Scientific and precise evaluations of the megafaunal and landform characteristics of seamounts are important guides for their protection and study.A series of manned and unmanned submersibles have provided invaluable ...Scientific and precise evaluations of the megafaunal and landform characteristics of seamounts are important guides for their protection and study.A series of manned and unmanned submersibles have provided invaluable observational imaging data for the ecological study of seamounts.However,traditional methods of artificial observation of seamount imaging data cannot accurately and efficiently determine the characteristics of megafauna and landforms.This research harnesses data-driven technology to systematically investigate the distributional traits and morphological features of megafaunal organisms,as well as the topographical characteristics,in the Caiwei Guyot region of the western Pacific’s Magellan Seamounts.To construct the landform and megafauna dataset of the Caiwei Guyot region,we used a data preprocessing technology based on image enhancement to provide high-quality imaging data for data-driven technologies.A megafaunal identification and counting algorithm based on YOLOv5(You Only Look Once Version 5)was developed to efficiently assess the abundance,variety,and dominant species of megafauna.Simultaneously,a landform three-dimensional(3D)reconstruction algorithm based on PatchmatchNet was developed to reconstruct the 3D form of the terrain accurately.This study pioneers the application of data-driven technology to deep-sea imaging within the Caiwei Guyot region,offering an innovative approach to accurately and efficiently characterize the region’s unique megafauna and landforms.展开更多
Weijia Guyot,located in the western Pacific Ocean,has become a research focus due to its abundant cobalt-rich ferromanganese(Fe-Mn)crusts.While most studies on Fe-Mn crusts on seamounts have focused on the exposed var...Weijia Guyot,located in the western Pacific Ocean,has become a research focus due to its abundant cobalt-rich ferromanganese(Fe-Mn)crusts.While most studies on Fe-Mn crusts on seamounts have focused on the exposed variety,less attention has been paid to potential buried crusts.This study presents a preliminary geochemical and chronological study of buried Fe-Mn crusts at Weijia Guyot.The findings suggest that these buried crusts began to form around 57.5 Ma and ceased growing at approximately 46.3 Ma.Following the formation of Weijia Guyot through volcanic eruption,it did not experience continuous and steady subsidence to its current depth.Instead,an exhumation process took place from deep to shallow depths between 46.3 and 11.6 Ma.This process brought the Fe-Mn crusts into shallow water environments,halting their growth.During this time,Weijia Guyot was located near the equatorial Pacific Ocean and was exposed to an extended period of phosphatization.This exposure led to a depletion of key metallogenic elements,such as Co,Ni and Cu,within the Fe-Mn crusts,while P2O5 and CaO levels increased significantly.Since the Middle Miocene,the crusts have been progressively buried by pelagic sediments.展开更多
Massive seamounts have been surveyed and documented in the last decades.However,the morphologies of seamounts are usually described in qualitative manners,yet few quantitative detections have been carried out.Here,bas...Massive seamounts have been surveyed and documented in the last decades.However,the morphologies of seamounts are usually described in qualitative manners,yet few quantitative detections have been carried out.Here,based on the high-re solution multi-beam bathymetric data,we report a recentlysurveyed guy ot on the Caroline Ridge in the West Pacific,and the large-scale volcanic structures and smallscale erosive-depositional landforms in the guyot area have been identified.The multifractal features of the guyot are characterized for the first time by applying multifractal detrended fluctuation analysis on the surveyed bathymetric data.The results indicate that the multifractal spectrum parameters of the seafloor have strong spatial dependency on the fluctuations of local landforms.Both small-and large-scale components contribute to the degree of asymmetry of the multifractal spectrum(B),while the fluctuations of B are mostly attributed to the changes in small-scale roughness.The maximum singularity strength(α0)correlates well with the roughness of large-scale landforms and likely reflects the large-scale topographic irregularity.Comparing to traditional roughness parameters or monofractal exponents,multifractal spectra are able to depict not only the multiscale characteristics of submarine landforms,but also the spatial variations of scaling behaviors.Although more comparative works are required for various seamounts,we hope this study,as a case of quantifying geomorphological characters and multiscale behaviors of seamounts,can encourage further studies on seamounts concerning geomorphological processes,ocean bottom circulations,and seamount ecosystems.展开更多
Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between th...Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between the sub-bottom structures, revealed by sub-bottom profiling, and crust distribution can be revealed for the first time by the synchronous application of sub-bottom profiling and deep-sea video recording. The lower boundary of the sediment corresponds with the upper boundary of the crust. By analysis of these two kinds of data, the lower boundary of the sediment can be determined; therefore, the upper boundary of the crust distribution can be deduced. According to this method of analysis, the upper boundary of water depth of crust distribution of a seamount in the western Pacific is about 1 560 m.展开更多
Seamounts are ubiquitous topographic units in global oceans,and their influences on local oceanic circulation have attracted great attention in physical oceanography;however,previous efforts were less made in paleocli...Seamounts are ubiquitous topographic units in global oceans,and their influences on local oceanic circulation have attracted great attention in physical oceanography;however,previous efforts were less made in paleoclimatology and paleoceanography.The Caiwei Guyot in the Magellan Seamounts of the western Pacific is a typical seamount,and in this study,we investigate a well-dated sediment core by magnetic properties to reveal the relationship between deep-sea sedimentary processes and global climate changes.The principal results are as follows:(1)the dominant magnetic minerals in the sediments are low-coercivity magnetite in pseudo-single domain range,probably including a biogenic contribution;(2)the variabilities of magnetic parameters can be clustered into two sections at~500 ka,and the differences between the two units are evident in amplitudes and means;(3)changes in the grainsize-dependent magnetic parameters can be well correlated to records of global ice volume and atmospheric CO;in the middle Pleistocene.Based on these results,a close linkage was proposed between deep-sea sedimentary processes in the Caiwei Guyot and global climate changes.This linkage likely involves different roles of biogenic magnetite in the sediments between interglacial and glacial intervals,responding to changes in marine productivity and deep-sea circulation and displaying a major change in the MidBrunhes climate event.Therefore,we proposed that the sedimentary archives at the bottom of the Caiwei Guyot record some key signals of global climate changes,providing a unique window to observe interactions between various environmental systems on glacial-interglacial timescales.展开更多
基金The Key Research and Development Program of Shandong Province of China under contract No.2020JMRH0101the National Key Research and Development Project of China under contract No.2021YFC2802100the Qingdao Natural Science Foundation under contract No.24-4-4-zrij-127-jch.
文摘Scientific and precise evaluations of the megafaunal and landform characteristics of seamounts are important guides for their protection and study.A series of manned and unmanned submersibles have provided invaluable observational imaging data for the ecological study of seamounts.However,traditional methods of artificial observation of seamount imaging data cannot accurately and efficiently determine the characteristics of megafauna and landforms.This research harnesses data-driven technology to systematically investigate the distributional traits and morphological features of megafaunal organisms,as well as the topographical characteristics,in the Caiwei Guyot region of the western Pacific’s Magellan Seamounts.To construct the landform and megafauna dataset of the Caiwei Guyot region,we used a data preprocessing technology based on image enhancement to provide high-quality imaging data for data-driven technologies.A megafaunal identification and counting algorithm based on YOLOv5(You Only Look Once Version 5)was developed to efficiently assess the abundance,variety,and dominant species of megafauna.Simultaneously,a landform three-dimensional(3D)reconstruction algorithm based on PatchmatchNet was developed to reconstruct the 3D form of the terrain accurately.This study pioneers the application of data-driven technology to deep-sea imaging within the Caiwei Guyot region,offering an innovative approach to accurately and efficiently characterize the region’s unique megafauna and landforms.
基金financial support from the National Natural Science Foundation of China(Grant No.U2244222,42576244,42072324,42442603)the Guangzhou Basic and Applied Basic Research Foundation(Grant No.202201011367,202201011487).
文摘Weijia Guyot,located in the western Pacific Ocean,has become a research focus due to its abundant cobalt-rich ferromanganese(Fe-Mn)crusts.While most studies on Fe-Mn crusts on seamounts have focused on the exposed variety,less attention has been paid to potential buried crusts.This study presents a preliminary geochemical and chronological study of buried Fe-Mn crusts at Weijia Guyot.The findings suggest that these buried crusts began to form around 57.5 Ma and ceased growing at approximately 46.3 Ma.Following the formation of Weijia Guyot through volcanic eruption,it did not experience continuous and steady subsidence to its current depth.Instead,an exhumation process took place from deep to shallow depths between 46.3 and 11.6 Ma.This process brought the Fe-Mn crusts into shallow water environments,halting their growth.During this time,Weijia Guyot was located near the equatorial Pacific Ocean and was exposed to an extended period of phosphatization.This exposure led to a depletion of key metallogenic elements,such as Co,Ni and Cu,within the Fe-Mn crusts,while P2O5 and CaO levels increased significantly.Since the Middle Miocene,the crusts have been progressively buried by pelagic sediments.
基金the Senior User Project of R/V Kexue(No.KEXUE2018G11)the Science and Technology Basic Resources Investigation Program ofChina(No.2017FY100801)the Open Fund of the Key Laboratoryof Marine Geology and Environment,Chinese Academy of Sciences(No.MGE2018KG02)。
文摘Massive seamounts have been surveyed and documented in the last decades.However,the morphologies of seamounts are usually described in qualitative manners,yet few quantitative detections have been carried out.Here,based on the high-re solution multi-beam bathymetric data,we report a recentlysurveyed guy ot on the Caroline Ridge in the West Pacific,and the large-scale volcanic structures and smallscale erosive-depositional landforms in the guyot area have been identified.The multifractal features of the guyot are characterized for the first time by applying multifractal detrended fluctuation analysis on the surveyed bathymetric data.The results indicate that the multifractal spectrum parameters of the seafloor have strong spatial dependency on the fluctuations of local landforms.Both small-and large-scale components contribute to the degree of asymmetry of the multifractal spectrum(B),while the fluctuations of B are mostly attributed to the changes in small-scale roughness.The maximum singularity strength(α0)correlates well with the roughness of large-scale landforms and likely reflects the large-scale topographic irregularity.Comparing to traditional roughness parameters or monofractal exponents,multifractal spectra are able to depict not only the multiscale characteristics of submarine landforms,but also the spatial variations of scaling behaviors.Although more comparative works are required for various seamounts,we hope this study,as a case of quantifying geomorphological characters and multiscale behaviors of seamounts,can encourage further studies on seamounts concerning geomorphological processes,ocean bottom circulations,and seamount ecosystems.
文摘Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between the sub-bottom structures, revealed by sub-bottom profiling, and crust distribution can be revealed for the first time by the synchronous application of sub-bottom profiling and deep-sea video recording. The lower boundary of the sediment corresponds with the upper boundary of the crust. By analysis of these two kinds of data, the lower boundary of the sediment can be determined; therefore, the upper boundary of the crust distribution can be deduced. According to this method of analysis, the upper boundary of water depth of crust distribution of a seamount in the western Pacific is about 1 560 m.
基金The Natural Science Foundation of Shanghai under contract No.19ZR1459800the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)under contract No.GML2019ZD0106the Project of Global Changing and Air-sea Interaction under contract No.GASI-GEOGE-04
文摘Seamounts are ubiquitous topographic units in global oceans,and their influences on local oceanic circulation have attracted great attention in physical oceanography;however,previous efforts were less made in paleoclimatology and paleoceanography.The Caiwei Guyot in the Magellan Seamounts of the western Pacific is a typical seamount,and in this study,we investigate a well-dated sediment core by magnetic properties to reveal the relationship between deep-sea sedimentary processes and global climate changes.The principal results are as follows:(1)the dominant magnetic minerals in the sediments are low-coercivity magnetite in pseudo-single domain range,probably including a biogenic contribution;(2)the variabilities of magnetic parameters can be clustered into two sections at~500 ka,and the differences between the two units are evident in amplitudes and means;(3)changes in the grainsize-dependent magnetic parameters can be well correlated to records of global ice volume and atmospheric CO;in the middle Pleistocene.Based on these results,a close linkage was proposed between deep-sea sedimentary processes in the Caiwei Guyot and global climate changes.This linkage likely involves different roles of biogenic magnetite in the sediments between interglacial and glacial intervals,responding to changes in marine productivity and deep-sea circulation and displaying a major change in the MidBrunhes climate event.Therefore,we proposed that the sedimentary archives at the bottom of the Caiwei Guyot record some key signals of global climate changes,providing a unique window to observe interactions between various environmental systems on glacial-interglacial timescales.
