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Qinsheng Wei
Acidification induced by the individual
Ocean conditions
First Institute of Oceanography, SOA, China
WESTPAC Workshop on “Research and Monitoring of the
Ecological Impacts of Ocean Acidification on Coral Reef
Ecosystems”
ALOHA
pH
CO
2
Jim Orr (2010)
Background
BATS
ESTOC
Ocean Acidification: the other CO2 problem
associated to the climate change
pH
Decreased
30% in the
last century
OA signals in some typical ocean conditions
Semi-enclosed marginal sea: southern Yellow Sea
Large river estuary: Changjiang river estuary
Upwelling system: western area of the South China Sea
Concluding remarks
Summary of this presentation
The Yellow Sea is a marginal sea of the Pacific Ocean.
It is located between the Korean Peninsula and mainland China .
Its name comes from the yellowish suspended particles in the
seawater.
southern Yellow Sea
Bottom, August
southern Yellow Sea
A southward movement of coastal water and a northwestward
inshore intrusion of the Yellow Sea Warm Current in wintertime.
The notable Yellow Sea Cold Water Mass (YSCWM) in summertime.
Hydrography:
Yuan et al., 2008
Long-term variation of chemical parameters in the SYS
From 1976 to 2006
OA in the southern Yellow Sea
Temperature
Temperature
Salinity
Salinity
DO pH
DO pH
Winter
Summer
OA in the southern Yellow Sea
Combined effects of global atmospheric CO2 increase, regional environmental changes, and local biogeochemical processes.
Significant correlations exist between those parameters.
Cai et al., 2011
Changjiang River estuary
One of the most polluted area in China
1989
Li et al., 2002
Chemical Oceanography Atlas, 1989
120o
121o
122o
123o
124o
125o
126o
127o
27o
28o
29o
30o
31o
32o
33o
34o
Yellow Sea
Eas
tC
hina
Sea
N
E
China
Hangzhou Bay
1999 2006
Zhou et al., 2010
Hypoxia off the Changjiang
River estuary
Annual cycle
of hypoxia
Aug. 2013
OA in the Changjiang River estuary
Bottom hypoxia and acidification occurred off the estuary from the
spring to summer, and the extensive area of low pH coincided with the
hypoxic zone in summer.
Seasonal OA in the Changjiang River
estuary
The analysis of data revealed a significant positive correlation between bottom water
pH and DO concentration, which linked the acidification to oxygen consumption via
local organic matter remineralization.
Yin et al., 2004
The tendency of Lowest DO on bottom layer in Summer(Aug)
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DO(m
g/L)
The lowest DO concentration in summer
Indicating that the long-term OA in the hypoxic zone off the
Changjiang River estuary may be also obvious.
South China Sea
• 3.6×106 km2
• Max depth: >5000 m, average=1350 m
• Basin oligotrophic
– P: < 10 nM
– N: ~10 nM
• Large rivers (Pearl, Mekong Rivers)
Frequently influenced by monsoons, typhoons, strong
internal waves and ENSOMulti-year averaged SST
Upwelling signal in the western SCS
Conducted during June – July
2009. Totally 28 stations were
visited.
Cold patches with
high salinity are
very distinct in the
upper layer waters.
Declining pH induced by upwelling in the western SCS
T S Nitrate Chl-a pH
CO2 can be upwelled into the upper ocean. And there is excess
CO2 in the upper layer waters of the upwelling .
Significant positive correlation between pH and temperature was observed
in 50m layer.
The signals of acidification are discussed in the
different marine systems: semi-enclosed marginal
sea, river estuary and open upwelling system.
The intense acidification may be closely related to the
typical/special ocean conditions.
Concluding remarks
Stramma et al, 2010
Diaz & Rosenberg, 2008
Ocean oxygen minimum zone expands
globally.
Spreading dead zones off the coastThe strength of stratification and
upwelling may be also changed.
