Limits...
Anoxia/high temperature double whammy during the Permian-Triassic marine crisis and its aftermath.

Song H, Wignall PB, Chu D, Tong J, Sun Y, Song H, He W, Tian L - Sci Rep (2014)

Bottom Line: The relative tolerance of groups to this double whammy provides the first clear explanation for the selective extinction losses during this double-pulsed crisis and also the fitful recovery.Thus, high temperature intolerant shallow-water dwellers, such as corals, large foraminifers and radiolarians were eliminated first whilst high temperature tolerant ostracods thrived except in anoxic deeper-waters.Limited Early Triassic benthic recovery was restricted to mid-water depths and coincided with intervals of cooling and deepening of water column anoxia that expanded the habitable mid-water refuge zone.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China.

ABSTRACT
The Permian-Triassic mass extinction was the most severe biotic crisis in the past 500 million years. Many hypotheses have been proposed to explain the crisis, but few account for the spectrum of extinction selectivity and subsequent recovery. Here we show that selective losses are best accounted for by a combination of lethally warm, shallow waters and anoxic deep waters that acted to severely restrict the habitable area to a narrow mid-water refuge zone. The relative tolerance of groups to this double whammy provides the first clear explanation for the selective extinction losses during this double-pulsed crisis and also the fitful recovery. Thus, high temperature intolerant shallow-water dwellers, such as corals, large foraminifers and radiolarians were eliminated first whilst high temperature tolerant ostracods thrived except in anoxic deeper-waters. In contrast, hypoxia tolerant but temperature intolerant small foraminifers were driven from shallow-waters but thrived on dysoxic slopes margins. Only those mollusc groups, which are tolerant of both hypoxia and high temperatures, were able to thrive in the immediate aftermath of the extinction. Limited Early Triassic benthic recovery was restricted to mid-water depths and coincided with intervals of cooling and deepening of water column anoxia that expanded the habitable mid-water refuge zone.

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Related in: MedlinePlus

Biological effects of decreased oxygen concentration and increased temperature.(a), Generally, crustaceans are more sensitive to reduced oxygen concentrations than bryozoans and echinoderms, followed by corals. Foraminifers and molluscs are the most tolerant. (b), Upper thermal limits are higher in ostracods and bivalves than in foraminifers, echinoderms, gastropods and non-ostracod crustacean, and are lowest in corals and radiolarians. (c), The relationship between the upper lethal thermal limits and the maximum habitat temperature of selected animals shows a latitudinal relationship, with warm-adapted forms the most tolerant. Relationships and ranges data are given in Tables S1–S3.
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f1: Biological effects of decreased oxygen concentration and increased temperature.(a), Generally, crustaceans are more sensitive to reduced oxygen concentrations than bryozoans and echinoderms, followed by corals. Foraminifers and molluscs are the most tolerant. (b), Upper thermal limits are higher in ostracods and bivalves than in foraminifers, echinoderms, gastropods and non-ostracod crustacean, and are lowest in corals and radiolarians. (c), The relationship between the upper lethal thermal limits and the maximum habitat temperature of selected animals shows a latitudinal relationship, with warm-adapted forms the most tolerant. Relationships and ranges data are given in Tables S1–S3.

Mentions: Experimental studies show that marine organisms are adversely affected by dissolved oxygen concentration below 10% of air saturation and they die below 4% (Fig. 1a). Hypoxia tolerance varies considerably among phyla and orders and even between species of the same order but nonetheless there are clear differences in hypoxia tolerance amongst higher taxa allowing a ranked order of relative susceptibility to be determined (Fig. 1). In overall order of intolerance to hypoxia, generally crustaceans (including ostracods) are more sensitive than bryozoans, echinoderms and corals whilst molluscs (i.e. cephalopods, gastropods and bivalves) are more tolerant and foraminifers are the most resilient of all (Table S1 and Fig. 1a).


Anoxia/high temperature double whammy during the Permian-Triassic marine crisis and its aftermath.

Song H, Wignall PB, Chu D, Tong J, Sun Y, Song H, He W, Tian L - Sci Rep (2014)

Biological effects of decreased oxygen concentration and increased temperature.(a), Generally, crustaceans are more sensitive to reduced oxygen concentrations than bryozoans and echinoderms, followed by corals. Foraminifers and molluscs are the most tolerant. (b), Upper thermal limits are higher in ostracods and bivalves than in foraminifers, echinoderms, gastropods and non-ostracod crustacean, and are lowest in corals and radiolarians. (c), The relationship between the upper lethal thermal limits and the maximum habitat temperature of selected animals shows a latitudinal relationship, with warm-adapted forms the most tolerant. Relationships and ranges data are given in Tables S1–S3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928575&req=5

f1: Biological effects of decreased oxygen concentration and increased temperature.(a), Generally, crustaceans are more sensitive to reduced oxygen concentrations than bryozoans and echinoderms, followed by corals. Foraminifers and molluscs are the most tolerant. (b), Upper thermal limits are higher in ostracods and bivalves than in foraminifers, echinoderms, gastropods and non-ostracod crustacean, and are lowest in corals and radiolarians. (c), The relationship between the upper lethal thermal limits and the maximum habitat temperature of selected animals shows a latitudinal relationship, with warm-adapted forms the most tolerant. Relationships and ranges data are given in Tables S1–S3.
Mentions: Experimental studies show that marine organisms are adversely affected by dissolved oxygen concentration below 10% of air saturation and they die below 4% (Fig. 1a). Hypoxia tolerance varies considerably among phyla and orders and even between species of the same order but nonetheless there are clear differences in hypoxia tolerance amongst higher taxa allowing a ranked order of relative susceptibility to be determined (Fig. 1). In overall order of intolerance to hypoxia, generally crustaceans (including ostracods) are more sensitive than bryozoans, echinoderms and corals whilst molluscs (i.e. cephalopods, gastropods and bivalves) are more tolerant and foraminifers are the most resilient of all (Table S1 and Fig. 1a).

Bottom Line: The relative tolerance of groups to this double whammy provides the first clear explanation for the selective extinction losses during this double-pulsed crisis and also the fitful recovery.Thus, high temperature intolerant shallow-water dwellers, such as corals, large foraminifers and radiolarians were eliminated first whilst high temperature tolerant ostracods thrived except in anoxic deeper-waters.Limited Early Triassic benthic recovery was restricted to mid-water depths and coincided with intervals of cooling and deepening of water column anoxia that expanded the habitable mid-water refuge zone.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China.

ABSTRACT
The Permian-Triassic mass extinction was the most severe biotic crisis in the past 500 million years. Many hypotheses have been proposed to explain the crisis, but few account for the spectrum of extinction selectivity and subsequent recovery. Here we show that selective losses are best accounted for by a combination of lethally warm, shallow waters and anoxic deep waters that acted to severely restrict the habitable area to a narrow mid-water refuge zone. The relative tolerance of groups to this double whammy provides the first clear explanation for the selective extinction losses during this double-pulsed crisis and also the fitful recovery. Thus, high temperature intolerant shallow-water dwellers, such as corals, large foraminifers and radiolarians were eliminated first whilst high temperature tolerant ostracods thrived except in anoxic deeper-waters. In contrast, hypoxia tolerant but temperature intolerant small foraminifers were driven from shallow-waters but thrived on dysoxic slopes margins. Only those mollusc groups, which are tolerant of both hypoxia and high temperatures, were able to thrive in the immediate aftermath of the extinction. Limited Early Triassic benthic recovery was restricted to mid-water depths and coincided with intervals of cooling and deepening of water column anoxia that expanded the habitable mid-water refuge zone.

Show MeSH
Related in: MedlinePlus