Trace element bioaccumulation in hypersaline ecosystems and implications of a global invasion

Hypersaline ecosystems are under increasing threat due to anthropogenic pressures such as environmental pollution and biological invasions. Here we address the ecotoxicological implications of the Artemia franciscana (Crustacea) invasion in saltpans of southern Spain. This North American species is causing the extinction of native Artemia populations in many parts of the globe. The bioaccumulation of trace elements (As, Cd, Cu, Co, Cr, Mn, Ni, Pb and Zn) in native populations (A. parthenogenetica) from Cabo de Gata and Odiel saltpans and invasive Artemia from Cádiz saltpan was studied at different salinities. Furthermore, in Odiel, the most polluted study site, we also analysed the bioaccumulation of trace elements by Chironomus salinarius larvae (Diptera) and Ochthebius notabilis adults (Coleoptera). High levels of trace elements were detected in the studied saltpans, many of them exceeding the recommended threshold guidelines for aquatic life. Bioaccumulation of trace elements by Artemia was lowest at the highest salinity. The invasive A. franciscana showed higher potential to bioaccumulate trace elements than its native counterpart (in particular for As, Cd, Ni and Cr). In Odiel, O. notabilis stood out as showing the highest potential to bioaccumulate As and Cu. Results showed that the shift from a native to an alien Artemia species with a higher bioaccumulation capacity may increase the transfer of trace elements in hypersaline food webs, especially for waterbirds that depend on Artemia as food. Thus, our study identifies an indirect impact of the Artemia franciscana invasion that had not previously been recognised.
This work was funded by the Spanish Ministry of Economy and Competitiveness research project CGL2013-47674-P to MIS. Financial support was also provided by the Portuguese ‘Fundação para a Ciência e a Tecnologia’ (FCT) through MARE (UID/MAR/04292/2013), from the programs POPH (Portuguese Operational Human Potential Program) and QREN (Portuguese National Strategic Reference Framework) (FSE and national funds of MEC), and through the PhD grant of AJPC (SFRH/BD/108224/2015). MMH is funded by Junta de Comunidades de Castilla-La Mancha and the European Regional Development Fund (SBPLY/17/180501/000514).