Crustose Coralline Red Algae Frameworks and Rhodoliths: Past and Present

Crustose coralline red algae (CCA) are main agents in fossil and recent ecosystems, both in terms of geoscience and biology. They can form extensive carbonate accumulations in a wide range of fossil and extant environments, such as rhodolith beds and entire reef frameworks. At the same time they are autogenic ecosystem engineers, providing living space for other organisms, especially in areas where other habitat providers, like corals, are lacking. Framework building abilities of CCA can be seen on different scales. On a microscopic scale they build crusts and branches providing substratum for microborers, encrusters and various smaller invertebrates. On the macroscopic scale they form consecutive crusts as well as rhodoliths and their accumulations. These can provide shelter for larger invertebrates and vertebrates, such as nurseries for fishes. On a megascale, CCA can form entire reef bodies, rhodolith fields and maerl megadunes, controlling extensive marine areas. Their sensitivity to ecological parameters – that are not well understood – should make them also valuable paleoecological indicators.

Despite the abundance and ecological importance in time and space, crustose coralline algae frameworks and rhodoliths are only poorly understood. This Research Topic aims to significantly advance our scientific knowledge on crustose coralline red algae frameworks and rhodoliths through different time slices and (paleo)biogeography. What controlled and controls the distribution of rhodolith beds? To which extent do they reflect the effects of hydrodynamics linked to the sedimentary environment, which in some extreme circumstances (hurricanes) may control framework development and rhodolith accumulations along the shallow shelf, as well as the effects of climate change?

A wide range of contributions from all disciplines concerning the study of calcareous red algae from the fossil to the recent is welcome. Contributions considering the accommodation space of corallines and competition with other carbonate-forming groups are also welcome. We encourage interdisciplinary works including new observations, experimental and theoretical studies.