Acetylcholinesterase activity of the polychaete Nereis diversicolor: effects of temperature and salinity

In order to estimate the potential use of the mean wholebody acetylcholinesterase (AChE) activity from the ragworm Nereis diversicolor for the biological assessment of pollution by anticholinesterase agents in estuarine areas, we measured the effects of the main abiotic factors (i.e. temperature and salinity) on AChE activity. We report here that AChE activity tends to decrease in individuals sampled in tanks at a salinity of 30 per thousand as temperature increases. No tendencies in the evolution of AChE activity were observed in individuals sampled in tanks at a salinity of 15 per thousand. In contrast, salinity seems to have a greater effect on AChE activity than temperature. At a temperature of 12 degrees C, a salinity of 30 per thousand provokes a significant transient increase of AChE 2 days after the beginning of the maintenance period compared with a salinity of 15 per thousand. The effects are short-term stress effects. We noticed only a transient increase of AChE activity between 2 days for individuals maintained in tanks at temperature of 20 degrees C and salinity of 15 and 30 per thousand, respectively, and 8 days for individuals maintained in tanks at salinity of 30 per thousand and at a temperature of 12 degrees C after the beginning of the maintenance period, confirming the more pronounced effect of salinity over temperature.