The vulnerable ocean: Decadal changes in the ocean carbon and oxygen cycles Holger Brix 1 , Curtis Deutsch 2 , Scott C. Doney 3 , Arne Koertzinger 4 , Doug W. R. Wallace 4 , and Rik Wanninkhof 5 Nicolas Gruber Environmental Physics, Institute of Biogeochemistry and Pollutant Dynami ETH Zürich, Switzerland (1) IGPP, UCLA, Los Angeles, USA; (2) Univ. of Washington, Seattle, USA; (3) WHOI, Woods Hole, USA; (4) Leibniz Inst. for Marine Sciences, GER; (5) NOAA AOML, Miami, USA.
Transcript
The vulnerable ocean: Decadal changes in the ocean carbon and oxygen cycles
Holger Brix1, Curtis Deutsch2, Scott C. Doney3, Arne Koertzinger4, Doug W. R. Wallace4, and Rik Wanninkhof5
Nicolas Gruber
Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics,ETH Zürich, Switzerland
(1) IGPP, UCLA, Los Angeles, USA; (2) Univ. of Washington, Seattle, USA; (3) WHOI, Woods Hole, USA; (4) Leibniz Inst. for Marine Sciences, GER; (5) NOAA AOML, Miami, USA.
1955-1998: Rate of 3.3x1021 J yr-1 = 0.2 W m-2 = 0.1 PW
APPA
REN
T O
XYG
EN
UTIL
IZA
TIO
NAAIW
MED
LAB
AAIW
NADW
MED
STMW
NADW
LAB
SPMW
SPMW
AOU = [O2sat] - [O2]
AO
U C
HA
NG
ES
20
03
-19
93
AO
U A
ND
DIC
CH
AN
GES
200
3-1
993
Expected change from anthropogenic CO2: max 0-8 mol/kg
IMBER-SOLAS CO2/CLIVAR Repeat Hydrography Program
status ~2005
ARGO: The next generation observing system
A global array of profiling floats that measure the temperature and
salinity of the upper 2000 m on a ~10 day repeat cycle.
How to get oxygen on ARGO floats: Promising oxygen sensors
Electrochemical sensor(Seabird SBE 43/IDO)
Optode sensor (Aanderaa 3830)
Measurement range:120% of surface saturation
Initial accuracy:2% of saturation
Response time:6 s (e-folding time)
Measurement range:0-120% of surface saturation(0-500 µM)
Precision:<1 µM (0.4%)
Initial accuracy:8 µM or 5% (whichever is greater)
Response time:25 s (63% e-folding time)
Principle: Life time based dynamic fluorescence quenching
• Oxygen concentrations in the thermocline of the North Atlantic have decreased substantially over the last decade, accompanied by a faster than expected increase in DIC.
• The records are too short to attribute these changes to anthropogenic climate change or to natural variability.
• Oxygen is a very sensitive tracer for studying and understanding the response of ocean biogeochemistry to climate variability and global climate change.
• Most of these changes are likely due to a reduction in the circulation rate of thermocline waters, possibly related to the predominantly positive phase of NAO during the 1990s.
