Species composition and biomass density of mesopelagic nekton of the South China Sea continental slope

Abstract. Coccolithophore contributions to the global marine carbon cycle are regulated by the calcite content of their scales (coccoliths), and the relative cellular levels of photosynthesis and calcification. All three of these factors vary between coccolithophore species, and with response to the growth environment. Here, water samples were collected in the northern basin of the South China Sea (SCS) during summer 2014 in order to examine how environmental variability influenced species composition and cellular levels of calcite content. The vertical structure of the coccolithophore community was strongly regulated by mesoscale eddies. All living coccolithophores produced within the euphotic zone (1 % of surface irradiance), and Florisphaera profunda was a substantial coccolithophore and coccolith-calcite producer in the Deep Chlorophyll-a Maximum (DCM), especially in most oligotrophic anti-cyclonic eddy centers. Placolith-bearing coccolithophores, plus F. profunda, and other larger and numerically rare species made almost equal contributions to coccolith-based calcite in the water column. For Emiliania huxleyi biometry measurements, coccolith size positively correlated with nutrients, and it is suggested that coccolith length is influenced by nutrient and light related growth rates. However, larger sized coccoliths were related to low pH and calcite saturation, although it is not a simple cause and effect relationship. Genotypic or ecophenotypic variation may also be linked to coccolith size variation.

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Measurement and modeling of sound propagation over continental slope in the South China Sea

The Journal of the Acoustical Society of America ◽

10.1121/10.0000801 ◽

2020 ◽

Vol 147 (3) ◽

pp. EL209-EL214

Author(s):

Jin Liu ◽

Zhaohui Peng ◽

Zhenglin Li ◽

Wenyu Luo ◽

Xishan Yang

Keyword(s):

South China Sea ◽

Continental Slope ◽

South China ◽

Sound Propagation ◽

The South China Sea ◽

The South ◽

China Sea

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Submarine Sand Dunes on the Continental Slope in the South China Sea and Their Impact on Internal Wave Transformation and Acoustic Propagation

10.21236/ada598325 ◽

2013 ◽

Author(s):

Steven R. Ramp

Keyword(s):

South China Sea ◽

Internal Wave ◽

Continental Slope ◽

South China ◽

Sand Dunes ◽

Acoustic Propagation ◽

The South China Sea ◽

Wave Transformation ◽

The South ◽

China Sea

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Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

Biogeosciences ◽

10.5194/bg-13-4843-2016 ◽

2016 ◽

Vol 13 (16) ◽

pp. 4843-4861 ◽

Cited By ~ 14

Author(s):

Xiaobo Jin ◽

Chuanlian Liu ◽

Alex J. Poulton ◽

Minhan Dai ◽

Xianghui Guo

Keyword(s):

South China Sea ◽

Species Composition ◽

Water Column ◽

South China ◽

Water Samples ◽

Environmental Variability ◽

Emiliania Huxleyi ◽

The South China Sea ◽

The South ◽

China Sea

Abstract. Coccolithophore contributions to the global marine carbon cycle are regulated by the calcite content of their scales (coccoliths) and the relative cellular levels of photosynthesis and calcification rates. All three of these factors vary between coccolithophore species and with response to the growth environment. Here, water samples were collected in the northern basin of the South China Sea (SCS) during summer 2014 in order to examine how environmental variability influenced species composition and cellular levels of calcite content. Average coccolithophore abundance and their calcite concentration in the water column were 11.82 cells mL−1 and 1508.3 pg C mL−1, respectively, during the cruise. Water samples can be divided into three floral groups according to their distinct coccolithophore communities. The vertical structure of the coccolithophore community in the water column was controlled by the trophic conditions, which were regulated by mesoscale eddies across the SCS basin. The evaluation of coccolithophore-based calcite in the surface ocean also showed that three key species in the SCS (Emiliania huxleyi, Gephyrocapsa oceanica, Florisphaera profunda) and other larger, numerically rare species made almost equal contributions to total coccolith-based calcite in the water column. For Emiliania huxleyi biometry measurements, coccolith size positively correlated with nutrients (nitrate, phosphate), and it is suggested that coccolith length is influenced by light and nutrients through the regulation of growth rates. Larger-sized coccoliths were also linked statistically to low pH and calcite saturation states; however, it is not a simple cause and effect relationship, as carbonate chemistry was strongly co-correlated with the other key environmental factors (nutrients, light).

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