Seasonality of phytoplankton growth limitation by iron and manganese in subantarctic waters

Phytoplankton indirectly influence climate through their role in the ocean biological carbon pump. In the Southern Ocean, the subantarctic zone represents an important carbon sink, yet variables limiting phytoplankton growth are not fully constrained. Using three shipboard bioassay experiments on three separate voyages, we evaluated the seasonality of iron (Fe) and manganese (Mn) co-limitation of subantarctic phytoplankton growth south of Tasmania, Australia. We observed a strong seasonal variation in a phytoplankton Fe limitation signal, with a summer experiment showing the greatest response to Fe additions. An autumn experiment suggested that other factors co-limited phytoplankton growth, likely low silicic acid concentrations. The phytoplankton responses to Mn additions were subtle and readily masked by the responses to Fe. Using flow cytometry, we observed that Mn may influence the growth of some small phytoplankton taxa in late summer/autumn, when they represent an important part of the phytoplankton community. In addition, Mn induced changes in the bulk photophysiology signal of the spring community. These results suggest that the importance of Mn may vary seasonally, and that its control on phytoplankton growth may be associated with specific taxa.

Identification info

Date (Publication): 2023-06-06T00:00:00

Citation identifier

doi:10.25959/BFF2-RC77

Title: Information and documentation - Digital object identifier system

Date (Publication): 2023-06-06

Citation identifier: ISO 26324:2012

Citation identifier: https://doi.org/10.25959/BFF2-RC77

Resource provider

Institute for Marine and Antarctic Studies (IMAS)

Private Bag 129

Hobart

Tasmania

7001

Australia

Author

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Latour, Pauline

Private Bag 129

Hobart

TAS

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Bowie, Andrew

Private Bag 129

Hobart

TAS

7001

Australia

ORCID ID >

Credit: We acknowledge the officers and crew of the RV Investigator (CSIRO Australian Marine National Facility; https://ror.org/01mae9353) for the deployment of all the instruments and the hydro-chemistry team who performed the macronutrient analyses onboard. This work was funded through the Antarctic Climate & Ecosystems Cooperative Centre (ACE CRC) and by the Australian Antarctic Program Partnership (AAPP; ASCI000002).

Status: Completed

Point of contact

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Latour, Pauline

Hobart

TAS

7001

Australia

0473212891

ORCID ID >

Topic category

Biota

Extent

Temporal extent

Time period: 2018-09-12 2021-05-31

Maintenance and update frequency: Not planned

Keywords (Theme)

iron
manganese
co-limitation
radioisotopes
flow cytometry

Global Change Master Directory Earth Science Keywords, Version 8.5

AODN Discovery Parameter Vocabulary

Nitrate
Silicate
Phosphate
Photochemical efficiency of Photosystem II
Functional absorption cross-section of Photosystem II
Dissolved iron concentrations
Dissolved manganese concentrations
Concentration of ammonium {NH4} per unit volume of the water body
Flow cytometry measurements

AODN Geographic Extents Vocabulary

Global / Oceans | Global / Oceans | Southern Ocean/ Australia extension

Australian and New Zealand Standard Research Classification (ANZSRC): Fields of Research

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Use limitation: Data, products and services from IMAS are provided "as is" without any warranty as to fitness for a particular purpose.

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Other constraints: This dataset is the intellectual property of the University of Tasmania (UTAS) through the Institute for Marine and Antarctic Studies (IMAS).

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Linkage: https://licensebuttons.net/l/by/4.0/88x31.png
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Title: Creative Commons Attribution 4.0 International License

Alternate title: CC-BY

Edition: 4.0

Website: https://creativecommons.org/licenses/by/4.0/
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Other constraints: Cite data as: Latour, P., Strzepek, R., Wuttig, K., van der Merwe, P., Bach, L., Eggins, S., Boyd, P., Ellwood, M., Pinfold, T., & Bowie, A. (2023). Seasonality of phytoplankton growth limitation by iron and manganese in subantarctic waters [Data set]. Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS). https://doi.org/10.25959/BFF2-RC77

Language: English

Character encoding: UTF8

Supplemental Information: Seasonality of phytoplankton growth limitation by iron and manganese in subantarctic waters

Content Information

Content type: Physical measurement

Identifier

Code: Nitrate

Identifier: http://vocab.nerc.ac.uk/collection/P06/current/UPOX

Name: Micromoles per litre

Identifier

Code: Silicate

Name: Silicate

Identifier: http://vocab.nerc.ac.uk/collection/P06/current/UPOX

Name: Micromoles per litre

Identifier

Code: Phosphate

Identifier: http://vocab.nerc.ac.uk/collection/P06/current/UPOX

Name: Micromoles per litre

Identifier

Code: Photochemical efficiency of Photosystem II

Name: Fv/Fm

Name: no unit

Identifier

Code: Functional absorption cross-section of Photosystem II

Name: nm-2 quanta-1

Identifier

Code: Dissolved iron concentrations

Name: dFe

Name: Nanomoles per litre

Identifier

Code: Dissolved manganese concentrations

Name: dMn

Name: Nanomoles per litres

Identifier

Code: Concentration of ammonium {NH4} per unit volume of the water body

Name: Ammonia

Identifier: http://vocab.nerc.ac.uk/collection/P06/current/UPOX

Name: Micromoles per litre

Identifier

Code: Flow cytometry measurements

Name: no unit

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Microsoft Excel and .fcs files

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OnLine resource: DATA ACCESS - download all files as. zip package

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Statement: We performed three field bioassays experiments onboard RV Investigator, in the subantarctic zone, to study iron (Fe) and manganese (Mn) co-limitation of phytoplankton growth. The first experiment (spring) was performed at Process Station 2 (45.44°S, 153.31°) during IN2018_V04 and the two other experiments (summer and autumn) were conducted at the Southern Ocean Time Series (SOTS) station (46.80°S, 141.884°E) during IN2019_V02 (autumn) and IN2020_V08 (summer). Unfiltered trace metal clean seawater was collected using a trace metal rosette and incubated with Fe and/or Mn additions in deck-board incubators. Neutral-density mesh bags were used to reproduce the light penetrating the surface ocean. Incubations bottles were sampled at the end of the experiment (day = 7) for macronutrient concentrations, measured through segmented flow analysis, photophysiology, measured using Light-induced Fluorescence Transients Fast Repetition Rate (LIFT-FRR) fluorometer and community composition using flow cytometry. Flow cytometry samples were fixed at sea and analysed back onshore using an Aurora Cytek flow cytometer (Cytek Biosciences). In addition, carbon and iron uptake rates were measured through radioisotopes additions: after 7 days of incubation, a portion of the incubated water was dispensed into smaller bottles and spiked with 14-carbon (NaH14CO3; specific activity 1.85 GBq mmol-1; PerkinElmer, USA) and 55-iron (55FeCl3 in 0.1 M Ultrapure HCl; specific activity 30 MBq mmol-1; PerkinElmer) solutions. Iron and carbon uptake rates were determined by measuring disintegrations per minute (DPM) on a liquid scintillation counter (PerkinElmer Tri-Carb 2910 TR) after incubation of the filters in Ultima Gold liquid scintillation cocktail at least 24h prior to analysis (PerkinElmer).

Hierarchy level: Dataset

Hierarchy level: Dataset

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Metadata identifier: urn:uuid/2d9be445-e1da-4572-927b-b13bf7d1b601

Language: English

Character encoding: UTF8

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IMAS Data Manager - Data Officer

Institute for Marine and Antarctic Studies

Private Bag 129

Hobart

Tasmania

7001

Australia

Institute for Marine and Antarctic Studies (IMAS) website >

Type of resource

Resource scope: Dataset

Name: IMAS Dataset level record

Metadata linkage: https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/2d9be445-e1da-4572-927b-b13bf7d1b601
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Date info (Creation): 2023-05-05T00:00:00

Date info (Revision): 2023-10-30T11:10:07

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Title: ISO 19115-3:2018

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