Distinct iron cycling in a Southern Ocean eddy.
Journal
Nature communications
ISSN: 2041-1723
Titre abrégé: Nat Commun
Pays: England
ID NLM: 101528555
Informations de publication
Date de publication:
11 02 2020
11 02 2020
Historique:
received:
16
08
2019
accepted:
07
01
2020
entrez:
13
2
2020
pubmed:
13
2
2020
medline:
24
4
2020
Statut:
epublish
Résumé
Mesoscale eddies are ubiquitous in the iron-limited Southern Ocean, controlling ocean-atmosphere exchange processes, however their influence on phytoplankton productivity remains unknown. Here we probed the biogeochemical cycling of iron (Fe) in a cold-core eddy. In-eddy surface dissolved Fe (dFe) concentrations and phytoplankton productivity were exceedingly low relative to external waters. In-eddy phytoplankton Fe-to-carbon uptake ratios were elevated 2-6 fold, indicating upregulated intracellular Fe acquisition resulting in a dFe residence time of ~1 day. Heavy dFe isotope values were measured for in-eddy surface waters highlighting extensive trafficking of dFe by cells. Below the euphotic zone, dFe isotope values were lighter and coincident with peaks in recycled nutrients and cell abundance, indicating enhanced microbially-mediated Fe recycling. Our measurements show that the isolated nature of Southern Ocean eddies can produce distinctly different Fe biogeochemistry compared to surrounding waters with cells upregulating iron uptake and using recycling processes to sustain themselves.
Identifiants
pubmed: 32047154
doi: 10.1038/s41467-020-14464-0
pii: 10.1038/s41467-020-14464-0
pmc: PMC7012851
doi:
Substances chimiques
Trace Elements
0
Chlorophyll
1406-65-1
Carbon
7440-44-0
Iron
E1UOL152H7
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
825Références
Frenger, I., Münnich, M., Gruber, N. & Knutti, R. Southern Ocean eddy phenomenology. J. Geophys. Res. Oceans 120, 7413–7449 (2015).
doi: 10.1002/2015JC011047
Chelton, D. B., Schlax, M. G. & Samelson, R. M. Global observations of nonlinear mesoscale eddies. Prog. Oceanogr. 91, 167–216 (2011).
doi: 10.1016/j.pocean.2011.01.002
Patel, R. S., Phillips, H. E., Strutton, P. G., Lenton, A. & Llort, J. Meridional heat and salt transport across the subantarctic front by cold-core eddies. J. Geophys. Res. Oceans 124, 981–1004 (2019).
doi: 10.1029/2018JC014655
Moreau, S. et al. Eddy-induced carbon transport across the Antarctic circumpolar current. Global Biogeochem. Cycles 31, 2017GB005669 (2017).
doi: 10.1002/2017GB005669
Sheen, K. L. et al. Eddy-induced variability in Southern Ocean abyssal mixing on climatic timescales. Nat. Geosci. 7, 577–582 (2014).
doi: 10.1038/ngeo2200
Pollard, R., Tréguer, P. & Read, J. Quantifying nutrient supply to the Southern Ocean. J. Geophys. Res. Oceans 111, C05011 (2006).
Cotroneo, Y., Budillon, G., Fusco, G. & Spezie, G. Cold core eddies and fronts of the Antarctic circumpolar current south of New Zealand from in situ and satellite data. J. Geophys. Res. Oceans 118, 2653–2666 (2013).
doi: 10.1002/jgrc.20193
Swart, N. C., Ansorge, I. J. & Lutjeharms, J. R. E. Detailed characterization of a cold Antarctic eddy. J. Geophys. Res. Oceans 113, C01009 (2008).
Frenger, I., Münnich, M. & Gruber, N. Imprint of Southern Ocean mesoscale eddies on chlorophyll. Biogeosciences 15, 4781–4798 (2018).
doi: 10.5194/bg-15-4781-2018
Kahru, M., Mitchell, B. G., Gille, S. T., Hewes, C. D. & Holm-Hansen, O. Eddies enhance biological production in the Weddell-Scotia Confluence of the Southern Ocean. Geophys. Res. Lett. 34, L14603 (2007).
doi: 10.1029/2007GL030430
Dawson, H. R. S., Strutton, P. G. & Gaube, P. The unusual surface chlorophyll signatures of Southern Ocean eddies. J. Geophys. Res. Oceans 123, 6053–6069 (2018).
doi: 10.1029/2017JC013628
Lehahn, Y., d'Ovidio, F., Lévy, M., Amitai, Y. & Heifetz, E. Long range transport of a quasi isolated chlorophyll patch by an Agulhas ring. Geophys. Res. Lett. 38, L16610 (2011).
Ansorge, I. J., Pakhomov, E. A., Kaehler, S., Lutjeharms, J. R. E. & Durgadoo, J. V. Physical and biological coupling in eddies in the lee of the South-West Indian Ridge. Polar Biol. 33, 747–759 (2010).
doi: 10.1007/s00300-009-0752-9
Boyd, P. W. & Ellwood, M. J. The biogeochemical cycle of iron in the ocean. Nat. Geosci. 3, 675–682 (2010).
doi: 10.1038/ngeo964
Coale, K. H., Gordon, R. M. & Wang, X. The distribution and behavior of dissolved and particulate iron and zinc in the Ross Sea and Antarctic circumpolar current along 170 W. Deep Sea Res. Part I 52, 295–318 (2005).
doi: 10.1016/j.dsr.2004.09.008
Tagliabue, A. et al. Surface-water iron supplies in the Southern Ocean sustained by deep winter mixing. Nat. Geosci. 7, 314–320 (2014).
doi: 10.1038/ngeo2101
Flierl, G. R. Particle motions in large-amplitude wave fields. Geophys. Astrophys. Fluid Dyn. 18, 39–74 (1981).
doi: 10.1080/03091928108208773
Boyd, P. et al. Control of phytoplankton growth by iron supply and irradiance in the subantarctic Southern Ocean: experimental results from the SAZ Project. J. Geophys. Res. 106, 573–531 (2001).
doi: 10.1029/2000JC000348
Jickells, T. D. et al. Global iron connections between desert dust, ocean biogeochemistry, and climate. Science 308, 67–71 (2005).
pubmed: 15802595
doi: 10.1126/science.1105959
Harrison, G. I. & Morel, F. M. M. Response of the Marine diatom Thalassiosira-Weissflogii to iron stress. Limnol. Oceanogr. 31, 989–997 (1986).
doi: 10.4319/lo.1986.31.5.0989
Law, C. S., Abraham, E. R., Watson, A. J. & Liddicoat, M. I. Vertical eddy diffusion and nutrient supply to the surface mixed layer of the Antarctic circumpolar current. J. Geophys. Res. Oceans 108, 3272 (2003).
doi: 10.1029/2002JC001604
Waterhouse, A. F. et al. Global patterns of diapycnal mixing from measurements of the turbulent dissipation rate. J. Phys. Oceanogr. 44, 1854–1872 (2014).
doi: 10.1175/JPO-D-13-0104.1
Johnson, C. M., Beard, B. L. & Roden, E. E. The iron isotope fingerprints of redox and biogeochemical cycling in modern and ancient Earth. Annu. Rev. Earth Planet. Sci. 36, 457–493 (2008).
doi: 10.1146/annurev.earth.36.031207.124139
Zakem, E. J. et al. Ecological control of nitrite in the upper ocean. Nat. Commun. 9, 1206 (2018).
pubmed: 29572474
pmcid: 5865239
doi: 10.1038/s41467-018-03553-w
Song, H. et al. Seasonal variation in the correlation between anomalies of sea level and chlorophyll in the Antarctic circumpolar current. Geophys. Res. Lett. 45, 5011–5019 (2018).
doi: 10.1029/2017GL076246
Hausmann, U., McGillicuddy, D. J. & Marshall, J. Observed mesoscale eddy signatures in Southern Ocean surface mixed-layer depth. J. Geophys. Res. Oceans 122, 617–635 (2017).
doi: 10.1002/2016JC012225
Llort, J., Lévy, M., Sallée, J. B. & Tagliabue, A. Nonmonotonic response of primary production and export to changes in mixed-layer depth in the Southern Ocean. Geophys. Res. Lett. 46, 3368–3377 (2019).
doi: 10.1029/2018GL081788
Armstrong, F. A. J., Stearns, C. R. & Strickland, J. D. H. The measurement of upwelling and subsequent biological process by means of the technicon autoanalyzer and associated equipment. Deep Sea Res. Oceanogr. Abstr. 14, 381–389 (1967).
doi: 10.1016/0011-7471(67)90082-4
Wood, E. D., Armstrong, F. A. J. & Richards, F. A. Determination of nitrate in sea water by cadmium-copper reduction to nitrite. J. Mar. Biol. Assoc. UK 47, 23–31 (1967).
doi: 10.1017/S002531540003352X
Boyd, P. & Harrison, P. J. Phytoplankton dynamics in the NE subarctic Pacific. Deep Sea Res. II 46, 2405–2432 (1999).
doi: 10.1016/S0967-0645(99)00069-7
Hudson, R. J. M. & Morel, F. M. M. Distinguishing between extracellular and intracellular iron in marine-phytoplankton. Limnol. Oceanogr. 34, 1113–1120 (1989).
doi: 10.4319/lo.1989.34.6.1113
Tang, D. & Morel, F. M. M. Distinguishing between cellular and Fe-oxide-associated trace elements in phytoplankton. Mar. Chem. 98, 18–30 (2006).
doi: 10.1016/j.marchem.2005.06.003
Hassler, C. S. & Schoemann, V. Discriminating between intra- and extracellular metals using chemical extractions: an update on the case of iron. Limnol. Oceanogr. Methods 7, 479–489 (2009).
doi: 10.4319/lom.2009.7.479
Marie, D., Shi, X. L., Rigaut-Jalabert, F. & Vaulot, D. Use of flow cytometric sorting to better assess the diversity of small photosynthetic eukaryotes in the English channel. FEMS Microbiol. Ecol. 72, 165–178 (2010).
pubmed: 20236325
doi: 10.1111/j.1574-6941.2010.00842.x
Eggimann, D. W. & Betzer, P. R. Decomposition and analysis of refractory oceanic suspended materials. Anal. Chem. 48, 886–890 (1976).
doi: 10.1021/ac60370a005
Ellwood, M. J. et al. Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom. Proc. Natl Acad. Sci. USA 112, E15–E20 (2015).
pubmed: 25535372
doi: 10.1073/pnas.1421576112
Ellwood, M. J. et al. Pelagic iron cycling during the subtropical spring bloom, east of New Zealand. Mar. Chem. 160, 18–33 (2014).
doi: 10.1016/j.marchem.2014.01.004
Conway, T. M., Rosenberg, A. D., Adkins, J. F. & John, S. G. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry. Anal. Chim. Acta 793, 44–52 (2013).
pubmed: 23953205
doi: 10.1016/j.aca.2013.07.025
Lacan, F. et al. High-precision determination of the isotopic composition of dissolved iron in iron depleted seawater by double spike multicollector-ICPMS. Anal. Chem. 82, 7103–7111 (2010).
pubmed: 20701301
doi: 10.1021/ac1002504
pmcid: 20701301
Poitrasson, F. & Freydier, R. Heavy iron isotope composition of granites determined by high resolution MC-ICP-MS. Chem. Geol. 222, 132–147 (2005).
doi: 10.1016/j.chemgeo.2005.07.005
John, S. G. & Adkins, J. F. Analysis of dissolved iron isotopes in seawater. Mar. Chem. 119, 65–76 (2010).
doi: 10.1016/j.marchem.2010.01.001
Dideriksen, K., Baker, J. A. & Stipp, S. L. S. Iron isotopes in natural carbonate minerals determined by MC-ICP-MS with a 58Fe-54Fe double spike. Geochim. Cosmochim. Acta 70, 118–132 (2006).
doi: 10.1016/j.gca.2005.08.019
Conway, T. M. et al. The competing influence of local cycling, regional sources and Southern Ocean processes in influencing Fe isotope cycling at lower latitudes in the oceans, Ocean Sciences, Portland, Oregon. CT31A-03 (2018).
Samanta, M., Ellwood, M. J. & Mortimer, G. E. A method for determining the isotopic composition of dissolved zinc in seawater by MC-ICP-MS with a 67Zn–68Zn double spike. Microchem. J 126, 530–537 (2016).
doi: 10.1016/j.microc.2016.01.014
Johnson, K. S., Gordon, R. M. & Coale, K. H. What controls dissolved iron concentrations in the world ocean? Mar. Chem. 57, 137–161 (1997).
doi: 10.1016/S0304-4203(97)00043-1
Ellwood, M. J., Strzepek, R., Chen, X., Trull, T. W. & Boyd, P. W. Some observations on the biogeochemical cycling of zinc in the Australian sector of the Southern Ocean: a dedication to Keith Hunter. Mar. Freshw. Res. https://doi.org/10.1071/MF19200 (2020).
John, S. G. Optimizing sample and spike concentrations for isotopic analysis by double-spike ICPMS. J. Anal. At. Spectrom. 27, 2123–2131 (2012).
doi: 10.1039/c2ja30215b
Sieber, M., Conway, T., De Souza, G., Ellwood, M. & Vance, D. Iron cycling in the Upper Southern Ocean—insights from Fe isotopes. Goldschmidt, 3106, (2019).
Schlosser, C. et al. Seasonal ITCZ migration dynamically controls the location of the (sub)tropical Atlantic biogeochemical divide. Proc. Natl Acad. Sci. USA 111, 1438–1442 (2014).
pubmed: 24367112
doi: 10.1073/pnas.1318670111
Speer, K., Rintoul, S. R. & Sloyan, B. The diabatic Deacon cell. J. Phys. Oceanogr. 30, 3212–3222 (2000).
doi: 10.1175/1520-0485(2000)030<3212:TDDC>2.0.CO;2
Trull, T. W., Bray, S. G., Manganini, S. J., Honjo, S. & Francois, R. Moored sediment trap measurements of carbon export in the Subantarctic and Polar Frontal Zones of the Southern Ocean, south of Australia. J. Geophys. Res. Oceans 106, 31489–31510 (2001).
doi: 10.1029/2000JC000308
Trull, T., Rintoul, S. R., Hadfield, M. & Abraham, E. R. Circulation and seasonal evolution of polar waters south of Australia: implications for iron fertilization of the Southern Ocean. Deep Sea Res. II 48, 2439–2466 (2001).
doi: 10.1016/S0967-0645(01)00003-0
Bowie, A. R. et al. The fate of added iron during a mesoscale fertilisation experiment in the Southern Ocean. Deep Sea Res. II 48, 2703–2743 (2001).
doi: 10.1016/S0967-0645(01)00015-7
McKay, R. M. L. et al. Impact of phytoplankton on the biogeochemical cycling of iron in subantarctic waters southeast of New Zealand during FeCycle. Glob. Biogeochem. Cycles 19, (2005).
doi: 10.1029/2005GB002482
Twining, B. S., Baines, S. B., Fisher, N. S. & Landry, M. R. Cellular iron contents of plankton during the Southern Ocean iron Experiment (SOFeX). Deep Sea Res. Part I 51, 1827–1850 (2004).
doi: 10.1016/j.dsr.2004.08.007
Bowie, A. R. et al. Biogeochemical iron budgets of the Southern Ocean south of Australia: decoupling of iron and nutrient cycles in the subantarctic zone by the summertime supply. Glob. Biogeochem. Cycles 23 (2009).
doi: 10.1029/2009GB003500