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Phytoplankton morphology controls on marine snow sinking velocity

Citation

Laurenceau-Cornec, EC and Trull, TW and Davies, DM and De La Rocha, CL and Blain, S, Phytoplankton morphology controls on marine snow sinking velocity, Marine Ecology Progress Series, 520 pp. 35-56. ISSN 0171-8630 (2015) [Refereed Article]


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Copyright Statement

Copyright 2015 Marine Ecology Progress Series

DOI: doi:10.3354/meps11116

Abstract

During the second KErguelen Ocean and Plateau compared Study (KEOPS2) in October-November 2011, marine snow was formed in roller tanks by physical aggregation of phytoplankton assemblages sampled at 6 stations over and downstream of the Kerguelen Plateau. Sinking velocities, morphology, bulk composition (transparent exopolymer particles, biogenic silica, particulate organic carbon), and phytoplankton contents were measured individually on 66 aggregates to identify controls on sinking velocities. Equivalent spherical diameters (ESD) ranged from 1 to 12 mm, and the particle aspect ratios, Corey shape factors, and fractal dimensions (DF1 = 1.5, DF2 = 1.8) were close to those of smaller natural aggregates (0.2 to 1.5 mm) collected in polyacrylamide gel-filled sediment traps (DF1 = 1.2, DF2 = 1.9). Sinking velocities ranged between 13 and 260m d-1, and were correlated with aggregate size only when considering individually the experiments conducted at each station, suggesting that a site-dependent control prevailed over the general influence of size. Variation in dominant diatom morphologies among the sites (classified as small spine-forming or chain without spines) appeared to be a determinant parameter influencing the sinking velocity (SV [m d-1] = 168 - 1.48 (% small spine-forming cells), r2 = 0.98), possibly via a control on species-specific coagulation efficiency affecting particle structure and excess density. Our results emphasize the importance of ecological considerations over that of simple compositional perspectives in the control of particle formation, and in accurate parameterizations of marine snow sinking velocities that are essential to predictions of biological carbon sequestration.

Item Details

Item Type:Refereed Article
Keywords:sinking velocity, marine snow, aggregation, phytoplankton, porosity
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Environment
Objective Group:Other Environment
Objective Field:Antarctic and Sub-Antarctic Oceanography
Author:Laurenceau-Cornec, EC (Mr Emmanuel Laurenceau)
Author:Trull, TW (Professor Thomas Trull)
Author:Davies, DM (Ms Diana Davies)
ID Code:98751
Year Published:2015
Web of Science® Times Cited:6
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2015-02-27
Last Modified:2017-11-01
Downloads:0

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