1. Happy Golden Anniversary SCOR!
From…
Trace element cycles in a changing world
Gideon Henderson
Bob Anderson
2003 meeting - 2 big debates….. Name, and whether to be global change or not.

2. Iron measurements <-- Before 2003 What we can do now -->
From science plan. Old figures, but probably some of the most compelling…
Know so little about distribution of TEIs, but there is so much TO know - and an ability to know it for the first time
What we can
do now -->

3. GEOTRACES - A trace element timeslice
Obviously not measured at single time - decade
But… each section done once - captures conditions at a single time - not directly assessing global change
Still a strong gc component - understanding the inputs provides knowledge about how they might have changed etc.
And proxy developent as mentioned by Jean yesterday.
Just getting going - look to the future… .

4. Trace elements in a changing ocean
Monitoring / time-series / sensors
Accidental change (e.g. ocean acidification)
Intentional change (e.g. geoengineering)
Transition Point from Planning to Implementation
Timeline

5. Variable chemical inputs
WG John told us about yesterday
Timeline

6. Arctic Transect
Antarctic Transect UK D
UK/D/Es
USA F
F/Can Nl
USA/D/Mex
F/Es/It
Monitoring Linking to existing time-series (including GOOS) And to SCOR programmes - SOLAS, IMBER
Very few monitor TEIs
Need to explore ways to add TEI measurements to existing and new timeseries stations
Sensors… Martin told us about O2 sensors. Nitrate, metals Fe, etc. Coastal models exist

7. Trace elements in a changing ocean
Monitoring / time-series / sensors
Accidental change (e.g. ocean acidification)
Intentional change (e.g. geoengineering)
Transition Point from Planning to Implementation
Timeline

8. Ocean acidification Big uncertainties are biological
0.3 pH unit decrease
Leads to 50% decrease in [OH-]
Links to IMBER and SOLAS
As such - disciplinary mission with clear focus on marine geochemistry
Mission

9. Trace elements in a changing ocean
Monitoring / time-series / sensors
Accidental change (e.g. ocean acidification)
Intentional change (e.g. geoengineering)
Transition Point from Planning to Implementation
Timeline

10. As such - disciplinary mission with clear focus on marine geochemistry

11. Geoengineering
Companies actively planning to mess with ocean chemistry to alter the carbon cycle….. By Fe addition or alkalinity addition.
Many oceanographers are instinctively opposed to these schemes, and there is a tendency to ignore them.
But we have a responsibility to engage with these ideas and test them against the best ocean science.
Mission

12. Trace elements in a changing ocean
Monitoring / time-series / sensors
Accidental change (e.g. ocean acidification)
Intentional change (e.g. geoengineering)
Measure, understand and predict trace element cycles in a changing ocean
Links to other programmes / WGs: GOOS, IMBER, SOLAS, WG129, WG131…
Timeline