Heterogeneous Sources, Distribution, and removal processes of dissolved black carbon from East China Sea shelf to open ocean of Northwest Pacific

IF 3.8 3区地球科学 Q1 OCEANOGRAPHY

Progress in Oceanography Pub Date : 2024-10-30 DOI:10.1016/j.pocean.2024.103374

Xi Zhang , Yasong Wang , Zhiliang Liu , Bilin Liu , Weichao Wu , Liang Liu , Ding He , Yunping Xu

{"title":"Heterogeneous Sources, Distribution, and removal processes of dissolved black carbon from East China Sea shelf to open ocean of Northwest Pacific","authors":"Xi Zhang , Yasong Wang , Zhiliang Liu , Bilin Liu , Weichao Wu , Liang Liu , Ding He , Yunping Xu","doi":"10.1016/j.pocean.2024.103374","DOIUrl":null,"url":null,"abstract":"<div><div>Absract: Dissolved black carbon (DBC) can be transported from land to the ocean, representing a significant slow-cycling component in the global carbon cycle. However, the source, distribution, and degradation of DBC in the ocean are not well understood. In this study, water samples were collected from the East China Sea (ECS) shelf to the Northwest Pacific Ocean. The benzene polycarboxylic acid (BPCA) method and ultraviolet–visible spectroscopy were used to analyze DBC and dissolved organic matter, respectively. The concentration of DBC and the (B6CA + B5CA)/BPCAs ratio in surface water showed a decreasing trend from the ECS inner shelf towards the open ocean. This trend indicates the preferential removal of condensed aromatic compounds by photodegradation, while also implicating dilution by open ocean water as a significant factor contributing to the reduction of DBC concentrations. A significant negative correlation between DBC concentration and salinity was observed in surface water samples (r = − 0.88; p < 0.01). However, this relationship weakened and disappeared in offshore samples, suggesting a reduced influence of riverine inputs. Furthermore, vertical profiles of water samples (0 – 1000 m) revealed a decrease in DBC concentrations and an increase in the ratio of (B6CA + B5CA)/BPCAs, indicating the preferential photodegradation of condensed aromatic DBC molecules in the euphotic zone and the selective accumulation of these molecules in the ocean interior. The DBC flux into the Northwest Pacific Ocean was estimated to be 1.46 Tg/year with 51.7 to 73.1 % removed through photodegradation, while the remaining DBC was either transported into the deep ocean or biodegraded. Given the important role of photodegradation in regulating the DBC flux in the Northwest Pacific Ocean, we recommend further research into its impact on the refractory carbon cycle in global oceans.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103374"},"PeriodicalIF":3.8000,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Progress in Oceanography","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0079661124001800","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"OCEANOGRAPHY","Score":null,"Total":0}

引用次数: 0

Abstract

Absract: Dissolved black carbon (DBC) can be transported from land to the ocean, representing a significant slow-cycling component in the global carbon cycle. However, the source, distribution, and degradation of DBC in the ocean are not well understood. In this study, water samples were collected from the East China Sea (ECS) shelf to the Northwest Pacific Ocean. The benzene polycarboxylic acid (BPCA) method and ultraviolet–visible spectroscopy were used to analyze DBC and dissolved organic matter, respectively. The concentration of DBC and the (B6CA + B5CA)/BPCAs ratio in surface water showed a decreasing trend from the ECS inner shelf towards the open ocean. This trend indicates the preferential removal of condensed aromatic compounds by photodegradation, while also implicating dilution by open ocean water as a significant factor contributing to the reduction of DBC concentrations. A significant negative correlation between DBC concentration and salinity was observed in surface water samples (r = − 0.88; p < 0.01). However, this relationship weakened and disappeared in offshore samples, suggesting a reduced influence of riverine inputs. Furthermore, vertical profiles of water samples (0 – 1000 m) revealed a decrease in DBC concentrations and an increase in the ratio of (B6CA + B5CA)/BPCAs, indicating the preferential photodegradation of condensed aromatic DBC molecules in the euphotic zone and the selective accumulation of these molecules in the ocean interior. The DBC flux into the Northwest Pacific Ocean was estimated to be 1.46 Tg/year with 51.7 to 73.1 % removed through photodegradation, while the remaining DBC was either transported into the deep ocean or biodegraded. Given the important role of photodegradation in regulating the DBC flux in the Northwest Pacific Ocean, we recommend further research into its impact on the refractory carbon cycle in global oceans.

查看原文本刊更多论文

东海陆架至西北太平洋公海溶解黑碳的异质来源、分布和清除过程

摘要：溶解黑碳（DBC）可从陆地迁移到海洋，是全球碳循环中重要的慢循环成分。然而，人们对海洋中 DBC 的来源、分布和降解还不甚了解。本研究从中国东海（ECS）大陆架到西北太平洋采集了水样。采用苯多羧酸（BPCA）法和紫外可见光谱法分别分析了 DBC 和溶解有机物。地表水中 DBC 的浓度和（B6CA + B5CA）/BPCAs 比值呈现出从 ECS 内大陆架向公海递减的趋势。这一趋势表明光降解作用优先去除缩合芳香族化合物，同时也表明开阔洋海水的稀释作用是导致 DBC 浓度降低的一个重要因素。在地表水样本中观察到，DBC 浓度与盐度之间存在明显的负相关（r = - 0.88; p < 0.01）。然而，这种关系在近海样本中减弱并消失了，这表明河流输入的影响减弱了。此外，水样（0 - 1000 米）的垂直剖面显示，DBC 浓度下降，（B6CA + B5CA）/BPCAs 的比值上升，表明在极光带，缩合芳香族 DBC 分子优先发生光降解，这些分子选择性地在海洋内部积累。据估计，进入西北太平洋的二溴环十二烷通量为 1.46 吨/年，其中 51.7% 至 73.1% 通过光降解去除，其余的二溴环十二烷要么被运入深海，要么被生物降解。鉴于光降解在调节西北太平洋 DBC 通量方面的重要作用，我们建议进一步研究光降解对全球海洋难降解碳循环的影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Progress in Oceanography 地学-海洋学

CiteScore

7.20

自引率

4.90%

发文量

138

审稿时长

3 months

期刊介绍： Progress in Oceanography publishes the longer, more comprehensive papers that most oceanographers feel are necessary, on occasion, to do justice to their work. Contributions are generally either a review of an aspect of oceanography or a treatise on an expanding oceanographic subject. The articles cover the entire spectrum of disciplines within the science of oceanography. Occasionally volumes are devoted to collections of papers and conference proceedings of exceptional interest. Essential reading for all oceanographers.