Effects of typhoon Roke and Haitang on phytoplankton community structure in northeastern South China sea

Figures & data

Figure 1. The investigation map in the neSCS (R: Typhoon Roke route; H: Typhoon Haitang route; K: Kuroshio current intrusion route)

Figure 2. The temperature (a) and salinity (b) distribution of 5 m water depth in the survey area

Figure 3. Sectional distribution of temperature (a) and salinity (b) in section K

Figure 4. Sectional distribution of temperature (a) and salinity (b) in section R

Figure 5. Sectional distribution of temperature (a) and salinity (b) in Section H

Table 1. Dominant phytoplankton species in the northeastern South China sea in summer 2017

Species	Percentage of the ratio to total phytoplankton(%)	Frequency(fi)	Dominance(Y)
Trichodesmium thiebautii	80.26	0.515	0.4136
Thalassionema nitzschioides	2.28	0.827	0.0189
Thalassionema frauenfeldii	1.61	0.76	0.0122
Prorocentrum lenticulatum	1.57	0.964	0.0151
Thalassiosira minima	1.23	0.898	0.011
Prorocentrum minimum	1.15	0.878	0.0101
Thalassiothrix longissima	0.99	0.505	0.005
Navicula spp.	0.91	0.893	0.0082
Prorocentrum compressum	0.58	0.806	0.0047
Cyclotella striata	0.45	0.735	0.0033

Figure 6. Vertical distribution of phytoplankton cell abundance (Log base 10). (a): Phytoplankton; (b): Bacillariophyta;(c): Dinophyta; (d): Cyanophyta

Figure 7. Horizontal distribution of phytoplankton cell abundance in the surface water layer (10³ cells L⁻¹). (a): Phytoplankton; (b): Bacillariophyta; (c): Dinophyta; (d): Cyanophyta

Table 2. Horizontal distributions of the dominant species in the survey area

Species	Maximum(10^3 cells L^−1)	Average(10^3 cells L^−1)	Maximum stations
Trichodesmium thiebautii	41.020	3.560	N2
Thalassionema nitzschioides	0.445	0.134	N2
Thalassionema frauenfeldii	0.203	0.096	A10
Prorocentrum lenticulatum	0.161	0.078	N2、DC6
Thalassiosira minima	0.116	0.059	N2
Prorocentrum minimum	0.099	0.058	C3
Thalassiothrix longissima	1.037	0.048	A10
Navicula spp.	0.138	0.047	N2、DC6
Prorocentrum compressum	0.09	0.027	N2、DC6
Cyclotella striata	0.054	0.026	D2

Figure 8. Horizontal distribution of dominant species (10³ cells L⁻¹). (a): Trichodesmium thiebautii; (b): Thalassionema nitzschioides; (c): Thalassionema frauenfeldii; (d): Prorocentrum compressum; €: Thalassiosira minima; (f): Prorocentrum minimum; (g): Thalassiothrix longissima; (h): Navicula spp.; (i): Prorocentrum compressum; (j): Cyclotella striata

Figure 9. Horizontal distribution of Shannon–Wiener diversity index (a) and Pielou’s evenness index (b) surface for phytoplankton communities

Table 3. Historical data of the phytoplankton community in the northern South China sea in summer

Date	Sampling areas	Layer /m	Richness	Abundance /10^3cells·L^−1	Analytical methods	References
2017.08	15°~22°N,114°~120°E	Surface	150	6.76	Utermöhl	This study
2017.08	15°~22°N,114°~120°E	0～200	298	5.30	Utermöhl	This study
2014.08	18°~22°N,114°~116°E	Surface	98	0.225	Utermöhl	Xue, Sun, and Li 2016
2014.08	18°~22°N,114°~116°E	0～200	229	14.653	Utermöhl	Xue, Sun, and Li 2016
2009.07	18°~23.5°N,109°~120°E	0～200	150	26.49	Utermöhl	Xue, Sun, and Li 2016
2007.08	18°~23°N,110°~120°E	0～200	216	11.22	Concentration counting	Ke, Huang, and Tan 2011
2004.08	18°~22°N,110°~117°E	0～200	159	115.05	Utermöhl	Le et al. 2006
1999.08	18°~22°N,105°~117°E	Surface	58	181.00	Concentration counting	Zhu et al. 2003
1998.06	5°~25°N,105°~120°E	Surface	63	0.83	Concentration counting	Zhu et al. 2003

Table 4. Pearson correlation between phytoplankton and environmental factors

	Phytoplankton	Bacillariophyta	Dinophyta	Cyanophyta
PO4^3-	0.14**	−0.072	.425**	0.117**
NO2^−	−0.116	0.126	0.047	−0.136
NH4 ^+	0.08*	−0.021	−0.015	−0.104
SiO3^2-	.187**	0.073**	−.597	−0.172
NO3 ^−	−.166*	−0.074	−.570**	−0.144
Temperature	.256**	0	.656**	.232*
Salinity	−0.098	0.117	−.421**	−0.022

* for P < 0.05, **for P < 0.01.

Figure 10. Sectional distribution of phytoplankton abundance in Section K (10³ cells L⁻¹). (a): Phytoplankton; (b): Bacillariophyta; (c): Dinophyta; (d): Trichodesmium thiebautii.

Figure 11. Sectional distribution of phytoplankton abundance in Section R (10³ cells L⁻¹). (a): Phytoplankton; (b): Bacillariophyta; (c): Dinophyta; (d): Cyanophyta

Figure 12. Sectional distribution of phytoplankton abundance in Section H (10³ cells L⁻¹). (a): Phytoplankton; (b): Bacillariophyta; (c): Dinophyta; d: Cyanophyta

Xue, B., J. Sun, and T. Li. 2016. “Phytoplankton Community Structure of Northern South China Sea in Summer 2014.” [In Chinese.] Acta Oceanologica Sinica 38 (4): 54–65. doi:10.3969/j.issn.0253-4193.2016.04.005.

 Google Scholar

Ke, Z., L. Huang, and Y. Tan. 2011. “Species Composition and Abundance of Phytoplankton in the Northern South China Sea in Summer 2007.” [In Chinese.] Journal of Tropical Oceanography 30 (1): 131–143. doi:10.3969/j.issn.1009-5470.2011.01.020.

 Google Scholar

Le, F., J. Sun, X. Ning, S. Song, Y. Cai, and C. Liu. 2006. “Phytoplankton in Northern South China Sea in Summer 2004.” [In Chinese.] Oceanologia Et Limnologia Sinica 37 (3): 238–248. doi:10.3321/j.issn:0029-814X.2006.03.008.

 Google Scholar

Zhu, G., X. Ning, Y. Cai, Z. Liu, and C. Liu. 2003. “Studies on Species Composition and Abundance Distribution of Phytoplankton in the South China Sea.” Acta Oceanologica Sinica (in Chinese) 25 (2): 8–23.

 Google Scholar