The adaptive significance of life history characters in selectedorders of marine brown maeroalgae

Abstract

Life history eharaeters. whieh are generally eonsidered to be of eritieal signifteanee in evolution, consist of various pheiiotypie trails eoneerned with growth and reproduetion. Siiite.s ot Hie history eharaeters are frequently referred to as 'strategies'. These are hypotheses whieh attempt to e.xplain the adaptive .signifieanee of partieular suites of eharaeters. This paper reviews lije history eharaeters of speeies belonging to various orders of brown algae (Phaeophyeeae) and diseusses their possible adaptive .'^igni/ieanee. together with the e.xtent to whieh they are eonsistent with opportunistie. stress tolerant and biotieally eompetent strategies. In general, speeies belonging to the same order have broadly similar suites of life history eharaeters and. thus, to some degree they share eomparable adaptive strategies. For e.\ample. the Laminariales, Fueales and Durvillaeales inelude a high proportion of biotieally eompetent speeies. many ofthe Dietyotales appear to be stress tolerant, and the Eetoearpales are typieally opportunistie. The two heteromorphie generations of speeies in the Seytosiphonales are viewed as having divergent strategies, the erustose stages showing a greater degree of stress toleranee than the opportunislie ereet stages.

Development of a transplantation technique of Cystoseira amentacea var. stricta and Cystoseira compressa

“…stricta recolonization has still not recolonized its former habitat . One can hypothesize that the lack of recolonization in disturbed areas could be explained by a small dispersal range and therefore by recruitment being linked to the presence of reproductive individuals in the neighborhood, as reported by Clayton (1990) for the order Fucales. Since natural restoration has never occurred, we propose to develop a technique for recolonization of impacted areas.…”

Self-replacement and community modification by the southern bull kelp Durvillaea antarctica

“…The fucoid algae that surround Durvillaea habitats are relatively poor dispersers due to their relatively large egg sizes (Clayton 1990, 1992, Chapman 1995. Consequently, zygotes rarely settle more than a few meters from adult plants (D.I.T.…”

Variations in photosynthetic characteristics of the Antarctic marine brown algaAscoseira mirabilisin relation to thallus age and size

“…The adult plants have perennial thalli, with a basal meristem and strap-like lamina closely resembling Laminaria species from the Northern Hemisphere (Clayton, 1990). Laboratory studies under simulated Antarctic daylength conditions have shown A. mirabilis to be welladapted to the Antarctic light regime, characterized by strong seasonal variations of daylength and irradiance.…”