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The particle fluxes in sediment traps from Niulang Guyot area in the Northwest Pacific Ocean

Acta Oceanologica Sinica 2022年第11期41卷 34-44页

作者： Xiuwu Sun Jinmin Chen Baohong Chen Cai Lin Yang Liu Jiang Huang Zhong Pan Kaiwen Zhou Qing He Fangfang Kuang Hui Lin Laboratory of Marine Ecological and Environment Early Warning and Monitoring Third Institute of OceanographyMinistryof Natural ResourcesXiamen 361005China Ocean Dynamics Laboratory Third Institute of OceanographyMinistry of Natural ResourcesXiamen 361005China

The flux of settling particles in the ocean has been widely explored since 1980s due to its important role in biogenic elements cycling,especially in the transport of particulate organic carbon(POC)in the deep ***,research in the seamount area of the oligotrophic subtropical Northwest Pacific Ocean is *** this work,two sediment traps were deployed at the foot and another two at the hillside of Niulang Guyot from August2017 to July *** magnitude and composition of particle fluxes were *** main factors influencing the spatial variations of the fluxes were *** results indicated a low particulate flux from Niulang Guyot area in the Northwest Pacific Ocean,reflecting low primary productivity of the oligotrophic *** total mass flux(TMF)decreased from 2.57 g/(m^(2)·a)to 0.56 g/(m^(2)·a)with increasing depth from 600 m to 4850 m.A clear seasonal pattern of TMF was observed,with higher flux in summer than that in *** peak flux of 26.52 mg/(m^(2)·d)occurred in August at 600 m,while the lowest value of 0.07 mg/(m^(2)·d)was shown in February at 4850 *** settling particles at the deep layers had similar biochemical composition,with calcium carbonate(CaCO_(3))accounting for up to 90%,followed by organic matter and opal,characteristics of Carbonate *** POC flux decreased more rapidly in the twilight layer because of faster decomposition,remineralization,and higher temperature.A small fraction of POC was transported into the deep ocean by biological *** fluxes were mainly controlled by the calcareous ballasts besides the primary productivity of the surface *** advection may be another important factor affecting the flux in the seamount *** combination of settled matters rich in foraminiferal tests with topography and currents may be the reason for regulating the local abundance of benthos on *** results will fill in the knowledge gap of sedimentation flux,improve the understanding of ecosyste

关键词： sediment trap flux seamount POC Northwest Pacific Ocean

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Design of sediment detention basins: Scaled model experiments and application

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International Journal of sediment Research 2021年第1期36卷 136-150页

作者： Anita Moldenhauer-Roth Guillaume Piton Sebastian Schwindt Mona Jafarnejad Anton J.Schleiss Hydraulic Constructions Platform (PL-LCH) Swiss Federal Institute of Technology Lausanne (EPFL) Université Grenoble Alpes Institut National de Recherche en Sciences et Technologies Pour L'environnement et L'agriculture (IRSTEA)

sediment detention basins are implemented on mountain rivers to trap solid material that may aggravate the flooding of downstream ***,retention structures built in the past may unnecessarily retain sediment during non-hazardous flood events,resulting in high maintenance costs and sediment deficit *** addition,the so-called spontaneous self-flushing of previously retained sediment during floods has occasionally been *** research suggests to design sediment detention basins for controlling sediment passage with a guiding channel across the deposition area upstream of a hybrid *** barriers consist of a check dam with a slot orifice and an upstream bar screen with a bottom clearance in order to benefit from a combined mechanical-hydraulic retention *** present paper enhances this pioneering research with the help of new experimental data,including a wide range of sediment mixtures and large wood,as well as variable barrier *** design criteria are provided regarding the bar screen and the basin storage *** functionality of the enhanced concept for sediment detention is illustrated by a case study on a physical model:the protection of the Villard-Bonnot village(France) against torrential hazards.

关键词： sediment continuity sediment trap Bedload Open check dam sediment flushing

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Dinocyst microlaminations and freshwater“red tides”recorded in Lake Xiaolongwan,northeastern China

Dinocyst microlaminations and freshwater“red tides”recorde...

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中国科学院地质与地球物理研究所2008学术年会

作者： Patrick Rioual Andres Boltovskoy Institute of Geology and Geophysics Chinese Academy of Sciences

We reported a special type of lamination formed in the sediments of Lake Xiaolongwan, northeastern *** lamination consists of light-and brown-colored laminate couplets in the thin *** brown-colored layer is composed mainly of dinoflagellate *** grey-colored layer consists of other organic and siliceous matter(plant detritus,diatoms,chrysophyte cysts) and clastics. Preliminary sediment trap results show that a distinct peak of dinocyst flux occurred in *** dinocyst flux maximum also corresponds to the peaks of diatom flux and chrysophyte stomatocyst flux. These suggest that "red tide blooms" occur in this freshwater *** speculate that the dinocyst flux maximum could be related to autumn overturn due to increased nutrients,and the availability of cysts for germination from the lake ***,it may also reflect increasing dissolved organic matter after leaf *** independent chronology derived from Cs and Pb shows a good agreement with counted *** the sediment trap data and the independent chronology data,the dinocyst mi-crolaminae appear to be annually laminated,and probably could be called dinocyst *** vegetative(thecate stage) cells of Peridinium volzii and Ceratium furcoides are found in the water samples,it is not possible to relate the dinocysts to these two dinoflagellate *** on morphological and ecological analyses,we suggested that they have affinities with species of Peridinium(sensu lato),most probably to *** investigations should be carried out to understand the red tide history in this freshwater *** laminated dinocyst microlayers in freshwater and marine sediments not only provide an uncommon archive for understanding the history of red tides and harmful algal blooms,and why and how certain species periodically bloom over several thousands years,but also provide important records of paleo-environmental and paleoclimatic changes at seasonal to an

关键词： Dinocyst microlamination sediment trap Dinocyst flux Radiometric dating Red tide history

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IMPORTANCE OF sediment RESEARCH IN GLOBAL WATER SYSTEM SCIENCE

IMPORTANCE OF SEDIMENT RESEARCH IN GLOBAL WATER SYSTEM SCIEN...

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第九次河流泥沙国际学术大会

作者： Kuniyoshi TAKEUCHI University of Yamanashi Kofu 400-8511 Japan

＜正＞The global production of suspended sediments to discharge into the ocean is estimated about 20×109t·y-1, of which over 25% may be trapped by about 45,000 large dams constructed around the world. Both sediment production and reservoir trapping are increasing. sediment production, transport, deposition and its temporal and spatial balance have a major impact on global landscape and upon water and nutrient circulation. These issues need major attention, but are, unfortunately, not well studied on a global basis. A proper sediment production function is not available. The detail global distribution of dam reservoirs, and therefore sediment trapping, is unknown. The USLE （Universal Soil Loss Equation） formula developed by USDA-ARS （Agricultural Research Service） for sheet and rill erosion is literally universally used around the world, including in mountainous regions where landslides and debris flows are the major sources of sediment production. After reviewing the current sediment production studies and information about the global distribution of large reservoirs, this paper introduces the Japanese land slides and debris flow prediction methods, the Soil-Rainfall Index and the Snake Curve. These methods would provide a new alternative for developing a better sediment production function applicable in orogenically active regions of the world. Due to the importance of sediment production and transport in the global water system science, it is concluded that the current GEOSS （Global Earth Observation System of Systems） and GWSP （Global Water Systems Project） plans should include the proper sediment study component as an observation target. The IAHS （International Association of Hydrological Sciences） PUB （Prediction in Ungaged Basins） initiative supports this target since sediment is one of the most important phenomena of ungaged hydrology.

关键词： Large dams sediment trap USLE Soil-Rainfall Index Snake Curve GEOSS PUB

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