Sinking fluxes of minor and trace elements in the North Pacific Ocean measured during the VERTIGO program

As part of the Vertical Transport in the Global Ocean (VERTIGO) program, we collected and analyzed sinking particles using sediment traps at three depths in the oceanic mesopelagic zone and at two biogeochemically contrasting sites (N. Central Pacific at ALOHA; N. Pacific Western Subarctic Gyre at K2). In this paper, we present the results of minor and trace element determinations made on these samples. Minor and trace elements in the sinking material showed 2 trends in flux with depth: increasing and constant. The sinking particulate phase of some elements (Al, Fe, Mn) was dominated by material of lithogenic origin and exhibited flux that was constant with depth and consistent with eolian dust inputs (ALOHA), or increasing in flux with depth as a result of lateral inputs from a shelf (K2). This shelf-derived material also appears to have been confined to very small particles, whose inherent sinking rates are slow, and residence time within the mesopelagic ‘‘twilight zone’’ would be consequently long. Furthermore, the flux of this material did not change with substantial changes in the rain of biogenic material from the surface (K2), suggesting mechanistic decoupling from the flux of organic carbon and macronutrients. Micronutrient (Fe, Co, Zn and Cu) fluxes examined in a 1-D mass balance suggest widely differing sources and sinks in the water column as well as impacts from biological uptake and regeneration. For example, total Fe fluxes into and out of the euphotic zone appeared to be dominated by lithogenic material and far exceed biological requirements. The export flux of Fe, however, appeared to be balanced by the eolian input of soluble Fe. For Zn and Cu, the situation is reversed, with atmospheric inputs insufficient to support fluxes, and the cycling therefore dominated by the draw down of an internal pool. For Co, the situation lies in between, with important, but ultimately insufficient atmospheric inputs.

[1]  John H. Martin,et al.  VERTEX: manganese transport with CaCO3 , 1983 .

[2]  S. Tohno,et al.  Properties of individual Asian dust storm particles collected at Kosan, Korea during ACE-Asia , 2004 .

[3]  J. Valdes,et al.  A comparison of major and minor elemental fluxes collected in neutrally buoyant and surface-tethered sediment traps , 2004 .

[4]  P. Falkowski,et al.  Irradiance and the elemental stoichiometry of marine phytoplankton , 2006 .

[5]  C. L. De La Rocha,et al.  Accumulation of mineral ballast on organic aggregates , 2006 .

[6]  D. Lowenthal,et al.  Elemental Tracers of Distant Regional Pollution Aerosols , 1984, Science.

[7]  J. Valdes,et al.  A Neutrally Buoyant, Upper Ocean Sediment Trap , 2000 .

[8]  Zhi-gang Guo,et al.  The elemental and organic characteristics of PM2.5 in Asian dust episodes in Qingdao, China, 2002 , 2004 .

[9]  H. Johnson,et al.  A comparison of 'traditional' and multimedia information systems development practices , 2003, Inf. Softw. Technol..

[10]  S. Wakeham,et al.  Effectiveness of various treatments in retarding microbial activity in sediment trap material and their effects on the collection of swimmers , 1992 .

[11]  James K. B. Bishop,et al.  The continental margin is a key source of iron to the HNLC North Pacific Ocean , 2008 .

[12]  S. Fowler,et al.  An assessment of the use of sediment traps for estimating upper ocean particle fluxes , 2007 .

[13]  P. Statham,et al.  Total dissolved zinc in the upper water column of the subarctic North East Pacific , 2002 .

[14]  T. Jickells,et al.  Solubilisation of aerosol trace metals by cloud processing: A laboratory study , 1994 .

[15]  J. Kuss,et al.  Particulate trace element fluxes in the deep northeast Atlantic Ocean , 1999 .

[16]  Deborah K. Steinberg,et al.  Revisiting Carbon Flux Through the Ocean's Twilight Zone , 2006, Science.

[17]  S. Wakeham,et al.  A new, mechanistic model for organic carbon fluxes in the ocean based on the quantitative association of POC with ballast minerals , 2001 .

[18]  Rachel M. Jeffreys,et al.  Deep-Sea Research II , 2008 .

[19]  Deborah K. Steinberg,et al.  VERTIGO (VERtical Transport In the Global Ocean) : A study of particle sources and flux attenuation in the North Pacific , 2008 .

[20]  B. Murton,et al.  Heterogeneity in southern Central Indian Ridge MORB: Implications for ridge–hot spot interaction , 2005 .

[21]  C. Pohl,et al.  A sediment trap flux study for trace metals under seasonal aspects in the stratified Baltic Sea (Gotland Basin; 57°19.20′N; 20°03.00′E) , 2004 .

[22]  M. Fleisher,et al.  Particulate manganese dynamics in Gulf Stream warm-core rings and surrounding waters of the N.W. Atlantic , 1987 .

[23]  D. Karl,et al.  The Hawaiian Ocean Time-series (HOT) and Bermuda Atlantic Time-series study (BATS) , 1996 .

[24]  P. Brewer,et al.  Sediment trap experiments in the deep north Atlantic: isotopic and elemental fluxes , 1980 .

[25]  H. Hasegawa,et al.  Distribution of Trace Bioelements in the Subarctic North Pacific Ocean and the Bering Sea (the R/V Hakuho Maru Cruise KH-97-2) , 2001 .

[26]  K. Johnson,et al.  Cobalt and copper distributions in the waters of Santa Monica Basin, California , 1988, Nature.

[27]  P. Streu,et al.  Saharan dust influenced trace element fluxes in deep North Atlantic subtropical waters , 1993 .

[28]  J. Nishioka,et al.  A Mesoscale Iron Enrichment in the Western Subarctic Pacific Induces a Large Centric Diatom Bloom , 2003, Science.

[29]  J. Reid,et al.  On the total geostrophic circulation of the pacific ocean: flow patterns, tracers, and transports , 1997 .

[30]  S. Bograd,et al.  Near-surface circulation of the northeast Pacific Ocean derived from WOCE-SVP satellite-tracked drifters , 1999 .

[31]  M. Lyle,et al.  Flux comparisons between sediments and sediment traps in the eastern tropical Pacific: Implications for atmospheric C02 variations during the Pleistocene1 , 1985 .

[32]  Y. Nojiri,et al.  The biological pump in the northwestern North Pacific based on fluxes and major components of particulate matter obtained by sediment-trap experiments (1997–2000) , 2002 .

[33]  S. Baines,et al.  Element stoichiometries of individual plankton cells collected during the Southern Ocean Iron Experiment (SOFeX) , 2004 .

[34]  S. Tohno,et al.  Determination of the chemical properties of residues retained in individual cloud droplets by XRF microprobe at SPring-8 , 2004 .

[35]  J. Moffett,et al.  Oxidation of cobalt and manganese in seawater via a common microbially catalyzed pathway , 1996 .

[36]  Antonietta Quigg,et al.  THE ELEMENTAL COMPOSITION OF SOME MARINE PHYTOPLANKTON 1 , 2003 .

[37]  Kenneth W. Bruland,et al.  Oceanographic distributions of cadmium, zinc, nickel, and copper in the North Pacific , 1980 .

[38]  Deborah K. Steinberg,et al.  The flux of bio- and lithogenic material associated with sinking particles in the mesopelagic “twilight zone” of the northwest and North Central Pacific Ocean , 2008 .

[39]  A. Knap,et al.  The sedimentation rates of trace elements in the Sargasso Sea measured by sediment trap , 1984 .

[40]  C. Measures,et al.  Dust deposition to the surface waters of the western and central North Pacific inferred from surface water dissolved aluminum concentrations , 2005 .

[41]  J. H. Martin,et al.  Zinc in north-east Pacific water , 1978, Nature.

[42]  Wallace S. Broecker,et al.  The Carbon cycle and atmospheric CO[2] : natural variations Archean to present , 1985 .

[43]  L. Talley,et al.  North Pacific Intermediate Water in the Kuroshio/Oyashio Mixed Water Region , 1995 .

[44]  N. Mahowald,et al.  Global Iron Connections Between Desert Dust, Ocean Biogeochemistry, and Climate , 2005, Science.

[45]  Ken O. Buesseler,et al.  Primary, new and export production in the NW Pacific subarctic gyre during the vertigo K2 experiments , 2008 .

[46]  W. Sunda,et al.  Iron uptake and growth limitation in oceanic and coastal phytoplankton , 1995 .

[47]  J. Nishioka,et al.  Dynamics of trace metals during the subarctic Pacific iron experiment for ecosystem dynamics study (SEEDS2001) , 2005 .

[48]  David Archer,et al.  Association of sinking organic matter with various types of mineral ballast in the deep sea: Implications for the rain ratio , 2002 .

[49]  W. K. Johnson,et al.  Iron supply to the western subarctic Pacific: Importance of iron export from the Sea of Okhotsk , 2007 .

[50]  M. Conte,et al.  Application of high‐temperature fusion for analysis of major and trace elements in marine sediment trap samples , 2007 .

[51]  M. Kusakabe,et al.  Interdecadal variability in dissolved oxygen in the intermediate water layer of the Western Subarctic Gyre and Kuril Basin (Okhotsk Sea) , 2001 .

[52]  M. Saito,et al.  Cobalt, manganese, and iron near the Hawaiian Islands: A potential concentrating mechanism for cobalt within a cyclonic eddy and implications for the hybrid-type trace metals , 2008 .

[53]  David M. Karl,et al.  VERTEX: carbon cycling in the northeast Pacific , 1987 .

[54]  David M. Karl,et al.  In situ effects of selected preservatives on total carbon, nitrogen and metals collected in sediment traps , 1984 .

[55]  Jean-Pierre Gattuso,et al.  Marine calcification as a source of carbon dioxide : positive feedback of increasing atmospheric CO2 , 1994 .

[56]  W. Landing,et al.  Dissolved and particulate Fe in the western and central North Pacific: Results from the 2002 IOC cruise , 2005 .

[57]  B. Hicks,et al.  The atmospheric input of trace species to the world ocean , 1991 .

[58]  K. H. Wedepohl,et al.  The Composition of the Continental Crust , 1995 .

[59]  Sung-Nam Oh,et al.  Chemical composition and source signature of spring aerosol in Seoul, Korea , 2001 .

[60]  L. Balistrieri,et al.  Suboxic trace metal geochemistry in the Eastern Tropical North Pacific , 2002 .

[61]  K. Haines,et al.  North Atlantic Subtropical Mode Waters and Ocean Memory in HadCM3 , 2006 .

[62]  G. Gordon,et al.  Atmospheric aerosol trace element chemistry at Mauna Loa Observatory: 1. 1979–1985 , 1995 .

[63]  S. Chisholm,et al.  Cobalt limitation and uptake in Prochlorococcus , 2002 .

[64]  P. Sedwick,et al.  Impact of anthropogenic combustion emissions on the fractional solubility of aerosol iron: Evidence from the Sargasso Sea , 2007 .

[65]  W. Sunda,et al.  Cobalt and zinc interreplacement in marine phytoplankton: Biological and geochemical implications , 1995 .

[66]  Mark Gall,et al.  Quantifying the surface– subsurface biogeochemical coupling during the VERTIGO ALOHA and K2 studies , 2008 .

[67]  Deborah K. Steinberg,et al.  Upper Ocean Carbon Export and the Biological Pump , 2001 .

[68]  K. Linge,et al.  Trends in the solubility of iron, aluminium, manganese and phosphorus in aerosol collected over the Atlantic Ocean , 2006 .

[69]  S. Vink,et al.  On the use of dissolved aluminum in surface waters to estimate dust deposition to the ocean , 2000 .

[70]  W. Sunda,et al.  Low iron requirement for growth in oceanic phytoplankton , 1991, Nature.

[71]  Deborah K. Steinberg,et al.  A comparison of mesopelagic mesozooplankton community structure in the subtropical and subarctic North Pacific Ocean , 2008 .

[72]  W. Sunda,et al.  Feedback interactions between zinc and phytoplankton in seawater , 1992 .

[73]  T. Coley,et al.  Manganese Flux from Continental Margin Sediments in a Transect Through the Oxygen Minimum , 1992, Science.

[74]  George W. Luther,et al.  What controls dissolved iron concentrations in the world ocean? — a comment , 1997 .

[75]  J. Resing,et al.  Aerosol iron and aluminum solubility in the northwest Pacific Ocean: Results from the 2002 IOC cruise , 2006 .

[76]  S. Sander,et al.  Physical mixing effects on iron biogeochemical cycling: FeCycle experiment , 2007 .

[77]  Marine Bioinorganic Chemistry: The Role of Trace Metals in the Oceanic Cycles of Major Nutrients , 2003 .

[78]  Martin A. Schmidt,et al.  A trace metal (Pb, Cd, Zn, Cu) balance for surface waters in the eastern Gotland Basin, Baltic Sea , 2006 .

[79]  T. Jickells.  The inputs of dust derived elements to the Sargasso Sea; a synthesis , 1999 .

[80]  N. Mahowald,et al.  Atmospheric global dust cycle and iron inputs to the ocean , 2005 .

[81]  P. Boyd,et al.  Particulate iron dynamics during FeCycle in subantarctic waters southeast of New Zealand , 2006 .

[82]  J. Valdes,et al.  A comparison of the quantity and composition of material caught in a neutrally buoyant versus surface-tethered sediment trap , 2000 .

[83]  A. Antia.  Particle-associated dissolved elemental fluxes: revising the stochiometry of mixed layer export , 2005 .