Modern bioturbation structures and their mixing effects in the Yangtze River Estuary and its adjacent sea areas

IF 2.6 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Marine Geology Pub Date : 2025-03-07 DOI:10.1016/j.margeo.2025.107533

Xin Zhang , Dejiang Fan , Baoduo Wang , Peng Cheng , Judong Mao , Xiaolin Ren , Xueshi Sun

{"title":"Modern bioturbation structures and their mixing effects in the Yangtze River Estuary and its adjacent sea areas","authors":"Xin Zhang , Dejiang Fan , Baoduo Wang , Peng Cheng , Judong Mao , Xiaolin Ren , Xueshi Sun","doi":"10.1016/j.margeo.2025.107533","DOIUrl":null,"url":null,"abstract":"<div><div>Bioturbation structures are not only critical indicators to the state of the seafloor environment but also serve as important proxies for reconstructing paleo-environments. Furthermore, bioturbation processes will cause the redistribution of materials and early diagenesis in sediments, which makes it a challenging component to explore elements cycles or interpret sedimentary records over centennial time scale. This study, based on sediment cores from 31 stations in the Yangtze River Estuary and its adjacent areas, utilized high-resolution X-ray computed tomography (CT) scanning technology and MATLAB data processing method, along with measurements of sediment grain size and <sup>210</sup>Pb activity, to qualitatively and quantitatively characterize the bioturbation structures in the area and estimate mixing intensity. The results indicate that bioturbation structures can be functionally categorized into four types: biodiffusor structure, conveyors structure, regenerator structure and gallery-diffusor structure, with conveyors structure and gallery-diffusor structure being the most common. The vertical distribution patterns of bioturbation structures within the cores exhibit variations, including exponential decay pattern, fluctuating decay pattern, pulse distribution pattern, and uniform distribution pattern. Based on bioturbation intensity and their combinations, three bioturbation structural zones were identified: the Yangtze River Estuary bioturbation zone, the coastal sand ridge and northern Zhejiang-Fujian bioturbation zone, and the transitional phase and northern Zhejiang-Fujian muddy bioturbation zone. The mixing coefficients in this area ranges from 0.02 to 884.24 cm<sup>2</sup>/yr, exhibiting significant spatial variation. Strong mixing is observed in the pro-delta and delta front-shelf transition zones, while weaker mixing occurs in the northern Zhejiang-Fujian muddy area and the southern coastal region of northern Jiangsu coastal. The mixing effects are influenced not only by bioturbation but also by non-biological factors such as physical mixing.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"484 ","pages":"Article 107533"},"PeriodicalIF":2.6000,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Marine Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0025322725000581","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

Bioturbation structures are not only critical indicators to the state of the seafloor environment but also serve as important proxies for reconstructing paleo-environments. Furthermore, bioturbation processes will cause the redistribution of materials and early diagenesis in sediments, which makes it a challenging component to explore elements cycles or interpret sedimentary records over centennial time scale. This study, based on sediment cores from 31 stations in the Yangtze River Estuary and its adjacent areas, utilized high-resolution X-ray computed tomography (CT) scanning technology and MATLAB data processing method, along with measurements of sediment grain size and ²¹⁰Pb activity, to qualitatively and quantitatively characterize the bioturbation structures in the area and estimate mixing intensity. The results indicate that bioturbation structures can be functionally categorized into four types: biodiffusor structure, conveyors structure, regenerator structure and gallery-diffusor structure, with conveyors structure and gallery-diffusor structure being the most common. The vertical distribution patterns of bioturbation structures within the cores exhibit variations, including exponential decay pattern, fluctuating decay pattern, pulse distribution pattern, and uniform distribution pattern. Based on bioturbation intensity and their combinations, three bioturbation structural zones were identified: the Yangtze River Estuary bioturbation zone, the coastal sand ridge and northern Zhejiang-Fujian bioturbation zone, and the transitional phase and northern Zhejiang-Fujian muddy bioturbation zone. The mixing coefficients in this area ranges from 0.02 to 884.24 cm²/yr, exhibiting significant spatial variation. Strong mixing is observed in the pro-delta and delta front-shelf transition zones, while weaker mixing occurs in the northern Zhejiang-Fujian muddy area and the southern coastal region of northern Jiangsu coastal. The mixing effects are influenced not only by bioturbation but also by non-biological factors such as physical mixing.

查看原文本刊更多论文

求助全文

约1分钟内获得全文求助全文

来源期刊

Marine Geology 地学-地球科学综合

CiteScore

6.10

自引率

6.90%

发文量

175

审稿时长

21.9 weeks

期刊介绍： Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.