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212 results on '"Honjo, Susumu"'

1. Evidence of old carbon in the deep water column of the Panama Basin from natural radiocarbon measurements

Author

Druffel, Ellen R. M, Griffin, Sheila, Honjo, Susumu, and Manganini, Steven J

Abstract

Radiocarbon (Δ14C) analyses were performed on sinking and suspended particulate matter, dissolved inorganic carbon (DIC), sediment and sediment fluff from a deep-water station in the Panama Basin. Δ14C signatures for sinking particulate inorganic and organic carbon (PIC, FOC) collected at 3354 meters depth were lower than surface DIC Δ14C values, and higher than the inorganic and organic carbon from the sediment (SIC, SOC). We compare these data with those obtained for other Pacific and Atlantic sites and show that the gradient between surface DIC Δ14C and deep suspended POC Δ14C is the same irrespective of distance from the coast. This indicates that: 1) resuspended SOC is an equally important contributor to deep POC at locations close to and far from continental slopes, and/or 2) DOC sorption is a significant contributor for causing low Δ14C values of deep POC.

Published
1998

3. Fractionation of 226Ra and Ba in the Upper North Pacific Ocean

Author

van Beek, Pieter, François, Roger, Honda, Makio, Charette, Matthew, Reyss, Jean-Louis, Ganeshram, Raja, Monnin, Christophe, Honjo, Susumu, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Océan et Interfaces (OCEANIS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
ratio, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, barium, Ocean Engineering, Aquatic Science, Oceanography, radium, suspended particles, ocean circulation, fractionation, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, dating, seawater, Water Science and Technology
Abstract

Investigations conducted during the GEOSECS program concluded that radium-226 (T1/2 = 1602 y) and barium are tightly correlated in waters above 2500 m in the Atlantic, Pacific and Antarctic Oceans, with a fairly uniform 226Ra/Ba ratio of 2.3 ± 0.2 dpm µmol-1 (4.6 nmol 226Ra/mol Ba). Here, we report new 226Ra and Ba data obtained at three different stations in the Pacific Ocean: stations K1 and K3 in the North-West Pacific and station old Hale Aloha, off Hawaii Island. The relationship between 226Ra and Ba found at these stations is broadly consistent with that reported during the GEOSECS program. At the three investigated stations, however, we find that the 226Ra/Ba ratios are significantly lower in the upper 500 m of the water column than at greater depths, a pattern that was overlooked during the GEOSECS program, either because of the precision of the measurements or because of the relatively low sampling resolution in the upper 500 m. Although not always apparent in individual GEOSECS profiles, this trend was noted before from the non-zero intercept of the linear regression when plotting the global data set of Ba versus 226Ra seawater concentration and was attributed, at least in part, to the predominance of surface input from rivers for Ba versus bottom input from sediments for 226Ra. Similarly, low 226Ra/Ba ratios in the upper 500 m have been reported in other oceanic basins (e.g. Atlantic Ocean). Parallel to the low 226Ra/Ba ratios in seawater, higher 226Ra/Ba ratios were found in suspended particles collected in the upper 500 m. This suggests that fractionation between the two elements may contribute to the lower 226Ra/Ba ratios found in the upper 500 m, with 226Ra being preferentially removed from surface water, possibly as a result of mass fractionation during celestite formation by acantharians and/or barite precipitation, since both chemical elements have similar ionic radius and the same configuration of valence electrons. This finding has implications for dating of marine carbonates by 226Ra, which requires a constant initial 226Ra/Ba ratio incorporated in the shells and for using 226Ra as an abyssal circulation and mixing tracer.

Published
2022

14. Monsoon winds and carbon cycles in the Arabian Sea

Author

Honjo, Susumu and Weller, Robert A.

Subjects
Arabian Sea -- Environmental aspects, Carbon cycle (Biogeochemistry) -- Environmental aspects, Marine sediments -- Environmental aspects, Monsoons -- Environmental aspects, Sediment, Suspended -- Environmental aspects, Marine productivity -- Environmental aspects, Environmental issues, Earth sciences, Environmental aspects
Abstract

The monsoon, a giant sea breeze between the Asian massif and the Indian Ocean, is one of the most significant natural phenomena that influences the everyday life of more than [...]

Published
1997

15. The rain of ocean particles and earth's carbon cycle

Author

Honjo, Susumu

Subjects
Carbon cycle (Biogeochemistry) -- Research -- Environmental aspects, Marine sediments -- Environmental aspects -- Research, Sedimentation and deposition -- Research -- Environmental aspects, Environmental issues, Earth sciences, Research, Environmental aspects
Abstract

Phytoplankton photosynthesis has provided Earth's inhabitants with oxygen since early life began. Without this process the atmosphere would consist of carbon dioxide (C[O.sub.2]) plus a small amount of nitrogen, the [...]

Published
1997

21. From the Gobi to the bottom of the North Pacific

Author

Honjo, Susumu

Subjects
Marine sediments -- Research -- Analysis, Eolian processes -- Analysis -- Research, Sediment transport -- Research -- Analysis, Environmental issues, Earth sciences, Analysis, Research
Abstract

Rock Particles Travel from High Mountains to the Oceanic Abyss Earth's crustal materials are recycled by water, wind, ice, and fire. In order for this recycling to occur, crust must [...]

Published
1992

22. Distribution and transport of marine snow aggregates in the Panama Basin

Author

Asper, Vernon L., Honjo, Susumu, and Orsi, Thomas H.

Subjects
Sediment, Suspended -- Measurement, Sedimentation and deposition -- Research, Marine snow -- Research, Earth sciences
Abstract

The role of marine snow aggregates in ocean vertical transport was investigated. A photographic method was used to understand the regional and temporal variations in snow aggregate abundances in several stations in the Panam Basin. Abundances were generally higher in the surface water and near the sea floor. The interactions among fast-sinking aggregates, suspended aggregates, lateral transport and re-suspended aggregates are explained in a particle transport model, which predicts that aggregate size as determined by the photographic method may be a poor indicator of sinking speed and therefore does not provide a good estimate of actual vertical flux.

Published
1992

23. A sediment trap intercomparison experiment in the Panama Basin, 1979

Author

Honjo, Susumu, Spencer, Derek W., and Gardner, Wilford D.

Subjects
Sediment, Suspended -- Measurement, Oceanographic instruments -- Evaluation, Earth sciences
Abstract

Twenty-eight sediment traps of 11 designs were deployed at different depths in the Panama Basin to compare their collection efficiency of settling particles. The results showed that the trapping efficiency of a large funnel trap with a baffle was identical to that of an intermediate-size cylinder trap. The highest trapping efficiency was in a funnel-type trap with a more effective baffle. The results for box type traps compared with other trap types were inconclusive.

Published
1992

25. Storm-driven Mixing and Potential Impact on the Arctic Ocean

Author

Yang, Jiayan, Comiso, Josefino, Walsh, David, Krishfield, Richard, Honjo, Susumu, and Koblinsky, Chester J

Subjects
Environment Pollution
Abstract

Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys (IOEBs) indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean. Our analysis suggests that these mixing events were mechanically forced by intense storms moving across the buoy sites. In this study, we analyzed these mixing events in the context of storm developments that occurred in the Beaufort Sea and in the general area just north of Fram Strait, two areas with quite different hydrographic structures. The Beaufort Sea is strongly influenced by inflow of Pacific water through Bering Strait, while the area north of Fram Strait is directly affected by the inflow of warm and salty North Atlantic water. Our analyses of the basin-wide evolution of the surface pressure and geostrophic wind fields indicate that the characteristics of the storms could be very different. The buoy-observed mixing occurred only in the spring and winter seasons when the stratification was relatively weak. This indicates the importance of stratification, although the mixing itself was mechanically driven. We also analyze the distribution of storms, both the long-term climatology as well as the patterns for each year in the last two decades. The frequency of storms is also shown to be correlated- (but not strongly) to Arctic Oscillation indices. This study indicates that the formation of new ice that leads to brine rejection is unlikely the mechanism that results in the type of mixing that could overturn the halocline. On the other hand, synoptic-scale storms can force mixing deep enough to the halocline and thermocline layer. Despite a very stable stratification associated with the Arctic halocline, the warm subsurface thermocline water is not always insulated from the mixed layer.

Published
2001

29. The Scanning Electron Microsope Science

Author

Honjo, Susumu

Abstract

Describes the operation and use of the scanning electron microscope as an important tool for ocean scientists. Numerous electron micrographs are included. (MA)

Published
1978

32. Autonomous microbial sampler (AMS), a device for the uncontaminated collection of multiple microbial samples from submarine hydrothermal vents and other aquatic environments

Author

Taylor, Craig D., Doherty, Kenneth W., Molyneaux, Stephen J., Morrison, Archie T., III, Billings, John D., Engstrom, Ivory B., Pfitsch, Don W., and Honjo, Susumu

Subjects
Hydrothermal vents -- Environmental aspects, Microorganisms -- Genetic aspects, Earth sciences
Abstract

An Autonomous Microbial Sampler (AMS) is accounted that obtains uncontaminated and exogenous DNA-free microbial samples from most marine, freshwater and hydrothermal ecosystems. The technical functioning of the AMS and procedures for sterilization and DNA removal are also described.

Published
2006

48. Vertical budgets for organic carbon and biogenic silica in the Pacific sector of the Southern Ocean, 1996–1998

Author

Nelson, David M, primary, Anderson, Robert F, additional, Barber, Richard T, additional, Brzezinski, Mark A, additional, Buesseler, Ken O, additional, Chase, Zanna, additional, Collier, Robert W, additional, Dickson, Mary-Lynn, additional, François, Roger, additional, Hiscock, Michael R, additional, Honjo, Susumu, additional, Marra, John, additional, Martin, William R, additional, Sambrotto, Raymond N, additional, Sayles, Frederick L, additional, and Sigmon, Daniel E, additional

Published
2002
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