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Conservation of marine species requires the ability to predict the effects of climate-related stressors in an uncertain future. Experiments and observations in modern settings provide crucial information, but lack temporal scale and cannot anticipate emergent effects during ongoing global change. By contrast, the deep-time fossil record contains the long-term perspective at multiple global change events that can be used, at a broad scale, to test hypothesized effects of climate-related stressors. For example, geologically rapid carbon cycle disruption has often caused crises in reef ecosystems, and selective extinctions support the hypothesis that greater activity levels promote survival. Geographical patterns of extinction and extirpation were more variable than predicted from modern physiology, with tropical and temperate extinction peaks observed at different ancient events. Like any data source, the deep-time record has limitations but also provides opportunities that complement the limitations of modern and historical data. In particular, the deep-time record is the best source of information on actual outcomes of climate-related stressors in natural settings and over evolutionary timescales. Closer integration of modern and deep-time evidence can expand the types of hypotheses testable with the fossil record, yielding better predictions of extinction risk as climate-related stressors continue to intensify in future oceans. This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'

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 pCO2 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.

Studies of modern ecological communities demonstrate that climate change may trigger changes in diversity and taxonomic composition; however, these studies are fundamentally limited to short timescales and therefore cannot demonstrate the full impact of major climate change. Understanding the ecological response of marine invertebrate communities to the Late Paleozoic Ice Age (LPIA), the last complete transition from icehouse to greenhouse, can establish a more complete picture of the climate-faunal relationship. We analyzed brachiopod community structure in Moscovian-Sakmarian (mid-Pennsylvanian to Early Permian) samples spanning the greatest extent of the LPIA, collected from four localities of the Copacabana Formation in Bolivia: Ancoraimes, Yaurichambi, Cuyavi, and Yampupata. Cluster analysis reveals three main groups that appear to coincide with pre-, syn-, and post-glacial times. Genus richness was significantly greater in samples during the Asselian glacial episode; however, the difference may be due to a combination of smaller body size and time averaged mixing of genera from different depths during more rapid glacioeustatic sea level change. Genera present in Bolivia consistently had warm-water affinities, even during the main glaciation, but warm-water taxa increased in abundance over time and the samples became increasingly dominated by characteristically North American genera. Overall mean body size and the size of particular genera were smaller in the Asselian cluster. These size changes likely reflect variations in substrate because marine invertebrates should be larger at cooler temperatures due to oxygen limitation at higher temperatures. The monotonic increase in abundance of warm-water genera and increasingly North American biogeographic affinity imply that community change was most likely the result of the northward drift of Bolivia rather than a response to late Paleozoic glacial-nonglacial cycles. This lack of climate related faunal change was probably a result of Bolivia's mid-latitude location during the late Paleozoic because both the rate of temperature change and its magnitude were likely smaller at lower latitudes, reducing the impact of climate change on marine communities. © 2013 Elsevier B.V.

Flood basalts were Earth's largest volcanic episodes that, along with related intrusions, were often emplaced rapidly and coincided with environmental disruption: oceanic anoxic events, hyperthermals, and mass extinction events. Volatile emissions, both from magmatic degassing and vaporized from surrounding rock, triggered short-term cooling and longer-term warming, ocean acidification, and deoxygenation. The magnitude of biological extinction varied considerably, from small events affecting only select groups to the largest extinction of the Phanerozoic, with less-active organisms and those with less-developed respiratory physiology faring especially poorly. The disparate environmental and biological outcomes of different flood basalt events may at first order be explained by variations in the rate of volatile release modulated by longer trends in ocean carbon cycle buffering and the composition of marine ecosystems. Assessing volatile release, environmental change, and biological extinction at finer temporal resolution should be a top priority to refine ancient hyperthermals as analogs for anthropogenic climate change. ▪ Flood basalts, the largest volcanic events in Earth history, triggered dramatic environmental changes on land and in the oceans. ▪ Rapid volcanic carbon emissions led to ocean warming, acidification, and deoxygenation that often caused widespread animal extinctions. ▪ Animal physiology played a key role in survival during flood basalt extinctions, with reef builders such as corals being especially vulnerable. ▪ The rate and duration of volcanic carbon emission controlled the type of environmental disruption and the severity of biological extinction. [ABSTRACT FROM AUTHOR]

The greatest loss of biodiversity in the history of animal life occurred at the end of the Permian Period (∼252 million years ago). This biotic catastrophe coincided with an interval of widespread ocean anoxia and the eruption of one of Earth's largest continental flood basalt provinces, the Siberian Traps. Volatile release from basaltic magma and sedimentary strata during emplacement of the Siberian Traps can account for most end-Permian paleontological and geochemical observations. Climate change and, perhaps, destruction of the ozone layer can explain extinctions on land, whereas changes in ocean oxygen levels, CO2, pH, and temperature can account for extinction selectivity across marine animals. These emerging insights from geology, geochemistry, and paleobiology suggest that the end-Permian extinction may serve as an important ancient analog for twenty-first century oceans. [ABSTRACT FROM AUTHOR]

Abstract: Deglaciation following the late Paleozoic ice age was a complex climate transition marked by smaller glacial–interglacial transitions superimposed on an overall Permian warming trend. In contrast to this growing recognition of a dynamic climate system, few studies have investigated geographic variations in postglacial climate changes, which may have been as dynamic as the temporal variations. Because temperature and ocean circulation are important controls on the biogeography of marine invertebrates, many Permian taxa were characteristic of either paleotropical or high-latitude faunal realms. This study takes advantage of that temperature sensitivity, using a database of more than 5000 Permian fossil collections from northwestern Pangea to reconstruct spatial variations in Permian climate changes throughout the region. Cluster analysis demonstrates that localities in the Phosphoria basin (Nevada/Idaho/Wyoming) were taxonomically distinct from coeval faunas in Texas and occupied the transitional zone between Paleoequatorial and Boreal realms. Quantitative scoring of the faunal affinity of all taxa in 1 by 1° paleolatitudinal bins suggests that the western margin of Laurentia was affected by a persistent southward-flowing cool boundary current, and that the effects of the current became more pronounced throughout the Permian in conjunction with cooling in the Boreal ocean. The increasingly cool-water nature of Phosphoria basin faunas contrasted with warming in Texas and implies that northern and northwest Pangea were decoupled from the broader global warming trend following the late Paleozoic ice age. [ABSTRACT FROM AUTHOR]

During the Permian, major icehouse-greenhouse climate shifts and tectonic reconfiguration had important biogeographic implications, especially for climate-sensitive organisms such as fusulinids. Here we present multivariate methods on a global fusulinid species dataset including 1546 species from 58 localities in the Early (Asselian, Sakmarian, Artinskian and Kungurian) and Middle (Roadian, Wordian and Capitanian) Permian. Our results show that fusulinid global provincialism was high in the Asselian, Sakmarian, and Artinskian, driven by the development of multiple fusulinid bioregions in and near the Tethys Ocean. During the Asselian, Uralian sites and nearby regions of western Tethys were distinct from eastern Tethys, while stations in Arctic Russia and Norway formed a separate Boreal bioregion. Tectonic closure of the oceanic gateway in the southern Urals resulted in progressive isolation of the Uralian and Boreal bioregions during the Sakmarian and Artinskian and their ultimate disappearance by the Kungurian. Climate warming likely was the most important control on the Sakmarian formation of the distinct peri-Gondwana bioregion, because its development coincided with deglaciation following the Late Paleozoic Ice Age but preceded the separation of the Cimmerian terranes from northern margin of Gondwana. On the other hand, northward movement of the Cimmerian blocks following Artinskian-Kungurian rifting ultimately led to the merger of the peri-Gondwanan bioregion with tropical Tethyan faunas, resulting in lower provincialism in the Guadalupian and minimal faunal differentiation across Tethys. In contrast, faunal similarity between Tethys and eastern Panthalassa (the McCloud region and southwestern United States) was higher in the Asselian-Artinskian but decreased in the Kungurian and Middle Permian, perhaps as the result of sluggish ocean circulation following the warming episode of Late Paleozoic deglaciation. • In the Asselian, similarity between Uralian sites and western Tethys. • Climate warming was the main trigger of the peri-Gondwanan bioregion in Sakmarian. • Lower provincialism in the Guadalupian follows merger of Peri-Gondwana and Tethys. • Lower faunal similarity between Tethys and eastern Panthalassa in the Guadalupian. [ABSTRACT FROM AUTHOR]