Modularity explains large-scale reef booms in Earth’s history

Abstract

Drivers of reef decline are well known both today and in the geological past. Considerably less is known about the preconditions for a pantropical expansion of coral reefs. The geological record of reef building is characterised by considerably long intervals with very limited reef expansion and geologically brief (< 20 million years) episodes of prolific, pantropical reef growth. Here, we propose a new "co-occurrence hypothesis" (COH), which posits that reefs thrive when fast-growing hypercalcifiers co-occur with encrusting organisms such as calcifying microbes or coralline algae to construct wave-resistant structures. While there is little evidence of the effect of abiotic drivers on reef proliferation, we find that positive co-occurrence patterns are significantly more common in reefal as compared to non-reefal communities, suggesting that biological interactions are more relevant in reefs than in non-reefs. Supporting COH, we also show that reefs after the end-Permian mass extinction became more modular in nature with limited membership in reef assemblages during reef booms than in typical periods of reef growth (background intervals). Modularity in reefs may have led to the stabilisation of reef ecosystems, giving them the ability to recover from small perturbations, promoting reefal carbonate accretion and prolific reef growth.

Neverovsky Palaeoreef and Associated Deep-Marine Facies: High-Value Late Devonian Geoheritage from the Rudny Altai

“…The field examination of outcrops and the revision of the published information imply that the potential for new high-class research remains high. This is especially important taking into account the relatively small volume of Late Devonian reefs in the world [30]. Indeed, palaeoreefs are important for extending the knowledge of university students and training their skills [64][65][66], as well as for tourist attractions [67,68].…”

“…Among the many unique geological sites of the Altai, one should take note of the Devonian reefs [25,27,28]. They are covered only marginally in the famous PARED database [29], although their consideration can be important to better understand the shift from reef abundance in the Early-Middle Devonian to their decline at the Devonian-Carboniferous transition [30]. Moreover, the geoheritage-related knowledge of pre-Quaternary reefs, including those of Late Devonian age, remains poor [31], and, thus, investigations of the Devonian reefs of the Altai will help to fill this gap.…”

A Geo-Itinerary to Foster Sustainable Tourism in West African Islands: Storytelling the Evolution of the Ancient Cameroon Volcanic Line Coral Reefs

“…The Plio-Pleistocene (2.5 My) corresponded to a sea-level fall, but Quaternary reefs recorded an important episode of proliferation because of the Holocene sea-level rise that occurred at the end of the Pleistocene ice age [44]. Raja et al [11] argue that the Pleistocene is among the most recent reef-boom intervals to be found in the geological record.…”

“…These sunken volcanic islands' offshore areas and seamounts are capped by former shallow-water carbonate platforms and reefs that developed during the mid-Neogene reef boom [11]. Local inhabitants empirically recognize the shallower parts of these ancient reefs and seamounts and they head to them for the traditional practice of artisanal fishing.…”

“…According to Davis [9], the climatic oscillations in ocean level of Daly's glacial-control theory and the intermittent subsidence and sporadic uplifts of Darwin's theory may work together. However, more recently, Droxler and Jorry [10] claimed that the late Quaternary formation of the presentday atolls, which were formed on top of late Pliocene flat-topped banks from the Maldives archipelago and from the tropical Pacific and southwest Indian Oceans, was unaffected by the volcanic substrate, while Raja et al [11] considered that throughout the Phanerozoic, global abiotic variables had little effect on reef volume.…”