Late Oligocene to Late Pliocene Benthic Foraminifers from Depth Traverses in the Central Indian Ocean

Boersma, Anne

doi:10.2973/odp.proc.sr.115.146.1990

Cited by 33 publications

(13 citation statements)

References 28 publications

(74 reference statements)

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“…The elongate, cylindrical shape of most extinct species that disappeared in the last global extinction has been interpreted to be an adaptation to infaunal, higher carbon flux and lower oxygen conditions [Corliss, 1985;Boersma, 1990;Gupta, 1993]. The functions of the different targeted apertural modifications are unknown.…”

Section: Causes Of the Last Global Extinction In The Deep Sea?mentioning

confidence: 99%

“…[25] Unlike the P-E deep-sea extinction event [MacLeod et al, 2000], this last global extinction preferentially impacted on certain foraminiferal morphologies and types of apertures ( Figure 2). The elongate, cylindrical shape of most extinct species that disappeared in the last global extinction has been interpreted to be an adaptation to infaunal, higher carbon flux and lower oxygen conditions [Corliss, 1985;Boersma, 1990;Gupta, 1993]. The functions of the different targeted apertural modifications are unknown.…”

Section: Causes Of the Last Global Extinction In The Deep Sea?mentioning

confidence: 99%

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Last global extinction in the deep sea during the mid‐Pleistocene climate transition

Hayward

Kawagata²,

Grenfell

et al. 2007

Paleoceanography

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[1] Twenty percent (19 genera, 95 species) of cosmopolitan, deep-sea (500-4000 m), benthic foraminiferal species became extinct during the late Pliocene-Middle Pleistocene (3-0.12 Ma), with the peak of extinctions (76 species) occurring during the mid-Pleistocene Climate Transition (MPT, 1.2-0.55 Ma). One whole family (Stilostomellidae, 30 species) was wiped out, and a second (Pleurostomellidae, 29 species) was decimated with just one species possibly surviving through to the present. Our studies at 21 deep-sea core sites show widespread pulsed declines in abundance and diversity of the extinction group species during more extreme glacials, with partial interglacial recoveries. These declines started in the late Pliocene in southern sourced deep water masses (Antarctic Bottom Water, Circumpolar Deep Water) and extending into intermediate waters (Antarctic Intermediate Water, North Atlantic Deep Water) in the MPT, with the youngest declines in sites farthest downstream from high-latitude source areas for intermediate waters. We infer that the unusual apertural types that were targeted by this extinction period were adaptations for a specific kind of food source and that it was probably the demise of this microbial food that resulted in the foraminiferal extinctions. We hypothesize that it may have been increased cold and oxygenation of the southern sourced deep water masses that impacted on this deep water microbial food source during major late Pliocene and Early Pleistocene glacials when Antarctic ice was substantially expanded. The food source in intermediate water was not impacted until major glacials in the MPT when there were significant expansion of polar sea ice in both hemispheres and major changes in the source areas, temperature, and oxygenation of global intermediate waters.

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Section: Causes Of the Last Global Extinction In The Deep Sea?mentioning

confidence: 99%

Section: Causes Of the Last Global Extinction In The Deep Sea?mentioning

confidence: 99%

Last global extinction in the deep sea during the mid‐Pleistocene climate transition

Hayward

Kawagata²,

Grenfell

et al. 2007

Paleoceanography

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“…Corliss (1979) reported that this species dominates the faunal assemblage where relatively warm (0.6°−0.8°C) AABW is present. Boersma (1990) investigated environmental variations in the size of G. subglobosa and found a direct relationship between estimates of good carbonate preservation and higher abundances of large size G. subglobosa in the Oligocene and Miocene sections. Mackensen et al (1995) suggested that this species is more common on steep flanks of ridges.…”

Section: Discussionmentioning

confidence: 99%

“…Studies on recent benthic foraminiferal assemblages likewise revealed a relation between faunal composition and hydrographic parameters such as temperature, salinity, oxygen content, and carbonate saturation (Murray, 1973;Lohmann, 1978;Corliss, 1979;Corliss and Honjo, 1981;Peterson, 1984;Mead, 1985). Many different authors have attempted to correlate the distribution of deep-water benthic foraminifers with changes in water mass circulation patterns in the deep oceans, and benthic foraminiferal faunal changes have been linked to changes in stable isotope records (e.g., Woodruff and Savin, 1989;Boersma, 1990;Hermelin, 1991;Thomas, 1992).…”

Section: Introductionmentioning

confidence: 99%

Late Miocene–Holocene paleoceanography of the western equatorial Atlantic: evidence from deep-sea benthic foraminifers

Yasuda¹

1997

Proceedings of the Ocean Drilling Program

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Changes in deep-water environments of the western Atlantic over the past six million years were investigated by studying benthic foraminiferal abundance changes in 335 samples from Sites 926 (3598 m), 928 (4010 m), and 929 (4358 m) on the Ceara Rise. The location of these sites on a transect at lower abyssal depths provides a unique opportunity to evaluate changes in water mass properties as well as in the supply of organic matter from the surface waters, especially because other Leg 154 studies provided a precise time scale for correlations between the sites.Relative abundances and ßuxes of the most abundant species were calculated, with emphasis on the four most common speciesÑ Nuttallides umbonifera, Globocassidulina subglobosa, Epistominella exigua, and Alabaminella weddellensis. There are two patterns in relative abundance of these species with time: the Þrst group of species ( N. umbonifera and G. subglobosa ) shows abundance variations that differ from site to site (i.e., with depth). The other group ( E. exigua and A. weddellensis ) shows variations in relative abundance that are similar at all three sites and thus independent of depth.In the Þrst group, G. subglobosa increased in relative abundance at the shallowest Site 926 from 2.4 to 1 Ma, but decreased at the two deeper sites. In contrast, N. umbonifera, a marker species for corrosive bottom waters and speciÞcally for Antarctic Bottom Water (AABW), shows large ßuctuations in relative abundance, but overall increased in relative abundance at the two deeper sites and decreased at the shallower site from 2.1 Ma to the present. Its relative abundance shows three peaks during the last 0.9 m.y., which were coeval at the two deeper sites. These large ßuctuations in abundance of N. umbonifera suggest that production of AABW ßuctuated in intensity, with increases during interglacial periods. AABW formation increased overall from about 3 Ma, and the amplitude of the ßuctuations increased from 0.9 Ma to present. The differences between sites are interpreted as showing that the deeper Sites 928 and 929 were commonly within AABW, whereas the shallower site was not.The species in the second group, E. exigua and A. weddellensis, occur in the recent oceans commonly in oceanic regions where spring blooms lead to seasonal deposition of phytodetrital material. At the Ceara Rise sites, they show variations in relative abundance that are similar at all three sites from 4.5 to 1.2 Ma, conÞrming that these species react to environmental factors that are not depth related, and thus possibly to surface productivity. The two species, however, do not covary exactly: at 2.6 Ma, for example, E. exigua decreased in relative abundance whereas A. weddellensis increased.

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“…Zahn and others (1986) argued that "the test morphology of Uvigerina species may indicate a near surface infaunal habitatwith a preference for the decaying 'soup' of organic matter on the sea-floor.'' Increased relative abundances of this species have been observed in intervals of high surface productivity during the Neogene (Boersma, 1985;Woodruff, 1985;Gupta and Srinivasan, 1992;Wells and others, 1994). Increased relative abundances of this species have been observed in intervals of high surface productivity during the Neogene (Boersma, 1985;Woodruff, 1985;Gupta and Srinivasan, 1992;Wells and others, 1994).…”

Section: Assemblagementioning

confidence: 95%

Paleoceanographic and paleoclimatic history of the Somali Basin during the Pliocene-Pleistocene; multivariate analyses of benthic foraminifera from DSDP Site 241 (Leg 25)

Gupta

1997

The Journal of Foraminiferal Research

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This study quantitatively examines benthic foraminifera (X25p.m) from 40 Pliocene-Pleistocene samples from Deep Sea Drilling Project (DSDP) Site 241, Somali Basin. R-mode factor and Q-mode cluster analyses of the 26 highest ranked species define five significant factor assemblages and five clusters reflecting different environmental characteristics in the Plio-Pleistocene sequence. Assemblage 1, consisting of Bulimina marginata, Nonionella japonicum, Cassidulina carinata, and Uvigerina proboscidea, reflects high flux of organic matter from high surface productivity and dominates Custer 11. Eggerella bradyi, Melonis pompilioides, and Oridorsalis umbonatus constitute Assemblage 2, which is inferred to reflect intermediate flux of relatively degraded organic matter (Cluster IV). Assemblage 3, characterized by Cibicides wuellerstorj and Epistominella exigua, coincides with Cluster I. This assemblage indicates increased oxygenation and strongly pulsed food supply. Assemblage 4, marked by Loxostomum karrerianum (=Bolivina karrerianum), Trifarina angulosa and Bolivina spathulata,corresponds to Cluster I11 and suggests an oxygen-deficient, organic carbon-rich environment. The principal species of Assemblage 5 is Nuttallides umbonifera, with Astrononion umbilicatulum and Epistominella exigua as secondary species. This assemblage, which corresponds to Cluster V, suggests low food, high oxygen and increased bottom water corrosiveness. Mean test diameters of the planktic foraminifer Orbulina universa were used to interpret sea-surface temperature history a t Site 241. Based on earlier observations that a positive correlation exists between the mean test diameter of 0. universa and surface water temperature, several intervals of cool and warm sea-surface temperatures have been interpreted in the Pleistocene. The Pliocene surface water temperatures were less variable than those of the Pleistocene, indicating increased monsoonal activity in the younger interval.

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Late Oligocene to Late Pliocene Benthic Foraminifers from Depth Traverses in the Central Indian Ocean

Cited by 33 publications

References 28 publications

Last global extinction in the deep sea during the mid‐Pleistocene climate transition

Last global extinction in the deep sea during the mid‐Pleistocene climate transition

Late Miocene–Holocene paleoceanography of the western equatorial Atlantic: evidence from deep-sea benthic foraminifers

Paleoceanographic and paleoclimatic history of the Somali Basin during the Pliocene-Pleistocene; multivariate analyses of benthic foraminifera from DSDP Site 241 (Leg 25)

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