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Biological and physical influences on marine snowfall at the equator

Nature Geoscience volume 10, pages 852–858 (2017)Cite this article

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Abstract

High primary productivity in the equatorial Atlantic and Pacific oceans is one of the key features of tropical ocean biogeochemistry and fuels a substantial flux of particulate matter towards the abyssal ocean. How biological processes and equatorial current dynamics shape the particle size distribution and flux, however, is poorly understood. Here we use high-resolution size-resolved particle imaging and Acoustic Doppler Current Profiler data to assess these influences in equatorial oceans. We find an increase in particle abundance and flux at depths of 300 to 600 m at the Atlantic and Pacific equator, a depth range to which zooplankton and nekton migrate vertically in a daily cycle. We attribute this particle maximum to faecal pellet production by these organisms. At depths of 1,000 to 4,000 m, we find that the particulate organic carbon flux is up to three times greater in the equatorial belt (1° S–1° N) than in off-equatorial regions. At 3,000 m, the flux is dominated by small particles less than 0.53 mm in diameter. The dominance of small particles seems to be caused by enhanced active and passive particle export in this region, as well as by the focusing of particles by deep eastward jets found at 2° N and 2° S. We thus suggest that zooplankton movements and ocean currents modulate the transfer of particulate carbon from the surface to the deep ocean.

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Figure 1: Primary production is enhanced at the Atlantic and Pacific equator and fuels marine equatorial snowfall.
Figure 2: Zonal current velocity and calculated POC content transects across the equatorial Atlantic at 23° W.
Figure 3: Zonal current velocity and calculated POC content transects across the equatorial Pacific at different longitudes.
Figure 4: POC flux increase coincides with diel vertical migration depth at the equatorial Atlantic and Pacific.
Figure 5: POC flux at bathypelagic depth is dominated by micrometric particles and enhanced at the equator.

References

  1. Behrenfeld, M. J. & Falkowski, P. G. Photosynthetic rates derived from satellite-based chlorophyll concentration. Limnol. Oceanogr. 42, 1–20 (1997).

    Article  Google Scholar 

  2. Burd, A. B. et al. Assessing the apparent imbalance between geochemical and biochemical indicators of meso-and bathypelagic biological activity: What the @$#! is wrong with present calculations of carbon budgets? Deep-Sea Res. II 57, 1557–1571 (2010).

    Article  Google Scholar 

  3. Giering, S. L. et al. Reconciliation of the carbon budget in the ocean’s twilight zone. Nature 507, 480–483 (2014).

    Article  Google Scholar 

  4. Lampitt, R. S. et al. Ocean fertilization: a potential means of geoengineering? Phil. Trans. R. Soc. A 366, 3919–3945 (2008).

    Article  Google Scholar 

  5. Kwon, E. Y., Primeau, F. & Sarmiento, J. L. The impact of remineralization depth on the air-sea carbon balance. Nat. Geosci. 2, 630–635 (2009).

    Article  Google Scholar 

  6. Falkowski, P. G., Barber, R. T. & Smetacek, V. Biogeochemical controls and feedbacks on ocean primary production. Science 281, 200–206 (1998).

    Article  Google Scholar 

  7. Alldredge, A. L. & Gotschalk, C. In situ settling behavior of marine snow. Limnol. Oceanogr. 33, 339–351 (1988).

    Article  Google Scholar 

  8. Steinberg, D. K. et al. Bacterial vs. zooplankton control of sinking particle flux in the ocean’s twilight zone. Limnol. Oceanogr. 53, 1327–1338 (2008).

    Article  Google Scholar 

  9. Siegel, D. A. & Deuser, W. G. Trajectories of sinking particles in the Sargasso Sea: modeling of statistical funnels above deep-ocean sediment traps. Deep-Sea Res. I 44, 1519–1541 (1997).

    Article  Google Scholar 

  10. Waite, A. M. et al. The wineglass effect shapes particle export to the deep ocean in mesoscale eddies. Geophys. Res. Lett. 43, 9791–9800 (2016).

    Article  Google Scholar 

  11. Alldredge, A. L. & Silver, M. W. Characteristics, dynamics and significance of marine snow. Prog. Oceanogr. 20, 41–82 (1988).

    Article  Google Scholar 

  12. Honjo, S., Manganini, S. J., Krishfield, R. A. & Francois, R. Particulate organic carbon fluxes to the ocean interior and factors controlling the biological pump: a synthesis of global sediment trap programs since 1983. Prog. Oceanogr. 76, 217–285 (2008).

    Article  Google Scholar 

  13. Schnetzer, A. & Steinberg, D. K. Active transport of particulate organic carbon and nitrogen by vertically migrating zooplankton in the Sargasso Sea. Mar. Ecol. Prog. Ser. 234, 71–84 (2002).

    Article  Google Scholar 

  14. Zhang, X. & Dam, H. G. Downward export of carbon by diel migrant mesozooplankton in the central equatorial Pacific. Deep-Sea Res. II 44, 2191–2202 (1997).

    Article  Google Scholar 

  15. Morales, C. E. Carbon and nitrogen fluxes in the oceans: the contribution by zooplankton migrants to active transport in the North Atlantic during the Joint Global Ocean Flux Study. J. Plankton. Res. 21, 1799–1808 (1999).

    Article  Google Scholar 

  16. Hidaka, K., Kawaguchi, K., Murakami, M. & Takahashi, M. Downward transport of organic carbon by diel migratory micronekton in the western equatorial Pacific: its quantitative and qualitative importance. Deep-Sea Res. I 48, 1923–1939 (2001).

    Article  Google Scholar 

  17. Turner, J. T. Zooplankton fecal pellets, marine snow, phytodetritus and the ocean’s biological carbon pump. Prog. Oceanogr. 130, 205–248 (2015).

    Article  Google Scholar 

  18. Beaulieu, S. E. Accumulation and fate of phytodetritus on the sea floor. Oceanogr. Mar. Biol. 40, 171–232 (2002).

    Google Scholar 

  19. Alonso-González, I. J. et al. Role of slowly settling particles in the ocean carbon cycle. Geophys. Res. Lett. 37, 2921–2927 (2010).

    Article  Google Scholar 

  20. Durkin, C. A., Estapa, M. L. & Buesseler, K. O. Observations of carbon export by small sinking particles in the upper mesopelagic. Mar. Chem. 175, 72–81 (2015).

    Article  Google Scholar 

  21. Dilling, L. & Alldredge, A. L. Fragmentation of marine snow by swimming macrozooplankton: a new process impacting carbon cycling in the sea. Deep-Sea Res. I 47, 1227–1245 (2000).

    Article  Google Scholar 

  22. Iversen, M. H. & Poulsen, L. K. Coprorhexy, coprophagy, and coprochaly in the copepods Calanus helgolandicus, Pseudocalanus elongatus and Oithona similis. Mar. Ecol. Prog. Ser. 350, 79–89 (2007).

    Article  Google Scholar 

  23. Cavan, E. L., Trimmer, M., Shelley, F. & Sanders, R. Remineralization of particulate organic carbon in an ocean oxygen minimum zone. Nat. Commun. 8, 14847 (2017).

    Article  Google Scholar 

  24. Pérez, V., Fernández, E., Marañón, E., Serret, P. & García-Soto, C. Seasonal and interannual variability of chlorophyll a and primary production in the equatorial Atlantic: in situ and remote sensing observations. J. Plankton Res. 27, 189–197 (2005).

    Article  Google Scholar 

  25. Pennington, J. T. et al. Primary production in the eastern tropical Pacific: a review. Prog. Oceanogr. 69, 285–317 (2006).

    Article  Google Scholar 

  26. Subramaniam, A., Mahaffey, C., Johns, W. & Mahowald, N. Equatorial upwelling enhances nitrogen fixation in the Atlantic Ocean. Geophys. Res. Lett. 40, 1766–1771 (2013).

    Article  Google Scholar 

  27. Moum, J. N., Perlin, A., Nash, J. D. & McPhaden, M. J. Seasonal sea surface cooling in the equatorial Pacific cold tongue controlled by ocean mixing. Nature 500, 64–67 (2013).

    Article  Google Scholar 

  28. Walsh, I. D. et al. Particle dynamics as controlled by the flow field of the eastern equatorial Pacific. Deep-Sea Res. II 44, 2025–2047 (1997).

    Article  Google Scholar 

  29. Gorsky, G., Le Borgne, R., Picheral, M. & Stemmann, L. Marine snow latitudinal distribution in the equatorial Pacific along 180°. J. Geophys. Res. 108, 8146 (2003).

    Article  Google Scholar 

  30. Bochdansky, A. B., van Aken, H. M. & Herndl, G. J. Role of macroscopic particles in deep-sea oxygen consumption. Proc. Natl Acad. Sci. USA 107, 8287–8291 (2010).

    Article  Google Scholar 

  31. Firing, E., Wijffels, S. E. & Hacker, P. Equatorial subthermocline currents across the Pacific. J. Geophys. Res. 103, 21413–21423 (1998).

    Article  Google Scholar 

  32. Gouriou, Y. et al. Deep circulation in the Equatorial Atlantic Ocean. Geophys. Res. Lett. 28, 819–822 (2001).

    Article  Google Scholar 

  33. Perez, R. C. et al. Mean meridional currents in the central and eastern equatorial Atlantic. Clim. Dynam. 43, 2943–2962 (2014).

    Article  Google Scholar 

  34. Perez, R. C. & Kessler, W. S. The three-dimensional structure of tropical cells in the central equatorial Pacific Ocean. J. Phys. Oceanogr. 39, 27–49 (2009).

    Article  Google Scholar 

  35. Picheral, M. et al. The Underwater Vision Profiler 5: an advanced instrument for high spatial resolution studies of particle size spectra and zooplankton. Limnol. Oceanogr.-Meth. 8, 462–473 (2010).

    Article  Google Scholar 

  36. Kriest, I. Different parameterizations of marine snow in a 1D-model and their influence on representation of marine snow, nitrogen budget and sedimentation. Deep-Sea Res. I 49, 2133–2162 (2002).

    Article  Google Scholar 

  37. Bianchi, D., Galbraith, E. D., Carozza, D. A., Mislan, K. A. S. & Stock, C. A. Intensification of open-ocean oxygen depletion by vertically migrating animals. Nat. Geosci. 6, 545–548 (2013).

    Article  Google Scholar 

  38. Martin, J. H., Knauer, G. A., Karl, D. M. & Broenkow, W. W. VERTEX: carbon cycling in the northeast Pacific. Deep-Sea Res. I 34, 267–285 (1987).

    Article  Google Scholar 

  39. Schmittner, A., Oschlies, A., Matthews, H. D. & Galbraith, E. D. Future changes in climate, ocean circulation, ecosystems, and biogeochemical cycling simulated for a business-as-usual CO2 emission scenario until year 4000 AD. Glob. Biogeochem. Cycles 22, GB1013 (2008).

    Article  Google Scholar 

  40. Aumont, O., Ethe, O., Tagliabue, A., Bopp, L. & Gehlen, M. PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies. Geosci. Model Dev. 8, 2465–2513 (2015).

    Article  Google Scholar 

  41. Yool, A., Popova, E. E. & Anderson, T. R. MEDUSA-2.0: an intermediate complexity biogeochemical model of the marine carbon cycle for climate change and ocean acidification. Geosci. Model Dev. 6, 1767–1811 (2013).

    Article  Google Scholar 

  42. Maier-Reimer, E. Geochemical cycles in an ocean general circulatiol model. Preindustrial tracer distributions. Glob. Biogeochem. Cycles 7, 645–677 (1993).

    Article  Google Scholar 

  43. Kriest, I. & Oschlies, A. On the treatment of particulate organic matter sinking in large-scale models of marine biogeochemical cycles. Biogeosciences 5, 55–72 (2008).

    Article  Google Scholar 

  44. Iversen, M. H. & Ploug, H. Temperature effects on carbon-specific respiration rate and sinking velocity of diatom aggregates—potential implications for deep ocean export processes. Biogeosciences 10, 4073–4085 (2013).

    Article  Google Scholar 

  45. Aumont, O. et al. Variable reactivity of particulate organic matter in a global ocean biogeochemical model. Biogeosciences 14, 2321–2341 (2017).

    Article  Google Scholar 

  46. McDonnell, A. M., Boyd, P. W. & Buesseler, K. O. Effects of sinking velocities and microbial respiration rates on the attenuation of particulate carbon fluxes through the mesopelagic zone. Glob. Biogeochem. Cycles 29, 175–193 (2015).

    Article  Google Scholar 

  47. Biddanda, B. A. & Pomeroy, L. R. Microbial aggregation and degradation of phytoplankton-derived detritus in seawater. I Microbial succession. Mar. Ecol. Prog. Ser. 42, 79–88 (1988).

    Article  Google Scholar 

  48. Greatbatch, R., Brandt, P., Claus, M., Didwischus, S. & Fu, Y. On the width of the equatorial deep jets. J. Phys. Oceanogr. 42, 1729–1740 (2012).

    Article  Google Scholar 

  49. Ménesguen, C., Hua, B. L., Fruman, B. & Schopp, R. Dynamics of the combined extra-equatorial and equatorial deep jets in the Atlantic. J. Mar. Res. 67, 323–346 (2009).

    Article  Google Scholar 

  50. Mullison. Backscatter estimation using broadband Acoustic Doppler Current Profilers – Updated (2017); http://go.nature.com/2fsJv1p

  51. White, M., Mohn, C. & Kiriakoulakis, K. in Environmental Sampling, in Biological Sampling in the Deep Sea (eds Clark, R., Consalvey, M. & Rowden, A. A.) 57–79 (John Wiley, 2016).

    Book  Google Scholar 

  52. Blanke, B., Arhan, M., Madec, G. & Roche, S. Warm water paths in the Equatorial Atlantic as diagnosed with a general circulation model. J. Phys. Oceanogr. 29, 2753–2768 (1999).

    Article  Google Scholar 

  53. Duteil, O., Schwarzkopf, F. U., Böning, C. W. & Oschlies, A. Major role of the equatorial current system in setting oxygen levels in the eastern tropical Atlantic Ocean: A high-resolution model study. Geophys. Res. Lett. 41, 2033–2040 (2014).

    Article  Google Scholar 

  54. Schwarzkopf, F. U. Ventilation Pathways in the Tropical Atlantic and Pacific Oceans with a Focus on the Oxygen Minimum Zones: Development and Application of a Nested High-Resolution Global Model System PhD thesis, Christian-Albrechts-University Kiel (2016).

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Acknowledgements

This study was supported by the German Science Foundation through the Collaborative Research Center 754 ‘Climate-Biogeochemistry Interactions in the Tropical Ocean’ and by the German Federal Ministry of Education and Research through the cooperative project ‘RACE’. The enthusiastic and continued support of UVP5 operations and maintenance by Jerome Coindat and Sylvain Fevre (Hydroptic) is gratefully acknowledged. For the Tara Oceans expedition we thank the commitment of the CNRS (in particular Groupement de Recherche GDR3280), European Molecular Biology Laboratory (EMBL), Genoscope/CEA, VIB, Stazione Zoologica Anton Dohrn, UNIMIB, Fund for Scientific Research—Flanders, Rega Institute, KU Leuven, The French Ministry of Research and the French Government ‘Investissements d’Avenir’ programmes OCEANOMICS (ANR-11-BTBR-0008). We are also grateful for the support and commitment of Agnès b. and Etienne Bourgois, the Veolia Environment Foundation, Région Bretagne, Lorient Agglomération, World Courier, Illumina, the EDF Foundation, FRB and the Prince Albert II de Monaco Foundation. This article is contribution number 59 from Tara Oceans. The contributions of M.P. and L.S. were supported by the Chair VISION of the CNRS and UPMC. A.M. acknowledges support from the National Science Foundation, the US Global Ocean Carbon and Repeat Hydrography Program, and the University of Alaska Fairbanks. US GO_SHIP funding through NSF OCE-1437015 is gratefully acknowledged for the acquisition of the P16N L-ADCP data. S.C. and F.M. acknowledge support by the French national programme LEFE/INSU (ZEBRE) and IRD, which also supported the CASSIOPEE cruise. The backward tracking experiments and the underlying ocean model integrations were performed at the North-German Supercomputing Alliance (HLRN) and the computing centre at Kiel University. We would like to thank captains and crews of RV Meteor, RV Maria S. Merian, RV Ron Brown, RV L’Atalante and the Tara schooner for their support, P. Vandromme for conducting UVP5 deployments during RV Meteor cruise M119, DT-INSU and US-IMAGO for the acquisition and processing of CTD, L-ADCP and UVP5 measurements and G. Eldin for the shipboard ADCP data from the CASSIOPEE cruise. Furthermore, we would like to thank G. Krahmann for processing of L-ADCP and CTD data from RV Meteor cruises M106 and M119 and RV Maria S Merian cruise MSM22, as well as H. Mehrtens for help with data management. F. Melzner and C. Bowler provided very valuable comments on the article.

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Authors and Affiliations

  1. GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany

    R. Kiko, A. Biastoch, P. Brandt, H. Hauss, R. Hummels, I. Kriest, A. Oschlies & F. U. Schwarzkopf

  2. Faculty of Mathematics and Natural Sciences, University of Kiel, 24148, Kiel, Germany

    P. Brandt & A. Oschlies

  3. LEGOS, University of Toulouse, IRD, CNES, CNRS, UPS, 31400, Toulouse, France

    S. Cravatte & F. Marin

  4. University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fairbanks, Alaska, 99775-7220, USA

    A. M. P. McDonnell

  5. CNRS, UMR 7093, Laboratoire d’Océanographie de Villefranche-sur-Mer (LOV), Observatoire Océanologique, F-06230, Villefranche-sur-Mer, France

    M. Picheral

  6. Lamont-Doherty Earth Observatory, Palisades, New York, 10964-8000, USA

    A. M. Thurnherr

  7. Sorbonne Universités, UPMC Univ Paris 06, UMR 7093, LOV, Observatoire Océanologique, F-06230, Villefranche-sur-Mer, France

    L. Stemmann

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  1. R. Kiko
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Contributions

R.K. and L.S. led the project and designed the study. A.M.P.M., H.H., M.P., L.S., I.K. and R.K. processed and analysed UVP5 data. F.U.S. and A.B. conducted particle backtracking simulations. P.B., R.H., A.M.T., S.C. and F.M. provided CTD and ADCP data. R.K. compiled all data and led the drafting of the manuscript. All authors contributed to the interpretation of the results and provided substantial input to the manuscript.

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Correspondence to R. Kiko.

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Kiko, R., Biastoch, A., Brandt, P. et al. Biological and physical influences on marine snowfall at the equator. Nature Geosci 10, 852–858 (2017). https://doi.org/10.1038/ngeo3042

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