Prokaryotic bias in surface ocean particles

While the ocean's photosynthetic production of organic matter rivals that on land, a combination of heterotrophy and sinking prevents significant accumulation of particulate organic matter (POM) in open ocean surface waters. The origins and fates of POM in ocean surface waters are unclear, in part due to the dominance of nonliving, altered material. From the natural nitrogen isotopic composition of chlorophyll and its degradation products, we estimate the fraction of particles from eukaryotic vs. prokaryotic phytoplankton. In subtropical gyres and along the eastern North Pacific margin, the eukaryotic-to-prokaryotic ratio in particles matches that of living phytoplankton. However, in the North Atlantic outside its subtropical gyre, particles have a lower eukaryotic-to-prokaryotic ratio than do the living phytoplankton. This discrepancy at least partly arises from preferential sinking of eukaryotic biomass, consistent with the canonical but disputed paradigm that cyanobacteria disproportionately fulfill the energetic demands of the upper ocean microbial community while eukaryotes drive export production. The prokaryotic bias in surface ocean particles may also result from slow decomposition of specific components of prokaryotic biomass, a possible bottleneck in the ocean's microbial loop. The different fates of organic matter produced by eukaryotic and prokaryotic phytoplankton affect the productivity of the surface ocean, carbon export to the interior, and the signals recorded in deep-sea sediments.

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Publication Details

Journal
Proceedings of the National Academy of Sciences
Published
2026-04-01
DOI
https://doi.org/10.1073/pnas.2500624123
Primary Topic
Marine and coastal ecosystems
Type
article
Field-Weighted Citation Impact
0.00

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article

Prokaryotic bias in surface ocean particles

Hans A. Slagter, Bess B. Ward, Hedy M. Aardema, Adrian Marchetti et al.
Proceedings of the National Academy of Sciences
Marine and coastal ecosystems
article

Prokaryotic bias in surface ocean particles

Hans A. Slagter, Bess B. Ward, Hedy M. Aardema, Adrian Marchetti, Ralf Schiebel, Sarah E. Fawcett, Nicolas Van Oostende, Meytal B. Higgins, Julie Granger, Natalie R. Cohen, Claire C.Z. Cook, Daniel M. Sigman, Sergey Oleynik, Ashley E. Maloney, Victoria H. Luu, Yeongjun Ryu, Erica M. Ewton, Susanne Menden-Deuer, Lingkun Guo, Gerald H. Haug
article en

Abstract

While the ocean's photosynthetic production of organic matter rivals that on land, a combination of heterotrophy and sinking prevents significant accumulation of particulate organic matter (POM) in open ocean surface waters. The origins and fates of POM in ocean surface waters are unclear, in part due to the dominance of nonliving, altered material. From the natural nitrogen isotopic composition of chlorophyll and its degradation products, we estimate the fraction of particles from eukaryotic vs. prokaryotic phytoplankton. In subtropical gyres and along the eastern North Pacific margin, the eukaryotic-to-prokaryotic ratio in particles matches that of living phytoplankton. However, in the North Atlantic outside its subtropical gyre, particles have a lower eukaryotic-to-prokaryotic ratio than do the living phytoplankton. This discrepancy at least partly arises from preferential sinking of eukaryotic biomass, consistent with the canonical but disputed paradigm that cyanobacteria disproportionately fulfill the energetic demands of the upper ocean microbial community while eukaryotes drive export production. The prokaryotic bias in surface ocean particles may also result from slow decomposition of specific components of prokaryotic biomass, a possible bottleneck in the ocean's microbial loop. The different fates of organic matter produced by eukaryotic and prokaryotic phytoplankton affect the productivity of the surface ocean, carbon export to the interior, and the signals recorded in deep-sea sediments.

Proceedings of the National Academy of SciencesVol. 123(14)
Skidaway Institute of Oceanography (US), University of Connecticut (US), University of Cape Town (ZA), University of Georgia (US), University of Rhode Island (US), Princeton University (US), Sustainability Institute (ZA), ExxonMobil (Germany) (DE), Max Planck Institute for Chemistry (DE)
National Science Foundation, National Aeronautics and Space Administration, Princeton University, European Commission, Max-Planck-Gesellschaft
Life below water
Openalex Percentile: Top 27%
Marine and coastal ecosystems
DOIOpen Access PDFOpenAlex
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