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One pathway of the biological pump that remains largely unquantified in many export models is the active transport of carbon from the surface ocean to the mesopelagic by zooplankton diel vertical migration (DVM). Here, we develop a simple representation of zooplankton DVM and implement it in a global export model as a thought experiment to illustrate the effects of DVM on carbon export and mesopelagic biogeochemistry. The model is driven by diagnostic satellite measurements of net primary production, algal biomass, and phytoplankton size structure. Due to constraints on available satellite data, the results are restricted to the latitude range from 60°N to 60°S. The modeled global export flux from the base of the euphotic zone was 6.5 PgC/year, which represents a 14% increase over the export flux in model runs without DVM. The mean (± standard deviation, SD) proportional contribution of the DVM‐mediated export flux to total carbon export, averaged over the global domain and the climatological seasonal cycle, was 0.16 ± 0.04 and the proportional contribution of DVM activity to total respiration within the twilight zone was 0.16 ± 0.06. Adding DVM activity to the model also resulted in a deep local maximum in the oxygen utilization profile. The model results were most sensitive to the assumptions for the fraction of individuals participating in DVM, the fraction of fecal pellets produced in the euphotic zone, and the fraction of grazed carbon that is metabolized.
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This content will become publicly available on July 28, 2026
Active Carbon Transport by Diel Vertical Migrating Zooplankton: Calculated and Modeled, but Never Measured
Zooplankton diel vertical migration (DVM) is a globally ubiquitous phenomenon and a critical component of the ocean's biological pump. During DVM, zooplankton metabolism leads to carbon and nutrient export to mesopelagic depths, where carbon can be sequestered for decades to millennia, while also introducing labile, energy-rich food sources to midwater ecosystems. Three pervasive metabolic pathways allow zooplankton to sequester carbon: fecal pellet egestion, dissolved organic matter excretion, and respiration. Additionally, there are several less well-parameterized sources of DVM transport associated with growth, feeding, reproduction, and mortality. These processes are challenging to measure in situ and difficult to extrapolate from laboratory experiments, making them some of the most poorly constrained factors in assessments and models of the biological pump. In this review, we evaluate and compare observational and modeling approaches to estimate zooplankton DVM and the resulting active carbon flux, highlighting major discrepancies and proposing directions for future research.
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- Award ID(s):
- 1948162
- PAR ID:
- 10649846
- Publisher / Repository:
- Annual Reviews
- Date Published:
- Journal Name:
- Annual Review of Marine Science
- ISSN:
- 1941-1405
- Subject(s) / Keyword(s):
- Active Carbon Transport zooplankton
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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