Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)

Study region:: Lake Urmia, northwestern Iran Study focus:: This study investigates the stratification and vertical mixing dynamics of Lake Urmia, a transboundary hypersaline lake under critical ecological stress. Using multi-year, high-resolution in-situ temperature and salinity measurements (2016–2...

Full description

Saved in:
Bibliographic Details
Main Authors: Peygham Ghaffari, Jafar Azizpour, Evgeniy Yakushev, Hamid A.K. Lahijani
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Journal of Hydrology: Regional Studies
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2214581825005269
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849233529842434048
author Peygham Ghaffari
Jafar Azizpour
Evgeniy Yakushev
Hamid A.K. Lahijani
author_facet Peygham Ghaffari
Jafar Azizpour
Evgeniy Yakushev
Hamid A.K. Lahijani
author_sort Peygham Ghaffari
collection DOAJ
description Study region:: Lake Urmia, northwestern Iran Study focus:: This study investigates the stratification and vertical mixing dynamics of Lake Urmia, a transboundary hypersaline lake under critical ecological stress. Using multi-year, high-resolution in-situ temperature and salinity measurements (2016–2019), we characterize seasonal mixing patterns and quantify the relative contributions of salinity and temperature to vertical water column stability. A lake-specific density formulation and thermal energy estimates are applied to assess buoyancy structure and overturn dynamics across contrasting seasonal phases. New hydrogeological insights from the region:: Lake Urmia exhibits a dual-phase mixing regime, polymictic during the warm season with recurrent full-depth mixing, and inverse meromictic during the cold season due to salinity-enhanced density stratification. Salinity is shown to be the dominant stabilizing factor, while temperature plays a supporting role, primarily as a long-term tracer. The lake is classified as Hyperhalimictic, where mixing is governed by salinity rather than classical thermal stratification. A seasonal salinity pump mechanism is identified—winter brine rejection deepens stratification, while summer halite re-dissolution erodes it. Thermal inertia in lakebed sediments contributes to persistent cold-phase stratification. Findings indicate a trend toward increasing vertical decoupling, reduced overturning, and elevated risk of ecological stress. These insights support improved understanding of hypersaline lake behavior and can guide monitoring and resilience strategies in similar terminal lakes worldwide.
format Article
id doaj-art-2ab2a33d40ea4b4c94d6b09a32c1e933
institution Kabale University
issn 2214-5818
language English
publishDate 2025-10-01
publisher Elsevier
record_format Article
series Journal of Hydrology: Regional Studies
spelling doaj-art-2ab2a33d40ea4b4c94d6b09a32c1e9332025-08-20T05:06:56ZengElsevierJournal of Hydrology: Regional Studies2214-58182025-10-016110269710.1016/j.ejrh.2025.102697Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)Peygham Ghaffari0Jafar Azizpour1Evgeniy Yakushev2Hamid A.K. Lahijani3Akvaplan-niva, Dept. Arctic R&D, Økernveien 94, Oslo, 0579, Norway; Corresponding author.Iranian National Institute for Oceanography and Atmospheric Science, Tehran, IranNorwegian Institute for Water Research, Økernveien 94, Oslo, 0579, NorwayIranian National Institute for Oceanography and Atmospheric Science, Tehran, IranStudy region:: Lake Urmia, northwestern Iran Study focus:: This study investigates the stratification and vertical mixing dynamics of Lake Urmia, a transboundary hypersaline lake under critical ecological stress. Using multi-year, high-resolution in-situ temperature and salinity measurements (2016–2019), we characterize seasonal mixing patterns and quantify the relative contributions of salinity and temperature to vertical water column stability. A lake-specific density formulation and thermal energy estimates are applied to assess buoyancy structure and overturn dynamics across contrasting seasonal phases. New hydrogeological insights from the region:: Lake Urmia exhibits a dual-phase mixing regime, polymictic during the warm season with recurrent full-depth mixing, and inverse meromictic during the cold season due to salinity-enhanced density stratification. Salinity is shown to be the dominant stabilizing factor, while temperature plays a supporting role, primarily as a long-term tracer. The lake is classified as Hyperhalimictic, where mixing is governed by salinity rather than classical thermal stratification. A seasonal salinity pump mechanism is identified—winter brine rejection deepens stratification, while summer halite re-dissolution erodes it. Thermal inertia in lakebed sediments contributes to persistent cold-phase stratification. Findings indicate a trend toward increasing vertical decoupling, reduced overturning, and elevated risk of ecological stress. These insights support improved understanding of hypersaline lake behavior and can guide monitoring and resilience strategies in similar terminal lakes worldwide.http://www.sciencedirect.com/science/article/pii/S2214581825005269Lake UrmiaHypersaline lake dynamicsStratificationBuoyancy frequencyInverse meromixisHyperhalimictic
spellingShingle Peygham Ghaffari
Jafar Azizpour
Evgeniy Yakushev
Hamid A.K. Lahijani
Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)
Journal of Hydrology: Regional Studies
Lake Urmia
Hypersaline lake dynamics
Stratification
Buoyancy frequency
Inverse meromixis
Hyperhalimictic
title Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)
title_full Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)
title_fullStr Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)
title_full_unstemmed Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)
title_short Stratification and mixing dynamics of hypersaline Lake Urmia (Iran)
title_sort stratification and mixing dynamics of hypersaline lake urmia iran
topic Lake Urmia
Hypersaline lake dynamics
Stratification
Buoyancy frequency
Inverse meromixis
Hyperhalimictic
url http://www.sciencedirect.com/science/article/pii/S2214581825005269
work_keys_str_mv AT peyghamghaffari stratificationandmixingdynamicsofhypersalinelakeurmiairan
AT jafarazizpour stratificationandmixingdynamicsofhypersalinelakeurmiairan
AT evgeniyyakushev stratificationandmixingdynamicsofhypersalinelakeurmiairan
AT hamidaklahijani stratificationandmixingdynamicsofhypersalinelakeurmiairan