Long-term persistence of the floating bull kelp Durvillaea antarctica from the South-East Pacific: Potential contribution to local and transoceanic connectivity

• Published in: Marine Environmental Research
• Main Authors: Tala, Fadia, López, Boris A., Velásquez, Marcel, Jeldres, Ricardo, Macaya, Erasmo C., Mansilla, Andrés, Ojeda, Jaime, Thiel, Martin
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Ltd 2019
• Subjects: Chile; Dispersal; Durvillaea antarctica; Floating persistence; Floating seaweeds; Rafting; Temperature; Austral; Pacific; Antarc*; Antarctica
• Online Access: https://doi.org/10.1016/j.marenvres.2019.05.013; https://repositorio.uchile.cl/handle/2250/172596

Current knowledge about the performance of floating seaweeds as dispersal vectors comes mostly from mid latitudes (30°–40°), but phylogeographic studies suggest that long-distance dispersal (LDD) is more common at high latitudes (50°–60°). To test this hypothesis, long-term field experiments with floating southern bull kelp Durvillaea antarctica were conducted along a latitudinal gradient (30°S, 37°S and 54°S) in austral winter and summer. Floating time exceeded 200d in winter at the high latitudes but in summer it dropped to 90d, being still higher than at low latitudes (<45d). Biomass variations were due to loss of buoyant fronds. Reproductive activity diminished during long floating times. Physiological changes included mainly a reduction in photosynthetic (Fv/Fm and pigments) rather than in defence variables (phlorotannins and antioxidant activity). The observed long floating persistence and long-term acclimation responses at 54°S support the hypothesis of LDD by kelp rafts at high latitudes.