Pyrosome fecal pellet production: Implications for grazing and carbon export
Abstract
This study quantifies the fecal pellet production and pellet sinking rates of the pyrosome Pyrosoma atlanticum in the Southern California Current across a range of conditions, from the productive nearshore to the oligotrophic offshore. Fecal pellet production rates averaged 1310 ± 76 pellets h −1 , resulting in the production of up to 390,380 pellets h −1 m −2 in locations with high densities of 298 ind. m −2 . Fecal pellet mean size was 354 ± 111 μ m, and sinking rates of fresh pellets averaged 47 ± 38 m d −1 , while aged pellets had lower rates averaging 31 ± 28 m d −1 . We estimate ingestion rates of 55.5 ± 9.5 mg C m −2 d −1 in the offshore and 41.1 ± 8.28 mg C m −2 d −1 in nearshore coastal waters. Based on pellet production rates, colony abundance, carbon content per pellet, and literature values of assimilation efficiencies, we estimate that pyrosomes consume the carbon equivalent of ~ 30% of net primary production in offshore waters and 1–26% in coastal waters. We present novel measurements of biogenic silica in pyrosome fecal pellets, indicating that pyrosomes can directly remove 0.5–4% of the euphotic zone‐integrated diatom standing stock, with higher rates in nearshore environments. Direct observation of fecal pellets showed unassimilated diatom chains, confirming direct consumption. Our results suggest that pyrosomes contribute to both carbon and silica export, important processes to constrain for understanding biogeochemistry in the region.
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BibTeX
@article{cawley2026pyrosome,
title = {{Pyrosome fecal pellet production: Implications for grazing and carbon export}},
author = {Grace Cawley and Stephanie Matthews and Natalia Llopis-Monferrer and Minerva Padilla Villa and Katherine Barbeau and Moira Décima},
journal = {Limnology and Oceanography},
year = {2026},
month = sep,
doi = {10.1002/lno.70506},
url = {https://hal.sorbonne-universite.fr/hal-05778229v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Pyrosome fecal pellet production: Implications for grazing and carbon export
AU - Grace Cawley
AU - Stephanie Matthews
AU - Natalia Llopis-Monferrer
AU - Minerva Padilla Villa
AU - Katherine Barbeau
AU - Moira Décima
PY - 2026
DA - 2026/09/17
JO - Limnology and Oceanography
DO - 10.1002/lno.70506
UR - https://hal.sorbonne-universite.fr/hal-05778229v1
AB - This study quantifies the fecal pellet production and pellet sinking rates of the pyrosome Pyrosoma atlanticum in the Southern California Current across a range of conditions, from the productive nearshore to the oligotrophic offshore. Fecal pellet production rates averaged 1310 ± 76 pellets h −1 , resulting in the production of up to 390,380 pellets h −1 m −2 in locations with high densities of 298 ind. m −2 . Fecal pellet mean size was 354 ± 111 μ m, and sinking rates of fresh pellets averaged 47 ± 38 m d −1 , while aged pellets had lower rates averaging 31 ± 28 m d −1 . We estimate ingestion rates of 55.5 ± 9.5 mg C m −2 d −1 in the offshore and 41.1 ± 8.28 mg C m −2 d −1 in nearshore coastal waters. Based on pellet production rates, colony abundance, carbon content per pellet, and literature values of assimilation efficiencies, we estimate that pyrosomes consume the carbon equivalent of ~ 30% of net primary production in offshore waters and 1–26% in coastal waters. We present novel measurements of biogenic silica in pyrosome fecal pellets, indicating that pyrosomes can directly remove 0.5–4% of the euphotic zone‐integrated diatom standing stock, with higher rates in nearshore environments. Direct observation of fecal pellets showed unassimilated diatom chains, confirming direct consumption. Our results suggest that pyrosomes contribute to both carbon and silica export, important processes to constrain for understanding biogeochemistry in the region.
SN - 0024-3590
SN - 1939-5590
ER -