Vertical distribution of fluorescent organic matter along with AOU and nutrients in the equatorial Central Pacific

Hayase, Kohji; Shinozuka, Noriko

doi:10.1016/0304-4203(94)00051-e

Cited by 118 publications

(101 citation statements)

References 22 publications

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“…It is comparable to previous observations [Hayase and Shinozuka, 1995]. Although R 2 was lower than those at higher latitudinal regions (0.48), the linear relationship between the intensity and AOU was significant (p < 0.001) even at 15°N.…”

Section: Distribution Of Fluorescence Intensity Of Fdom Msupporting

confidence: 90%

“…This inversion trend in the concentrations of FDOM M and TOC may imply that FDOM M is not quantitatively important to the DOC pool and that FDOM M is not the controlling factor in the variability of the TOC concentration. Although the carbon-based contribution of FDOM M to DOM is still poorly understood, a low contribution of FDOM M to DOC (1%) was proposed so far [Hayase and Shinozuka, 1995].…”

Section: Roles Of Fdom M In Doc Poolmentioning

confidence: 99%

“…In the open ocean, meanwhile, relatively limited measurements of the fluorescence intensity of humic substances have been carried out so far. Although vertical profiles [Chen and Bada, 1992;Mopper and Schultz, 1993;Hayase and Shinozuka, 1995;Yamashita et al, 2007] and spatial variation [Chen and Bada, 1992;Determann et al, 1996;Yamashita and Tanoue, 2008] have been determined, the observations are rather fragmentary and little systematic study has been conducted to date covering spatial and temporal changes in the fluorescence intensity.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between the seasonal change in fluorescent dissolved organic matter and mixed layer depth in the subtropical western North Pacific

Omori

Hama

Ishii³

et al. 2010

J. Geophys. Res.

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[1] Spatial and temporal distributions of marine humic-like fluorescent dissolved organic matter (FDOM M ) were determined in the subtropical western North Pacific to evaluate the controlling factors of FDOM M behaviors. The observations were conducted at 4 stations (15-30°N) along 137°E in a subtropical area between January 2006 and April 2007. The florescence intensity of FDOM M was low (0.14-0.25 quinine sulfate units (QSU)) in the surface layer probably due to photodegradation, and increased with depth (0.90-1.10 QSU at 1000 m), irrespective of season and station. In the surface layer, the thickness of the water mass with low fluorescence intensity (<0.3 QSU) showed the seasonal change by being deeper in winter and shallower in summer, depending on the mixed layer depth (MLD). The average fluorescence intensity within the mixed layer also varied seasonally at midlatitudes; the intensity in summer was 40.8-53.8% of that in winter. Since the MLD was very much shallower in summer than in winter, FDOM M in the mixed layer would be kept within a shallow depth during the summer where intensive photodegradation could occur. The concentration of total organic carbon (TOC) was at its maximum at the water surface and decreased with depth, being adverse to FDOM M . Thus, the ratio of fluorescence intensity to TOC concentration was lowest (0.002-0.003) in surface water, which implies that FDOM M is not quantitatively important to the dissolved organic carbon pool. However, considering the possible difference in the stabilities of FDOM M against photochemical and microbial degradation, it is conceivable that photobleached FDOM M is one of the important organic groups constituting marine dissolved organic matter.Citation: Omori, Y., T. Hama, M. Ishii, and S. Saito (2010), Relationship between the seasonal change in fluorescent dissolved organic matter and mixed layer depth in the subtropical western North Pacific,

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Section: Distribution Of Fluorescence Intensity Of Fdom Msupporting

confidence: 90%

Section: Roles Of Fdom M In Doc Poolmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Relationship between the seasonal change in fluorescent dissolved organic matter and mixed layer depth in the subtropical western North Pacific

Omori

Hama

Ishii³

et al. 2010

J. Geophys. Res.

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“…The global pattern in the dark ocean of an increase in the humiclike components concomitant to water mass ageing (high AOU values) has been previously reported 5,6,18,19 . Although it has been recently hypothesized that this relationship could also be caused by further transformations of terrestrial humic-like materials in the open ocean 20 , culture experiments have unequivocally demonstrated that these materials can be produced in situ in the oceans 21 .…”

Section: Discussionmentioning

confidence: 76%

Turnover time of fluorescent dissolved organic matter in the dark global ocean

et al. 2015

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Marine dissolved organic matter (DOM) is one of the largest reservoirs of reduced carbon on Earth. In the dark ocean (4200 m), most of this carbon is refractory DOM. This refractory DOM, largely produced during microbial mineralization of organic matter, includes humic-like substances generated in situ and detectable by fluorescence spectroscopy. Here we show two ubiquitous humic-like fluorophores with turnover times of 435 ± 41 and 610 ± 55 years, which persist significantly longer than the B350 years that the dark global ocean takes to renew. In parallel, decay of a tyrosine-like fluorophore with a turnover time of 379 ± 103 years is also detected. We propose the use of DOM fluorescence to study the cycling of resistant DOM that is preserved at centennial timescales and could represent a mechanism of carbon sequestration (humic-like fraction) and the decaying DOM injected into the dark global ocean, where it decreases at centennial timescales (tyrosine-like fraction).

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“…Therefore, 3D-EEMs is an effective method for the characterization of fluorescent organic matter in sea water. Fluorescent organic matter which seems to be refractory organic substances is present in the deep layer of the Pacific Ocean (Hayase and Shinozuka, 1995;Yamaguchi et al, 2001;Nakaguchi et al, 2003). 3D-EEMs were measured by using the same samples which were collected by the R/V Hakuho-Maru KH-02-4 cruise.…”

Section: The Relationship Between Organic Selenide and Fluorescent Ormentioning

confidence: 99%

Dissolved selenium species in the Sulu Sea, the South China Sea and the Celebes Sea

et al. 2004

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We have measured the vertical profiles of selenite, selenate and organic selenide in the Southeast Asian Basins (the Celebes Sea, the Sulu Sea and the South China Sea) for the two years, 1996 and 2002. Total selenium, selenite and selenate showed nutrient-like profiles. In particular, the vertical profiles of selenate and organic selenide in the Sulu Sea differed greatly between 1996 and 2002. The salinity and selenite/selenate ratio in the surface layer showed that the Sulu Sea surface water in these two years was derived from different sources. The vertical profiles of selenite, selenate and organic selenide in the South China Sea in 1996 and 2002 were almost the same. Both selenite and selenate were slightly elevated at the surface in the South China Sea. These inorganic selenium species seemed to be derived from atmospheric input, admixture of the East China Sea surface water, West Philippine Sea surface water, and fluvial, coastal and shelf waters of the South China Sea. The relationship between the concentration of organic selenide and the relative fluorescent intensity of fluorescent organic matter in the South China Sea suggested the organic selenide exists in the refractory DOC fraction possibility as humic-like substances. The total dissolved selenium concentration and the selenite/selenate ratio in deep water indicated that the water mass age of the Celebes Sea deep water was similar to that of the western North Pacific deep water. On the other hand, the water mass age of the Sulu Sea is younger than that of the western North Pacific. The selenite/selenate ratio in the South China Sea deep water was two times higher than that of the western North Pacific. This result suggested that a large amount of organic detritus was supplied to the South China Sea, and then the organic selenide in the organic detritus rapidly oxidized to selenite.

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Vertical distribution of fluorescent organic matter along with AOU and nutrients in the equatorial Central Pacific

Cited by 118 publications

References 22 publications

Relationship between the seasonal change in fluorescent dissolved organic matter and mixed layer depth in the subtropical western North Pacific

Relationship between the seasonal change in fluorescent dissolved organic matter and mixed layer depth in the subtropical western North Pacific

Turnover time of fluorescent dissolved organic matter in the dark global ocean

Dissolved selenium species in the Sulu Sea, the South China Sea and the Celebes Sea

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