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134498 - An approach for particle sinking velocity measurements.pdf (532.86 kB)

An approach for particle sinking velocity measurements in the 3–400 μm size range and considerations on the effect of temperature on sinking rates

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posted on 2023-05-20, 06:24 authored by Lennart BachLennart Bach, Riebesell, U, Sett, S, Febiri, S, Rzepka, P, Schulz, KG

The flux of organic particles below the mixed layer is one major pathway of carbon from the surface into the deep ocean. The magnitude of this export flux depends on two major processes—remineralization rates and sinking velocities. Here, we present an efficient method to measure sinking velocities of particles in the size range from approximately 3–400 μm by means of video microscopy (FlowCAM®). The method allows rapid measurement and automated analysis of mixed samples and was tested with polystyrene beads, different phytoplankton species, and sediment trap material. Sinking velocities of polystyrene beads were close to theoretical values calculated from Stokes’ Law. Sinking velocities of the investigated phytoplankton species were in reasonable agreement with published literature values and sinking velocities of material collected in sediment trap increased with particle size. Temperature had a strong effect on sinking velocities due to its influence on seawater viscosity and density. An increase in 9 °C led to a measured increase in sinking velocities of ~40 %. According to this temperature effect, an average temperature increase in 2 °C as projected for the sea surface by the end of this century could increase sinking velocities by about 6 % which might have feedbacks on carbon export into the deep ocean.


Publication title

Marine Biology










Institute for Marine and Antarctic Studies



Place of publication

175 Fifth Ave, New York, USA, Ny, 10010

Rights statement

Copyright 2012 The Authors. Licensed under Creative Commons Attribution 2.0 Generic (CC BY 2.0)

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  • Open

Socio-economic Objectives

Expanding knowledge in the earth sciences

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