Effects of Changjiang Diluted Water

on the planktonic ecology of the Yellow Sea Cold

Water Mass

PU Xinming

Research Center for Marine Ecology

First Institute of Oceanography, Ministry of Natural Resources

June 10-11, 2019, Penglai

YSCWM

Average bottom temperature in

August (GUO, 2004)Sun et al, 2002

➢ strong thermocline

➢ Low nutrient and Chla at

surface

➢ Pico- and nano- sized

phytoplankton

➢ Bottom gathering of inactive

zooplankton

Eutrophication

Spring/Summer

phytoplankton /

macroalgae bloom

Hypoxia

Primary production and

species succession

Zooplankton population

and community dynamics

Fish and Jellyfish

Land Ocean Air

Marine Ecosystem

Climate Change

China

Korea

Changjiang

External sources of YSCWM

➢ Kuroshio / YS warm current

➢ Coastal currents

➢ Air/ spring dust storm

➢ Changjiang Diluted Water

Parameters July 2013:

✓ T, S

✓Nutrients, DO, pH

✓Chla, phytoplankton,

zooplankton

✓C13, N15 of POC

Changjiang Diluted Water: one of the most

important external forces

123E

123E 124E

124E

Temperature

Salinity

DO pH 123E

124E 124E

123E

POC 123E

PN 123E

TSS 123E

124E

POC 124E

PN 124E

124E123E

TIN

PO4

SiO3

Nutrients

Chlorophyll a

123E

124E

Pico-phytoplankton124E

123E

Phytoplankton (nano- and micro-)

123E

124E

Cell abundance (10x cells/L)

Diatom%

Dino-%

Dominant species:

Diatom:Chaetoceros, Pseudonitzschia, Thalassiosira

Dino: Noctiluca scientillans, Prorocentrum dentatum

δ13C POC

123E

124E

δ13C POC in Changjiang River

Terrestrial sources −27‰– −25‰

Marine sources −21‰– −19‰

(Wu et al., 2007b; Zhang et al., 2007)

δ15N PN

124E

123E

zooplankton

123E

124E

Longer body length vs shorter

C4 and C4 dominated vs. C6 female

Deep layer vs surface layer

Connectional model for CDW-YSCWM

North-east flow of CDW during summer

Surface bloom of diatom and noctiluca

Fast sinking of POC

Decomposition and DO depletion at bottom

Changes of environments and food sources of zooplankton

Intrusion of POC to YSCWM at bottom layers

The physical, chemical and biological patterns of

YSCWM in summer are greatly modified by

Changjiang Diluted Water(CDW).

CDW induced phytoplankton summer blooms in the

southern Yellow Sea. The sunk POC caused

hypoxia, and maybe a food source for cold-dwelling

Calanus sinicus.

Conclusion

Field cruises supported by FIO-KIOST joint program

on YSCWM. PI: Zongling Wang

Physical : Changshui Xia

Chemical: Ming Xin, and Xia Sun

Phytoplankton: Ping Sun, Yan Li

Zooplankton: Xiao Wang, Ping Liu

Stable isotopes: Mingya Diao,Jingjin Pan, Jinfen

Pan

Acknowledgement

Thank You

Three gorges of Changjiang River

Thank You

Cruise 2011 Cruise 2013

Noctiluca scientillans