Skip to content


Helgoland Marine Research

Open Access

Temperature tolerance and daylength effects in isolates ofScytosiphon lomentaria (Phaeophyceae) of the North Atlantic and Pacific Ocean

  • Inka tom Dieck1
Helgoländer Meeresuntersuchungen41:BF02366195


Fifteen geographical isolates ofScytosiphon lomentaria were investigated for their daylength response with regard to upright thallus formation, and nineteen isolates for their upper temperature tolerance. Six new day-neutral and two new photoperiodic strains were found. It became evident that day-neutral strains represent a common reaction group in this species, besides the photoperiodic group. The temperature regulation of photoperiodic and day-neutral strains did not show striking differences and it is assumed that temperature regulation may trigger seasonality of occurrrence in this species as well as photoperiod. The upper survival temperature after two weeks of heart stress is 28–29°C in all tested isolates. No temperature ecotypes were found.