Tolerance to copper and to salinity in Daphnia longispina: implications within a climate change scenario

• Published in: PloS one 2013-08, Vol.8 (8), p.e68702
• Main Authors: Leitão, João, Ribeiro, Rui, Soares, Amadeu M V M, Lopes, Isabel
• Format: Article
• Language: English
• Subjects: Animals; Biology; Chemical contaminants; Chemical contamination; Chemical pollution; Chemicals; Chlorine compounds; Cladocera; Climate Change; Climate change scenarios; Coastal aquifers; Coastal ecosystems; Contaminants; Contamination; Copper; Copper - toxicity; Crustacea; Daphnia - drug effects; Daphnia - physiology; Daphnia longispina; Daphnia magna; Earth Sciences; Ecosystem; Ecosystem biology; Environmental changes; Exposure; Female; Fresh Water; Freshwater; Freshwater organisms; Genotype; Genotypes; Growth rate; Hydrogen-Ion Concentration; Hypotheses; Intrusion; Laboratories; Lethal levels; Lumbricus; Metals; Microsatellite Repeats; Neonates; Newborn babies; Nickel; Oxygen - chemistry; Population; Population genetics; Potassium; Quantitative genetics; Saline water; Saline water intrusion; Salinity; Salinity effects; Salts - chemistry; Seawater; Seawater intrusion; Sodium; Sodium chloride; Sodium Chloride - chemistry; Toxicity; Water Pollutants, Chemical - toxicity
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0068702

Considering IPPC climate change scenarios, it is pertinent to predict situations where coastal ecosystems already impacted with chemical contamination became exposed to an additional stressor under a future scenario of seawater intrusion. Accordingly, the present study aimed at evaluating if a negative association between tolerance to a metal and to saltwater exists among genotypes of a freshwater organism. For this, five clonal lineages of the cladoceran Daphnia longispina O.F. Müller, exhibiting a differential tolerance to lethal levels of copper, were selected. Each clonal lineage was exposed to lethal and sublethal concentrations of sodium chloride (assumed as a protective surrogate to evaluate the toxicity of increased salinity to freshwater organisms). Mortality, time to release the first brood and total number of neonates per female were monitored and the somatic growth rate and intrinsic rate of natural increase were computed for each clonal lineage. Data here obtained were compared with their lethal responses to copper and significant negative correlations were found. These results suggest that genetically eroded populations of D. longispina, due to copper or salinity, may be particularly susceptible to a later exposure to the other contaminant supporting the multiple stressors differential tolerance.