Pub Date : 1992-09-01DOI: 10.1016/S0198-0149(06)80016-6
Eric A. D'Asaro , James H. Morison
The variability of internal wave shear levels in the eastern Arctic Ocean is explored using velocity profiler and CTD data from Fram Strait and the Nansen Basin. Shear levels are consistently low over the abyssal plains and higher over rougher topography. Applying the parameterization of GREGG (1989, Journal of Geophysical Research, 94, 9686-9698) to these data gives diapycnal diffusivities that vary from about 10-6 to above 10-4 m s-2. Extrapolating these diffusivities to the entire Arctic Basin suggests that internal wave mixing could play a major role in transporting heat from the warm intermediate water to the surface. Internal wave generation by the barotropic tide on rough topography may explain the higher shear levels found there.
利用速度剖面仪和来自Fram海峡和Nansen盆地的CTD资料,探讨了北冰洋东部内波切变水平的变化。深海平原上的剪切水平始终较低,而在崎岖地形上则较高。将GREGG (1989, Journal Geophysical Research, 94, 9686-9698)的参数化方法应用到这些数据中,可以得到大约10-6到10-4 m s-2以上的典型扩散系数。将这些扩散系数外推到整个北极盆地表明,内波混合可能在将热量从温暖的中间水输送到地表方面发挥重要作用。正压潮在粗糙地形上产生的内波可以解释那里较高的切变水平。
{"title":"Internal waves and mixing in the Arctic Ocean","authors":"Eric A. D'Asaro , James H. Morison","doi":"10.1016/S0198-0149(06)80016-6","DOIUrl":"10.1016/S0198-0149(06)80016-6","url":null,"abstract":"<div><p>The variability of internal wave shear levels in the eastern Arctic Ocean is explored using velocity profiler and CTD data from Fram Strait and the Nansen Basin. Shear levels are consistently low over the abyssal plains and higher over rougher topography. Applying the parameterization of GREGG (1989, Journal of Geophysical Research, 94, 9686-9698) to these data gives diapycnal diffusivities that vary from about 10<sup>-6</sup> to above 10<sup>-4</sup> m s<sup>-2</sup>. Extrapolating these diffusivities to the entire Arctic Basin suggests that internal wave mixing could play a major role in transporting heat from the warm intermediate water to the surface. Internal wave generation by the barotropic tide on rough topography may explain the higher shear levels found there.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 2","pages":"Pages S459-S484"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0198-0149(06)80016-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"111705971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/S0198-0149(06)80013-0
Stephanie L. Pfirman , Jörn Thiede
{"title":"Arctic deep-sea research: the Nansen Basin Section","authors":"Stephanie L. Pfirman , Jörn Thiede","doi":"10.1016/S0198-0149(06)80013-0","DOIUrl":"10.1016/S0198-0149(06)80013-0","url":null,"abstract":"","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 2","pages":"Pages S419-S423"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0198-0149(06)80013-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"95069564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/S0198-0149(06)80020-8
P.M. Goldschmidt , S.L. Pfirman , I. Wollenburg , R. Henrich
Sediment cores from the Norwegian and Greenland Seas and the Nansen Basin were studied to determine the origin of sediment pellets, centimetre-sized aggregations of clay to sandsized sediment occurring in the cores. By comparing the grain size, grain shape and composition of the pellet sediments to sediments collected directly from the surfaces of sea ice in the Nansen Basin and from icebergs in the Barents Sea, the pelleted sediment was found to be more similar to that in the icebergs than that on the sea ice. The pellets may be formed on, in or under a glacier or during transport on/in an iceberg. When icebergs overturn or melt, the pellets fall out and are consolidated enough to survive a drop of up to 4 km to the ocean bottom and to retain their integrity even after burial on the seafloor.
{"title":"Origin of sediment pellets from the Arctic seafloor: sea ice or icebergs?","authors":"P.M. Goldschmidt , S.L. Pfirman , I. Wollenburg , R. Henrich","doi":"10.1016/S0198-0149(06)80020-8","DOIUrl":"10.1016/S0198-0149(06)80020-8","url":null,"abstract":"<div><p>Sediment cores from the Norwegian and Greenland Seas and the Nansen Basin were studied to determine the origin of sediment pellets, centimetre-sized aggregations of clay to sandsized sediment occurring in the cores. By comparing the grain size, grain shape and composition of the pellet sediments to sediments collected directly from the surfaces of sea ice in the Nansen Basin and from icebergs in the Barents Sea, the pelleted sediment was found to be more similar to that in the icebergs than that on the sea ice. The pellets may be formed on, in or under a glacier or during transport on/in an iceberg. When icebergs overturn or melt, the pellets fall out and are consolidated enough to survive a drop of up to 4 km to the ocean bottom and to retain their integrity even after burial on the seafloor.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 2","pages":"Pages S539-S565"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0198-0149(06)80020-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"94308930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/S0198-0149(06)80014-2
Leif G. Anderson , E. Peter Jones
Measurements of chemical tracers obtained during the 1987 cruise of F.S. Polarstern across the Nansen Basin of the Arctic Ocean are used to suggest the general flow of upper waters in the Arctic Ocean. In surface water, total carbonate concentrations distinguish between a northern freshwater component whose origin is river run-off and a southern freshwater component whose origin is sea ice meltwater. Below the surface layer, sub-surface water formed in the Barents-Kara Seas with low concentrations of “NO” must divide, some flowing with the Atlantic layer to the east and north before flowing in the same direction as the Transpolar Drift to Fram Strait, and some flowing to the west and south. The former characterizes the lower halocline water observed at the CESAR and LOREX ice camps in the central Arctic Ocean. The latter can be traced in a general way to Fram Strait where the two meet and the two low NO waters merge.
{"title":"Tracing upper waters of the Nansen Basin in the Arctic Ocean","authors":"Leif G. Anderson , E. Peter Jones","doi":"10.1016/S0198-0149(06)80014-2","DOIUrl":"10.1016/S0198-0149(06)80014-2","url":null,"abstract":"<div><p>Measurements of chemical tracers obtained during the 1987 cruise of F.S. <em>Polarstern</em> across the Nansen Basin of the Arctic Ocean are used to suggest the general flow of upper waters in the Arctic Ocean. In surface water, total carbonate concentrations distinguish between a northern freshwater component whose origin is river run-off and a southern freshwater component whose origin is sea ice meltwater. Below the surface layer, sub-surface water formed in the Barents-Kara Seas with low concentrations of “NO” must divide, some flowing with the Atlantic layer to the east and north before flowing in the same direction as the Transpolar Drift to Fram Strait, and some flowing to the west and south. The former characterizes the lower halocline water observed at the CESAR and LOREX ice camps in the central Arctic Ocean. The latter can be traced in a general way to Fram Strait where the two meet and the two low NO waters merge.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 2","pages":"Pages S425-S433"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0198-0149(06)80014-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"97913532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/0198-0149(92)90048-X
Mike I. Moore , C. Matthew Walkington
We discuss the effect of the changing temperature of CTD electronics on the measured pressure and temperature. An example is presented from a Guildline 8715 CTD which illustrates that substantial errors in measured quantities (order 10 m °C in temperature for our example) can result from transient effects not detectable by static tests of electronic stability. We use a simple linear system model to investigate the effect and to correct data. Such a model is necessary simply to permit quantification of the effect and to enable the design and interpretation of laboratory experiments for that purpose.
{"title":"Transient temperature effects in CTD measurements","authors":"Mike I. Moore , C. Matthew Walkington","doi":"10.1016/0198-0149(92)90048-X","DOIUrl":"10.1016/0198-0149(92)90048-X","url":null,"abstract":"<div><p>We discuss the effect of the changing temperature of CTD electronics on the measured pressure and temperature. An example is presented from a Guildline 8715 CTD which illustrates that substantial errors in measured quantities (order 10 m °C in temperature for our example) can result from transient effects not detectable by static tests of electronic stability. We use a simple linear system model to investigate the effect and to correct data. Such a model is necessary simply to permit quantification of the effect and to enable the design and interpretation of laboratory experiments for that purpose.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 9","pages":"Pages 1573-1582"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0198-0149(92)90048-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133502858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/0198-0149(92)90045-U
A.L. New , R.D. Pingree
Large-amplitude internal solitary waves (solitons) near the shelf break in the Bay of Biscay are now well documented and understood. A similar phenomenon recently has been reported in the central Bay, about 150 km from the nearest shelf topography. By making several transects with the ship's acoustic Doppler current profiler, we present convincing evidence that these solitons, instead of having travelled along the thermocline from the shelf break, are generated locally at about the position where the beam of internal tidal energy, originating from the shelf break, reflects from the ocean surface.
{"title":"Local generation of internal soliton packets in the central bay of Biscay","authors":"A.L. New , R.D. Pingree","doi":"10.1016/0198-0149(92)90045-U","DOIUrl":"10.1016/0198-0149(92)90045-U","url":null,"abstract":"<div><p>Large-amplitude internal solitary waves (solitons) near the shelf break in the Bay of Biscay are now well documented and understood. A similar phenomenon recently has been reported in the central Bay, about 150 km from the nearest shelf topography. By making several transects with the ship's acoustic Doppler current profiler, we present convincing evidence that these solitons, instead of having travelled along the thermocline from the shelf break, are generated locally at about the position where the beam of internal tidal energy, originating from the shelf break, reflects from the ocean surface.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 9","pages":"Pages 1521-1534"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0198-0149(92)90045-U","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"97735565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/0198-0149(92)90041-Q
Masahisa Kubota , Koji Ono
The abyssal circulation in the Philippine Sea is investigated by use of a linear reduced-gravity model. It is assumed that the deep water is supplied from the main western North Pacific into the Philippine Sea through the Yap-Mariana Junction, as suggested by observational results. Two different numerical experiments are carried out, with and without bottom topography. The results of the flat-bottom model show that a strong abyssal boundary current is formed along the western and northern boundaries. However, a stagnation point cannot be found in this case. Although the results from the experiment that includes topographical effects display a complicated pattern, abyssal water flowing into the Philippine Sea mainly appears to move northward in the West Mariana Basin. Also, the Model results suggest that the abyssal circulation is more active in the eastern Philippine Sea (the Shikoku and West Mariana Basins) than in the western Philippine Sea (the Philippine Basin). It is remarkable that not only the circulation pattern but also the relative strenghts of the current velocity from the present model are fairly consistent with the observational results from moored current meters and hydrographic data, in spite of the simplicity of the model.
{"title":"Abyssal circulation model of the Philippine Sea","authors":"Masahisa Kubota , Koji Ono","doi":"10.1016/0198-0149(92)90041-Q","DOIUrl":"10.1016/0198-0149(92)90041-Q","url":null,"abstract":"<div><p>The abyssal circulation in the Philippine Sea is investigated by use of a linear reduced-gravity model. It is assumed that the deep water is supplied from the main western North Pacific into the Philippine Sea through the Yap-Mariana Junction, as suggested by observational results. Two different numerical experiments are carried out, with and without bottom topography. The results of the flat-bottom model show that a strong abyssal boundary current is formed along the western and northern boundaries. However, a stagnation point cannot be found in this case. Although the results from the experiment that includes topographical effects display a complicated pattern, abyssal water flowing into the Philippine Sea mainly appears to move northward in the West Mariana Basin. Also, the Model results suggest that the abyssal circulation is more active in the eastern Philippine Sea (the Shikoku and West Mariana Basins) than in the western Philippine Sea (the Philippine Basin). It is remarkable that not only the circulation pattern but also the relative strenghts of the current velocity from the present model are fairly consistent with the observational results from moored current meters and hydrographic data, in spite of the simplicity of the model.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 9","pages":"Pages 1439-1452"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0198-0149(92)90041-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"105379718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-09-01DOI: 10.1016/S0198-0149(06)80018-X
JÖrn Carstens , Gerold Wefer
Planktonic foraminifera were collected in the Arctic Ocean with net tows (>63 μin) along a S-N transect from 81 to 86°N. Five depth intervals were sampled vertically between 500 m water depth and the sea surface. The most common species are Neogloboquadrina pachyderma and Globigerina quinqueloba. Based on the depth habitat, the faunal composition and the population structure, the planktonic foraminifera can be divided into two distinct provinces having a latitudinal boundary at 83°N. In the southern area, the concentrations of planktonic foraminifera are highest as well as the per cent of subpolar species and right-coiling individuals. Both species prefer the water below the pycnocline at about 100 m. North of 83°N, the two species display maximum abundance in the upper 50 m, where the water is colder and fresher than below the pycnocline. The proportions of right-coiling individuals and subpolar species are decreasing going northward. The observed changes are caused by the input of Atlantic water masses transported into the Arctic Ocean.
{"title":"Recent distribution of planktonic foraminifera in the Nansen Basin, Arctic Ocean","authors":"JÖrn Carstens , Gerold Wefer","doi":"10.1016/S0198-0149(06)80018-X","DOIUrl":"10.1016/S0198-0149(06)80018-X","url":null,"abstract":"<div><p>Planktonic foraminifera were collected in the Arctic Ocean with net tows (>63 μin) along a S-N transect from 81 to 86°N. Five depth intervals were sampled vertically between 500 m water depth and the sea surface. The most common species are <em>Neogloboquadrina pachyderma</em> and <em>Globigerina quinqueloba</em>. Based on the depth habitat, the faunal composition and the population structure, the planktonic foraminifera can be divided into two distinct provinces having a latitudinal boundary at 83°N. In the southern area, the concentrations of planktonic foraminifera are highest as well as the per cent of subpolar species and right-coiling individuals. Both species prefer the water below the pycnocline at about 100 m. North of 83°N, the two species display maximum abundance in the upper 50 m, where the water is colder and fresher than below the pycnocline. The proportions of right-coiling individuals and subpolar species are decreasing going northward. The observed changes are caused by the input of Atlantic water masses transported into the Arctic Ocean.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 2","pages":"Pages S507-S524"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0198-0149(06)80018-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"107476990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-07-01DOI: 10.1016/0198-0149(92)90058-2
U. Riebesell , D.A. Wolf-Gladrow
Since large, rapidly-sinking particles account for most of the vertical flux in the ocean, mechanisms responsible for particle aggregation largely control the transport of carbon to depth. The particle flux resulting from a variety of different phytoplankton bloom conditions was simulated with a numerical model in which phytoplankton growth dynamics were combined with physical aggregation, particle size-dependent sedimentation and degradation. Model results demonstrated that particle flux to the deep ocean be generated by solely invoking physical aggregation during phytoplankton blooms. Sensitivity of the model in response to variations of both physico-chemical and biological paramters was tested. The model outcome, described as the fraction of export production leaving the upper ocean carbon pool, proved to be most sensitive to biological variables such as phytoplankton cell size, stickness, and growth characteristics (i.e. solitary vs chain-forming). Changes in these factors strongly affect the efficiency of the “biological pump” and could be explain interannual and geographic variance in deep-ocean flux.
{"title":"The relationship between physical aggregation of phytoplankton and particle flux: a numerical model","authors":"U. Riebesell , D.A. Wolf-Gladrow","doi":"10.1016/0198-0149(92)90058-2","DOIUrl":"https://doi.org/10.1016/0198-0149(92)90058-2","url":null,"abstract":"<div><p>Since large, rapidly-sinking particles account for most of the vertical flux in the ocean, mechanisms responsible for particle aggregation largely control the transport of carbon to depth. The particle flux resulting from a variety of different phytoplankton bloom conditions was simulated with a numerical model in which phytoplankton growth dynamics were combined with physical aggregation, particle size-dependent sedimentation and degradation. Model results demonstrated that particle flux to the deep ocean be generated by solely invoking physical aggregation during phytoplankton blooms. Sensitivity of the model in response to variations of both physico-chemical and biological paramters was tested. The model outcome, described as the fraction of export production leaving the upper ocean carbon pool, proved to be most sensitive to biological variables such as phytoplankton cell size, stickness, and growth characteristics (i.e. solitary vs chain-forming). Changes in these factors strongly affect the efficiency of the “biological pump” and could be explain interannual and geographic variance in deep-ocean flux.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 7","pages":"Pages 1085-1102"},"PeriodicalIF":0.0,"publicationDate":"1992-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0198-0149(92)90058-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72275706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-07-01DOI: 10.1016/0198-0149(92)90057-Z
G Gust , R.H Byrne , R.E Bernstein , P.R Betzer , W Bowles
A series of synchronous, 24-h experiments using sensor-equipped sediment traps revealed that higher particle collection rates were associated with higher approach velocieties. Surface-tethered traps with variable drag configurations provided distinct differences in approach velocities for paired 400 m deployments and paired 1500 m deployments. Small-scale hot-film hydrodynamics sensors located both inside and outside the sediment traps detected flow cells within the traps with velocities between 50 and 100% of the external fluid approach velocities. In conjunction with laboratory flume simulations, these observations reveal that particles do not settle gravitationally across trap apertures. Intead, particles are swept advectively into traps at the downstream portion of trap apertures, and most are then expelled at the upstream portions of trap apertures. Fluid flows detected inside the drifting traps, which ranged from 1.2 to 31 cm s−1,l probably overwhelm all but the strongest “swimmers” that interact with these sampling divices. At our two sampling horizons (400 and 1500 m), tether-line motions generated trap depth oscillations with a period of the order of 10 s and an amplitude of about 0.5 m. Such effects have not been accounted for in flume simulated of sediment traps collection experiments.
{"title":"Particles fluxes and moving fluids: experience from synchronous trap collection in the Sargassso sea","authors":"G Gust , R.H Byrne , R.E Bernstein , P.R Betzer , W Bowles","doi":"10.1016/0198-0149(92)90057-Z","DOIUrl":"https://doi.org/10.1016/0198-0149(92)90057-Z","url":null,"abstract":"<div><p>A series of synchronous, 24-h experiments using sensor-equipped sediment traps revealed that higher particle collection rates were associated with higher approach velocieties. Surface-tethered traps with variable drag configurations provided distinct differences in approach velocities for paired 400 m deployments and paired 1500 m deployments. Small-scale hot-film hydrodynamics sensors located both inside and outside the sediment traps detected flow cells within the traps with velocities between 50 and 100% of the external fluid approach velocities. In conjunction with laboratory flume simulations, these observations reveal that particles do not settle gravitationally across trap apertures. Intead, particles are swept advectively into traps at the downstream portion of trap apertures, and most are then expelled at the upstream portions of trap apertures. Fluid flows detected inside the drifting traps, which ranged from 1.2 to 31 cm s<sup>−1</sup>,l probably overwhelm all but the strongest “swimmers” that interact with these sampling divices. At our two sampling horizons (400 and 1500 m), tether-line motions generated trap depth oscillations with a period of the order of 10 s and an amplitude of about 0.5 m. Such effects have not been accounted for in flume simulated of sediment traps collection experiments.</p></div>","PeriodicalId":81079,"journal":{"name":"Deep-sea research. Part A, Oceanographic research papers","volume":"39 7","pages":"Pages 1071-1083"},"PeriodicalIF":0.0,"publicationDate":"1992-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0198-0149(92)90057-Z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72275707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}