The vertical distribution of Radiolaria in the waters surrounding Japan

Ishitani, Yoshiyuki; Takahashi, Kozo

doi:10.1016/j.marmicro.2007.06.002

Cited by 32 publications

(20 citation statements)

References 26 publications

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“…profunda / truncatum group, and D . elegans [e.g., Ishitani and Takahashi , ; Kamikuri et al ., ; Lombari and Boden , ; Matsuzaki et al ., ; Yamashita et al ., ; Okazaki et al ., ] belong into our factor S‐1 (Table ). As described above the factor S‐1 corresponds to the area influenced by the NPEC and the KC (Figure ).…”

Section: Discussionmentioning

confidence: 99%

“…First, the tool proposed by the University of Bremen is only applicable to near‐surface depths. The second is that based on previously published works, intermediate water radiolarians are not restricted to a single water depth, but rather occur over a range of depths [ Ishitani and Takahashi , ; Matsuzaki et al ., ; Okazaki et al ., ; Tanaka and Takahashi , ; Yamashita et al , ]. The last problem is that intermediate water temperature varies drastically from 200 to 500 m, while a relatively low temperature change is recorded between 500 and 1000 m [ Locarnini et al ., ].…”

Section: Methodsmentioning

confidence: 98%

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New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

Matsuzaki

Itaki

2017

Paleoceanography

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A new radiolarian data set for transfer function estimates of past sea surface temperature (SST) and intermediate water temperature was developed in this study for the northwestern Pacific Ocean covering a region from 1° to 50°N and 120° to 167°E. We analyzed 87 sediments surface samples, selected 30 species and/or species group found in shallow water for estimating past summer SST and 17 species and/or species group found in the intermediate water for estimating past intermediate water temperature. Since the intermediate water temperature changes greatly between 200 and 500 m, our estimates provide values at 500 m because temperatures are relatively stable between 500 and 1000 m. In this context, we estimated past summer SST and intermediate water (at ~500 m) temperature within an error margin of 0.9 and 1.2°C, respectively. A test of the accuracy of our transfer functions, conducted on core samples provided by IODP Expedition 346 Site U1429 in the northern East China Sea, showed that the reconstructed summer SSTs fluctuated between 17.2 and 26.5°C in selected late Pleistocene sequences. These temperatures corresponded to modern winter and summer SST, respectively, which highlights the ability of our new database to accurately reconstruct summer SST. The reconstructed intermediate water temperature fluctuates between 3 and 8°C, which corresponds to the observed temperature range at depths of ~500 m at high and midlatitudes, respectively.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 98%

New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

Matsuzaki

Itaki

2017

Paleoceanography

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“…On the other hand, a ‘retreat’ from the surface habitat could have occurred in response to the tracking of a particular food resource or oceanic regime in high latitudes, which are manifested at greater depths in the lower latitudes. Such pattern of tropical submergence is known from assemblages of pelagic radiolaria, where surface‐dwelling subpolar species occur at mesopelagic depth in the tropics (Ishitani & Takahashi 2007). However, we find no trace of such hypothetical high‐latitude surface‐dwelling ancestor of the deep‐dwelling type, which would consequently have to become extinct or replaced in its habitat by the surface‐dwelling type after their divergence.…”

Section: Discussionmentioning

confidence: 99%

“…Many groups of heterotrophic microplankton occur across a wide depth range, but their species are typically limited to a much narrower vertical interval (e.g. Ishitani & Takahashi 2007). Most morphospecies of planktonic foraminifera also occupy a restricted habitat in the water column, defined by their temperature tolerance or the possession of symbionts, limiting them to the mixed layer above the thermocline (e.g.…”

Section: Introductionmentioning

confidence: 99%

Vertical niche partitioning between cryptic sibling species of a cosmopolitan marine planktonic protist

et al. 2012

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A large portion of the surface-ocean biomass is represented by microscopic unicellular plankton. These organisms are functionally and morphologically diverse, but it remains unclear how their diversity is generated. Species of marine microplankton are widely distributed because of passive transport and lack of barriers in the ocean. How does speciation occur in a system with a seemingly unlimited dispersal potential? Recent studies using planktonic foraminifera as a model showed that even among the cryptic genetic diversity within morphological species, many genetic types are cosmopolitan, lending limited support for speciation by geographical isolation. Here we show that the current two-dimensional view on the biogeography and potential speciation mechanisms in the microplankton may be misleading. By depth-stratified sampling, we present evidence that sibling genetic types in a cosmopolitan species of marine microplankton, the planktonic foraminifer Hastigerina pelagica, are consistently separated by depth throughout their global range. Such strong separation between genetically closely related and morphologically inseparable genetic types indicates that niche partitioning in marine heterotrophic microplankton can be maintained in the vertical dimension on a global scale. These observations indicate that speciation along depth (depth-parapatric speciation) can occur in vertically structured microplankton populations, facilitating diversification without the need for spatial isolation.

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“…Living radiolarians in the Japan Sea have been examined using plankton tows, and most of warm-water species are recognized in shallower depths (Itaki 2003;Ishitani and Takahashi 2007;Kurihara and Matsuoka 2010;Itaki et al 2010). In the Tsushima Strait, radiolarian assemblages are similar with those in the East China Sea, while it is different from those in the northern Japan Sea (Itaki et al 2010).…”

Section: Radiolariansmentioning

confidence: 99%

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

Gallagher

Kitamura

Iryu

et al. 2015

Prog. in Earth and Planet. Sci.

159

121

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The Kuroshio Current is a major western boundary current controlled by the North Pacific Gyre. It brings warm subtropical waters from the Indo-Pacific Warm Pool to Japan exerting a major control on Asian climate. The Tsushima Current is a Kuroshio offshoot transporting warm water into the Japan Sea. Various proxies are used to determine the paleohistory of these currents. Sedimentological proxies such as reefs, bedforms, sediment source and sorting reveal paleocurrent strength and latitude. Proxies such as coral and mollusc assemblages reveal past shelfal current activity. Microfossil assemblages and organic/inorganic geochemical analyses determine paleo-sea surface temperature and salinity histories. Transportation of tropical palynomorphs and migrations of Indo-Pacific species to Japanese waters also reveal paleocurrent activity. The stratigraphic distribution of these proxies suggests the Kuroshio Current reached its present latitude (35°N) by~3 Ma when temperatures were 1 to 2°C lower than present. At this time a weak Tsushima Current broke through Tsushima Strait entering the Japan Sea. Similar oceanic conditions persisted until~2 Ma when crustal stretching deepened the Tsushima Strait allowing inflow during every interglacial. The onset of stronger interglacial/glacial cycles~1 Ma was associated with increased North Pacific Gyre and Kuroshio Current intensity. This triggered Ryukyu Reef expansion when reefs reached their present latitude (~31°N), thereafter the reef front advanced (~31°N) and retreated (~25°N) with each cycle. Foraminiferal proxy data suggests eastward deflection of the Kuroshio Current from its present path at 24°N into the Pacific Ocean due to East Taiwan Channel restriction during the Last Glacial Maximum. Subsequently Kuroshio flow resumed its present trajectory during the Holocene. Ocean modeling and geochemical proxies show that the Kuroshio Current path may have been similar during glacials and interglacials, however the glacial mode of this current remains controversial. Paleohistorical studies form important analogues for current behavior with future climate change, however, there are insufficient studies at present in the region that may be used for this purpose. Modeling of the response of the Kuroshio Current to future global warming reveals that current velocity may increase by up to 0.3 m/sec associated with a northward migration of the Kuroshio Extension.

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The vertical distribution of Radiolaria in the waters surrounding Japan

Cited by 32 publications

References 26 publications

New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

Vertical niche partitioning between cryptic sibling species of a cosmopolitan marine planktonic protist

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

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