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Slow particle remineralization, rather than suppressed disaggregation, drives efficient flux transfer through the Eastern Tropical North Pacific Oxygen Deficient Zone
  • +11
  • Jacob Cram,
  • Clara Fuchsman,
  • Megan Duffy,
  • Jessica Pretty,
  • Rachel Lekanoff,
  • Jacquelyn Neibauer,
  • Shirley Leung,
  • Klaus B. Huebert,
  • Thomas Weber,
  • Daniele Bianchi,
  • Natalya Evans,
  • Allan Devol,
  • Richard Keil,
  • Andrew McDonnell
Jacob Cram
Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA.

Corresponding Author:[email protected]

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Clara Fuchsman
Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA.
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Megan Duffy
School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA.
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Jessica Pretty
College of Fisheries and Ocean Sciences, College of Fisheries and Ocean Sciences, College of Fisheries and Ocean Sciences, College of Fisheries and Ocean Sciences, College of Fisheries and Ocean Sciences, College of Fisheries and Ocean Sciences
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Rachel Lekanoff
College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA., College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA., College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA., College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA., College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA., College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA.
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Jacquelyn Neibauer
School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA.
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Shirley Leung
School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA.
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Klaus B. Huebert
Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA., Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA.
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Thomas Weber
School of Arts and Sciences, University of Rochester, Rochester, NY, USA., School of Arts and Sciences, University of Rochester, Rochester, NY, USA., School of Arts and Sciences, University of Rochester, Rochester, NY, USA., School of Arts and Sciences, University of Rochester, Rochester, NY, USA., School of Arts and Sciences, University of Rochester, Rochester, NY, USA., School of Arts and Sciences, University of Rochester, Rochester, NY, USA.
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Daniele Bianchi
Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, CA, USA., Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, CA, USA., Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, CA, USA., Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, CA, USA., Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, CA, USA., Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, CA, USA.
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Natalya Evans
Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
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Allan Devol
School of Oceanography, School of Oceanography, School of Oceanography, School of Oceanography, School of Oceanography, School of Oceanography
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Richard Keil
School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, University of Washington Seattle, Seattle, WA, USA., School of Oceanography, School of Oceanography, School of Oceanography
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Andrew McDonnell
University of Alaska Fairbanks, College of Fisheries and Ocean Sciences Fairbanks, AK, USA., University of Alaska Fairbanks, College of Fisheries and Ocean Sciences Fairbanks, AK, USA., University of Alaska Fairbanks, College of Fisheries and Ocean Sciences Fairbanks, AK, USA., University of Alaska Fairbanks, College of Fisheries and Ocean Sciences Fairbanks, AK, USA., University of Alaska Fairbanks, College of Fisheries and Ocean Sciences Fairbanks, AK, USA., University of Alaska Fairbanks, College of Fisheries and Ocean Sciences Fairbanks, AK, USA.
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Abstract

Models and observations suggest that particle flux attenuation is lower across the mesopelagic zone of anoxic environments compared to oxic environments. Flux attenuation is controlled by microbial metabolism as well as aggregation and disaggregation by zooplankton, all of which also shape the relative abundance of differently sized particles. Observing and modeling particle spectra can provide information about the contributions of these processes. We measured particle size spectrum profiles at one station in the oligotrophic Eastern Tropical North Pacific Oxygen Deficient Zone (ETNP ODZ) using an underwater vision profiler (UVP), a high-resolution camera that counts and sizes particles. Measurements were taken at different times of day, over the course of a week. Comparing these data to particle flux measurements from sediment traps collected over the same time-period allowed us to constrain the particle size to flux relationship, and to generate highly resolved depth and time estimates of particle flux rates. We found that particle flux attenuated very little throughout the anoxic water column, and at some time-points appeared to increase. Comparing our observations to model predictions suggested that particles of all sizes remineralize more slowly in the ODZ than in oxic waters, and that large particles disaggregate into smaller particles, primarily between the base of the photic zone and 500 m. Acoustic measurements of multiple size classes of organisms suggested that many organisms migrated, during the day, to the region with high particle disaggregation. Our data suggest that diel-migrating organisms both actively transport biomass and disaggregate particles in the ODZ core.
Jan 2022Published in Global Biogeochemical Cycles volume 36 issue 1. 10.1029/2021GB007080