Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C

<p>Particulate organic carbon (POC) serves as the main carrier of the biological pump and determines its transmission efficiency, yet the transformation processes of POC remain incompletely understood. This study reports the vertical distribution of POC, dissolved inorganic carbon (DIC), <s...

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Main Authors: D. Tian, X. Li, J. Song, J. Ma, H. Yuan, L. Duan
Format: Article
Language:English
Published: Copernicus Publications 2025-07-01
Series:Ocean Science
Online Access:https://os.copernicus.org/articles/21/1627/2025/os-21-1627-2025.pdf
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author D. Tian
D. Tian
X. Li
X. Li
X. Li
X. Li
J. Song
J. Song
J. Song
J. Song
J. Ma
J. Ma
H. Yuan
H. Yuan
H. Yuan
H. Yuan
L. Duan
L. Duan
L. Duan
L. Duan
author_facet D. Tian
D. Tian
X. Li
X. Li
X. Li
X. Li
J. Song
J. Song
J. Song
J. Song
J. Ma
J. Ma
H. Yuan
H. Yuan
H. Yuan
H. Yuan
L. Duan
L. Duan
L. Duan
L. Duan
author_sort D. Tian
collection DOAJ
description <p>Particulate organic carbon (POC) serves as the main carrier of the biological pump and determines its transmission efficiency, yet the transformation processes of POC remain incompletely understood. This study reports the vertical distribution of POC, dissolved inorganic carbon (DIC), <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC, and <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-DIC in the tropical Northwestern Pacific Ocean (TNPO). The research identified three distinct biogeochemical layers governing POC transformation: the POC rapid synthesis-degradation layer (RSDL, 0–300 m), the net degradation layer (NDL, 300–1000 m), and the stable layer (SL, 1000–2000 m). From the top to the bottom of the RSDL, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC values decreased by an average of 2.23 ‰, while the carbon-to-nitrogen (<span class="inline-formula">C:N</span>) ratios increased by an average of <span class="inline-formula">2.3:1</span>, indicating the selective degradation of POC. In the NDL, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC and <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-DIC exhibited a significant negative correlation (<span class="inline-formula"><i>r</i>=0.43</span>, <span class="inline-formula"><i>p</i>&lt;0.05</span>), indicating a net transformation of POC to DIC. In the SL, POC proved to be resistant to degradation, with POC exhibiting the highest <span class="inline-formula">C:N</span> (<span class="inline-formula">15:1</span> on average) and the lowest <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC values (average <span class="inline-formula">−</span>27.71 ‰).</p>
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language English
publishDate 2025-07-01
publisher Copernicus Publications
record_format Article
series Ocean Science
spelling doaj-art-0e7bcc9af5d046be92ebd40bf21cdc6a2025-08-20T03:34:51ZengCopernicus PublicationsOcean Science1812-07841812-07922025-07-01211627163910.5194/os-21-1627-2025Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>CD. Tian0D. Tian1X. Li2X. Li3X. Li4X. Li5J. Song6J. Song7J. Song8J. Song9J. Ma10J. Ma11H. Yuan12H. Yuan13H. Yuan14H. Yuan15L. Duan16L. Duan17L. Duan18L. Duan19CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266000, China Institute of Oceanology, University of Chinese Academy of Sciences, Beijing 100049, ChinaCAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266000, China Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, ChinaInstitute of Oceanology, University of Chinese Academy of Sciences, Beijing 100049, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266000, ChinaCAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266000, China Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, ChinaInstitute of Oceanology, University of Chinese Academy of Sciences, Beijing 100049, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266000, ChinaCAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266000, China Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, ChinaCAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266000, China Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, ChinaInstitute of Oceanology, University of Chinese Academy of Sciences, Beijing 100049, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266000, ChinaCAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266000, China Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, ChinaInstitute of Oceanology, University of Chinese Academy of Sciences, Beijing 100049, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266000, China<p>Particulate organic carbon (POC) serves as the main carrier of the biological pump and determines its transmission efficiency, yet the transformation processes of POC remain incompletely understood. This study reports the vertical distribution of POC, dissolved inorganic carbon (DIC), <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC, and <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-DIC in the tropical Northwestern Pacific Ocean (TNPO). The research identified three distinct biogeochemical layers governing POC transformation: the POC rapid synthesis-degradation layer (RSDL, 0–300 m), the net degradation layer (NDL, 300–1000 m), and the stable layer (SL, 1000–2000 m). From the top to the bottom of the RSDL, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC values decreased by an average of 2.23 ‰, while the carbon-to-nitrogen (<span class="inline-formula">C:N</span>) ratios increased by an average of <span class="inline-formula">2.3:1</span>, indicating the selective degradation of POC. In the NDL, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC and <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-DIC exhibited a significant negative correlation (<span class="inline-formula"><i>r</i>=0.43</span>, <span class="inline-formula"><i>p</i>&lt;0.05</span>), indicating a net transformation of POC to DIC. In the SL, POC proved to be resistant to degradation, with POC exhibiting the highest <span class="inline-formula">C:N</span> (<span class="inline-formula">15:1</span> on average) and the lowest <span class="inline-formula"><i>δ</i><sup>13</sup></span>C-POC values (average <span class="inline-formula">−</span>27.71 ‰).</p>https://os.copernicus.org/articles/21/1627/2025/os-21-1627-2025.pdf
spellingShingle D. Tian
D. Tian
X. Li
X. Li
X. Li
X. Li
J. Song
J. Song
J. Song
J. Song
J. Ma
J. Ma
H. Yuan
H. Yuan
H. Yuan
H. Yuan
L. Duan
L. Duan
L. Duan
L. Duan
Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C
Ocean Science
title Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C
title_full Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C
title_fullStr Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C
title_full_unstemmed Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C
title_short Biogeochemical layering and transformation of particulate organic carbon in the Tropical Northwestern Pacific Ocean inferred from <i>δ</i><sup>13</sup>C
title_sort biogeochemical layering and transformation of particulate organic carbon in the tropical northwestern pacific ocean inferred from i δ i sup 13 sup c
url https://os.copernicus.org/articles/21/1627/2025/os-21-1627-2025.pdf
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