Trapping efficiencies of sediment traps from the deep Eastern North Atlantic:

Scholten, Jan; Fietzke, Jan; Vogler, S.; Loeff, Michiel Rutgers v. d.; Mangini, Augusto; Koeve, Wolfgang; Waniek, Joanna J; Stoffers, Peter; Antia, Avan; Kuss, Joachim

doi:10.1016/s0967-0645(00)00176-4

Cited by 161 publications

(95 citation statements)

References 46 publications

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“…The 230 Th normalization method has been supported by findings from both modeling [Henderson et al, 1999] and sediment trap studies [Scholten et al, 2001;Yu et al, 2001;Scholten et al, 2005].…”

Section: Study Area and Methodsmentioning

confidence: 86%

Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial‐interglacial changes in the ocean silicon cycle

et al. 2007

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The Silicic Acid Leakage Hypothesis (SALH) suggests that, during glacial periods, excess silicic acid was transported from the Southern Ocean to lower latitudes, which favored diatom production over coccolithophorid production and caused a drawdown of atmospheric CO2. Downcore records of 230Th‐normalized opal fluxes and 231Pa/230Th ratios from seven equatorial Atlantic cores were used to reconstruct diatom productivity over the past 30 ka (where a is years) and to test the SALH. Downcore records of 231Pa/230Th ratios and opal fluxes are highly correlated, suggesting that they constitute a production‐based record of opal flux. Opal flux records support the SALH in that glacial opal burial exceeded Holocene burial by 1.8 Gt opal/ka in the area 0°–40°W and 5°N–5°S. Earlier results from the eastern equatorial Pacific Ocean showed the opposite trend, with greater Holocene than glacial opal burial, but approximately the same magnitude of difference between glacial and interglacial opal burial. We suggest four (nonexclusive) scenarios to explain the data from both basins: (1) Increased upwelling in the equatorial Atlantic and El Niño–like conditions suppressing upwelling in the eastern equatorial Pacific altered the overall nutrient supply to both basins; (2) Si leaked from the Southern Ocean because of Fe fertilization, but was prevented from upwelling in the equatorial Pacific because of El Niño–like conditions during the LGM; (3) Si leaked from the Southern Ocean because diatom productivity was limited by increased sea ice extent and was again prevented from upwelling in the equatorial Pacific; or (4) changes in ocean circulation related to the decreased input of Agulhas water to the glacial South Atlantic provided excess dissolved Si to the equatorial Atlantic Ocean. A deglacial opal pulse is seen in both the Atlantic and Pacific Oceans. All four scenarios and the presence of the common deglacial opal pulse suggest a common driver in the Southern Ocean.

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Section: Study Area and Methodsmentioning

confidence: 86%

Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial‐interglacial changes in the ocean silicon cycle

et al. 2007

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“…Under these conditions the exportable production at K2 would be greater than ALOHA, but only for D1 (Elskens et al, this volume and unpublished data from ALOHA). When comparing traps at different depths and of differing designs, one should also consider complications due to trapping efficiencies (Buesseler, 1991;Scholten et al, 2001;Yu et al, 2001). For K2, Honda (unpublished data) show using 230 Th and 231 Pa data that the deep trap collection efficiency lies between 37-51%.…”

Section: Comparison Of Primary Production and Shallow Exportmentioning

confidence: 99%

VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific

Buesseler

Trull

Steinberg

et al. 2008

Deep Sea Research Part II: Topical Studies in Oceanography

119

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The VERtical Transport In the Global Ocean (VERTIGO) study examined particle sources and fluxes through the ocean's "twilight zone" (defined here as depths below the euphotic zone to 1000 m). Interdisciplinary process studies were conducted at contrasting sites off Hawaii (ALOHA) and in the NW Pacific (K2) during 3 week occupations in 2004 and 2005, respectively. We examine in this overview paper the contrasting physical, chemical and biological settings and how these conditions impact the source characteristics of the sinking material and the transport efficiency through the twilight zone. A major finding in VERTIGO is the considerably lower transfer efficiency (T eff ) of particulate organic carbon (POC), POC flux 500 / 150 m, at ALOHA (20%) vs. K2 (50%). This efficiency is higher in the diatom-dominated setting at K2 where silica-rich particles dominate the flux at the end of a diatom bloom, and where zooplankton and their pellets are larger. At K2, the drawdown of macronutrients is used to assess export and suggests that shallow remineralization above our 150 m trap is significant, especially for N relative to Si. We explore here also surface export ratios (POC flux/primary production) and possible reasons why this ratio is higher at K2, especially during the first trap deployment. When we compare the 500 m fluxes to deep moored traps, both sites lose about half of the sinking POC by >4000 m, but this comparison is limited in that fluxes at depth may have both a local and distant component.Certainly, the greatest difference in particle flux attenuation is in the mesopelagic, and we highlight other VERTIGO papers that provide a more detailed examination of the particle sources, flux and processes that attenuate the flux of sinking particles. Ultimately, we contend that at least three types of processes need to be considered: heterotrophic degradation of sinking particles, zooplankton migration and surface feeding, and lateral sources of suspended and sinking materials. We have evidence that all of these processes impacted the net attenuation of particle flux vs. depth measured in VERTIGO and would therefore need to be considered and quantified in order to understand the magnitude and efficiency of the ocean's biological pump.

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“…Average annual values obtained from monthly measurements during several years using these traps, both in the subtropical Atlantic (Station BATS; Lohrenz et al 1992) and central Pacific (Station ALOHA; Karl et al 1996), yield similar values (0.7-0.9 mol C m −2 a −1 ), about three to fourfold lower than geochemical estimates of new production Emerson et al 1997); that is, the part of the carbon fixed that is not respired until it has been removed from the epipelagic zone to the dark ocean (Platt et al 1992). Several studies using particle-reactive natural radio nuclides ( 234 Th, 230 Th, and 231 Pa) as a tracer for sinking particles, have convincingly demonstrated that both free-floating and moored sediment traps deployed in the mesopelagic zone severely underestimate the particle flux (Buesseler 1991;Buesseler et al 2000;Scholten et al 2001;Yu et al 2001). In contrast, traps in the bathypelagic zone seem to intercept the vertical flux of particles more effectively (Yu et al 2001).…”

Section: Delivery Of Pocmentioning

confidence: 99%

Respiration in the mesopelagic and bathypelagic zones of the oceans

Arı́stegui¹,

Agustı́²,

Middelburg³

et al. 2005

Respiration in Aquatic Ecosystems

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OutlineIn this chapter the mechanisms of transport and remineralization of organic matter in the dark water-column and sediments of the oceans are reviewed. We compare the different approaches to estimate respiration rates, and discuss the discrepancies obtained by the different methodologies. Finally, a respiratory carbon budget is produced for the dark ocean, which includes vertical and lateral fluxes of organic matter. In spite of the uncertainties inherent in the different approaches to estimate carbon fluxes and oxygen consumption in the dark ocean, estimates vary only by a factor of 1.5. Overall, direct measurements of respiration, as well as indirect approaches, converge to suggest a total dark ocean respiration of 1.5-1.7 Pmol C a −1 . Carbon mass balances in the dark ocean suggest that the dark ocean receives 1.5-1.6 Pmol C a −1 , similar to the estimated respiration, of which >70% is in the form of sinking particles. Almost all the organic matter (∼92%) is remineralized in the water column, the burial in sediments accounts for <1%. Mesopelagic (150-1000 m) respiration accounts for ∼70% of dark ocean respiration, with average integrated rates of 3-4 mol C m −2 a −1 , 6-8 times greater than in the bathypelagic zone (∼0.5 mol C m −2 a −1 ). The results presented here renders respiration in the dark ocean a major component of the carbon flux in the biosphere, and should promote research in the dark ocean, with the aim of better constraining the role of the biological pump in the removal and storage of atmospheric carbon dioxide.

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Trapping efficiencies of sediment traps from the deep Eastern North Atlantic:

Cited by 161 publications

References 46 publications

Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial‐interglacial changes in the ocean silicon cycle

Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial‐interglacial changes in the ocean silicon cycle

VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific

Respiration in the mesopelagic and bathypelagic zones of the oceans

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