Organism activity levels predict marine invertebrate survival during ancient global change extinctions

Abstract

Multistressor global change, the combined influence of ocean warming, acidification, and deoxygenation, poses a serious threat to marine organisms. Experimental studies imply that organisms with higher levels of activity should be more resilient, but testing this prediction and understanding organism vulnerability at a global scale, over evolutionary timescales, and in natural ecosystems remain challenging. The fossil record, which contains multiple extinctions triggered by multistressor global change, is ideally suited for testing hypotheses at broad geographic, taxonomic, and temporal scales. Here, I assess the importance of activity level for survival of well-skeletonized benthic marine invertebrates over a 100-million-year-long interval (Permian to Jurassic periods) containing four global change extinctions, including the end-Permian and end-Triassic mass extinctions. More active organisms, based on a semiquantitative score incorporating feeding and motility, were significantly more likely to survive during three of the four extinction events (Guadalupian, end-Permian, and end-Triassic). In contrast, activity was not an important control on survival during nonextinction intervals. Both the end-Permian and end-Triassic mass extinctions also triggered abrupt shifts to increased dominance by more active organisms. Although mean activity gradually returned toward pre-extinction values, the net result was a permanent ratcheting of ecosystem-wide activity to higher levels. Selectivity patterns during ancient global change extinctions confirm the hypothesis that higher activity, a proxy for respiratory physiology, is a fundamental control on survival, although the roles of specific physiological traits (such as extracellular pCO 2 or aerobic scope) cannot be distinguished. Modern marine ecosystems are dominated by more active organisms, in part because of selectivity ratcheting during these ancient extinctions, so on average may be less vulnerable to global change stressors than ancient counterparts. However, ancient extinctions demonstrate that even active organisms can suffer major extinction when the intensity of environmental disruption is intense.

Nature and timing of biotic recovery in Antarctic benthic marine ecosystems following the Cretaceous–Palaeogene mass extinction

“…) may have led to the preferential survival, and dominance of infaunal organisms following the extinction horizon in this location. Clapham () found that more motile organisms preferentially survived Mesozoic extinctions, suggesting that greater activity and therefore potentially higher respiratory physiology, controlled survival during extinction periods (Clapham ). Our data show little change in the taxonomic richness of facultatively motile taxa; however, abundance trends do show an increase in motility during the early Danian.…”

Impact of the Late Triassic mass extinction on functional diversity and composition of marine ecosystems

“…These functional groups, although not particularly diverse, all display feeding strategies that are expected to fare well in a stressed, post‐extinction world (i.e. deposit‐feeding, mining and chemosymbiosis) (Foster & Twitchett ; Clapham ). Some functional groups, such as pelagic, fast‐moving carnivores, suffered a significant reduction in relative richness at the LTE, but then quickly recovered to pre‐extinction levels by the late Hettangian, reinforcing the idea that both vertebrates (Thorne et al .…”

“…Apart from selection against specific regions, ecosystems or habitats (Foster & Twitchett, ), other studies have suggested that traits such as skeletal composition, motility and feeding are also critical in explaining patterns of selectivity. Past extinction events associated with elevated CO 2 have been shown to be selective against epifaunal, sessile, suspension feeders (Bush & Bambach ; Foster & Twitchett ; Clapham ), and selective against heavily calcified organisms (Hautmann ; Knoll et al . ; Hautmann et al .…”

Addressing priority questions of conservation science with palaeontological data

“…On the other hand, deep-time fossil data cannot inform about the effects of direct human impacts. A rich literature exists on how lifestyles, habitats and organismic traits affected extinction risk under past climate change [45][46][47][48][49][50][51][52]. A pressing question is, of course, how well these ancient vulnerabilities reflect modern vulnerabilities, that is, to what extent are they conserved over time.…”