Behavioural and Physiological Responses of Gammarus pulex Exposed to Cadmium and Arsenate at Three Temperatures: Individual and Combined Effects

Abstract

This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and15°C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane. After exposure, survival, [AsV] or [Cd] in body tissues, behavioural (ventilatory and locomotor activities) and physiological responses (iono-regulation of [Na+] and [Cl−] in haemolymph) were examined. The interactive effects (antagonistic, additive or synergistic) of binary mixtures were evaluated for each tested temperature using a predictive model for the theoretically expected interactive effect of chemicals. In single metal exposure, both the internal metal concentration in body tissues and the mortality rate increased along metallic gradient concentration. Cd alone significantly impaired both [Na+] and [Cl−] while AsV alone had a weak impact only on [Cl−]. The behavioural responses of G. pulex declined with increasing metal concentration suggesting a reallocation of energy from behavioural responses to maintenance functions. The interaction between AsV and Cd was considered as ‘additive’ for all the tested binary mixtures and temperatures (except for the lowest combination at 10°C considered as “antagonistic”). In binary mixtures, the decrease in both ventilatory and locomotor activities and the decline in haemolymphatic [Cl−] were amplified when respectively compared to those observed with the same concentrations of AsV or Cd alone. However, the presence of AsV decreased the haemolymphatic [Na+] loss when G. pulex was exposed to the lowest Cd concentration. Finally, the observed physiological and behavioural effects (except ventilation) in G. pulex exposed to AsV and/or Cd were exacerbated under the highest temperature. The discussion encompasses both the toxicity mechanisms of these metals and their interaction with rising temperature.

Species-specific behaviours in amphipods highlight the need for understanding baseline behaviours in ecotoxicology

“…The light/dark choice chamber has been used with the marine amphipod Echinogammarus marinus to assess phototactic behaviours (Guler and Ford, 2010) and swimming velocity has also been shown as a sensitive endpoint in this species for the assessment of effects of antidepressants on behaviours (Bossus et al, 2014). The freshwater amphipod Gammarus pulex has been used in numerous studies using behaviour as an endpoint to assess the effects of environmental pollution in freshwater systems (Gerhardt, 1995;Gerhardt et al, 1998;Watts, Pascoe and Carroll, 2001;Lauridsen and Friberg, 2005;De Lange, Sperber and Peeters, 2006;Felten et al, 2008;Alonso, De Lange and Peeters, 2009;De Lange, Peeters and Lurling, 2009;Vellinger et al, 2012;Nyman et al, 2013;De Castro-Català et al, 2017) Our overall aim was to provide information on the baseline unconditioned behaviours of a marine and freshwater amphipod (Echinogammarus marinus and Gammarus pulex), to aid in the advancement of behavioural assays on complex behaviours in model crustaceans.…”

Quantifying diet-borne metal uptake in Gammarus pulex using stable isotope tracers

“…Gammarids can accumulate waterborne and diet-borne metals. The waterborne uptake route has been intensively studied (e.g., Bourgeault et al, 2013;Lebrun et al, 2012;Vellinger et al, 2012). Although the diet-borne uptake of metals may be a significant pathway for metal accumulation in gammarids (Abel and Bärlocher, 1988), this type of uptake has been poorly documented.…”

Temperature and salinity effects on cadmium toxicity on lethal and sublethal responses of Amphibalanus amphitrite nauplii

“…Kwok and Leung (2005) supported this statement by demonstrating that copper and TBT toxicity to the copepod Tigriopus japonicus was significantly greater at higher temperatures. An increase in toxic effect due to temperature increase was also reported for the brine shrimp Artemia franciscana (Koutsaftis and Aoyama, 2008), in a study with cadmium for the amphipod Corophium insidiosum (Prato et al, 2008), for Mysidopsis bahia (Voyer and Modica, 1990), for Gammarus pulex (Vellinger et al, 2012) and for the copepod Acartia tonsa exposed to 2,4-dihydrobenzophenone (Kusk et al, 2011). Since these model organisms were not fed during the test period, increasing metabolic rate by increasing temperature can lead to faster energy reserve depletion and thus increased susceptibility to the reference toxicant.…”