MEPS 216:141-149 (2001)  -  doi:10.3354/meps216141

ABSTRACT: For the first time, in vivo heat-exposure experiments were conducted on the hydrothermal vent polychaete Hesiolyra bergi from the hottest part of the vent biotope. Using a pressurised incubator equipped with video-facilities, we found that H. bergi, which forages around and in the tubes of the thermophilic Alvinella sp., became hyperactive once temperature exceeded 35°C and further lost co-ordination in the 41 to 46°C interval, just before death occurred. Another exposure experiment at 39°C for 3 to 4 h led to 80% mortality (max) 9 h after heat shock, and 100% thereafter. In view of the much higher temperatures recorded in this organism¹s habitat, these results suggest that tolerance to high temperatures (exceeding 40°C) is not a pre-requisite for life amongst alvinellid tubes. Behavioural responses (escape from heat) may suffice.

KEY WORDS: Hydrothermal vents · Behaviour · Adaptation to heat · IPOCAMP