Long-term persistence of the floating bull kelp Durvillaea antarctica from the South-East Pacific: Potential contribution to local and transoceanic connectivity
Thiel, Martin
- 1Universidad Catolica del Norte
- 2Universidad de Los Lagos
- 3
- 4Universidad de Concepcion
- 5
- 6
Journal
Marine Environmental Research
ISSN
0141-1136
1879-0291
Open Access
closed
Volume
149
Start page
67
End page
79
Current knowledge about the performance of floating seaweeds as dispersal vectors comes mostly from mid latitudes (30 degrees-40 degrees), but phylogeographic studies suggest that long-distance dispersal (LDD) is more common at high latitudes (50 degrees-60 degrees). To test this hypothesis, long-term field experiments with floating southern bull kelp Durvillaea antarctica were conducted along a latitudinal gradient (30 degrees S, 37 degrees S and 54 degrees 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 (F-v/F-m and pigments) rather than in defence variables (phlorotannins and antioxidant activity). The observed long floating persistence and long-term acclimation responses at 54 degrees S support the hypothesis of LDD by kelp rafts at high latitudes.