Isotopic tracers for water masses in the coastal region of eastern Hokkaido

Oguma, Sachiko; Ono, Tsuneo; Kusaka, Akira; Kasai, Hiromi; Kawasaki, Yasuhiro; Azumaya, Tomonori

doi:10.1007/s10872-008-0044-y

Cited by 34 publications

(19 citation statements)

References 19 publications

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“…According to the dis- tribution of sea surface temperature derived from the Moderate Resolution Imaging Spectroradiometers (MODIS) images in 2014 ( Fig. 4; http://oceancolor.gsfc.nasa.gov/cms/), the oceanic boundary of Furen Lagoon was the Oyashio throughout the year except from late summer to autumn when the Soya warm current intrudes into the boundary (Oguma et al, 2008;Takizawa, 1982). The oceanic endmember 14 C DIC would reflect the value of the Oyashio from January to August 2014, when the Soya warm current did not reach the oceanic boundary of Furen Lagoon 6256 K. Watanabe and T. Kuwae: Radiocarbon isotopic evidence for assimilation of atmospheric CO 2 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Radiocarbon isotopic evidence for assimilation of atmospheric CO2 by the seagrass Zostera marina

Watanabe

Kuwae

2015

Biogeosciences

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Abstract. Submerged aquatic vegetation takes up watercolumn dissolved inorganic carbon (DIC) as a carbon source across its thin cuticle layer. It is expected that marine macrophytes also use atmospheric CO 2 when exposed to air during low tide, although assimilation of atmospheric CO 2 has never been quantitatively evaluated. Using the radiocarbon isotopic signatures ( 14 C) of the seagrass Zostera marina, DIC and particulate organic carbon (POC), we show quantitatively that Z. marina takes up and assimilates atmospheric modern CO 2 in a shallow coastal ecosystem. The 14 C values of the seagrass (−40 to −10 ‰) were significantly higher than those of aquatic DIC (−46 to −18 ‰), indicating that the seagrass uses a 14 C-rich carbon source (atmospheric CO 2 , +17 ‰). A carbon-source mixing model indicated that the seagrass assimilated 0-40 % (mean, 17 %) of its inorganic carbon as atmospheric CO 2 . CO 2 exchange between the air and the seagrass might be enhanced by the presence of a very thin film of water over the air-exposed leaves during low tide. Our radiocarbon isotope analysis, showing assimilation of atmospheric modern CO 2 as an inorganic carbon source, improves our understanding of the role of seagrass meadows in coastal carbon dynamics.

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Section: Resultsmentioning

confidence: 99%

Radiocarbon isotopic evidence for assimilation of atmospheric CO2 by the seagrass Zostera marina

Watanabe

Kuwae

2015

Biogeosciences

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“…1 together with salinity, temperature, and density. The water column in this area is considered to consist of intermediate cold water (ICW) (potential temperature of −1.8-+2 • C, salinity of 32.8-33.4) (50-300 m), transient layer water (TLW) (1-2 • C, 33.4-34.3) (300-1200 m), and deep layer water (below ∼ 1200 m to bottom) beneath the surface water (above ∼ 50 m) (Takizawa, 1982;Oguma et al, 2008). The variation of 226 Ra activity in surface and ICW is small (∼ 2 mBq l −1 ) ( fig.…”

Section: Resultsmentioning

confidence: 99%

Vertical distributions of²²⁶Ra,²²⁸Ra, and¹³⁷Cs activities in the southwestern part of the Sea of Okhotsk

Inoue

Yoshida

Minakawa

et al. 2012

EPJ Web of Conferences

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“…2) may be partly responsible. The low temperature in the Doto coastal area during winter is caused mainly by the outflow of East Sak halin Current water from the southern Okhotsk Sea (Oguma et al 2008); hence, the decreasing trend in pollock condition could be associated with water mass dynamics upstream of the Oyashio current.…”

Section: Variation In Conditionmentioning

confidence: 99%

Interannual variation in diets of walleye pollock in the Doto area, in relation to climate variation

Yamamura¹,

Funamoto²,

Chimura³

et al. 2013

Mar. Ecol. Prog. Ser.

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Interannual variation in the diet of walleye pollock Theragra chalcogramma along the southeastern coast of Hokkaido Island (Doto area) was analyzed using >15 000 specimens collected in the periods 1989−1992 and 1995−2011, in relation to oceanographic variables. The area experienced a warm period from 1998 to 2002, which was preceded and followed by cold periods. An apparent shift in diet occurred between the first cold period and the warm period. Appendicularians (larvaceans) became an important summer prey for small-sized pollock (≤300 mm SL) in addition to copepods and euphausiids, which were also important before the onset of the warm period. In medium-and large-sized pollock, an abrupt decrease in mesopelagic fishes (mainly myctophid Diaphus theta) was observed in stomach contents 3 yr after the 1997/1998 climate regime shift, possibly reflecting a recruitment failure of D. theta. Appendicularians, cannibalism and anchovy Engraulis japonica compensated for the disappearance of mesopelagic fishes from the diet. During autumn and winter, a similar shift from micronekton (mainly D. theta and firefly squid Watasenia scintillans) to euphausiids (exclusively Euphausia pacifica) and cannibalism was found between 2000 and 2001. Although diet changes lagged the onset of the warm period, condition factor increased immediately after the regime shift. This inconsistency may be attributable to the bioenergetic response of juvenile pollock, which attain better growth at warmer temperatures. Thus, in the Doto area, the effect of climate variation on the survival of pollock seemed to be limited, due to their flexible feeding behaviors.

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Isotopic tracers for water masses in the coastal region of eastern Hokkaido

Cited by 34 publications

References 19 publications

Radiocarbon isotopic evidence for assimilation of atmospheric CO<sub>2</sub> by the seagrass <i>Zostera marina</i>

Radiocarbon isotopic evidence for assimilation of atmospheric CO<sub>2</sub> by the seagrass <i>Zostera marina</i>

Vertical distributions of²²⁶Ra,²²⁸Ra, and¹³⁷Cs activities in the southwestern part of the Sea of Okhotsk

Interannual variation in diets of walleye pollock in the Doto area, in relation to climate variation

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Isotopic tracers for water masses in the coastal region of eastern Hokkaido

Cited by 34 publications

References 19 publications

Radiocarbon isotopic evidence for assimilation of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; by the seagrass &lt;i&gt;Zostera marina&lt;/i&gt;

Radiocarbon isotopic evidence for assimilation of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; by the seagrass &lt;i&gt;Zostera marina&lt;/i&gt;

Vertical distributions of226Ra,228Ra, and137Cs activities in the southwestern part of the Sea of Okhotsk

Interannual variation in diets of walleye pollock in the Doto area, in relation to climate variation

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Radiocarbon isotopic evidence for assimilation of atmospheric CO<sub>2</sub> by the seagrass <i>Zostera marina</i>

Radiocarbon isotopic evidence for assimilation of atmospheric CO<sub>2</sub> by the seagrass <i>Zostera marina</i>

Vertical distributions of²²⁶Ra,²²⁸Ra, and¹³⁷Cs activities in the southwestern part of the Sea of Okhotsk