_version_ 1867169115234369536
author Cheah, Wee
Soppa, Mariana A
Wiegmann, Sonja
Ossebaar, Sharyn
Laglera, Luis Miguel
Strass, Volker H
Santos-Echeandía, Juan
Hoppema, Mario
Wolf-Gladrow, Dieter A
Bracher, Astrid
author_facet Cheah, Wee
Soppa, Mariana A
Wiegmann, Sonja
Ossebaar, Sharyn
Laglera, Luis Miguel
Strass, Volker H
Santos-Echeandía, Juan
Hoppema, Mario
Wolf-Gladrow, Dieter A
Bracher, Astrid
collection Datos científicos de ciencias marinas y ambientales
contents Phytoplankton community structure and their physiological response in the vicinity of the Antarctic Polar Front (APF; 44°S to 53°S, centred at 10°E) were investigated as part of the ANT-XXVIII/3 Eddy-Pump cruise conducted in austral summer 2012. Our results show that under iron-limited (< 0.3 µmol/m**3) conditions, high total chlorophyll-a (TChl-a) concentrations (> 0.6 mg/m**3) can be observed at stations with deep mixed layer (> 60 m) across the APF. In contrast, light was excessive at stations with shallower mixed layer and phytoplankton were producing higher amounts of photoprotective pigments, diadinoxanthin (DD) and diatoxanthin (DT), at the expense of TChl-a, resulting in higher ratios of (DD+DT)/ TChl-a. North of the APF, significantly lower silicic acid (Si(OH)4) concentrations (< 2 mmol/m**3) lead to the domination of nanophytoplankton consisting mostly of haptophytes, which produced higher ratios of (DD+DT)/TChl-a under relatively low irradiance conditions. The Si(OH)4 replete (> 5 mmol/m**3) region south of the APF, on the contrary, was dominated by microphytoplankton (diatoms and dinoflagellates) with lower ratios of (DD+DT)/TChl-a, despite having been exposed to higher levels of irradiance. The significant correlation between nanophytoplankton and (DD+DT)/TChl-a indicates that differences in taxon-specific response to light are also influencing TChl-a concentration in the APF during summer. Our results reveal that provided mixing is deep and Si(OH)4 is replete, TChl-a concentrations higher than 0.6 mg/m**3 are achievable in the iron-limited APF waters during summer.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_866372
institution PANGAEA
language en
publishDate 2016
publisher PANGAEA
record_format pangaea
spellingShingle Phytoplankton composition derived from CHEMTAX along 10°E during POLARSTERN cruise ANT-XXVIII/3, Jan-March 2012
Cheah, Wee
Soppa, Mariana A
Wiegmann, Sonja
Ossebaar, Sharyn
Laglera, Luis Miguel
Strass, Volker H
Santos-Echeandía, Juan
Hoppema, Mario
Wolf-Gladrow, Dieter A
Bracher, Astrid
ANT-XXVIII/3; CHEMTAX (Lewitus et al., 2005); Chlorophytes; Cryptophytes; CTD/Rosette; CTD-RO; Cyanobacteria; Date/Time of event; DEPTH, water; Diatoms; Dinoflagellates; Elevation of event; Event label; Haptophytes; In situ pump; ISP; Latitude of event; Longitude of event; Polarstern; Prasinophytes; PS79; PS79/057-4; PS79/060-5; PS79/061-1; PS79/062-1; PS79/063-2; PS79/064-1; PS79/065-1; PS79/066-1; PS79/068-1; PS79/069-4; PS79/070-3; PS79/073-2; PS79/074-1; PS79/075-9; PS79/076-2; PS79/077-1; PS79/078-1; PS79/079-1; PS79/080-1; PS79/081-11; PS79/081-5; PS79/082-1; PS79/083-1; PS79/084-9; South Atlantic Ocean
Phytoplankton community structure and their physiological response in the vicinity of the Antarctic Polar Front (APF; 44°S to 53°S, centred at 10°E) were investigated as part of the ANT-XXVIII/3 Eddy-Pump cruise conducted in austral summer 2012. Our results show that under iron-limited (< 0.3 µmol/m**3) conditions, high total chlorophyll-a (TChl-a) concentrations (> 0.6 mg/m**3) can be observed at stations with deep mixed layer (> 60 m) across the APF. In contrast, light was excessive at stations with shallower mixed layer and phytoplankton were producing higher amounts of photoprotective pigments, diadinoxanthin (DD) and diatoxanthin (DT), at the expense of TChl-a, resulting in higher ratios of (DD+DT)/ TChl-a. North of the APF, significantly lower silicic acid (Si(OH)4) concentrations (< 2 mmol/m**3) lead to the domination of nanophytoplankton consisting mostly of haptophytes, which produced higher ratios of (DD+DT)/TChl-a under relatively low irradiance conditions. The Si(OH)4 replete (> 5 mmol/m**3) region south of the APF, on the contrary, was dominated by microphytoplankton (diatoms and dinoflagellates) with lower ratios of (DD+DT)/TChl-a, despite having been exposed to higher levels of irradiance. The significant correlation between nanophytoplankton and (DD+DT)/TChl-a indicates that differences in taxon-specific response to light are also influencing TChl-a concentration in the APF during summer. Our results reveal that provided mixing is deep and Si(OH)4 is replete, TChl-a concentrations higher than 0.6 mg/m**3 are achievable in the iron-limited APF waters during summer.
title Phytoplankton composition derived from CHEMTAX along 10°E during POLARSTERN cruise ANT-XXVIII/3, Jan-March 2012
topic ANT-XXVIII/3; CHEMTAX (Lewitus et al., 2005); Chlorophytes; Cryptophytes; CTD/Rosette; CTD-RO; Cyanobacteria; Date/Time of event; DEPTH, water; Diatoms; Dinoflagellates; Elevation of event; Event label; Haptophytes; In situ pump; ISP; Latitude of event; Longitude of event; Polarstern; Prasinophytes; PS79; PS79/057-4; PS79/060-5; PS79/061-1; PS79/062-1; PS79/063-2; PS79/064-1; PS79/065-1; PS79/066-1; PS79/068-1; PS79/069-4; PS79/070-3; PS79/073-2; PS79/074-1; PS79/075-9; PS79/076-2; PS79/077-1; PS79/078-1; PS79/079-1; PS79/080-1; PS79/081-11; PS79/081-5; PS79/082-1; PS79/083-1; PS79/084-9; South Atlantic Ocean
url https://doi.org/10.1594/PANGAEA.866372