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Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean

Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean
Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean
The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January–March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, ?5 mg GX eq. m?2 d?1, and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the traps consisting of intact protist plankton, although remains of taxa with hard body parts (diatoms, tintinnids, thecate dinoflagellates and foraminifera) were numerous, far more so than intact specimens of these taxa. Nevertheless, many small flagellates and coccoid cells, belonging to the pico- and nanoplankton, were found in the traps, and these small, soft-bodied cells probably contributed the majority of downward POC flux via mesozooplankton grazing and faecal pellet export. TEP likely played an important role by aggregating these small cells, and making them more readily available to mesozooplankton grazers.
Nano- and picoplankton, Export flux, Iron fertilisation, Protists, Sediment trap, Southern Ocean
0967-0637
94-103
Ebersbach, Friederike
00c810a1-6d7a-486f-92e6-3ba1934e812b
Assmy, Philipp
9a4ff1eb-ebc6-4778-8d52-32cb5b5d9f03
Martin, Patrick
01ce1c59-3926-46c9-a556-fac39e0ee16b
Schulz, Isabelle
6440b2d6-0717-40d4-8e1c-df3a74bc6334
Wolzenburg, Sina
d77f8e84-f68f-4354-82e2-5266ee034fc3
Nöthig, Eva-Maria
19f67d09-dfa4-4442-b672-e7ef2107b34b
Ebersbach, Friederike
00c810a1-6d7a-486f-92e6-3ba1934e812b
Assmy, Philipp
9a4ff1eb-ebc6-4778-8d52-32cb5b5d9f03
Martin, Patrick
01ce1c59-3926-46c9-a556-fac39e0ee16b
Schulz, Isabelle
6440b2d6-0717-40d4-8e1c-df3a74bc6334
Wolzenburg, Sina
d77f8e84-f68f-4354-82e2-5266ee034fc3
Nöthig, Eva-Maria
19f67d09-dfa4-4442-b672-e7ef2107b34b

Ebersbach, Friederike, Assmy, Philipp, Martin, Patrick, Schulz, Isabelle, Wolzenburg, Sina and Nöthig, Eva-Maria (2014) Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean. Deep Sea Research Part I: Oceanographic Research Papers, 89, 94-103. (doi:10.1016/j.dsr.2014.04.007).

Record type: Article

Abstract

The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January–March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, ?5 mg GX eq. m?2 d?1, and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the traps consisting of intact protist plankton, although remains of taxa with hard body parts (diatoms, tintinnids, thecate dinoflagellates and foraminifera) were numerous, far more so than intact specimens of these taxa. Nevertheless, many small flagellates and coccoid cells, belonging to the pico- and nanoplankton, were found in the traps, and these small, soft-bodied cells probably contributed the majority of downward POC flux via mesozooplankton grazing and faecal pellet export. TEP likely played an important role by aggregating these small cells, and making them more readily available to mesozooplankton grazers.

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Published date: July 2014
Keywords: Nano- and picoplankton, Export flux, Iron fertilisation, Protists, Sediment trap, Southern Ocean
Organisations: Ocean and Earth Science

Identifiers

Local EPrints ID: 367440
URI: http://eprints.soton.ac.uk/id/eprint/367440
ISSN: 0967-0637
PURE UUID: 4e3ea389-ba0d-49e7-a21c-f32eb4f5179a

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Date deposited: 30 Jul 2014 09:39
Last modified: 07 Oct 2019 18:31

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