|The geographical distribution of seaweed species in relation to temperature: present and past|
Van den Hoek, C.; Breeman, A.M.; Stam, W.T. (1990). The geographical distribution of seaweed species in relation to temperature: present and past, in: Beukema, J.J. et al. (Ed.) Expected effects of climatic change on marine coastal ecosystems. Developments in Hydrobiology, 57: pp. 55-67
In: Beukema, J.J. et al. (Ed.) (1990). Expected effects of climatic change on marine coastal ecosystems. Developments in Hydrobiology, 57. Kluwer Academic: Dordrecht. ISBN 0-7923-0697-X. 221 pp., more
In: Dumont, H.J. (Ed.) Developments in Hydrobiology. Kluwer Academic/Springer: The Hague; London; Boston; Dordrecht. ISSN 0167-8418, more
|Authors|| || Top |
- Van den Hoek, C.
- Breeman, A.M.
- Stam, W.T., more
Dumontia contorta exemplifies a number of temperate species occurring in the N Pacific Ocean and the N Atlantic Ocean and which were probably exchanged after the opening of the Bering Seaway (3.5 MA ago); their temperature responses indicate that their passage required a 6-8°C higher summer temperature than the present one in the Arctic Ocean. Some species in the above group, for instance Desmarestia viridis, have also an amphipolar distribution. Their passage across the tropics would have required a ca 5°C lowering of the equatorial sea surface temperature. This same temperature lowering can explain the extinction, along the east coasts of the Atlantic and Pacific Oceans, of tropical seaweeds such as Dictyosphaeria cavernosa with a W Atlantic-Indo W Pacific distribution. This lowering probably did not occur (sub)recently (for instance during Pleistocene glaciations), but earlier in the Cenozoic. We approached the question of the timing of the above temperature lowerings by estimating genetic divergence of disjunct populations of the same species or species complexes using the DNA-DNA hybridization method. Disjunct Atlantic and Pacific populations of several tropical and warm temperate species appeared to have genetically diverged in a high degree thus indicating a highly conservative morphology; this accords with their hypothetical divergence by the mid-Miocene (or earlier) closure of the Tethys Ocean. The divergence of amphipolar populations of the same species was probably more recent. Temperature changes of the sea surface predicted for the next century have a similar extent as those which have caused, in a more or less distant geologic past, profound alterations in the composition of the world's seaweed floras.