Middle Miocene to Quaternary Diatom Biostratigraphy in the Nankai Trough and Japan Trench, and Modified Lower Miocene through Quaternary Diatom Zones for Middle-to-High Latitudes of the North Pacific

Akiba, Fumio

doi:10.2973/dsdp.proc.87.106.1986

Cited by 165 publications

(80 citation statements)

References 9 publications

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“…These planktonic Bacillariaceae have simpler raphes than their benthic counterparts, notably in the absence of terminal fissures, which suggests that terminal fissures may be essential for directional movement. Adaptation of Bacillariaceae to a pelagic existence occurred by the Miocene (c. 22-5 Ma), with the evolution of Denticulopsis Simonsen and Crucidenticula Akiba & Yanagisawa, which link in chains by means of their valve faces and raphe: Akiba (1985) and Akiba & Yanagisawa (1986) give further information on these genera, which prefigure (and may be closely related to) Fragilariopsis and Pseudo-nitzschia.…”

Section: Diversification Of Raphid Diatomsmentioning

confidence: 99%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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Molecular sequence analyses have yielded many important insights into diatom evolution, but there have been few attempts to relate these to the extensive fossil record of diatoms, probably because of unfamiliarity with the data available, which are scattered widely through the geological literature. We review the main features of molecular phylogenies and concentrate on the correspondence between these and the fossil record; we also review the evolution of major morphological, cytological and life cycle characteristics, and possible diatom origins. The first physical remains of diatoms are from the Jurassic, and well-preserved, diverse floras are available from the Lower Cretaceous. Though these are unequivocally identifiable as centric diatoms, none except a possible Stephanopyxis can be unequivocally linked to lineages of extant diatoms, although it is almost certain that members of the Coscinodiscophyceae (radial centrics) and Mediophyceae (polar centrics) were present; some display curious morphological features that hint at an unorthodox cell division mechanism and life cycle. It seems most likely that the earliest diatoms were marine, but recently discovered fossil deposits hint that episodes of terrestrial colonization may have occurred in the Mesozoic, though the main invasion of freshwaters appears to have been delayed until the Cenozoic. By the Upper Cretaceous, many lineages are present that can be convincingly related to extant diatom taxa. Pennate diatoms appear in the late Cretaceous and raphid diatoms in the Palaeocene, though molecular phylogenies imply that raphid diatoms did in fact evolve considerably earlier. Recent evidence shows that diatoms are substantially underclassified at the species level, with many semicryptic or cryptic species to be recognized; however, there is little prospect of being able to discriminate between such taxa in fossil material.

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Section: Diversification Of Raphid Diatomsmentioning

confidence: 99%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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“…These spores are believed to characterize the late stage production in coastal upwelling areas, but it is also possible that in an offshore setting they indicate some degree of erosion and lateral advection from shelf sediments (Sancetta et al, 1992). Akiba (1986) discusses the possibility that mass occurrences of Chaetoceros resting spores might indicate a shallowing basin environment. Within the water column, diatom resting spores are most often abundant in coastal phytoplankton communities (Hargraves, 1979).…”

Section: Chaetoceros Resting Spores and Upwellingmentioning

confidence: 99%

Recent to Middle Miocene Diatom Productivity at Site 907, Iceland Plateau

Stabell¹,

Koç²

1996

Proceedings of the Ocean Drilling Program

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Surface water productivity at Ocean Drilling Program Site 907 has been assessed from total diatom abundance and Chaetoceros resting spore frequency. The sediments are divided into four intervals based on relative diatom abundance. Intervals 1 and 4 are mainly barren of diatoms. Interval 2 shows a highly fluctuating abundance pattern, whereas Interval 3 is a biosilicarich middle to late Miocene (13.7-10.1 Ma) sediment containing abundant diatoms dominated by Chaetoceros resting spores. Resting spores of Chaetoceros are classified according to their forms. The round to elongate spores with smooth surfaces or spines/ridges dominate the assemblage throughout the biosilica-rich interval. The transition from the diatom barren interval to the biosilica-rich interval at about 13.7 Ma is characterized by extremely high (100%-85%) Chaetoceros spore content. The late Miocene to late Pliocene (10.1-3.0 Ma) interval with highly variable diatom content is characterized with lower Chaetoceros percentages than in the biosilica-rich interval. We infer that the period between 13.7 and 10.1 Ma reflects high surface water productivity at Site 907. The high percentage of Chaetoceros resting spores at this interval suggests upwelling of nutrient-rich subsurface waters during this period.

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“…The Neogene Nordic Seas diatom zonation of Koç and Scherer (1996), the North Pacific diatom zonation of Akiba (1986), and the Neogene North Pacific diatom (NPD) zone code system of Yanagisawa and Akiba (1998) are used for the Neogene intervals. The Oligocene and Eocene zonation is modified from the Norwegian Sea diatom zonation of Schrader and Fenner (1976), Dzinoridze et al (1978), Fenner (1985, and Scherer and Koç (1996).…”

Section: Diatomsmentioning

confidence: 99%

“…However, strewn slides were prepared from the core catcher samples using the method of Akiba (1986) by placing a small amount of material in a snap-cap vial and removing part of the upper suspension with a pipette. The sample (~1 g) was placed in a 250 mL beaker, heated at 100°C for 1-2 h, and broken into pieces, after which 100 mL of boiling distilled water was added.…”

Section: Diatomsmentioning

confidence: 99%

Methods

2006

Proceedings of the IODP 302

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Middle Miocene to Quaternary Diatom Biostratigraphy in the Nankai Trough and Japan Trench, and Modified Lower Miocene through Quaternary Diatom Zones for Middle-to-High Latitudes of the North Pacific

Cited by 165 publications

References 9 publications

Evolution of the diatoms: insights from fossil, biological and molecular data

Evolution of the diatoms: insights from fossil, biological and molecular data

Recent to Middle Miocene Diatom Productivity at Site 907, Iceland Plateau

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