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Iron, primary production and carbon-nitrogen flux studies during the JGOFS North Atlantic bloom experiment
Title
Iron, primary production and carbon-nitrogen flux studies during the JGOFS North Atlantic bloom experiment,
Description
Primary production was measured every other day towards the end (18-31 May) of the 1989 North Atlantic spring bloom. Rates varied with light and averaged 90.4 mmol C m -2 day -1 at the 47°N, 20°W station. Productivities measured south of Iceland (59°30′N, 20°45′W) were somewhat lower, averaging 83.6 mmol C m -2 day -1. Carbon and nitrogen fluxes were estimated using free-floating, VERTEX type particle trap arrays. To obtain mean rates representative of the North Atlantic spring bloom, flux data from three trap deployments were combined and fitted to normalized power functions:. mmol C m -2 day -1 = 14.35 (z/100) -0.946, mmol N m -2 day -1 = 2.34(z/100) -1.02, with depth z in meters. Regeneration rates were:. mmol C m -2 day -1 = 0.136(z/100) -1.946, mmol N m -2 day -1 = 0.0239(z/100) -2.02. The carbon export rate from the upper 35 m for the entire NABE study period (24 April to 1 June) was 39 mmol m -2 day -1. This value divided by the averaged productivity for the entire study (86 mmol N m -2 day -1) gave an F-ratio of 0.45. Concentrations of Cu, Fe, Ni, Pb and Zn were determined in water samples provided by JGOFS NABE scientists involved with primary productivity measurements. Although little contamination was observed for Cu, Ni and Pb, relatively large amounts of Zn (10 nmol kg -1) were found in some cases. In subsequent studies it was learned that this quantity of Zn can depress productivity rates by 25%. North Atlantic dissolved Fe concentrations were similar to those occurring in the Pacific (surface = 0.07; deep = 0.5-0.6 nmol kg -1). Although no evidence of Fe deficiency was found in enrichment experiments, the addition of nmol amounts of Fe did increase CO 2 uptake and POC formation by factors of 1.3-1.7. In this region, most of the phytoplankton's Fe requirement is probably met via the lateral transport of Fe from distant continental margins., Cited By (since 1996):170, CODEN: DSROE, ,
Author
Martin, Fitzwater, Michael Gordon, Hunter, Tanner
Date
1993-01-01T00:00:00Z
Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean
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