Mid-Pleistocene extinction of bathyal benthic foraminifera in the Caribbean Sea

Abstract

During the mid-Pleistocene Transition (MPT), 2 families, 14 genera and 41 species of benthic foraminifera (Extinction Group) declined in abundance (8-12 % of early Pleistocene benthic foraminiferal fauna) and finally disappeared at mid-bathyal depths in the Caribbean Sea (ODP Site 1000A, 916m depth), as part of the global extinction of at least 73 deep-water species at this time. At this site, the final phase of pulsed glacial decline, partial interglacial recoveries (0.8-0.67 Ma), and final extinction (0.58 Ma) was essentially the same as the youngest level so far documented elsewhere (0.57 Ma). Extinction Group specimens had smaller average sizes during periods of decline than during favorable periods with higher abundances. Census counts on different size fractions indicate that this extinction event is best recorded by studies of shells in the 150-300µm size range. Pteropod dissolution proxies indicate that intermediate waters in the Caribbean became less corrosive around the onset of the MPT (after c. 1.2 Ma). This is interpreted to be a result of increased input of northern hemisphere-sourced intermediate water at the expense of southern-sourced Antarctic Intermediate Water. Intervals of enhanced Extinction Group decline in intermediate waters in the Caribbean occurred during glacials around the start (1.15-1.05 Ma) and end (0.83-0.65 Ma) of the MPT. During these glacial periods preservation of carbonate was optimal and ä 13 C values high (in source waters at mid-depths in the North Atlantic), suggesting a causal link with enhanced inflow of a less-corrosive, colder, nutrient-depleted, well-ventilated water mass, such as Glacial North Atlantic Intermediate Water.

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

“…The majority of significant declines at each site occurred during glacial intervals and were interspersed with interglacial recoveries (Figures 4 and 5) [Hayward, 2002;Kawagata et al, 2005Kawagata et al, , 2006Kawagata et al, , 2007Hayward et al, 2006;O'Neill et al, 2007]. This pattern was most prominent at intermediate depths during the MPT, with marked declines at various sites between marine isotope stages MIS 24 and 16 (0.92-0.65 Ma).…”

“…[4] The youngest interval has only recently been identified [Lutze, 1979;Weinholz and Lutze, 1989;Schönfeld, 1996], but our studies indicate that it was the most significant of the three younger species turnovers with 20 -25% of deep-sea foraminiferal diversity disappearing, mostly during the mid-Pleistocene Climate Transition (MPT, 1.2-0.55 Ma) [Hayward, 2001[Hayward, , 2002Kawagata et al, 2005Kawagata et al, , 2006Hayward et al, 2006;O'Neill et al, 2007]. The Eocene-Oligocene and mid-Miocene turnovers were more significant in turns of community structure but are reported to have resulted in fewer species originations or extinctions [Thomas, 1986a[Thomas, , 1986b[Thomas, , 1987.…”

“…[14] Our studies show that 19 genera and 95 species of three families of cosmopolitan deep-sea benthic foraminifera (see supporting material) became extinct globally during the late Pliocene -MPT (3 -0.12 Ma) [Hayward, 2002;Kawagata et al, 2005Kawagata et al, , 2006Kawagata et al, , 2007Hayward et al, 2006;O'Neill et al, 2007]. One whole family (Stilostomellidae, 30 species) was wiped out by the end of the MPT, and a second (Pleurostomellidae, 29 species) was also decimated with just one species possibly surviving through to the present in extremely low numbers [Hayward, 2002].…”

“…Gp species through the MPT in representative intermediate depth core sites from the north Atlantic Ocean (ODP 980), Caribbean Sea (ODP 1000), and north Indian Ocean (ODP 722). Also shown are graphs for oxygen isotopes, planktic foraminiferal fragmentation index, and absolute abundance of indicator species for high organic carbon flux [from Raymo et al, 2004;Kawagata et al, 2005Kawagata et al, , 2006Hayward et al, 2006]. AR, accumulation rate; Ext.…”

Neogene Changes in Caribbean Paleoproductivity and the Diversity and Paleobiogeography of Deep-sea Benthic Foraminifera

“…Gooday and Jorissen (2012) found that deeper-water benthic foraminifer have broad geographic ranges that are controlled more by the amount of organic matter they receive. Studies have examined the effects of a widespread, mid-Pleistocene extinction of benthic foraminifera in the Caribbean at mid-bathyal depths (Hayward, et al, , 2006.…”