Abstract

The importance of the posterior gills in the osmo and iono-regulatory processes in euryhaline crustacean species has been well documented and the mechanisms under-pinning these processes are well understood. However, little information is available with respect to the impacts of pharmaceutical agents on decapod crustaceans at environmentally realistic concentrations. This study examines the impacts of the non-steroidal anti-inflammatory drug, diclofenac, on the shore crab, Carcinus maenas at two environmentally realistic concentrations (10 and 100ng/l). Exposure to diclofenac impaired the osmoregulatory abilities of C. maenas at both concentrations p< 0.05), impacting on the passage and regulation of inorganic ions (Na⁺, Cl^-, and K_⁺). The effects of this pharmaceutical on the osmo and iono-regulatory abilities of C. maenas were a result of the actions of diclofenac and not attributed to a more general stress response. No change in haemolymph lactate and glucose concentrations was recorded (p> 0.05). Histological examination of the gill lamellae revealed that exposure to both concentrations of diclofenac increased the thickness of the cuticle / epithelial layer (p< 0.05). Nephrocyte counts per lamellae were also reduced by 20-23% in C. maenas exposed to diclofenac (p< 0.05). The results suggest that environmental concentrations of diclofenac can affect the ability of C. maenas to regulate the concentration of the body fluids as a whole and also the ability to regulate the concentrations of specific ions. Exposure to diclofenac also causes structural alterations within the cuticle / epithelial layer of the gill lamellae. These effects may limit the ability of C.maenas to tolerate salinity fluctuations, with potential ecological implications.

Additional Notes

Supervisors: Dr Colin Waring and Dr Alex Ford

Course: Master of Philosophy - MPhil

Date Deposited: 2017-05-08

URI/permalink: https://library.port.ac.uk/dissert/dis12870.html