Les phytolithaires (Ehrenberg)

Deflandre, Georges

doi:10.1007/bf01252058

Cited by 14 publications

(10 citation statements)

References 4 publications

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“…In the qualitative analysis, the specimens were removed from each sample and mounted on glycerin slides for later identification. Identification was based on the following sources: DEFLANDRE (1928DEFLANDRE ( , 1929; GAUTHIER LIÉVRE andTHOMAS (1958, 1960), VUCETICH (1973), OGDEN andHEDLEY (1980), VELHO et al (1996), HARDOIM (1997).…”

Section: Sampling and Data Analysesmentioning

confidence: 99%

Fluctuations of Testate Amoebae Populations (Rhizopoda) in Plankton from Different Environments on the Upper Paraná River Floodplain, Brazil

Alves

Lansac‐Tôha

Takahashi

et al. 2008

International Review of Hydrobiology

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Fluctuations in temporal and spatial abundance are remarkable features of all animal populations. Regional synchrony of local population dynamics has been verified in several studies. This study investigated the existence of coherent patterns in temporal fluctuations of the principal testate amoebae population abundance in plankton from the upper Paraná river floodplain in Brazil. Testate amoebae sampling was carried out every three months, from February 2000 to November 2002, and twice in 2003. Sampling occurred in 12 environments associated with three different rivers. Samples were obtained at the subsurface of the pelagic region, using a motorized pump and a 68 µm mesh plankton net. Ninety-three testate amoebae species from eight families were identified. The families Difflugiidae, Arcellidae, and Centropyxidae had the greatest number of species. Arcella conica, A. discoides, A. vulgaris, Centropyxis aculeata, C. ecornis, Difflugia gramen, D. pseudogramen and Cucurbitella dentata were the most abundant species, and they were chosen for spatial synchrony analysis. No coherent pattern of abundance fluctuation was found, in any of the floodplain environments studied. Nevertheless, when analyzing only the channels, spatial synchrony was observed to Centropyxis ecornis. Mantel tests showed that the synchrony level, as identified by Spearman and Pearson correlations, was not correlated to geographic distance between environments. We conclude that regional factors in the Upper Paraná River floodplain are not the main determinants of the population dynamics of testate amoebae. The high floodplain heterogeneity seems determine a great relevance of local factors.

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Section: Sampling and Data Analysesmentioning

confidence: 99%

Fluctuations of Testate Amoebae Populations (Rhizopoda) in Plankton from Different Environments on the Upper Paraná River Floodplain, Brazil

Alves

Lansac‐Tôha

Takahashi

et al. 2008

International Review of Hydrobiology

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“…Several classifications of discrete grass opal phytoliths have been proposed and expanded. Ehrenberg (1854) and Deflandre (1963) used a binomial taxonomic system with parataxa. Locker and Martini (1986) adopted this system in describing the phytoliths recovered from deep sea cores east of Australia that extend from the Middle Miocene to Early Pleistocene.…”

Section: Classification Of Grass Phytolithsmentioning

confidence: 99%

Predicted World Distribution of C3 and C4 Grass Phytoliths

Twiss¹

1992

Phytolith Systematics

266

193

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6The shapes of individual opal phytoliths from grasses, silica bodies formed in the epidermal cells of the leaf, are indicators of the ~ and C 4 photosynthetic pathways. Pooid phytoliths are circular, rectangular, elliptical, crescent or oblong forms and occur primarily in C 3 grasses, which are concentrated in high latitudes or high elevations. Chloridoid phytoliths are saddle-shaped, and occur dominantly in C 4 grasses that grow in warm, arid to semiarid regions in which the available soil moisture is very low. Panicoid phytoliths include many variations of crosses and dumbbells, and occur largely in C 4 grasses that flourish in warm, tropical to subtropical regions with a moderate amount of available soil moisture.Identifiable grass phytoliths, concentrated from soils, paleosols, sediment, archaeological sites and sedimentary rock, can be used to reconstruct the Cenozoic environment of a site or region. Taxa of the subfamily Pooideae grow in the higher latitudes and elevations. Taxa of subfamilies Chloridoideae and Panicoideae are restricted to the tropics and subtropics. The majority of extensive grasslands occur in continental interiors and are the dominant sources of identifiable phytoliths. High ratios of pooid to total pooid, chloridoid and panicoid phytoliths imply cool temperatures in the region. High ratios of chloridoid to total chloridoid and panicoid phytoliths imply a warm arid or semiarid region. Because the sources of phytoliths may be local or remote, the locations and directions of major wind belts and ocean currents must be considered in any interpretation.

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“…Phytoliths have been described from terrestial localities (Ehrenberg, 1854;Baker, 1960a;Deflandre, 1963;Hajós, 1968) as well as from marine sections (see Table 1). In marine sediments they commonly occur in areas which are close to continents and where permanent eolian transport of dust in particular directions is possible (Folger et al, 1967;Folger, 1970).…”

Section: Phytoliths In Marine Sedimentsmentioning

confidence: 99%

“…One concept uses only a descriptive nomenclature (Twiss et al, 1969;Bukry, 1980), and the other one a fixed nomenclature with parataxa (Deflandre, 1963;Dumitricà 1973), because phytoliths of identical shape may occur in grasses of quite different taxonomic positions.…”

Section: Phytolith Classificationmentioning

confidence: 99%

“…In the present study we prefer the concept of Deflandre (1963), which is based on Ehrenberg (1854), and includes the three genera Lithodontium, Lithomesites, and Lithostylidium. However, we treat these genera in the following sense: (1) lithodontioid group = phytoliths commonly conical or tetragonal, but also polygonal in outline; (2) lithomesitoid group = dumbbell-shaped phytoliths composed of two globules connected by a neck; (3) lithostyloid group = rodlike phytoliths showing a smooth, undulate, serrate, or spiny margin.…”

Section: Phytolith Classificationmentioning

confidence: 99%

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Phytoliths from the Southwest Pacific, Site 591

Locker¹,

Martini²

1986

Initial Reports of the Deep Sea Drilling Project

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Phytoliths are described from deep sea sediments at Site 591 in the southwestern Pacific. Their regional distribution is related to the arid and semiarid regions of Australia, from where they were blown by westerly winds into the Tasman Sea area. The stratigraphic record ranges from the middle Miocene, at about 14.4 m.y., until the early Pleistocene. A distinct increase in frequencies observed during the Pliocene and a maximum at about 2.5 m.y. coincide with important trends in paleogeography and paleoclimatology: the development of the Antarctic ice cap, the northward drift of the Australian Plate, and the generation of arid conditions on the Australian continent. INTRODUCTIONDuring Leg 90 phytoliths were found in fair numbers in Holes 591, 591 A, and 591B, and very sporadically also in Hole 594A. They were investigated in detail only in the first three holes. Site 591 is situated on the eastern flank of the Lord Howe Rise (31°35.06'S; 164°26.92'E) in a present water depth of 2131 m (Fig. 1). Sediments recovered at this site consist mainly of foraminifer-bearing or foraminifer-rich nannofossil ooze. Biosiliceous components are present in low numbers compared with calcareous components, and include diatoms, silicoflagellates, radiolarians, and phytoliths. The investigated sections cover the middle Miocene to early Pleistocene interval. PHYTOLITHS IN MARINE SEDIMENTSPhytoliths are siliceous casts of various shapes that occur mainly in epidermal cells of grasses. They generally indicate that a certain fraction of a sediment sample is derived from a terrestial source.Phytoliths have been described from terrestial localities (Ehrenberg, 1854;Baker, 1960a;Deflandre, 1963;Hajós, 1968) as well as from marine sections (see Table 1). In marine sediments they commonly occur in areas which are close to continents and where permanent eolian transport of dust in particular directions is possible (Folger et al., 1967;Folger, 1970). The main areas of phytolith distribution are in the Atlantic Ocean off the coast of northwest Africa and in the eastern equatorial Pacific. In both areas easterly winds, that is, winds blowing in a westerly direction, cause phytoliths to occur in Recent and ancient sediments. To these occurrences we can now add the southwest Pacific, where phytoliths were found in fair numbers during Leg 90 of the Deep Sea Drilling Project, distributed from Australia by westerly winds.Kennett, J. P., von der Borch, C. C, et al., Init. Repts. DSDP, 90: Washington (U.S.

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Les phytolithaires (Ehrenberg)

Cited by 14 publications

References 4 publications

Fluctuations of Testate Amoebae Populations (Rhizopoda) in Plankton from Different Environments on the Upper Paraná River Floodplain, Brazil

Fluctuations of Testate Amoebae Populations (Rhizopoda) in Plankton from Different Environments on the Upper Paraná River Floodplain, Brazil

Predicted World Distribution of C3 and C4 Grass Phytoliths

Phytoliths from the Southwest Pacific, Site 591

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