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Aragonit u Mljetskim jezerima: Procesi anorganske precipitacije i formiranje biogene strukture koralja Cladocora caespitosa

Sažetak: Aragonit se u Mljetskim jezerima pojavljuje u obliku anorganskih precipitata te kao dio biomineralne strukture koralja Cladocora caespitosa. Anorganski precipitati, kristalografski slabo definirane igličaste čestice aragonita, nastaju kemijskom precipitacijom tijekom jedinstvene prirodne pojave u Mediteranu, formiranja koloidnog bjelila. Određena je uloga anorganskih (fizikalno-kemijskih) i bioloških procesa u nastajanju, flokulaciji i sedimentaciji aragonita u istraživanom okolišu, čime se doprinijelo rješavanju dileme o značaju tih procesa u formiranju recentnih aragonitnih muljeva u morskim okolišima. Pojava biogenog aragonita vezana je za biološku aktivnost i rast koralja Cladocora caespitosa. Detaljna strukturna i morfološka istraživanja skeleta koralja pokazala su da je morfogeneza organiziranih vlaknastih formi aragonita uvjetovana složenim koloidno-kemijskim i biološkim procesima na nanorazini. Utvrđena je uloga organskog materijala i nano-agregacijskih procesa u formiranju vlaknastih struktura aragonita. Abstract: In the Mljet Lakes, aragonite occurs in the form of an inorganic precipitate and as a biomineral in the skeletal structure of the coral Cladocora caespitosa. Inorganic precipitate, crystallographically poor-defined needle-like aragonite particles are formed through chemical precipitation during whiting events, a unique natural phenomenon in the Mediterranean. The role of inorganic (physico-chemical) and biological processes in the formation, flocculation and sedimentation of aragonite in the examined environment was established, thus providing new evidence relating to the long-lasting dilemma about the importance of those processes in the formation of recent aragonite mud in marine environments. The appearance of aragonite as a biomineral is associated with the biological activity and growth processes of the coral Cladocora caespitosa. A detailed structural and morphological examination of the bio-inorganic skeletal architecture of the coral revealed that the morphogenesis of the aragonite fibers is a complex, colloid-chemical and biological mechanism occurring at the nanoscale. The role of the organic matter and nano-aggregation processes in the formation of complex aragonite structures was established.

aragonit; sedimenti; koralji; anorganska precipitacija; biomineralna struktura; proteini

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