Alternative Particle Formation pathways in the Eastern Tropical North Pacific's Biological Carbon Pump



Cavan, EL, Giering, SLC, Wolff, GA ORCID: 0000-0002-9380-1039, Trimmer, M and Sanders, R
(2018) Alternative Particle Formation pathways in the Eastern Tropical North Pacific's Biological Carbon Pump. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 123 (7). pp. 2198-2211.

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Abstract

A fraction of organic carbon produced in the oceans by phytoplankton sinks storing 5–15 gigatonnes of carbon annually in the ocean interior. The accepted paradigm is that rapid aggregation of phytoplankton cells occurs, forming large, fresh particles which sink quickly; this concept is incorporated into ecosystem models used to predict the future climate. Here we demonstrate a slower, less efficient export pathway in the Eastern Tropical North Pacific. Lipid biomarkers suggest that the large, fast‐sinking particles found beneath the mixed layer are compositionally distinct from those found in the mixed layer and thus not directly and efficiently formed from phytoplankton cells. We postulate that they are formed from the in situ aggregation of smaller, slow‐sinking particles over time in the mixed layer itself. This export pathway is likely widespread where smaller phytoplankton species dominate. Its lack of representation in biogeochemical models suggests that they may be currently overestimating the ability of the oceans to store carbon if large, fast‐sinking, labile particles dominate simulated particle export.

Item Type: Article
Uncontrolled Keywords: biological carbon pump, lipid biomarkers, particle aggregation, fast‐sinking particles, particulate organic carbon
Depositing User: Symplectic Admin
Date Deposited: 13 Aug 2018 06:09
Last Modified: 19 Jan 2023 01:28
DOI: 10.1029/2018JG004392
Open Access URL: https://doi.org/10.1029/2018JG004392
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3024879