Form 3

Annual Report
LaMer, Ehime University

Date (24 , 2 , 2017)
To Director of LaMer

Principle Investigator:
Affiliation Ocean University of China
Position

Associate professor

Name in print

Jie Shi

Include the report on the result of the project/meeting in a separate sheet.
1. Project / Meeting title
Interannual variations of spring phytoplankton bloom in the central Southern Yellow
Sea in response to the atmospheric forcing
2. Members of project / meeting
NameAffiliation

Position

Jie Shi

Ocean University ofChina

Associateprofessor

Yi LiuSouth China Sea
Institute of Oceanology
Ehime University，Faculty member of
LaMer
Ocean University of
China

Graduatestudent
Professor

Xinyu Guo

Huiwang Gao

Professor

Contribution part

Providingthemainscientific idea and writing
the paper
Satellite data processing
Beneficial discussion andhelping response to thecomments from reviewers
Beneficial discussion

Xinyan Mao

Ocean University of
China

Lecturer

Beneficial discussion

3. Contents (please write in separate sheet, A4-size, within 5 pages
including figures and tables. Itemize “Title, members’ names and affiliations, aim,
procedure, result, publication/conference presentation, perspectives in future”).
This report will be opened to the public through LaMer website and printedmatter. Please send additional products, i.e., abstract book, reprint, if available toLaMer Office of Research Support Division,
Ehime University, Bunkyo 2-5, Matsuyama, 790-8577 Japan
E-mail: lamer@stu.ehime-u.ac.jp
Tel and Fax: +81-89-927-8187

TitleInterannual variations of spring phytoplankton bloom in the central Southern Yellow
Sea in response to the atmospheric forcing

Members’ names and affiliations
NameJie Shi
Yi LiuInstitutionand Employment position
Department
Ocean University Associate Professorof China, OUC
South China Sea Graduate student
InstituteE-mailshijie@ouc.edu.cn
liuyi315@mails.ucas.ac.cn

ofOceanology
Xinyan Mao

Ocean

University Lecturer

maoxinyan@ouc.edu.cn

of China
Xinyu Guo

Faculty member of Professor

guoxinyu@sci.ehime-u.ac.jp

LaMer
Huiwang Gao

Ocean

University Professor

hwgao@ouc.edu.cn

of China, OUC

Aim
Under the help of Prof. Xinyu Guo, we carried out a study on the interannual variationof phytoplankton bloom in the central Southern Yellow Sea using the satellite date andsubmitted a paper to Continental Shelf Research. Based on the previous work, we didsome new research on the ecosystem dynamics in the regional seas of China.

Procedure
1. The principal investigator (Jie Shi) made an oral presentation to the researchers inCenter for Marine Environmental Studies (CMES), Ehime University. The title of thepresentation is “Contributions of physical and biogeochemical processes tophytoplankton biomass enhancement in the surface and subsurface layers duringTyphoon Damrey”.
2. The principal investigator (Jie Shi) carried out a deep discussion on the interannualvariations of the main primary production processes in the Yellow Sea of China and theinfluencing factors with Prof. Guo. These are the spring phytoplankton bloom and thesummer subsurface chlorophyll maximum.
3. The principal investigator (Jie Shi) and Prof. Guo wrote a proposal on the nutrients
cycle and budget in the Yellow Sea of China. A discussion has been made to confirm themain study contents.

Results
The interannual variations of the start timing, magnitude and duration of the spring
phytoplankton bloom (SPB) in the central southern Yellow Sea (SYS) (Fig. 1) werestudied using the satellite-derived surface chlorophyll-a concentrations (Chl-a) from2000 to 2014 (Fig. 2). The correlations between the characteristics of SPB and thegeneration rate of turbulent kinetic energy (TKERT) supplied from the atmosphere to theocean were examined. The start timing of SPB was delayed in years with high TKERT
supplied to the ocean before SPB (Fig. 3). The TKERT during SPB had no relationshipwith the magnitude of SPB, but had positive correlation with the duration (Fig. 4). A1-D physical-biological model was used to examine the influencing mechanisms of theTKERT on the characteristics of SPB quantitatively. The wind speeds and related TKERT
before the start of SPB were stronger in 2010 than in 2008. Comparison of the model
results forced by winds in the two years suggested that the enhanced physical dilution ofphytoplankton caused by the stronger TKERT in 2010 induced a later start timing of SPB.
When increasing the winds during SPB period, more phytoplankton was taken

downward from the surface layer by the enhanced vertical mixing. Meanwhile, more
nutrients were pumped upward to the surface layer and supported more net growth ofphytoplankton. These two contrary processes led to the independence of the magnitudeof SPB on the TKERT during the SPB period. However, larger TKERT along withstronger wind resulted in a longer duration of SPB because of more nutrients supply bystronger vertical mixing.

Fig.1 Bathymetric and geographic map of the YS

Fig.2 Spatial distribution of monthly mean surface Chl-a in the SYS calculated from all
the satellite data in the same month from 2000 to 2014. The colors represent the surfaceChl-a. The solid lines are the isobaths of 50 m and 70 m. The square is the study area.

Fig.3 Correlations between TKERT-1w (a), TKERT-2w (b), TKERT-1m (c), the weakening timeof TKERT (d) and the start timing of SPB.

Fig.4 Correlations between magnitudes (a), durations of SPB (b) and TKERT during SPB.

Publication/conference presentation
Publication:
Jie Shi, Yi Liu, Xinyan Mao, Xinyu Guo, Huiwang Gao, 2017. Interannual
variation of spring phytoplankton bloom and response to turbulent energy
generated by atmospheric forcing in the central Southern Yellow Sea of China:

Satellite observations and numerical model study. Continental Shelf Research,inpress.
Shanshan Pan, Jie Shi, Huiwang Gao, Xinyu Guo, Xiaohong Yao, Xiang Gong,
2017.

Contributionsofphysicalandbiogeochemical

processes

tophytoplankton biomass enhancement in the surface and subsurface layers
during the passage of Typhoon Damrey. Journal of Geophysical Research:
Biogeosciences, 122, doi: 10,1002/2016JG003331.
Oral presentation:
Title: Contributions of physical and biogeochemical processes to phytoplankton
biomass enhancement in the surface and subsurface layers during Typhoon
DamreyLecturer: Jie Shi.
Time: February 7, 2017.
Location: Ehime University.

Perspectives in future
The interannual variations of the Yellow Sea Cold Water Mass (YSCWM) will be
examined using the observations and model results. The ecological effects of theYSCWM will also be studied, such as the transport of nutrients, the promotion ofprimary production and so on. Besides, we will estimate the dynamic variation of thenutrient budget in the Yellow Sea and investigate the influencing factors.