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Physical-Biological Coupling in the Western South China Sea: The Response of Phytoplankton Community to a Mesoscale Cyclonic Eddy.

Wang L, Huang B, Chiang KP, Liu X, Chen B, Xie Y, Xu Y, Hu J, Dai M - PLoS ONE (2016)

Bottom Line: However the TChl a biomass in the surface layer (at 5 m) in the eddy center was promoted 2.6-fold compared to the biomass outside the eddy (p < 0.001).The TChl a biomass for most of the phytoplankton groups increased at the surface layer in the eddy center under the effect of nutrient pumping.So the slight increasing in the water column integrated phytoplankton biomass might be attributed to the stimulated phytoplankton biomass at the surface layer.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of the Coastal and Wetland Ecosystems, the Ministry of Education, Xiamen University, Xiamen, China.

ABSTRACT
It is widely recognized that the mesoscale eddies play an important part in the biogeochemical cycle in ocean ecosystem, especially in the oligotrophic tropical zones. So here a heterogeneous cyclonic eddy in its flourishing stage was detected using remote sensing and in situ biogeochemical observation in the western South China Sea (SCS) in early September, 2007. The high-performance liquid chromatography method was used to identify the photosynthetic pigments. And the CHEMical TAXonomy (CHEMTAX) was applied to calculate the contribution of nine phytoplankton groups to the total chlorophyll a (TChl a) biomass. The deep chlorophyll a maximum layer (DCML) was raised to form a dome structure in the eddy center while there was no distinct enhancement for TChl a biomass. The integrated TChl a concentration in the upper 100 m water column was also constant from the eddy center to the surrounding water outside the eddy. However the TChl a biomass in the surface layer (at 5 m) in the eddy center was promoted 2.6-fold compared to the biomass outside the eddy (p < 0.001). Thus, the slight enhancement of TChl a biomass of euphotic zone integration within the eddy was mainly from the phytoplankton in the upper mixed zone rather than the DCML. The phytoplankton community was primarily contributed by diatoms, prasinophytes, and Synechococcus at the DCML within the eddy, while less was contributed by haptophytes_8 and Prochlorococcus. The TChl a biomass for most of the phytoplankton groups increased at the surface layer in the eddy center under the effect of nutrient pumping. The doming isopycnal within the eddy supplied nutrients gently into the upper mixing layer, and there was remarkable enhancement in phytoplankton biomass at the surface layer with 10.5% TChl a biomass of water column in eddy center and 3.7% at reference stations. So the slight increasing in the water column integrated phytoplankton biomass might be attributed to the stimulated phytoplankton biomass at the surface layer.

No MeSH data available.


Related in: MedlinePlus

Maps of the study area (A) and location of sampling sites (B) during the September 2007 cruise. The red dots indicate the 29 stations where the phytoplankton pigment survey was carried out during the cruise.
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pone.0153735.g001: Maps of the study area (A) and location of sampling sites (B) during the September 2007 cruise. The red dots indicate the 29 stations where the phytoplankton pigment survey was carried out during the cruise.

Mentions: High performance liquid chromatography (HPLC) pigments were measured at 29 of the total 37 stations surveyed during this cruise (Fig 1). SeaBird SBE 9/11 and 9/17 Plus CTD systems were deployed to acquire hydrographic measurements. Current velocity was measured using a ship-mounted acoustic Doppler current profiler. To identify the locality of the eddy, the weekly merged data of the sea level anomaly (SLA) were acquired from the French Archiving, Validation, and Interpolation of Satellite Oceanographic (AVISO, http://www.aviso.oceanobs.com/en/data.html) data project. Seawater samples were collected in succession at standard depths (0, 25, 50, 75, 100 and 150 m) and in addition at the deep chlorophyll a maximum layer (DCML) using CTD-mounted rosette assemblies with 12 L or 30 L Niskin bottles (General Oceanic Inc.). The DCML was determined by both of the fluorescence and TChl a pigment profiles (S1 Fig). The euphotic zone (Zeu) was calculated using the depth with 1% intensity of surface photosynthetically active radiation (PAR) [30]. The mixed layer depth (MLD) was estimated according to the ± 0.2°C and 0.03 kg m-3 threshold criterion [31]. The stratification index (SI) was calculated according to the density difference normalized to the depth difference (100 m in this study) [32].


Physical-Biological Coupling in the Western South China Sea: The Response of Phytoplankton Community to a Mesoscale Cyclonic Eddy.

Wang L, Huang B, Chiang KP, Liu X, Chen B, Xie Y, Xu Y, Hu J, Dai M - PLoS ONE (2016)

Maps of the study area (A) and location of sampling sites (B) during the September 2007 cruise. The red dots indicate the 29 stations where the phytoplankton pigment survey was carried out during the cruise.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835056&req=5

pone.0153735.g001: Maps of the study area (A) and location of sampling sites (B) during the September 2007 cruise. The red dots indicate the 29 stations where the phytoplankton pigment survey was carried out during the cruise.
Mentions: High performance liquid chromatography (HPLC) pigments were measured at 29 of the total 37 stations surveyed during this cruise (Fig 1). SeaBird SBE 9/11 and 9/17 Plus CTD systems were deployed to acquire hydrographic measurements. Current velocity was measured using a ship-mounted acoustic Doppler current profiler. To identify the locality of the eddy, the weekly merged data of the sea level anomaly (SLA) were acquired from the French Archiving, Validation, and Interpolation of Satellite Oceanographic (AVISO, http://www.aviso.oceanobs.com/en/data.html) data project. Seawater samples were collected in succession at standard depths (0, 25, 50, 75, 100 and 150 m) and in addition at the deep chlorophyll a maximum layer (DCML) using CTD-mounted rosette assemblies with 12 L or 30 L Niskin bottles (General Oceanic Inc.). The DCML was determined by both of the fluorescence and TChl a pigment profiles (S1 Fig). The euphotic zone (Zeu) was calculated using the depth with 1% intensity of surface photosynthetically active radiation (PAR) [30]. The mixed layer depth (MLD) was estimated according to the ± 0.2°C and 0.03 kg m-3 threshold criterion [31]. The stratification index (SI) was calculated according to the density difference normalized to the depth difference (100 m in this study) [32].

Bottom Line: However the TChl a biomass in the surface layer (at 5 m) in the eddy center was promoted 2.6-fold compared to the biomass outside the eddy (p < 0.001).The TChl a biomass for most of the phytoplankton groups increased at the surface layer in the eddy center under the effect of nutrient pumping.So the slight increasing in the water column integrated phytoplankton biomass might be attributed to the stimulated phytoplankton biomass at the surface layer.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of the Coastal and Wetland Ecosystems, the Ministry of Education, Xiamen University, Xiamen, China.

ABSTRACT
It is widely recognized that the mesoscale eddies play an important part in the biogeochemical cycle in ocean ecosystem, especially in the oligotrophic tropical zones. So here a heterogeneous cyclonic eddy in its flourishing stage was detected using remote sensing and in situ biogeochemical observation in the western South China Sea (SCS) in early September, 2007. The high-performance liquid chromatography method was used to identify the photosynthetic pigments. And the CHEMical TAXonomy (CHEMTAX) was applied to calculate the contribution of nine phytoplankton groups to the total chlorophyll a (TChl a) biomass. The deep chlorophyll a maximum layer (DCML) was raised to form a dome structure in the eddy center while there was no distinct enhancement for TChl a biomass. The integrated TChl a concentration in the upper 100 m water column was also constant from the eddy center to the surrounding water outside the eddy. However the TChl a biomass in the surface layer (at 5 m) in the eddy center was promoted 2.6-fold compared to the biomass outside the eddy (p < 0.001). Thus, the slight enhancement of TChl a biomass of euphotic zone integration within the eddy was mainly from the phytoplankton in the upper mixed zone rather than the DCML. The phytoplankton community was primarily contributed by diatoms, prasinophytes, and Synechococcus at the DCML within the eddy, while less was contributed by haptophytes_8 and Prochlorococcus. The TChl a biomass for most of the phytoplankton groups increased at the surface layer in the eddy center under the effect of nutrient pumping. The doming isopycnal within the eddy supplied nutrients gently into the upper mixing layer, and there was remarkable enhancement in phytoplankton biomass at the surface layer with 10.5% TChl a biomass of water column in eddy center and 3.7% at reference stations. So the slight increasing in the water column integrated phytoplankton biomass might be attributed to the stimulated phytoplankton biomass at the surface layer.

No MeSH data available.


Related in: MedlinePlus