Aftermath of the Triassic–Jurassic Boundary Crisis: Spiculite Formation on Drowned Triassic Steinplatte Reef-Slope by Communities of Hexactinellid Sponges (Northern Calcareous Alps, Austria)

Could some coral reefs become sponge reefs as our climate changes?

“…Paleontological evidence suggests that this event was accompanied by ocean acidification, resulting from a wider disruption of the carbon cycle due to volcanic activity associated with the Central Atlantic Magmatic Province (Schaller et al ., ; Greene et al ., ). There is evidence in the geological record that the decimation of biocalcifier communities was followed by the proliferation of siliceous sponges, which appeared to persist over a geologically relevant time scale (millions of years) and be widespread across Europe (Delecat et al ., ). Changes in sea level and sedimentation processes at this time are thought to have led to the radiation of siliceous sponges from the deep ocean, from which they came to dominate mid‐shelf habitats previously occupied by biocalcifiers (Delecat et al ., and references within).…”

“…There is evidence in the geological record that the decimation of biocalcifier communities was followed by the proliferation of siliceous sponges, which appeared to persist over a geologically relevant time scale (millions of years) and be widespread across Europe (Delecat et al ., ). Changes in sea level and sedimentation processes at this time are thought to have led to the radiation of siliceous sponges from the deep ocean, from which they came to dominate mid‐shelf habitats previously occupied by biocalcifiers (Delecat et al ., and references within). Interestingly, it has been suggested that four out of the five global crises to affect reef metazoans in the past 500 Myr were affected, at least in part, by OA and rapid global warming (Kiessling & Simpson, ).…”

Numerical analyses of selected microencrusters from the Cipit boulders of the St Cassian Formation (Dolomites, NE Italy): palaeoecological implications

“…; Delecat et al . ) and also had a consequence in microencruster diversity and importance during the development of Early and Middle Triassic reef systems. In some cases, microencrusters were ubiquitous components in reefs, and there are even instances at which they were the main component.…”

Composition and origin of stromatactis‐bearing mud‐mounds (Upper Devonian, Frasnian), southern Rocky Mountains, western Canada

“…and biogenic/organic (recrystallized fossils, decaying organisms, burrowing, etc.). A widely promoted view is that it is due to collapse of loose material in sponges undergoing cementation under the sediment–water interface (Bourque & Gignac, ; Bourque & Boulvain, ; Neuweiler et al., ; Delecat & Reitner, ; Neuweiler & Bernoulli, ; Aubrecht et al., ; Delecat et al., ). The striking contrast between common stromatactis in Palaeozoic mud‐mounds versus their near‐absence in Mesozoic ones may be correlated to the degree of siliceous sponge skeletal rigidity and biological sediment recycling from bioerosion and deposit feeding that resulted in sediment accumulation in the original cavities (Neuweiler et al., ).…”

“…Sponge spicular networks and spicules are common in many mud‐mounds, which has led to the notion that siliceous sponges and their taphonomic products played a determinant role in the accretion and construction of mud‐mounds as well as stromatactis formation (Bourque & Boulvain, ; Reitner et al., ; Neuweiler et al., ; Leinfelder, ; Desrochers et al., ; Delecat et al., ). The commonly observed irregular shapes rather than intact spicular networks suggest a low preservation potential of sponge skeletons (Lee et al., ).…”