Silicoflagellates and Actiniscus : vertical fluxes at Pacific and Atlantic sediment trap stations

Takahashi, Kozo

doi:10.1575/1912/407

Cited by 9 publications

(7 citation statements)

References 26 publications

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“…The euphotic layer, into which nutrients can be advected from deeper layers, provides high concentrations of silicon that can be used to build up larger and more silicifi ed skeletons. Variable morphology in the skeletons of silicofl agellates is associated with high nutrient levels in other areas (Takahashi 1991 ).…”

Section: Seasonal Changesmentioning

confidence: 99%

“…This occurs by passive sinking of material in the form of amorphous aggregates and marine snow (Alldredge and Jackson 1995 ). However, much of the planktonic material is lost to zooplankton grazing as it falls through the water column; there are also losses to fragmentation and dissolution (Takahashi 1991, Buesseler et al 2007, so that only about 10 % of calcium carbonate and biogenic silica reach the ocean fl oor, where it is integrated, through burial, into the fossil record (Boltovskoy 1995 ).…”

Section: Introductionmentioning

confidence: 99%

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Climate variability and silicoflagellate fluxes in Alfonso Basin (southern Gulf of California)

López¹,

Álvarez-Gómez²,

Durazo³

2012

Botm

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We conducted a study from January 2002 to February 2008 on silicofl agellate fl uxes in Alfonso Basin at the entrance to the Gulf of California. Thirteen taxa were identifi ed in sediment trap samples, with Octactis pulchra as the dominant species. Total fl ux climatology reached a maximum value of 5 × 10 6 skeletons m -2 day -1 in December and then sharply decreased to a minimum value in February (2.3 × 10 3 skeletons m -2 day -1 ) concurrently with the climatological sea surface temperature (SST) minimum. Subsequently, there was a positive trend with a second relative maximum of 1.6 × 10 6 skeletons m -2 day -1 in September coincident with a maximum in climatological SST. During this period, there was a similar increase to 1.4 × 10 6 skeletons m -2 day -1 in May. Factor analysis identifi ed three patterns of variation: " subtropical oceanic, " " subarctic, " and " equatorial El Ni ñ o. " Factors had reasonable correlations with the Pacifi c decadal oscillation (PDO), North Pacifi c Gyre oscillation (NPGO), and El Ni ñ o Modoki indices (r = 0.53, 0.67, and 0.63, respectively). The fi rst and second modes were apparently linked to decadal climatic conditions correlated to PDO and NPGO, as suggested by the silicofl agellate species Dictyocha messanensis forma messanensis and the assemblage of D. epiodon and Distephanus speculum , respectively; the third mode was related to the presence of warm equatorial-oceanic waters identifi ed by D. messanensis forma spinosa , which defi nes El Ni ñ o infl uence. These results demonstrate the importance of the region where there is a confl uence of the low-frequency, high-latitude PDO, NPGO, and high-frequency El Ni ñ o signals.

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Section: Seasonal Changesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Climate variability and silicoflagellate fluxes in Alfonso Basin (southern Gulf of California)

López¹,

Álvarez-Gómez²,

Durazo³

2012

Botm

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“…The O. pulchra var. pulchra skeletal morphology is by far the better known and occurs in coastal areas and inlets such as the Gulf of California (Murray & Schrader 1983;Martinez-López et al 2012) and Adriatic Sea (Rigual-Hernández et al 2010), and has been observed off the coast of Panama (Takahashi 1991). This variety is also known from deep ocean sediments of the equatorial Pacific Ocean (e.g.…”

Section: Resultsmentioning

confidence: 99%

Did the silicoflagellate genusOctactisevolve fromBachmannocena?

McCartney

Jordan

Abe

2016

Journal of Micropalaeontology

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It has long been assumed that Octactis and Stephanocha (previously known as Distephanus) are closely related. Both have apical rings, but with Octactis possessing an apical ring of larger diameter relative to the basal ring and made of thinner elements. However, closer examination of the basal rings and double skeletons (doublets) shows other differences that have received little attention. The location of the struts and pikes on each side of the Neogene Stephanocha basal ring are consistently rotated towards the basal corners. This establishes a distinct basal element between the struts and pikes that is tilted to form a zigzag basal design that creates an interlocking of the doublet skeletons. The pikes project into the region of the paired skeleton and the apical ring is also rotated with respect to the basal ring. In contrast, Octactis has a flatter basal ring without pikes, and possesses strut attachments located midway between the corners with the doublet held together only by organic material. Recent examination of living Octactis from the Seto Inland Sea of southern Japan provides a better understanding about the variability and structure of Octactis skeletons than previously available. Among these are double skeletons that have an incompletely formed daughter that consists only of the basal ring. The older literature includes line drawings that illustrate similar double skeletons, but these have not been previously photographed or adequately understood. Such skeletons are also found singly after disarticulation, and have a strong resemblance to those of fossil Bachmannocena (formerly known as Mesocena), which also has a flat basal ring lacking apical structures and pikes. The hypothesis that Octactis evolved from Bachmannocena rather than from Stephanocha is presented, with the possible evolution of an apical ring in Bachmannocena accounting for the differences between the skeletal morphologies of Octactis and Stephanocha.

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“…The taxonomic and ecologic significance of minor skeletal features, such as the spinose collar, may be an important means to correlate modern culture studies to the fossil record for classification and paleoceanographic analysis. Takahashi (1991), working on modern sediment trap assemblages, has linked larger skeletal size to higher temperatures. This presents another line of potential study for relating controlled culture and modern oceanic results in order to assist paleoceanographic interpretation of the geologic record.…”

Section: Skeletonmentioning

confidence: 99%

“…In normal marine conditions silicoflagellates may avoid solution during sinking through the water column by the physical protection and rapid sinking afforded inside zooplankton fecal pellets (Takahashi, 1991). Evidence that this process happened in the past is given by fossil floras from different water depths which show little solution nor any range of dissolution stages.…”

Section: Dissolutionmentioning

confidence: 99%

Silicoflagellates and their geologic applications

Bukry¹

1995

Open-File Report

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Marine phytoplankton silicoflagellates have a geologic record from the Mesozoic through the Cenozoic. Their siliceous skeletons can be used as indicators for paleoceanographic currents and upwelling, relative paleotemperatures, and for local and transoceanic biostratigraphic zonations. Deep-ocean coring during the past quarter century has expanded the potential and applications for silicoflagellates to many new areas.

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Silicoflagellates and Actiniscus : vertical fluxes at Pacific and Atlantic sediment trap stations

Cited by 9 publications

References 26 publications

Climate variability and silicoflagellate fluxes in Alfonso Basin (southern Gulf of California)

Climate variability and silicoflagellate fluxes in Alfonso Basin (southern Gulf of California)

Did the silicoflagellate genusOctactisevolve fromBachmannocena?

Silicoflagellates and their geologic applications

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