Geomorphological Foundations for the Formation and Functioning of the "Caspiy" Aqua‐Territorial (Marine) Carbon Polygon on the Dagestan Coast of the Caspian Sea

The  study  investigates  the  geomorphological  structure,  morphodynamics and  landscape‐ecological  characteristics  of  the  Dagestan  coast  of  the Caspian  Sea  in  order  to  provide  a  scientific  rationale  for establishing  the aqua‐territorial  carbon  polygon  “Caspiy”.  Special  attention  is  given  to substantiating the uniqueness of this polygon as the first facility of its kind in Russia and worldwide to be created on a large inland closed water body. The  study  is  based  on  a  comprehensive  analysis  of  published  sources, remote  sensing data  (Sentinel‐2,  Landsat‐8),  digital elevation models and field observations. Methods applied include geomorphological typology of coasts,  shoreline  dynamics  analysis  and  assessment  of  landscape‐ ecological risks. 
It  has  been  established  that  the  ongoing  regression  of  Caspian  Sea  level intensifies accumulative processes, including the growth of spits and bars, lagoon  shallowing  and  expansion  of  saline  and  sandy  landforms.  High sensitivity of the Terek, Sulak, and Samur delta complexes to sea‐level and river  discharge  variations  has  been  identified.  Key  landscape‐ecological risks have been assessed, including desertification,  secondary salinisation and degradation of wetlands. 
The study substantiates the need to establish the “Caspiy” carbon polygon as a key and at the same time unique platform for long‐term monitoring of the  carbon  balance  and  coastal  ecosystem  dynamics  on  a  large  inland closed water body. It is shown that no analogous polygon exists in Russia or  globally,  which  underscores  its  significance  for  studying  the transformation of natural  systems and  for  testing GIS‐based methods  for predicting coastal zone changes under dynamic natural and anthropogenic conditions. 

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