Temperature effects on carbon-specific respiration rate and sinking velocity of diatom aggregates. Potential implications for deep ocean export processes


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morten.iversen [ at ] awi.de

Abstract

Most deep ocean carbon flux profiles show low and almost constant fluxes of particulate organic carbon (POC) in the deep ocean. However, the reason for the non-changing POC fluxes at depths is unknown. This study presents direct measurements of formation, degradation, and sinking velocity of diatom aggregates from laboratory studies performed at 15 °C and 4 °C during a three-week experiment. The average carbon-specific respiration rate during the experiment was 0.12 ± 0.03 at 15 °C, and decreased 3.5-fold when the temperature was lowered to 4 °C. No direct influence of temperature on aggregate sinking speed was observed. Using the remineralisation rate measured at 4 °C and an average particle sinking speed of 150 m d−1, calculated carbon fluxes were similar to those collected in deep ocean sediment traps from a global data set, indicating that temperature plays a major role for deep ocean fluxes of POC.



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Peer-reviewed
Publication Status
Published
Eprint ID
37912
DOI 10.5194/bg-10-4073-2013

Cite as
Iversen, M. and Ploug, H. (2013): Temperature effects on carbon-specific respiration rate and sinking velocity of diatom aggregates. Potential implications for deep ocean export processes , Biogeosciences, 10 , pp. 4073-4085 . doi: 10.5194/bg-10-4073-2013


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