Richard A. Feely, Ph.D.NOAA Pacific Marine Environmental Laboratory/NOAA

NOAA Ocean Climate Climate Observation 7th Annual System Review28 October 2008

Developing an Ocean Acidification Observing Network to Study the Other CO2 Problem

PMEL PIs: R. Feely, C. Sabine S. Alin, L. Juranek, A. Sutton, S. Hankin AOML PIs: R. Wanninkhof, T.-H. Peng, D. Gledhill, D. Manzello, J.-Z. Zhang University PIs: U. Send (SIO), A. Dickson (SIO), B. Hales (OSU), J. Salisbury (UNH), S. Lohrenz (USM), W. Cai (UG)

Conceptual Diagram of Ocean Acidification

Oce

an C

O2 C

hem

istry

Ocean Acidification OHCO 22 32COH 3HCOH 3

23 HCOCOH 32

232 2HCOOHCOCO

2−[CO3 ][CO2]

150−200% 50%

2100

8.2

8.1

8.0

7.9

7.81800 1900 2000 2100

50

40

30

20

10

0

300

240

180

120

60

0

pH

μmol kg

−1

Year

pH

CO2(aq)

CO32−

50% acidity16% [CO3 ]

2000

2−

Wolf-Gladrow et al. (1999)

Oce

an C

O2 C

hem

istry

Saturation State

calcium carbonate calcium carbonate

CO2 CO32 H2O 2HCO3

Ca2 CO32 CaCO3

Saturation State

W phase =Ca2[ ] CO3

2[ ]Ksp,phase

*

W>1= precipitationW=1=equilibriumW<1=dissolution

Change in Aragonite Saturation with CO2

Steinacher et al. Biogeosci., 2009

-Saturation state declines across all latitudes

-Undersaturated conditions appear for aragonite in high latitudes

WOCE/JGOFS/OACES Global CO2 Survey

~72,000 sample locations collected in the 1990sDIC ± 2 µmol kg-1

TA ± 4 µmol kg-1Sabine et al (2004)

2005/2006, 1991

Difference of present-day levels minus pre-industrial (year 1800)

Half trapped in upper 400m

Equivalent to about a third of all historical carbon emissions

Penetration of Anthropogenic CO2 into Ocean

Sabine et al. Science 2004

Oce

an C

O2 C

hem

istry

Observed aragonite & calcite saturation depthsFeely et al. (2004)

The aragonite saturation state migrates towards the surface at the rate of 1-2 m yr-1, depending on location.

DIC change due to ventilation and respiration processes

Total DIC change over 15 years in the Pacific

Sabine et al. (in prep)

DIC change due to uptake of anthropogenic CO2

Shoaling of aragonite saturation horizon of ~1-2 m yr-1

Large-scale decreases of aragonite saturation in the upper 1000m

Feely et al. (in prep)

Δ Sa

tura

tion

Dep

th (m

)

“The further development of current biogeochemical sensors and the development of new sensors is critical to the ongoing development of an integrated ocean observing system. Reliable sensors for autonomous platforms is an important research and development focus for pCO2 and other carbon sensors including DIC and total alkalinity. These sensors along with certified reference material would enable the ocean carbonate system to be constrained.”

An International Ocean Acidification Observing Network

An International Ocean Acidification Observing Network

from Feely et al., 2010

Ocean acidification Ocean Carbon Observatory Network

Updated 10/5/10

Coastal Moorings Operated by SIO

All real-time, with meteorological, physical, chemical, and biological variables

CCE1

CCE2

Del Mar

California Current Ecosystem (CCE) moorings

Pt.Conception

Gliders (CORC,LTER, Moore)

CalCOFI/LTER

CCE-1 (SIO/SWFSC/PMEL)

The power of CCE1/2 comes from the context of other measurements

- Ships sample many variables and provide ground truth- Gliders provide cross-shelf sampling with a few variables- Moorings give full time sampling, wide range of variables

CalCOFI line 80

CCE-2 (SIO/SWFSC/PMEL)

Chlorophyllshown on surface;salinity on cross-section

CCE-2Real-timedataexample

Send & Ohman

with Demer, Martz, Sabine, Feely, Dickson, Hildebrand

upwelling upwelling

SBE-37

Durafet

ISE Reference

Aanderaa 3835 Optode

SBE 5M pump

Flow manifold

Copper intake

SeapHOx

CCE-1 surface pH (Jan – Sept. 2010)

Figure provided by T. Martz,U. Send, M. Ohman, SIO

pH measured using a modified Honeywell Durafet and estimated from pCO2 using TA = f(S,T) provided by Simone Alin (PMEL).

Examining the agreement between the three different pH values provides a useful QC on sensor data.

7.98

8.00

8.02

8.04

8.06

8.08

8.10

8.12

8.14

D J F M A M J J A S

pH (t

otal

scal

e)

pH(FET|INT)

pH(FET|EXT)

pH(pCO2,TA)

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

D J F M A M J J A S

ΔpH

ΔpH (EXT-pCO2/TA)ΔpH (INT-pCO2/TA)ΔpH (EXT-INT)

An Ocean Acidification Observing Network What tools do we need to address ocean acidification?

Autonomous Underwater GlidersInnovating Technology

High resolution data

J. Barth, K. Shearman & A. Erofeev

CTDdissolved oxygenchlorophyll fluorescenceCDOM fluorescencelight backscatter

cross-margin transect twice per week since April 2006

Algorithms to predict Ωarag and pH in the N. Pacific

Juranek, Feely et al. (in prep)

Algorithm development data:CLIVAR P16 (March, 2006)STUD08 (Sept., 2008)

Data from 40-55°N, 50-500 db:Ωarag: R2=0.99, RMSE=0.05pH: R2=0.99, RMSE=0.017

(Ω,pH)

Conclusions and ChallengesSince the beginning of the industrial age surface ocean pH (~0.1), carbonate ion

concentrations (~16%), and aragonite and calcite saturation states (~16%) have been decreasing because of the uptake of anthropogenic CO2 by the oceans, i.e., ocean acidification. By the end of this century pH could have a further decrease by as much as 0.3-0.4 pH units.

An observational network of repeat surveys, moorings, floats and gliders for ocean acidification is under development as a strong collaboration between federal, state and private institutions using state-of-the-art technologies and new proxies.

Special Thanks to: Joan Kleypas, Uve Send, Sarah Cooley, and Scott Doney.

Moored and glider sensors for Dissolved Inorganic Carbon, Total Alkalinity and pH need development. Near real-time data transmission and uniform data management infrastructure is required with public availability.