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Journals / Marine and Life Sciences / 2026 / Cilt: 8 Sayı: 1

Structural and chemical characterization of gastroliths and calcium carbonate stability in narrow-clawed crayfish (Pontastacus leptodactylus (Eschscholtz, 1823)) from Atikhisar Reservoir, Türkiye

Selçuk Berber(Çanakkale Onsekiz Mart University, Faculty of Marine Sciences and Technology, Department of Basic Sciences of Fisheries, Department of Biology of Inland Waters, 17020, Çanakkale, Türkiye)0000-0003-1123-7217
Bayram Kızılkaya(Çanakkale Onsekiz Mart University, Faculty of Marine Sciences and Technology, Department of Aquaculture, 17020, Çanakkale, Türkiye)0000-0002-3916-3734
Semih Kale(Çanakkale Onsekiz Mart University, Faculty of Marine Sciences and Technology, Department of Fishing and Fish Processing Technology, 17020, Çanakkale, Türkiye)0000-0001-5705-6935
Sefa Acarlı(Çanakkale Onsekiz Mart University, Faculty of Marine Sciences and Technology, Department of Aquaculture, 17020, Çanakkale, Türkiye)0000-0002-5891-5938
Deniz Acarlı(Çanakkale Onsekiz Mart University, Vocational School of Maritime Underwater Technologies, Department of Motor Vehicles and Transportation Technologies, Technology Program, 17100, Çanakkale, Türkiye)0000-0001-8537-9969
Evren Tan0000-0003-3446-9889
Pages
41–53
Publication Date
2026-06-26
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

ICP-OES results showed that calcium concentration was higher in blue gastroliths, while phosphorus and magnesium concentrations were relatively higher in white gastroliths.

📌 3 Key Takeaways

🎯
Objective & Hypothesis:Narrow-clawed crayfish ( Pontastacus leptodactylus ) is an economically important freshwater species in inland fisheries.
📊
Key Findings & Data:When expressed as calculated calcium carbonate equivalent, the gastroliths contained approximately 75-78% CaCO 3 .
💡
Conclusion & Impact:ICP-OES results showed that calcium concentration was higher in blue gastroliths, while phosphorus and magnesium concentrations were relatively higher in white gastroliths.
🔬Design:Araştırma Makalesi
📍Scope:Comprehensive Sample
⚙️Variables:Pontastacus leptodactylus · Gastrolith · Calcium carbonate

Abstract

Narrow-clawed crayfish ( Pontastacus leptodactylus ) is an economically important freshwater species in inland fisheries. During molting, gastroliths function as temporary calcium carbonate storage structure and contribute to calcium mobilization for subsequent cuticle mineralization. In this study, the structural, chemical, and morphological properties of white and blue gastroliths extracted from mature P. leptodactylus individuals collected from Atikhisar Reservoir, Çanakkale, Türkiye, were investigated. Raman spectroscopy, X-ray diffraction (XRD), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) were used for complementary characterization. Raman spectra confirmed the presence of carbonate-related vibrational bands in both gastrolith types, while XRD patterns indicated differences in crystallinity between white and blue samples. Blue gastroliths exhibited sharper and more pronounced diffraction peaks, suggesting a higher crystalline calcium carbonate fraction, whereas white gastroliths showed broader features consistent with a greater amorphous component. ICP-OES results showed that calcium concentration was higher in blue gastroliths, while phosphorus and magnesium concentrations were relatively higher in white gastroliths. When expressed as calculated calcium carbonate equivalent, the gastroliths contained approximately 75-78% CaCO 3 . SEM-EDS observations revealed layered microstructures and fibrous organic-associated features, with Ca, O, C, P, and Mg as the dominant detected elements. Overall, the results suggest that color variation in P. leptodactylus gastroliths is associated with differences in elemental composition, crystallinity, and the relative contribution of amorphous and crystalline calcium carbonate phases. The higher phosphorus content in white gastroliths may contribute to the stabilization of amorphous calcium carbonate, whereas the higher calcium content and sharper XRD peaks in blue gastroliths indicate a more crystalline mineral structure. These findings provide baseline data for understanding gastrolith biomineralization in Turkish populations of P. leptodactylus and may contribute to future studies on molting physiology, calcium metabolism, and freshwater crayfish aquaculture.

Özet

Narrow-clawed crayfish ( Pontastacus leptodactylus ) is an economically important freshwater species in inland fisheries. During molting, gastroliths function as temporary calcium carbonate storage structure and contribute to calcium mobilization for subsequent cuticle mineralization. In this study, the structural, chemical, and morphological properties of white and blue gastroliths extracted from mature P. leptodactylus individuals collected from Atikhisar Reservoir, Çanakkale, Türkiye, were investigated. Raman spectroscopy, X-ray diffraction (XRD), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) were used for complementary characterization. Raman spectra confirmed the presence of carbonate-related vibrational bands in both gastrolith types, while XRD patterns indicated differences in crystallinity between white and blue samples. Blue gastroliths exhibited sharper and more pronounced diffraction peaks, suggesting a higher crystalline calcium carbonate fraction, whereas white gastroliths showed broader features consistent with a greater amorphous component. ICP-OES results showed that calcium concentration was higher in blue gastroliths, while phosphorus and magnesium concentrations were relatively higher in white gastroliths. When expressed as calculated calcium carbonate equivalent, the gastroliths contained approximately 75-78% CaCO 3 . SEM-EDS observations revealed layered microstructures and fibrous organic-associated features, with Ca, O, C, P, and Mg as the dominant detected elements. Overall, the results suggest that color variation in P. leptodactylus gastroliths is associated with differences in elemental composition, crystallinity, and the relative contribution of amorphous and crystalline calcium carbonate phases. The higher phosphorus content in white gastroliths may contribute to the stabilization of amorphous calcium carbonate, whereas the higher calcium content and sharper XRD peaks in blue gastroliths indicate a more crystalline mineral structure. These findings provide baseline data for understanding gastrolith biomineralization in Turkish populations of P. leptodactylus and may contribute to future studies on molting physiology, calcium metabolism, and freshwater crayfish aquaculture.

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Cite This Article

Berber, S., Kızılkaya, B., Kale, S., Acarlı, S., Acarlı, D., Tan, E. (2026). Structural and chemical characterization of gastroliths and calcium carbonate stability in narrow-clawed crayfish (Pontastacus leptodactylus (Eschscholtz, 1823)) from Atikhisar Reservoir, Türkiye. Marine and Life Sciences, Cilt: 8 Sayı: 1, 41–53. https://doi.org/10.51756/marlife.1837996

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