Coralline algal maerl frameworks-Islands within the phaeophytic kelp belt.

Freiwald, André (1993) Coralline algal maerl frameworks-Islands within the phaeophytic kelp belt. Facies, 29 (1). pp. 133-148. DOI 10.1007/BF02536925.

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Abstract

In the subtropical belt highly productive ecosystems are formed by coral reefs in oligotrophic seas. Towards more eutrophic conditions, coral reefs diminish and are subsequently replaced by highly productive kelp forests. In high latitudes framework constructing carbonate production is enhanced by the growth of branching coralline algae which predominantly generate maerl-type deposits. On a global view, these coralline algal ecosystems show an island-like distribution pattern within the phaeophytic kelp belt. Compared to kelp ecosystems, coralline-algaldominated ecosystems have low rates of productivity. Therefore, it is reasonable to seek the pronounced competitive value of the extremely slow-growing corallines. Due to their low annual growth increment, the coralline algae studied are very endangered by abiotic physical disturbances and by overgrowth of rapidly growing filamentous algae or sessile invertebrates. To overcome fouling pressure and storm-triggered physical disturbances, coralline algae thrive well in wave-sheltered headlands or skerry areas and generate characteristic ‘denuded areas’ by intense herbivory. This general distributional pattern is also true for high-boreal to subarctic coralline algal bioherms in northern Norway. Such a complex biological feedback maintains a high potential of self-regulation or self-organization in the algal reef bioherms. The different proponents involved in feedback processes include bacterial colonization, diatom microfouling and selective induction of larval metamorphosis. The negative impact of diatom microfouling and the important role of herbivores are relevant activities in the feedback system on a microscopic scale. Macroscopically, intense herbivory on coralline algae create denuded conditions, which are a widespread phenomenon in coralline algal ecosystems.

Document Type: Article
Keywords: Coralline Algae-Maerl; Kelp Forest; Competition; Diatom Microfouling; Herbivory; Self-Organization; Sea Urchin; Ostracoda; Polyplacophora; Gastropoda; Recent
Refereed: Yes
Open Access Journal?: No
Publisher: Springer
Projects: Enrichment
Date Deposited: 15 Apr 2016 07:22
Last Modified: 15 Apr 2016 07:22
URI: https://oceanrep.geomar.de/id/eprint/32043

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