Marine phytoplankton and the changing ocean iron cycle

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1 In the format provided by the authors and unedited. Marine phytoplankton and the changing ocean iron cycle D. A. Hutchins 1 * and P. W. Boyd 2 SUPPLEMENTARY INFORMATION DOI: 1.138/NCLIMATE3147 NATURE CLIMATE CHANGE Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

2 Marine phytoplankton and the changing ocean iron cycle Supplementary Information I. Supplementary Figures A) Global)Fe)cycle) B) Global)Ocean)Change)) Physiology) Reduced)Fe)uptake) Floris<cs) Altered)Fe)quotas) Fate)of)bio<c)Fe) Physiology) Luxury)Fe)uptake) "))Fe)demand))+) 4))CO 2) ))75) ) )))))))))Today)))Temp)))))+3C).2)).1)))))).1))).2)).3))).4)).5)) "))))Fe)supply)))))))+) "))Fe)demand))+) PAR))higher) )))))))))Today))))Temp))))+3C) S"Figure)1.)Sequence)of)changes)to)the)iron)uptake)of)resident)phytoplankton)in)a)future)ocean)in)response)to:)cumula<ve)effects)of))modifying)the)iron)cycle;)Feedbacks)to)iron)) supply)are)in)red.)b))upper)plot,)influence)of)warming)(black)symbols),)acidifica<on)(blue)symbols),)and)both)(red)symbol))on)colonial)n)fixers;)lower)plot)impact)of)warming)(black)) symbols),)shallower)mixed)layer)depth)(green)symbols),)and)both)(red)symbols))on)polar)diatoms.)panel)a)is)semi"quan<ta<ve)and)based)on)studies)from)(wells,)1999;)) Hutchins)et)al.,)22;)Boyd)et)al.)27;)Wilhelm)et)al.,)213),)whereas)B)is)largely)conceptual)and)based)on)preliminary)data)in)S"Table)1)and)S"Figure)2.)

3 Crocosphaera:+N A. N 2 fixation 2 +fixaon+rates+as+a+funcon+of+ B. Cellular Fe quota 5 pco 2+ and + Fe # N 2 fixation (nmol cell -1 hour -1 ) N 2 fixation (nmol cell -1 hour -1 ) 3e-8 2e-8 1e-8 3e-8 2e-8 1e-8 Fe-replete Fe-limited pco2 (ppm) Fe:P ratio (mmol:mol) Fe:P ratio (mmol:mol) Fe replete Fe limited 19 ppm 38 ppm 75 ppm pco2 S%Figure#2.#A)#N 2 &fixa)on&rates&and&b)&cellular&fe&quotas&(as&fe:p&ra)os,&mmol:mol)&as&a&func)on&of&growth&co 2 && concentra)ons&in&feareplete&(top&panels)&and&fealimited&(bodom&panels)&cultures&of&the&unicellular&n 2 &fixing&& cyanobacterium&crocosphaera.&n 2 &fixa)on&rates&and&fe&quotas&are&linearly&related&to&co 2 &levels&in&feareplete&cultures,&& but&both&rates&and&quotas&are&low&and&independent&of&co 2 &in&fealimited&cultures.&&values&are&means&and&error&bars& are&standard&devia)ons&of&triplicate&cultures&(from&fu&et&al.&28).& &

4 Fe:P ratio (mmol:mol) ppm 75 ppm pco2 S"Figure)3.))Cellular'Fe'quotas'(as'Fe:P'raos,'mmol:mol)'increase'~4%'when'cultures'of'the'N Trichodesmium'are'grown'using'trace'metal'clean'methodology'at'projected'year'21'CO 2 'levels'(75'ppm),'relave'to'' cells'grown'at'near@present'day'co 2 'concentraons'(37'ppm).''cellular'fe'and'p'was'measured'using'inducvely'coupled'' Plasma'Mass'Spectrometry'(ICP@MS),'as'described'in'Fu'et'al.'(28).'Values'are'means'and'error'bars'are'standard'deviaons'' of'triplicate'cultures'(hutchins'unpublished'data).'

5 II. Supplementary Table Study Organism Status Change Assumption IUE increase Sunda and Thalassiosira Fe- limited 1 o C 15.4 to 18.8 Huntsman pseudonana (85 PFD) warming 211 (22%) Clarke 1983, Southern Ocean review Strzepek et al. 212 Polar organisms Thalassiosira weissflogii Fe- limited, Irradiance = 7 μe 4 o C warming Irradiance increase to 11 μe Temperate Q1 equates to Q4 for polar waters Net estimated increase in IUE 3% Warming estimate: 22% increase Mixed layer shoaling estimate: 8% increase S- Table 1. Details of the calculation of an estimated future Iron Use Efficiency (IUE, kmols C fixed/mol cellular Fe/day) increase with 4 o C warming and 57% increase in irradiance (due to mixed layer shoaling) for polar diatoms, based on extrapolation of a lab culture study on temperate diatoms (Sunda and Huntsman 211) and one on polar and temperate diatoms (Strzepek et al., 212). The following assumptions were made: 1) Temperate diatoms will respond to light and warming in the same way as Southern Ocean diatoms; 2) T. pseudonana can be compared to T. weissflogii; 3) Q1 in temperate diatoms is equivalent to Q4 in polar species (Clarke 1983), 4) Effects of warming and irradiance on IUE are additive.

6 III. Supplementary Notes References for Supplementary Figures and Table Wells M.L., Manipulating iron availability in nearshore waters. Limnol Oceanogr., 44, , (1999) Hutchins, D.A., C.E. Hare, R.S. Weaver, Y. Zhang, G.F. Firme, et al., Phytoplankton iron limitation in the Humboldt Current and Peru Upwelling. Limnol. Oceanogr., 47, , (22). Boyd, P. W., Jickells, T., Law, C. S., Blain, S., Boyle, E. A., et al., Mesoscale iron enrichment experiments : Synthesis and future directions. Science, 315, doi: /science , (27). Wilhelm, S. W., King, A. L., Twining, B. S., LeCleir, G. R., DeBruyn, et al. Elemental quotas and physiology of a southwestern Pacific Ocean plankton community as a function of iron availability. Aq. Micr. Ecol., 68, , doi: /ame1611. (213). Fu, F.- X., Mulholland, M.R., Garcia, N., Beck, A., Bernhardt, P.W. et al., Interactions between changing pco 2, N 2 fixation, and Fe limitation in the marine unicellular cyanobacterium Crocosphaera. Limnol. Oceanogr. 53, , (28). Sunda, W.G. and Huntsman, S.A. Interactive effects of light and temperature on iron limitation in a marine diatom: Implications for marine productivity and carbon cycling. Limnol. Oceanogr., 56, , (211). Clarke, A. Life in cold water: the physiological ecology of polar marine ectotherms. Oceanogr. Mar Biol. Annu. Rev., 21, , (1983). Strzepek R., Maldonado M., Hunter K., Frew R., Boyd P.W., Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: uptake of organically complexed iron and reduced cellular iron requirements. Limnol Oceanogr., 56, doi: /lo , (212).

Iron, silicate, and light co-limitation of three Southern Ocean diatom species

DOI 1.17/s3-8-448-6 ORIGINAL PAPER Iron, silicate, and light co-limitation of three Southern Ocean diatom species L. J. Hoffmann Æ I. Peeken Æ K. Lochte Received: 21 August 27 / Revised: 19 March 28 /