Abstract
Nine iron fertilization experiments have been carried out in the Southern Ocean (SO) so far comprising of seven artificial fertilization and two naturally enriched events. The first artificial iron addition, SOIREE, was conducted south of the polar front in February 1999 followed by six more experiments (EisenEx, SOFeX-N, SOFeX-S, EIFEX, SOLAS-SAGE, and LOHAFEX) took place in different sectors of the SO involving multinational and trans-disciplinary efforts. Besides, two naturally fertilized studies (KEOPS and CROZEX) were carried out in the downstream of the SO islands. This article summarizes the significant findings of all the iron-enrichment experiments carried out in the SO and explains the phytoplankton bloom dynamics as observed by satellite data and recapitulates the possible sources of iron entrainment to the water column. Findings from the earlier artificial ocean fertilization experiments revealed strong influence of iron on phytoplankton biomass, community composition, and export production in the SO. Satellite-derived chlorophyll-a concentrations (2002–2016) are utilized to characterize the monthly evolution of phytoplankton blooms in the SO. Results suggest that the areal extent of the bloom varied from 1.1 to 18.1 million km2 during July (austral winter) and January (austral summer), respectively. The blooms are pronounced in a conducive environment with the optimal light condition, sedimentary source of iron from shallow bathymetric region (< 1 km), continental dust advection, and supply of iron from the marginal ice zone through sea-ice melting. In toto, the SO contributes up to 60% of global ocean phytoplankton blooms during December and January (austral summer), and the dominant region of bloom occurrence is located in the Atlantic sector of the SO, which could be ascribed to iron-rich dust input from Patagonia and regional physical processes.
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs41976-019-00012-y/MediaObjects/41976_2019_12_Fig1_HTML.png)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs41976-019-00012-y/MediaObjects/41976_2019_12_Fig2_HTML.png)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs41976-019-00012-y/MediaObjects/41976_2019_12_Fig3_HTML.png)
Similar content being viewed by others
References
Abbott MR, Richman JG, Letelier RM, Bartlett JS (2000) The spring bloom in the Antarctic polar frontal zone as observed from a mesoscale array of bio-optical sensors. Deep-Sea Res II 47:3285–3314
Arrigo KR, Worthen DL, Schnell A, Lizotte MP (1998) Primary production in southern ocean waters. J Geophys Res 103:15587–15600
Arrigo KR, van Dijken GL, Bushinsky S (2008) Primary production in the southern ocean, 1997-2006. J Geophys Res 113:C08004. https://doi.org/10.1029/2007JC004551
Assmy P, Henjes J, Klaas C, Smetacek V (2007) Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. Deep-Sea Res I 54:340–362
Assmy P et al (2013) Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic circumpolar current. Proc Natl Acad Sci U S A 110:20633–20638
Bakker DCE, Nielsdottir MC, Morris PJ, Venables HJ, Watson AJ (2007) The island mass effect and biological carbon uptake for the subantarctic Crozet archipelago. Deep-Sea Res II 54:2174–2190
Bange HW (2006) New directions: the importance of oceanic nitrous oxide emissions. Atmos Environ 40:198–199
Banse K (1996) Low seasonality of low concentrations of surface chlorophyll in the sub Antarctic water ring: underwater irradiance, iron, or grazing? Prog Oceanogr 37:241–291
Blain S et al (2007) Effect of natural iron fertilization on carbon sequestration in the Southern Ocean. Nature 446:1070–1074
Boyd PW (2013) Diatom traits regulate Southern Ocean silica leakage. Proc Natl Acad Sci U S A 110(51):20358–20359
Boyd PW, Law CS (2001) The Southern Ocean Iron Release Experiment (SOIREE) introduction and summary. Deep-Sea Res II 48:2425–2438
Boyd PW et al (2000) A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization. Nature 407:695–702
Boyd PW et al (2004) The decline and fate of an iron-induced subarctic phytoplankton bloom. Nature 428:549–553
Boyd PW et al (2007) Mesoscale iron enrichment experiments 1993-2005: synthesis and future directions. Science 315:612–617
Brzezinski MA, Jones JL, Demarest MA (2005) Control of silica production by iron and silicic acid during the Southern Ocean Iron Experiment (SOFeX). Limnol Oceanogr 50:810–824
Buesseler KO, Boyd PW (2003) Will ocean fertilization work? Science 300:67–68
Buesseler KO, Andrews JE, Pike SM, Charette MA (2004) The effects of iron fertilization on carbon sequestration in the Southern Ocean. Science 304:414–417
Cassar N et al (2007) The Southern Ocean biological response to aeolian iron deposition. Science 317:1067–1070
Cassar N et al (2008) Response to comment on “The Southern Ocean Biological Response to Aeolian Iron Deposition”. Science 319:159b. https://doi.org/10.1126/science.1150011
Chisholm SW, Falkowski PG, Cullen JJ (2001) Discrediting ocean fertilization. Science 294:309–310
Coale KH, Fitzwater SE, Gordon RM, Johnson KS, Barber RT (1996) Control of community growth and export production by up welled iron in the equatorial Pacific Ocean. Nature 379:621–624
Coale KH et al (2004) Southern Ocean iron enrichment experiment: carbon cycling in high- and low-Si waters. Science 304:408–414
Croot PL et al (2001) Retention of dissolved iron and FeII in an iron induced Southern Ocean phytoplankton bloom. Geophys Res Lett 28:3425–3428
Croot PL et al (2005) Spatial and temporal distribution of Fe(II) and H2O2 during EisenEx, an open ocean mesoscale iron enrichment. Mar Chem 95:65–88
de Baar HJW, Boyd PW (1999) The role of iron in plankton ecology and carbon dioxide transfer of the global oceans. In: Hanson RB, Ducklow HW, Filed JG (eds) The dynamic ocean carbon cycle. A midterm synthesis of the joint Global Ocean flux study. International geosphere biosphere book series, Cambridge University press, chapter 4, pp 61–141
de Baar HJW, de Jong JTM (2001) Distributions, sources and sinks of iron in seawater. In: Turner D, Hunter KA (eds) Biogeochemistry of iron in seawater, IUPAC book series on analytical and physical chemistry of environmental systems, vol 7, pp 123–254
de Baar HJW, de Jong JTM, Bakker DCE, Loscher BM, Veth C, Bathmann U, Smetacek V (1995) Importance of iron for plankton blooms and carbon dioxide drawdown in the Southern Ocean. Nature 373(2):412–415
de Baar HJW et al (2005) Synthesis of iron fertilization experiments: from the iron age in the age of enlightenment. J Geophys Res 110. https://doi.org/10.1029/2004JC002601
Duce RA, Tindale NW (1991) Atmospheric transport of iron and its deposition in the ocean. Limnol Oceanogr 36(8):1715–1726
Ebersbach F et al (2014) Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean. Deep-Sea Res I 89:94–103
Falkowski P (2012) The power of plankton. Nature 483:17–20
Field CB, Behrenfeld MJ, Randerson JT, Falkowski P (1998) Primary production of the biosphere: integrating terrestrial and oceanic components. Science 281(5374):237–240
Fitch DT, Moore JK (2007) Wind speed influence on phytoplankton bloom dynamics in the Southern Ocean marginal ice zone. J Geophys Res 112:C08006. https://doi.org/10.1029/2006JC004061
Gaiero DM et al (2003) Iron and other transition metals in Patagonian river borne and windborne materials: geochemical control and transport to the southern South Atlantic Ocean. Geochim Cosmochim Acta 67(19):3603–3623
Gasso S, Stein AF (2007) Does dust from Patagonia reach the sub-Antarctic Atlantic Ocean? Geophys Res Lett 34:L01801. https://doi.org/10.1029/2006GL027693
Gervais F, Riebesell U, Gorbunov MY (2002) Changes in primary productivity and chlorophyll a in response to iron fertilization in the southern polar frontal zone. Limnol Oceanogr 47(5):1324–1335
Graham RM, De Boer AM, Sebille EV, Kohfeld KE, Schlosser C (2015) Inferring source regions and supply mechanisms of iron in the Southern Ocean from satellite chlorophyll data. Deep-Sea Res I 104:9–25
Gran HH (1931) On the conditions for the production of plankton in the sea. Conseil Perm. Internat. pour I'Explor. de la Mer. Rapp. et Proces-Verb 75:37–46
Hamme RC et al (2010) Volcanic ash fuels anomalous plankton bloom in subarctic northeast Pacific. Geophys Res Lett 37:L19604. https://doi.org/10.1029/2010GL044629
Hart TJ (1942) Phytoplankton periodicity in Antarctic surface water. Discov Rep VIII:1–268
Harvey MJ et al (2011) The SOLAS air-sea gas exchange experiment (SAGE) 2004. Deep-Sea Res II 58(6):753–763
Hiscock WT, Millero FJ (2005) Nutrient and carbon parameters during the Southern Ocean Iron Experiment (SOFeX). Deep-Sea Res I 52(11):2086–2108
Jena B (2016) Satellite remote sensing of the island mass effect on the sub-Antarctic Kerguelen Plateau, Southern Ocean. Front Earth Sci 10(3):479–486
Jena B (2017) Effect of phytoplankton pigment composition and packaging on the retrieval of chlorophyll-a concentration from satellite observations in the Indian sector of Southern Ocean. Int J Rem Sen 38(13):3763–3784
Jena B, Kurian PJ, Swain D, Tyagi A, Ravindra R (2012) Prediction of bathymetry from satellite altimeter based gravity in the Arabian Sea: mapping of two unnamed deep seamounts. Int J Appl Earth Obs 16:1–4
Jickells TD, Spokes LJ (2001) Atmospheric iron inputs to the oceans. In: Turner D, Hunter KA (eds) Biogeochemistry of Iron in seawater, IUPAC book series on analytical and physical chemistry of environmental systems, vol 7. pp 85–122
Klinkhammer GP, Chin CS, Keller RA, Dahlman A, Sahling H, Sarthou G, Petersen S, Smith F, Wilson C (2001) Discovery of new hydrothermal vent sites in Bransfield Strait, Antarctica. Earth Planet Sc Lett 193(3–4):395–407
Klunder MB, Laan P, Middag R, De Baar HJW, van Ooijen JC (2011) Dissolved iron in the Southern Ocean (Atlantic sector). Deep-Sea Res II 58:2678–2694
Korb RE, Whitehouse M (2004) Contrasting primary production regimes around South Georgia, Southern Ocean: large blooms versus high nutrient, low chlorophyll waters. Deep-Sea Res I 51:721–738
Laglera LM et al (2017) Iron partitioning during LOHAFEX: copepod grazing as a major driver for iron recycling in the Southern Ocean. Mar Chem 196:148–161
Lampitt RS et al (2008) Ocean fertilization: a potential means of geoengineering? Phil Trans R Soc A 366:3919–3945
Lancelot C, Hannon E, Becquevort S, Veth C, De Baar HJW (2000) Modeling phytoplankton blooms and carbon export production in the Southern Ocean: dominant controls by light and iron in the Atlantic sector in austral spring 1992. Deep-Sea Res I 47:1621–1662
Lannuzel D, Schoemann V, De Jong JTM, Chou L, Delille B, Becquevort S, Tison JL (2008) Iron study during a time series in the western Weddell pack ice. Mar Chem 108(1–2):85–95
Latimer JC, Filipelli GM (2001) Terrigenous input and paleoproductivity in the Southern Ocean. Paleoceanogr 16:627–643
Law CS (2008) Predicting and monitoring the effects of large-scale ocean iron fertilization on marine trace gas emissions. Mar Ecol Prog Ser 364:283–288
Law CS, Ling RD (2001) Nitrous oxide flux and response to increased iron availability in the Antarctic circumpolar current. Deep-Sea Res II 48:2509–2527
Law CS et al (2011) Did dilution limit the phytoplankton response to iron addition in HNLCLSi sub-Antarctic waters during SAGE? Deep-Sea Res II 58(6):786–799
Lawrence MG (2002) Side effects of oceanic Iron fertilization. Science 297:1993
Laws EA, Falkowski P, Smith WO Jr, Ducklow H, McCarthy JJ (2000) Temperature effects on export production in the open ocean. Glob Biogeochem Cycles 14(4):213–1246
Llort J, Levy M, Sallee JB, Tagliabue A (2015) Onset, intensification, and decline of phytoplankton blooms in the Southern Ocean. ICES J Mar Sci. https://doi.org/10.1093/icesjms/fsv053
Loscher BM, De Baar HJW, De Jong JTM, Veth C, Dehairs F (1997) The distribution of Fe in the Antarctic circumpolar current. Deep-Sea Res II 44(1–2):143–187
Lucas M, Seeyave S, Sanders R, Moore MC, Williamson R, Stinchcombe M (2007) Nitrogen uptake responses to a naturally Fe-fertilised phytoplankton bloom during the 2004/2005 CROZEX study. Deep-Sea Res II 54:2138–2173
Martin JH (1992) Iron as a limiting factor in oceanic productivity. In: Falkowski PG, Woodhead AD (eds) Primary productivity and biogeochemical cycles in the sea. Springer, New York, pp 123–137
Martin P et al. (2013) Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX. Glob Biogeochem Cycles 27. https://doi.org/10.1002/gbc.20077
Mazzocchi MG et al. (2009) A non-diatom plankton bloom controlled by copepod grazing and amphipod predation: preliminary results from the LOHAFEX iron-fertilisation experiment. Glob Int Newslett 1–4
Millero FJ, Sotolongo S (1989) The oxidation of Fe(II) with H2O2 in seawater. Geochim Cosmochim Acta 53:1867–1873
Mitchell BG, Brody EA, Holm-Hansen O, McClain C, Bishop J (1991) Light limitation of phytoplankton biomass and macronutrient utilization in the Southern Ocean. Limnol Oceanogr 36:1662–1677
Mongin M, Molinaa E, Trull TW (2008) Seasonality and scale of the Kerguelen Plateau phytoplankton bloom: a remote sensing and modeling analysis of the influence of natural iron fertilization in the Southern Ocean. Deep-Sea Res II 55:880–892
Moore JK, Abbott MR (2000) Phytoplankton chlorophyll distributions and primary production in the Southern Ocean. J Geophys Res 105(C12):28709–28722
Moore JK, Doney SC (2006) Remote sensing observations of ocean physical and biological properties in the region of the Southern Ocean Iron Experiment (SOFeX). J Geophys Res 111:C06026. https://doi.org/10.1029/2005JC003289
Moore JK, Abbott MR, Richman JG, Smith WO, Cowles TJ, Coale KH, Gardner WD, Barber RT (1999) SeaWiFS satellite ocean color data from the Southern Ocean. Geophys Res Lett 26:1465–1468
Mosseri J, Queguiner B, Armand LK, Cornet-Barthaux V (2008) Impact of iron on silicon utilization by diatoms in the Southern Ocean: a case study of Si/N cycle decoupling in a naturally iron-enriched area. Deep-Sea Res II 55:801–819
Orsi AH, Whitworth T III, Nowlin WD Jr (1995) On the meridional extent and fronts of the Antarctic circumpolar current. Deep-Sea Res I 42:641–673
Peloquin J, Hall J, Safi K, Smith WO, Wright S, vanden Enden R (2011) The response of phytoplankton to iron enrichment in sub-Antarctic HNLCLSi waters: results from the SAGE experiment. Deep-Sea Res II 58(6):808–823
Planquette HF et al (2007) Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean. Deep-Sea Res II 54:1999–2019
Pollard RT, Sanders R, Lucas MI, Statham PJ (2007) The Crozet Natural Iron Bloom and Export Experiment (CROZEX). Deep-Sea Res II 54:1905–1914
Pollard RT et al (2009) Southern Ocean deep-water carbon export enhanced by natural iron fertilization. Nature 457:577–580
Prasanna K, Ghosh P, Anilkumar N (2015) Stable isotopic signature of Southern Ocean deep water CO2 ventilation. Deep-Sea Res II 118:178–185
Queguiner B (2013) Iron fertilization and the structure of planktonic communities in high nutrient regions of the Southern Ocean. Deep-Sea Res II 90:43–54
Ridgwell AJ, Watson A (2002) Feedback between aeolian dust, climate, and atmospheric CO2 in glacial time. Paleoceanogr 17:1059. https://doi.org/10.1029/2001PA000729
Robinson J et al (2016) A tale of three islands: downstream natural iron fertilization in the Southern Ocean. J Geophys Res Oceans 121:3350–3371
Sabine CL, Feely RA, Gruber N, Key RM, Lee K, Bullister JL, Wanninkhof R, Wong CS, Wallace DWR, Tilbrook B, Millero FJ, Peng TH, Kozyr A, Ono T, Rios AF (2004) The oceanic sink for anthropogenic CO2. Science 305:367–371
Sabu P, Anilkumar N, George JV, Chacko R, Tripathy SC, Achuthankutty CT (2014) The influence of air-sea-ice interactions on an anomalous phytoplankton bloom in the Indian Ocean sector of the Antarctic zone of the Southern Ocean during the austral summer. Polar Sci 8:370–384
Sallee JB, Llort J, Tagliabue A, Levy M (2015) Characterization of distinct bloom phenology regimes in the Southern Ocean. ICES J Mar Sci. https://doi.org/10.1093/icesjms/fsv069
Sanders R et al (2007) New production and the f-ratio around the Crozet Plateau in austral summer 2004-2005 diagnosed from seasonal changes in inorganic nutrient levels. Deep-Sea Res II 54:2191–2207
Sarmiento JL, Orr JC (1991) Three-dimensional simulations of the impact of Southern Ocean nutrient depletion on atmospheric CO2 and ocean chemistry. Limnol Oceanogr 36:1928–1950
Silver MW, Bargu S, Coale SL, Benitez-Nelson CR, Garcia AC, Roberts KJ, Sekula-Wood E, Bruland KW, Coale KH (2010) Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific. Proc Natl Acad Sci U S A 107:20762–20767
Smetacek VS (2001) EisenEx: international team conducts iron experiments in Southern Ocean. US JGOFS News 11:11–14
Smetacek V, Naqvi SWA (2008) The next generation of iron fertilisation experiments in the Southern Ocean. Philos Trans R Soc Lond 366:3947–3967
Smetacek V et al (2012) Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature 487:313–319
Sullivan CW, Arrigo KR, McClain CR, Comiso JC, Firestone J (1993) Distribution of phytoplankton blooms in the Southern Ocean. Science 262:1832–1837
Sverdrup HU (1953) On conditions for the vernal blooming of phytoplankton. J Conseil 18:287–295
Tagliabue A, Sallee JB, Bowie AR, Levy M, Swart S, Boyd P (2014) Surface-water iron supplies in the southern ocean sustained by deep winter mixing. Nat Geosci 7:314–320
Taylor MH, Losch M, Bracher A (2013) On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: a modeling approach. J Geophys Res Oceans 118:63–75
Thiele S, Fuchs BM, Ramaiah N, Amann R (2012) Microbial community response during the iron fertilization experiment LOHAFEX. Appl Environ Microbiol 78:8803–8812
Thiele S, Wolf C, Schulz IK, Assmy P, Metfies K, Fuchs BM (2014) Stable composition of the nano- and picoplankton community during the ocean iron fertilization experiment LOHAFEX. PLoS One 9(11):e113244. https://doi.org/10.1371/journal.pone.0113244
Thomalla SJ, Waldron HN, Lucas MI, Read JF, Ansorge IJ, Pakhomov E (2011) Phytoplankton distribution and nitrogen dynamics in the southwest Indian subtropical gyre and Southern Ocean waters. Ocean Sci 7(1):113–127
Tréguer P, Nelson DM, Van Bennekom AJ, DeMaster DJ, Leynaert A, Quéguiner B (1995) The silica balance in the world ocean: a reestimate. Science 268:375–379
Tripathy SC, Pavithran S, Sabu S, Naik RK, Noronha SB, Bhaskar PV, Anilkumar N (2014) Is phytoplankton productivity in the Indian Ocean sector of Southern Ocean affected by pigment packaging effect? Curr Sci 107(6):1019–1026
Tripathy SC, Pavithran S, Sabu P, Pillai HUK, Dessai DRG, Anilkumar N (2015) Deep chlorophyll maximum and primary productivity in the Indian Ocean sector of the Southern Ocean: case study in the subtropical and polar front during austral summer 2011. Deep-Sea Res II 118:240–249
Tripathy SC, Mishra RK, Naik RK (2017) Progress in Southern Ocean biology from the Indian sector: half-decadal (2009-13) overview. Proc Ind Natl Sci Acad 83(2):385–398
Tripathy SC, Patra S, Vishnu Vardhan K, Sarkar A, Mishra RK, Anilkumar N (2018) Nitrogen uptake by phytoplankton in surface waters of the Indian sector of Southern Ocean during austral summer. Front Earth Sci 12(1):52–62
Tyrell T et al. (2005) Effect of seafloor depth and phytoplankton blooms in high nitrate low chlorophyll (HNLC) regions. J Geophys Res 110. https://doi.org/10.1029/2005JG000041
Venables HJ, Moore CM (2010) Phytoplankton and light limitation in the Southern Ocean: learning from high nutrient high chlorophyll areas. J Geophys Res 115:C02015. https://doi.org/10.1029/2009JC005361
Venables HJ, Pollard RT, Popova EK (2007) Physical conditions controlling the development of a regular phytoplankton bloom north of the Crozet Plateau, Southern Ocean. Deep-Sea Res II 54:1949–1965
Walter S, Peeken I, Lochte K, Webb A, Bange HW (2005) Nitrous oxide measurements during EIFEX, the European Iron Fertilization Experiment in the subpolar South Atlantic Ocean. Geophys Res Lett 32:L23613
Watson AJ, Bakker DCE, Ridgwell AJ, Boyd PW, Law CS (2000) Effect of iron supply on Southern Ocean CO2 uptake and implications for glacial atmospheric CO2. Nature 407:730–733
Yoon JE et al (2016) Ocean Iron Fertilization Experiments: past–present–future with introduction to Korean Iron Fertilization Experiment in the Southern Ocean (KIFES) project. Biogeosci Discuss. https://doi.org/10.5194/bg-2016-472
Acknowledgments
Encouragement and support from the Director, ESSO-National Centre for Polar and Ocean Research (ESSO-NCPOR), is gratefully acknowledged. The institution like the NASA’s Goddard Space Flight Center is acknowledged for making the datasets available in public domain. The authors are thankful to the reviewers for their constructive comments that have substantially helped in improving the manuscript. This is NCPOR contribution no 74/2018.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflicts of Interest
The authors declare that they have no conflicts of interest.
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Tripathy, S.C., Jena, B. Iron-Stimulated Phytoplankton Blooms in the Southern Ocean: a Brief Review. Remote Sens Earth Syst Sci 2, 64–77 (2019). https://doi.org/10.1007/s41976-019-00012-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s41976-019-00012-y