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


Buesseler, KO and Trull, T and Steinberg, DK and Silver, MW and Siegel, DA and Saitoh, SI and Lamborg, CH and Lam, PJ and Karl, DM and Jiao, NZ and Honda, MC and Elskens, M and Dehairs, F and Brown, SL and Boyd, PW and Bishop, JKB and Bidigare, RR, VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific, Deep Sea Research Part II: Topical Studies in Oceanography, 55, (14-15) pp. 1522-1539. ISSN 0967-0645 (2008) [Refereed Article]

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DOI: doi:10.1016/j.dsr2.2008.04.024


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 (Teff) of particulate organic carbon (POC), POC flux 500/150m, at ALOHA (20%) vs. K2 (50%). This efficiency is higher in the diatomdominated 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 44000 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.

Item Details

Item Type:Refereed Article
Keywords:Particle flux, Sediment trap, Twilight zone
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Measurement and assessment of estuarine water quality
UTAS Author:Trull, T (Professor Thomas Trull)
UTAS Author:Boyd, PW (Professor Philip Boyd)
ID Code:54601
Year Published:2008
Web of Science® Times Cited:88
Deposited By:IASOS
Deposited On:2009-02-25
Last Modified:2014-10-14

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