Iron(III) hydroxide solubility and humic-type fluorescent organic matter in the deep water column of the Okhotsk Sea and the northwestern North Pacific Ocean

Abstract. Under modern conditions only North Pacific Intermediate Water is formed in the Northwest Pacific Ocean. This situation might have changed in the past. Recent studies with General Circulation Models indicate a switch to deep-water formation in the Northwest Pacific during Heinrich Stadial 1 (17.5–15.0 kyr) of the last glacial termination. Reconstructions of past ventilation changes based on paleoceanographic proxy records are still insufficient to test whether a deglacial mode of deep-water formation in the North Pacific Ocean existed. Here we present deglacial ventilation records based on radiocarbon-derived ventilation ages in combination with epibenthic stable carbon isotopes from the Northwest Pacific including the Okhotsk Sea and Bering Sea, the two potential source regions for past North Pacific ventilation changes. Evidence for most rigorous ventilation of the mid-depth North Pacific occurred during Heinrich Stadial 1 and the Younger Dryas, simultaneous to significant reductions in Atlantic Meridional Overturning Circulation. Concurrent changes in δ13C and ventilation ages point to the Okhotsk Sea as driver of millennial-scale changes in North Pacific Intermediate Water ventilation during the last deglaciation. Our records additionally indicate that changes in the δ13C intermediate water (700–1750 m water depth) signature and radiocarbon-derived ventilation ages are in antiphase to those of the deep North Pacific Ocean (>2100 m water depth) during the last glacial termination. Thus, intermediate and deep-water masses of the Northwest Pacific have a differing ventilation history during the last deglaciation.

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Pulses of enhanced North Pacific Intermediate Water ventilation from the Okhotsk Sea and Bering Sea during the last deglaciation

Climate of the Past ◽

10.5194/cp-10-591-2014 ◽

2014 ◽

Vol 10 (2) ◽

pp. 591-605 ◽

Cited By ~ 54

Author(s):

L. Max ◽

L. Lembke-Jene ◽

J.-R. Riethdorf ◽

R. Tiedemann ◽

D. Nürnberg ◽

...

Keyword(s):

Pacific Ocean ◽

Deep Water ◽

North Pacific ◽

North Pacific Ocean ◽

Northwest Pacific ◽

Intermediate Water ◽

Okhotsk Sea ◽

Last Deglaciation ◽

North Pacific Intermediate Water ◽

The Last Deglaciation

Abstract. Under modern conditions only North Pacific Intermediate Water is formed in the northwest Pacific Ocean. This situation might have changed in the past. Recent studies with general circulation models indicate a switch to deep-water formation in the northwest Pacific during Heinrich Stadial 1 (17.5–15.0 ka) of the last glacial termination. Reconstructions of past ventilation changes based on paleoceanographic proxy records are still insufficient to test whether a deglacial mode of deep-water formation in the North Pacific Ocean existed. Here we present deglacial ventilation records based on radiocarbon-derived ventilation ages in combination with epibenthic stable carbon isotopes from the northwest Pacific including the Okhotsk Sea and Bering Sea, the two potential source regions for past North Pacific ventilation changes. Evidence for most rigorous ventilation of the intermediate-depth North Pacific occurred during Heinrich Stadial 1 and the Younger Dryas, simultaneous to significant reductions in Atlantic Meridional Overturning Circulation. Concurrent changes in δ13C and ventilation ages point to the Okhotsk Sea as driver of millennial-scale changes in North Pacific Intermediate Water ventilation during the last deglaciation. Our records additionally indicate that changes in the δ13C intermediate-water (700–1750 m water depth) signature and radiocarbon-derived ventilation ages are in antiphase to those of the deep North Pacific Ocean (>2100 m water depth) during the last glacial termination. Thus, intermediate- and deep-water masses of the northwest Pacific have a differing ventilation history during the last deglaciation.

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Evidence for deep-water production in the North Pacific Ocean during the early Cenozoic warm interval

Nature ◽

10.1038/nature02639 ◽

2004 ◽

Vol 430 (6995) ◽

pp. 65-68 ◽

Cited By ~ 85

Author(s):

Deborah J. Thomas

Keyword(s):

Pacific Ocean ◽

Deep Water ◽

North Pacific ◽

North Pacific Ocean ◽

Water Production ◽

The North ◽

The North Pacific ◽

Early Cenozoic

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Antioxidant Activity and Phenolic Content of Marine Dissolved Organic Matter and Their Relation to Molecular Composition

Frontiers in Marine Science ◽

10.3389/fmars.2020.603447 ◽

2020 ◽

Vol 7 ◽

Author(s):

Teresa S. Catalá ◽

Pamela E. Rossel ◽

Félix Álvarez-Gómez ◽

Jan Tebben ◽

Félix L. Figueroa ◽

...

Keyword(s):

Antioxidant Activity ◽

Organic Matter ◽

Free Radical ◽

Pacific Ocean ◽

Dissolved Organic Matter ◽

North Pacific ◽

Phenolic Content ◽

North Pacific Ocean ◽

Molecular Composition ◽

Antioxidant Potential

The potential of marine dissolved organic matter (DOM) for free radical scavenging has been extensively evaluated, however, the quantitative assessment of the antioxidant potential has been recently measured for the first time. The linkage of the DOM antioxidant potential to its molecular composition has not yet been examined. Following this line, this article takes a step forward by assessing, throughout a polarity-mediated fractionation, (1) the antioxidant capacity and phenolic content and (2) the molecular characterization of DOM in a more exhaustive manner. (3) The DOM antioxidant potential and phenolic content was linked to the molecular composition of DOM, which was molecularly characterized using ultrahigh resolution Fourier transform Ion Cyclotron Resonance mass spectrometry (FT-ICR MS). Antioxidant activity and phenolic content were quantified by the free radical 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS⋅) and the Folin-Ciocalteu methods, respectively. We considered three types of different natural DOM samples: the deep North Pacific Ocean, the oligotrophic surface of the North Pacific Ocean and porewater from the sulfidic tidal flats of the Wadden Sea. Bulk porewater and its individual polarity fractions presented the highest antioxidant activity and phenolic content. DOM from the water column samples had lower antioxidant activity and phenolic content than porewater, but exceeded what it is commonly found in macroalgae, microalgae, fruits and vegetables with cosmeceutical purposes. Our values were similar to published values for terrestrial DOM. The variations in bioactivity were dependent on polarity and molecular composition. The high resolution and high mass accuracy used to determine the molecular composition of marine DOM and the chemometric and multistatistical analyses employed have allowed to distinguish molecular categories that are related to the bioactive potential. As a future perspective, we performed cytotoxicity tests with human cells and propose marine DOM as a natural ingredient for the development of cosmeceutical products.

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