The early Pliocene re-colonisation of the deep Mediterranean Sea by benthic Foraminifera and their pulsed late Pliocene-middle Pleistocene decline

Online Access: Get full text
doi: 10.1016/j.marmicro.2009.01.008
Author(s): Hayward, Bruce W.; Sabaa, Ashwaq T.; Kawagata, Shungo; Grenfell, Hugh R.
Author Affiliation(s): Primary:
Geomarine Research, Auckland, New Zealand
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 71(3-4), p.97-112. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. Based on Publisher-supplied data; includes 2 appendices
Summary: Ninety-five species and 19 genera of cosmopolitan, deep-sea benthic foraminifera belonging to the families Pleurostomellidae, Stilostomellidae and Nodosariidae, became extinct during the late Pliocene-middle Pleistocene. Only 50% of these (44 species) were present in the Pliocene or Pleistocene of the deep Mediterranean Sea (ODP Sites 654, 966, 967, 975, 976), being those which had successfully migrated in via the Strait of Gibraltar from the deep Atlantic following the annihilation of the Mediterranean deep-sea fauna during the late Miocene Messinian Crisis. Most colonization occurred within the first 0.8 myrs (5.3-4.5 Ma) after re-establishment of the Mediterranean-Atlantic link, with possibly a second lesser period of immigration in the late Pliocene (3.4-3.0 Ma). We infer that colonizations may have been fortuitous and few in number, as some common members of the group in the Atlantic never succeeded in establishing in the Mediterranean Sea. There is no evidence of any new immigration events during the Pleistocene, implying that the present anti-estuarine circulation may have been in place throughout this period. Our studies suggest that these deep-water, low-oxygen-tolerant foraminifera survived the many periods of deep-water sapropel formation in the Pliocene-early Pleistocene, possibly in somewhat shallower (∼500 m) refuges with dysoxic, rather than anoxic conditions. The Pliocene-Pleistocene stratigraphic record of this group of elongate, cylindrical benthic foraminifera with constricted and specialized apertures is similar in the west and east Mediterranean Basins. The group declined in abundance (flux) and diversity in two pulses, during the late Pliocene (3.1-2.7 Ma) and the late early Pleistocene (1.3-1.0 Ma) in concert with global, southern-sourced, deep-water sites (AABW, CPDW) and earlier than the single decline (1.0-0.6 Ma) in global, intermediate water sites (uNADW, AAIW). All species, with one possible exception, disappeared earlier in the Mediterranean than globally. The highest occurrence of any species of this group in Mediterranean sites was 0.8-0.43 Ma, comparable with 0.7-0.2 Ma outside with the youngest survivors being in abyssal, deep-water. Thus, despite the unusual oceanographic conditions and isolation, the deep Mediterranean Sea was in this case neither the center for the evolution of new species nor a refuge where species survived after they had disappeared elsewhere. Abstract Copyright (2009) Elsevier, B.V.
Year of Publication: 2009
Research Program: ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; 12 Stratigraphy, Historical Geology and Paleoecology; Alboran Sea; Benthic taxa; Biogeography; Cenozoic; Deep-sea environment; East Mediterranean; Faunal studies; Foraminifera; Invertebrata; Leg 107; Leg 160; Leg 161; Levantine Basin; Marine environment; Mediterranean Sea; Microfossils; Migration; Minorca Rise; Neogene; Nodosariacea; Nodosariidae; ODP Site 654; ODP Site 966; ODP Site 967; ODP Site 975; ODP Site 976; Ocean Drilling Program; Paleoecology; Paleoenvironment; Pleistocene; Pleurostomellidae; Pliocene; Protista; Quaternary; Rotaliina; Stilostomellidae; Tertiary; Tyrrhenian Sea; Upper Pliocene; West Mediterranean
Coordinates: N361219 N385348 E0043036 E0041845
N403445 N403446 E0104148 E0104148
N334748 N340411 E0324331 E0324205
Record ID: 2010013730
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands