Characterization of a Southern Ocean deep chlorophyll maximum: response of phytoplankton to light, iron, and manganese enrichment

• Other Authors: AODN Data Manager (distributor), Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC) (hasAssociationWith), Bach, Lennart (author), Bach, Lennart T. (author), Bowie, Andrew (author), Bowie, Andrew R. (author), Bowie, Andrew, Dr (author), Boyd, Philip (author), Boyd, Philip W. (author), Data Officer (distributor), Eggins, Sam (author), Ellwood, Michael (author), Ellwood, Michael J. (author), IMAS Data Manager (hasAssociationWith), Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) (hasAssociationWith), Latour, Pauline (pointOfContact), Latour, Pauline (hasPrincipalInvestigator), Pier van der Merwe (author), Research School of Earth Sciences (RSES), The Australian National University (ANU) (hasAssociationWith), Strzepek, Robert (author), Strzepek, Robert F. (author), Strzepek, Robert, Dr (author), Van Der Merwe, Pier (author), Wuttig, Kathrin (author), van der Merwe, Pier (author)
• Format: Dataset
• Language: unknown
• Published: Australian Ocean Data Network
• Subjects: biota; deep chlorophyll maximum; iron; light; manganese; photophysiology; PHYTOPLANKTON; EARTH SCIENCE; BIOSPHERE; AQUATIC ECOSYSTEMS; PLANKTON; BIOGEOCHEMICAL CYCLES; ECOLOGICAL DYNAMICS; ECOSYSTEM FUNCTIONS; Concentration of nitrate and nitrite {NO3 and NO2} per unit volume of the water body; Concentration of phosphate {PO4} per unit volume of the water body; Concentration of silicate {SiO4} per unit volume of the water body; Photochemical efficiency of Photosystem II; Functional absorption cross-section of Photosystem II; Flow cytometry; Iron uptake rates; Carbon uptake rates; Concentration of chlorophyll-a per unit volume of the water body; Particulate organic carbon; Biogenic silica; Global / Oceans | Global / Oceans | Southern Ocean; Southern Ocean
• Online Access: https://researchdata.edu.au/characterization-southern-ocean-manganese-enrichment/2828718; https://doi.org/10.25959/6S84-RM14

Maintenance and Update Frequency: notPlanned Statement: We performed a field bioassay experiment onboard RV Investigator in polar waters of the Southern Ocean (55.47°S, 138.34°E) to study the response of phytoplankton communities from a deep chlorophyll maximum (DCM) to changes in iron (Fe), manganese (Mn) and light conditions. 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 alter the light conditions. Two light treatments were used: a low light treatment (1% incident irradiance) to reproduce the light conditions at the DCM (located at 87m) and a high light treatment (12.4% of incident irradiance) to stimulate shoaling up to 40m. Incubations bottles were sampled at the end of the experiment (day = 10) for multiple parameters: chlorophyll-a/particulate organic carbon/biogenic silica concentrations. Macronutrient concentrations were measured onboard through segmented flow analysis. Photophysiology was studied using a Light-induced Fluorescence Transients Fast Repetition Rate (LIFT-FRR) fluorometer. Flow cytometry samples (for community composition) 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 10 days of incubation, 300 ml 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. The spiked bottles were incubated for 24h under initial conditions before sequential filtration though 20, 2 and 0.2 µm polycarbonate filters. 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 ...