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Title: Iron, nutrient and phytoplankton biomass relationships in upwelled waters of the California coastal system,
Description: We report measurements of dissolvable and particulate iron, particulate Al, nutrients and phytoplankton biomass in surface waters during the termination of one upwelling event and the initiation of a second event in August 2000. These events occurred in the area of the Año Nuevo upwelling center off the coast of central California. The first event was observed after ∼8 days of continuous upwelling favorable winds, while the second event was observed through the onset of upwelling favorable winds to wind reversals ∼3 days later. Coincident with the upwelling signatures of low temperature and high salinity were significantly elevated concentrations of nitrate and silicate with average concentrations greater than 15 and 20 μM, respectively, during both upwelling events. Dissolvable Fe concentrations (TD-Fe) were significantly higher in the second event, 6.5 versus 1.2 nM Fe found in the first event. Nitrate was reduced by ∼5 μM day-1 within this second upwelled plume as compared to a drawdown of ∼2 μM day-1 within the first plume. Silicate was reduced in a ratio of 1.2 mol Si:mol NO3 in the high Fe waters of the second plume as compared to a ratio of 2.2 in the lower Fe waters of the first plume. The observed differences in nutrient utilization are consistent with some degree of iron limitation. The area of increased dissolvable Fe in the second upwelling event was coincident with elevated particulate Fe concentrations, indicating the particulate pool as a possible source of the observed increase in TD-Fe. The elevated particulate Fe in surface waters was a result of resuspended sediments in the bottom boundary layer (BBL) of the shallow shelf being transported to the surface during upwelling. Particulate (and dissolvable) iron concentrations were significantly reduced as upwelling continued. This was most probably due to a decoupling of the BBL from upwelled source waters as the upwelling front moved offshore and/or reduced turbulence in the BBL as upwelling continued. The observed reduction in both particulate and dissolvable Fe, as upwelling continued to deliver macronutrients to surface waters, may result in varying levels of Fe limitation., Cited By (since 1996):35, CODEN: CSHRD, ,
Author: Fitzwater, Johnson, Elrod, Ryan, Coletti, Tanner, Gordon, Chavez
Date: 2003-01-01T00:00:00Z

Title: Southern Ocean Iron Enrichment Experiment,
Description: The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide., Cited By (since 1996):316, Oceanography, CODEN: SCIEA, ,
Author: Coale, Johnson, Chavez, Buesseler, Barber, Brzezinski, Cochlan, Millero, Falkowski, Bauer, Wanninkhof, Kudela, Altabet, Hales, Takahashi, Landry, Bidigare, Wang, Chase, Strutton, Friederich, Gorbunov, Lance, Hilting, Hiscock, Demarest, Hiscock, Sullivan, Tanner, Gordon, Hunter, Elrod, Fitzwater, Jones, Tozzi, Koblizek, Roberts, Herndon, Brewster, Ladizinsky, Smith, Cooper, Timothy, Brown, Selph, Sheridan, Twining, Johnson
Date: 2004-01-01T00:00:00Z

Title: Developing standards for dissolved iron in seawater
Description: Cited By (since 1996):114
Author: Johnson, Boyle, Bruland, Coale, Measures, Moffett, Aguilar-Islas, Barbeau, Bergquist, Bowie, Buck, Cai, Chase, Cullen, Doi, Elrod, Fitzwater, Gordon, King, Laan, Laglera-Baquer, Landing, Lohan, Mendez, Milne, Obata, Ossiander, Plant, Sarthou, Sedwick, Smith, Sohst, Tanner, Van den Berg, Wu
Date: 2007-01-01T00:00:00Z

Title: Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean,
Description: The idea that iron might limit phytoplankton growth in large regions of the ocean has been tested by enriching an area of 64 km 2 in the open equatorial Pacific Ocean with iron. This resulted in a doubling of plant biomass, a threefold increase in chlorophyll and a fourfold increase in plant production. Similar increases were found in a chlorophyll-rich plume down-stream of the Galapagos Islands, which was naturaly enriched in iron. These findings indicate that iron limitation can control rates of phytoplankton productivity and biomass in the ocean., Cited By (since 1996):749, Oceanography, CODEN: NATUA, ,
Author: Martin, Coale, Johnson, Fitzwater, Gordon, Tanner, Hunter, Elrod, Nowicki, Coley, Barber, Lindley, Watson, Van Scoy, Law, Liddicoat, Ling, Stanton, Stockel, Collins, Anderson, Bidigare, Ondrusek, Latasa, Millero, Lee, Yao, Zhang, Friederich, Sakamoto, Chavez, Buck, Kolber, Greene, Falkowski, Chisholm, Hoge, Swift, Yungel, Turner, Nightingale, Hatton, Liss, Tindale
Date: 1994-01-01T00:00:00Z

Title: Surface ocean-lower atmosphere interactions in the Northeast Pacific Ocean Gyre: Aerosols, iron, and the ecosystem response,
Description: Here we report measurements of iron and aluminum in surface and subsurface waters during late March and late May of 2001 on transects between central California and Hawaii. A large cloud of Asian dust was detected during April 2001, and there was a clear signal in surface water iron due to aerosol deposition on the May transect. Iron and aluminum concentrations increased synchronously by 0.5 and 2 nM along the southern portion of the transect, which includes the Hawaii Ocean Time series (HOT) station, from background values in March (0.1 to 0.2 nM Fe). These changes occured in a ratio that is close to the crustal abundance ratio of the metals, which indicates a soil aerosol source. A vertical profile of dissolved iron was also measured at the HOT station in late April and this profile also shows a large increase near the surface. Direct observations of aerosol iron concentration at Mauna Loa Observatory on Hawaii indicate that aerosol concentrations were significantly lower than climatological values during this period. Soil aerosol concentrations along the transect were estimated using the real-time Navy Aerosol Analysis and Prediction System (NAAPS). The NAAPS results show a large meridional gradient with maximum concentrations in the boundary layer north of 30°N. However, the deposition of iron and aluminum to surface waters was highest south of 25°N, near Hawaii. There were only weak signals in the ecosystem response to the aerosol deposition., Cited By (since 1996):64, Oceanography, , , Downloaded from: http://onlinelibrary.wiley.com/doi/10.1029/2002GB002004/pdf (16 June 2014).
Author: Johnson, Elrod, Fitzwater, Plant, Chavez, Tanner, Gordon, Westphal, Perry, Wu, Karl
Date: 2003-01-01T00:00:00Z