystems they have been used successfully in a variety of studies such as to describe major flow pathways of organic matter in food webs، reveal food web structure، determine vegetation selectivity of herbivores، track animal movements and migrations or elucidate feeding strate-gies and relationships among individual animals. Stable isotopes have also been used to moni-tor watershed level processes such as inputs of terrestrial organic material to aquatic ecosys-tems presented an overview of studies which examined carbon isotope signatures in freshwater and marine sediments to indicate carbon flow and to track terrestrial inputs.The basic principle of using carbon and nitrogen isotopes in paleo-diet determination is based on the observation that the isotope ratios of these elements (δ13C، δ15N)، mainly in collagen، will reflect the cor-responding isotopic ratios in the protein of the diet، with adjustment for fractionation through the system. The analysis of stable isotopes of carbon and nitrogen is used in the reconstruction of Diets، because the isotopic differences found in foods، transferred to the bones of individuals who consume these foods and evaluation of isotopic ratio of these elements in bones، can de-termine the kind of food that people consumed. In this Paper، we investigate the possibility of existence freshwater fish in diet of inhabitants of Gowhar Tepe by using of the Carbon and ni-trogen stable isotope analysis of tooth collagen of 12 human skeletons of the Iron Age Gowhar Tepe cemetery. This cemetery is located on the southern shore of the Caspian Sea، the East Ma-zandaran province. The geographical location of the site on the shore of Caspian Sea، and near the Neka-’ River would have provided abundant and reliable food sources. Because of the ex-tensive isotopic variation in fresh water ecosystems، studying the fresh water fish should be done in order to reconstruct the diet better، accordingly by studying samples tested Can be part-ly Approved the hypothesis of consumption of freshwater fish in the diet of inhabitants of Gowhar Tepe. Although، more reasoned proved of this issue is depends on Analysis of the re-gion’s freshwater organism’s environment.