CONICET | Buscador de Institutos y Recursos Humanos

The invasiveness of Corbicula largillierti has been underestimated but this bivalve iscurrently receiving more attention. The first study of the distribution of this speciesalong one of the major basins of central Argentina showed that it was completelyabsent in the major central reservoir, but was present along its tributary and effluentrivers. Ten years later, this discontinuous distribution has not changed despite thebivalve?s high dispersion capacity. The main environmental differences between thereservoir and the rivers are that the former has finer sediment grain size, highertemperatures, and lower oxygen concentration during summer months. This studyaimed to evaluate if one of these factors could be limiting C. largillierti distribution.We assessed the metabolic response and burial behavior (under different grainsizes) of C. largillierti during eight weeks at 30 ºC against a control condition of 20ºC. We also analyzed the oxygen consumption (vO2) as a function of environmentaloxygen concentration (pO2) at 25 ºC, estimating its metabolic regulation capacity(R). This showed the existence of an environmental oxygen concentration threshold(Pt), that could be indicative of physiological limiting concentrations that compromisespecies survival and settlement.After eight weeks at 30 °C, the metabolic rate of C. largillierti increased and its burialbehavior was slightly compromised but mostly for coarser sediments. Concerningenvironmental oxygen availability, C. largillierti is an oxyconformer with a low R=39.9%, with a clear pattern of negative regulation and a low Pt= 48.4% air saturation.The lack of any regulation capacity of C. largillierti under environmental oxygenlimitations and the extremely low pO2 at the bottom of the reservoir during summermonths may explain its failure to colonize and survive there.