BEHAVIORAL-RESPONSE OF 3 NEREID POLYCHAETES TO INJECTION OF SULFIDE INSIDE BURROWS

The behavioural response (ventilation rate, duration of ventilation bu rsts, length of pauses between ventilation bursts) of 3 closely relate d nereid polychaetes (Nereis virens, N. diversicolor and N. succinea) to various levels of sulfide exposure was investigated during spring a nd summer of 1992. The response to HS- was species specific. N. virens reacted strongly to HS- by increasing the duration of ventilation bur sts. Duration of rest periods was affected less severely while ventila tion failed to show any significant variation. The behavioural respons e of N. diversicolor did not show much variation under HS- exposure. T he only significant response was a decreased duration of rest periods at high HS- concentration. The type of reaction displayed by N. succin ea was similar to the response of N. virens, although less pronounced. N. diversicolor removed most HS- from the burrow in less than 10 min due to the generally high ventilation rate of this species. The slow r emoval of HS- by the other 2 species is caused by a slower response an d lower ventilation rate. The shape of the HS- efflux curve indicated that changes in the response during exposure are important in N. viren s and substantiate a possible toxic effect of HS-. N. diversicolor dis played the fastest recuperation following HS- exposure (restored venti lation behaviour). For all species, time of recuperation increased wit h increasing sulfide concentration.