Quantifying ecospace utilization and ecosystem engineering during the early Phanerozoic—The role of bioturbation and bioerosion

Abstract

The Cambrian explosion (CE) and the great Ordovician biodiversification event (GOBE) are the two most important radiations in Paleozoic oceans. We quantify the role of bioturbation and bioerosion in ecospace utilization and ecosystem engineering using information from 1367 stratigraphic units. An increase in all diversity metrics is demonstrated for the Ediacaran-Cambrian transition, followed by a decrease in most values during the middle to late Cambrian, and by a more modest increase during the Ordovician. A marked increase in ichnodiversity and ichnodisparity of bioturbation is shown during the CE and of bioerosion during the GOBE. Innovations took place first in offshore settings and later expanded into marginal-marine, nearshore, deep-water, and carbonate environments. This study highlights the importance of the CE, despite its Ediacaran roots. Differences in infaunalization in offshore and shelf paleoenvironments favor the hypothesis of early Cambrian wedge-shaped oxygen minimum zones instead of a horizontally stratified ocean.

What global biogeochemical consequences will marine animal–sediment interactions have during climate change?

“…Subsequent to the Cambrian Explosion, the Ordovician Radiation saw major increases in the diversity of burrow and boring architectures, with innovations in styles of bioturbation and bioerosion, respectively (Levinton and Bambach, 1975;Buatois et al, 2016aBuatois et al, , 2020. Novel and long-lasting strategies (Levinton and Bambach, 1975) of animal-substrate interactions first appeared in nearshore and shelf areas, but later expanded into brackish-water coastal environments and into deep marine environments; the latter represented by the establishment of diverse feeding strategies, including the appearance of trace fossils interpreted as taxa that enhance microbial farming and trapping of microorganisms (Seilacher, 1977;Orr, 2001;Buatois et al, 2009).…”

The interplay of environmental constraints and bioturbation on matground development along the marine depositional profile during the Ordovician Radiation

“…The Lashkerak and Ghelli Formations provide an integrated ichnologic, sedimentologic, and geobiologic record of the Ordovician Radiation, which represents a changeover point in the history of marine ecosystems (Mángano et al, 2016; Mángano & Droser, 2004; Sepkoski, 1995; Servais & Harper, 2018; Servais et al, 2010; Stigall et al, 2019). The increase in ichnodiversity and degree and depth of bioturbation that took place in marine environments during the Ordovician Radiation had major geobiologic impacts, including most notably the further disruption of microbially stabilized surfaces (Bayet‐Goll, Knaust, et al, 2021; Bayet‐Goll, Uchman, et al, 2021; Buatois & Mángano, 2012; Buatois et al, 2016; Buatois et al, 2020; Mángano et al, 2016; Mángano & Droser, 2004). In particular, bioturbation by large, relatively deep, highly mobile deposit feeders, including the so‐called sediment bulldozers, was particularly effective in sediment mixing, being detrimental to the formation of matgrounds.…”

“…During the Ordovician Radiation, a subsequent increase in the abundance and diversity of deposit feeders, filter feeders, and grazers in shallow benthic communities took place (Servais & Harper, 2018; Servais et al, 2008, 2010). From an ichnologic viewpoint, a gradual increase in ichnodiversity and complexity of tiering structure occurred during the Ordovician Buatois & Mángano, (2013; Buatois & Mángano, 2018; Buatois et al, 2016; Buatois et al, 2020; Mángano & Droser, 2004; Mángano et al, 2016; Orr, 2001). The increase in bioturbation in shallow‐marine environments resulting from the early Paleozoic evolutionary radiations made these settings less suitable for substrate stabilization by microbial activity (see Buatois & Mángano, 2012a, 2012b).…”

Sclerobionts associated with Orbiramus from the Early Ordovician of Hubei, China, the oldest known trepostome bryozoan

“…The increase in taxonomic diversity at various classificatory levels was accompanied by the profound ecological changes of ecology, including the Ordovician Bioerosion Revolution when endoliths appeared in greater numbers and varieties (Wilson & Palmer 2006; Buatois et al . 2020).…”