Iron and zinc effects on silicic acid and nitrate uptake kinetics in three high-nutrient, low-chlorophyll (HNLC) regions

Franck, Valerie M.; Bruland, Kenneth W.; Hutchins, David A.; Brzezinski, Mark A.

doi:10.3354/meps252015

Cited by 148 publications

(137 citation statements)

References 58 publications

(94 reference statements)

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“…Moreover, Bucciarelli et al (2010) examined the effect of Fe-light co-limitation on cellular silica, carbon and nitrogen in two marine diatom species, Thalassiosira oceanica and Ditylum brightwellii, observing a 1.4-fold increase in C:N ratio with a decrease in growth rate by 70% in both species and a decrease in biogenic silica per cell under severe Fe or Fe-light limitation. These results however are seemingly in contradiction with many previous lab and field studies showing increased diatom silicification under Fe limitation (Hutchins and Bruland, 1998;Takeda, 1998;Firme et al, 2003;Franck et al, 2003).…”

Section: Linking Biological Processes To Iron Chemistrycontrasting

confidence: 56%

“…Further, particulate Fe would undergo a transformation from lithogenic to biogenic iron during settling through the mixed layer. Rapid biological processing (bacterivory and herbivory, subsequent biological uptake) after dissolution of dust deposited iron hydroxides and presumably also photolysis of siderophore complexed Fe(III)-hydroxide (Borer et al, 2005) resulted in exchange from the lithogenic particulate phase via the soluble to the biogenic particulate phase (Frew et al, 2006;Strzepek et al, 2005;Maldonado et al, 2005). The rapid exchange with particulate iron phases provides new insight into iron cycling and export dynamics since the role of particulate iron in iron biogeochemistry appears more important than previously assumed.…”

Section: Colloidal Iron and Organic Mattermentioning

confidence: 94%

“…There is still considerable debate surrounding the drivers of this variation in solubility with four main possibilities; (i) atmospheric chemical processing during dust transport (Fan et al, 2006;Jickells and Spokes, 2001), (ii) systematic changes in aerosol particle size leading to changes in surface area and solubility , (iii) an additional source of iron beside crustal dust Schroth et al, 2009); (iv) active biological acquisition and uptake mechanisms such as siderophores and grazing that can circumvent abiotic dissolution limitations (Barbeau and Moffett, 2000;Yoshida et al, 2002;Frew et al, 2006).…”

Section: Atmospheric Deposition -Dustmentioning

confidence: 99%

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Iron biogeochemistry across marine systems – progress from the past decade

et al. 2010

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Abstract. Based on an international workshop (Gothenburg, 14-16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas.Correspondence to: E. Breitbarth (ebreitbarth@chemistry.otago.ac.nz)

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Section: Linking Biological Processes To Iron Chemistrycontrasting

confidence: 56%

Section: Colloidal Iron and Organic Mattermentioning

confidence: 94%

Section: Atmospheric Deposition -Dustmentioning

confidence: 99%

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Iron biogeochemistry across marine systems – progress from the past decade

et al. 2010

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“…Three carboys with no added Fe were sealed immediately as controls, and three were amended with 2 nmol L Ϫ1 Fe from a stock solution of FeCl 3 in 0.01 N Ultrex HCl and sealed. Fe additions were about a tenfold increase over ambient dissolved Fe concentrations, which ranged from ϳ0.1 nmol L Ϫ1 (Costa Rica, Humboldt) to 0.3 nmol L Ϫ1 (Peru) (Franck et al 2003). Since bottle enrichments typically show a 1-3-d lag period before a response to trace-metal addition is observed, one carboy was used for initial (immediate) measurements of size-fractionated uptake rates and the three control and three ϩFe carboys were incubated on deck until measurable differences in Si(OH) 4 concentrations were observed between ϩFe and control carboys (ϳ0.3 mol L Ϫ1 ).…”

Section: Methodsmentioning

confidence: 99%

Comparison of size‐dependent carbon, nitrate, and silicic acid uptake rates in high‐ and low‐iron waters

Franck

Smith

Bruland

et al. 2005

Limnology & Oceanography

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We compare the relative contribution of large phytoplankton (Ͼ5 and Ͼ10 m) to uptake rates of carbon (C), nitrate (NO ), and dissolved silicon (Si) and uptake ratios of Si : NO and Si : C in Monterey Bay, California (ahigh-iron region) with three low-iron regions in the eastern tropical Pacific: the Costa Rica upwelling dome, Humboldt current, and Peru upwelling. We also demonstrate the effect of iron enrichment on the above parameters in the latter three regions. In Monterey Bay waters, the Ͼ5-m size fraction accounted on average for the majority of particulate organic C and was responsible for 92% of total C uptake, 81% of total NO uptake, and 98% of totalSi uptake. In contrast, in low-iron eastern tropical Pacific waters, the Ͼ5-m size fraction accounted for less than half of the particulate organic C and was responsible for a substantially smaller proportion of total C and NO in much higher NO , C, and Si uptake rates, although increases were restricted to cells in the Ͼ5-m size fraction.Si : NO and Si : C uptake ratios decreased after iron addition at most locations, and decreases were a direct result Ϫ 3 of lower Si : NO and Si : C uptake ratios in the Ͼ5-m size fraction. Our results suggest that iron availability is a Ϫ 3 major factor regulating primary production, new production, Si uptake, and Si : NO and Si : C uptake ratios in thelarger phytoplankton size classes in high-nitrate, low-chlorophyll (HNLC) regions in the eastern tropical Pacific.Plankton community structure can determine biomass, new production, and carbon (C) export in marine systems. In highly productive upwelling ecosystems, the abundance of large (Ͼ5 m) phytoplankton often leads to high values of primary production, new (or nitrate based) production, and carbon export (Michaels

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“…Indeed, Fe is a cofactor in the enzymes nitrate and nitrite reductase (Raven 1976), which are essential for nitrate uptake in phytoplankton. Franck et al (2003) demonstrated that a 10 nmol L Ϫ1 Fe addition significantly increased nitrate maximum potential uptake rate (Vmax) in the California upwelling region (by 2.1 to 2.7 times). The same authors also reported that addition of Fe and Zn decreased Ks nitrate by 63%.…”

mentioning

confidence: 99%