Zinc concentration in two decapods of a Northern Patagonian oligotrophic lake before and after a volcanic eruption

MONTAÑEZ, J.C.; RIZZO, A.; JUNCOS, R.; ARCAGNI, M.; ARRIBÉRE, M.A.; CAMPBELL, L.M.; RIBEIRO GUEVARA, S.

Córdoba

Congreso; VI Congreso Argentino de la Sociedad de Toxicología y Química Ambiental; 2016

Zinc (Zn) is an essential element for life. Despite its importance, the trophodynamics in natural lake systems has been poorly studied, and is unknown in the Patagonian waterbodies. This element reaches the ecosystems from natural sources, such as volcanic eruptions, which are frequent in the study region, releasing Zn to the aquatic environment by ash leaching. In lacustrine ecosystem the decapods, Samastacus spinifrons and Aegla sp., transfer energy from the benthos to higher positions in the food web. They are a key prey in the diet of vertebrates such as native and exotic fish, mammals and birds.In this sense, the aim of this work was to study the concentrations of Zn (Zn) in two tissues (muscle and hepatopancreas) in the two decapod species collected from three sites in Lake Nahuel Huapi (Brazo Rincón BR, Bahía López BL, and Dina Huapi DH), before and after the Puyehue-Cordón Caulle volcanic complex eruption in 2011 to test the incidence of Zn releases from volcanic ash releases. Zinc concentrations were determined by Instrumental Neutron Activation Analysis.The highest Zn were recorded in S. spinifrons hepatopancreas (129-1027 µg g-1 dry weight; DW) but no significant differences were recorded before and after the eruption. Muscle values (52-174 µg g-1 DW) were significantly lower than those of hepatopancreas (Kruskal-Wallis p-value < 0.05). There was no difference in Zn from muscle tissue before and after the eruption. Zinc concentrations in Aegla sp. muscle (61-319 µg g-1 DW) were higher than the hepatopancreatic levels (39-152 µg g-1 DW), (Kruskal-Wallis p-value < 0.05) except in BL before the eruption. There was no difference in muscle tissue comparing before and after the eruption.No influence of the volcanic eruption, an important source of Zn, was observed in Zn in Samastacus spinifrons and Aegla sp. tissues. This could be indicating a high capacity of these two species for Zn regulation.