Limits...
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

The linear relationship between the TChl a biomass in the upper 100 m water column integration of (A) diatoms [mg m-2], (B) haptophytes_8 [mg m-2], (C) Synechococcus [mg m-2], (D) Prochlorococcus [mg m-2] and the temperature at the 50 m depth layer. The solid line and two dashed lines are the same as in Fig 8.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835056&req=5

pone.0153735.g009: The linear relationship between the TChl a biomass in the upper 100 m water column integration of (A) diatoms [mg m-2], (B) haptophytes_8 [mg m-2], (C) Synechococcus [mg m-2], (D) Prochlorococcus [mg m-2] and the temperature at the 50 m depth layer. The solid line and two dashed lines are the same as in Fig 8.

Mentions: The highly heterogeneous character of the physical properties in cyclonic eddy C2 [28] probably influenced the distribution of nutrients, therefore resulting in a significant spatial variation of phytoplankton biomass within the eddy. In this study, the temperature at the 50 m layer was used as a proxy of the nutrients pumping strength in C2. The concentration of NO2-+NO3- (unpublished data from Dai) was remarkably higher in IN than in EDGE and OUT (Fig 4D & 4E). The remarkable negative correlation between the concentration of NO2-+NO3- and the temperature at 50 m implied the gliding of nutrient gradients from the affluence eddy center to the barren adjacent water (Fig 8A). Furthermore, the thermal gradient between 23.0~26.0°C with few dot implied that the C2 front was relatively narrow, in spite of no sharper than the cyclone “Loretta” [44] and “Opal” [5]. The nutrients pumping from the deep water could induce a response of phytoplankton biomass, and hence there was a negative relationship between spatial variability in the total phytoplankton biomass and the temperature at 50 m (Fig 8). Thus, the temperature at 50 m was used as a proxy to represent the pumping intensity, as well as its intrinsic effect on the response of different phytoplankton groups (Figs 9–11). There were negative correlations between diatoms, Synechococcus and the temperature for the TChl a inventory (Fig 9). Negative relationships of diatoms and Synechococcus spp. with temperature at the DCML were also presented, while the haptophytes_8 and Prochlorococcus behaved positively with temperature (Fig 10). In the upper mixed zone (Fig 11), the response of phytoplankton to the upwelled nutrients was very notable as compared with the status at the DCML, including haptophytes_8 and Synechococcus spp. Diatoms showed a good positive response at the DCML and no response in the upper mixed zone.


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)

The linear relationship between the TChl a biomass in the upper 100 m water column integration of (A) diatoms [mg m-2], (B) haptophytes_8 [mg m-2], (C) Synechococcus [mg m-2], (D) Prochlorococcus [mg m-2] and the temperature at the 50 m depth layer. The solid line and two dashed lines are the same as in Fig 8.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0153735.g009: The linear relationship between the TChl a biomass in the upper 100 m water column integration of (A) diatoms [mg m-2], (B) haptophytes_8 [mg m-2], (C) Synechococcus [mg m-2], (D) Prochlorococcus [mg m-2] and the temperature at the 50 m depth layer. The solid line and two dashed lines are the same as in Fig 8.
Mentions: The highly heterogeneous character of the physical properties in cyclonic eddy C2 [28] probably influenced the distribution of nutrients, therefore resulting in a significant spatial variation of phytoplankton biomass within the eddy. In this study, the temperature at the 50 m layer was used as a proxy of the nutrients pumping strength in C2. The concentration of NO2-+NO3- (unpublished data from Dai) was remarkably higher in IN than in EDGE and OUT (Fig 4D & 4E). The remarkable negative correlation between the concentration of NO2-+NO3- and the temperature at 50 m implied the gliding of nutrient gradients from the affluence eddy center to the barren adjacent water (Fig 8A). Furthermore, the thermal gradient between 23.0~26.0°C with few dot implied that the C2 front was relatively narrow, in spite of no sharper than the cyclone “Loretta” [44] and “Opal” [5]. The nutrients pumping from the deep water could induce a response of phytoplankton biomass, and hence there was a negative relationship between spatial variability in the total phytoplankton biomass and the temperature at 50 m (Fig 8). Thus, the temperature at 50 m was used as a proxy to represent the pumping intensity, as well as its intrinsic effect on the response of different phytoplankton groups (Figs 9–11). There were negative correlations between diatoms, Synechococcus and the temperature for the TChl a inventory (Fig 9). Negative relationships of diatoms and Synechococcus spp. with temperature at the DCML were also presented, while the haptophytes_8 and Prochlorococcus behaved positively with temperature (Fig 10). In the upper mixed zone (Fig 11), the response of phytoplankton to the upwelled nutrients was very notable as compared with the status at the DCML, including haptophytes_8 and Synechococcus spp. Diatoms showed a good positive response at the DCML and no response in the upper mixed zone.

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