Population level variation in reproductive development and output in the golden kelp Laminaria ochroleuca under marine heat wave scenarios

Thermal tolerance is often interpreted as a species-wide thermal niche in the absence of studies focusing on adaptive potential populations to exhibit differential tolerance. Thus, considering intraspecific plasticity, local adaptation or both between along distributional gradients when interpreting and predicting species responses warming imperative. Removing effect environmental histories by raising kelp gametophyte generations vitro under common garden conditions allows unbiased comparison population-specific variation different conditions. Following this approach, study aims detect (potentially) differentiation microscopic life-stages (gametophytes) temperate forest forming kelp, Laminaria ochroleuca from locations with distinct Gametophytes four geographically were subjected temperature treatments (17, marine heat waves 23, 25 27°C) survival during stress well reproductive success photosynthetic recovery investigated. Intraspecific resilience output was found L. ; gametophytes most northern population (Brittany, France) thermally sensitive, mortality onset at 23°C, whereas remaining only apparent 27°C. Spain Morocco exhibited very low 23 25°C. However, recovering highest treatment (27°C) development sporophyte higher than France Italy (Mediterranean). The suggest genetic response regimes.