1. UK GEOTRACES Atlantic Ocean Water column Biogeochemistry
Eric Achterberg
Maeve Lohan-Simon Ussher
Gideon Henderson
Derek Vance
Mark Moore
Ric Williams
Tim Jickells-Alex Baker
Et al.

2. AMT-17 results, Atlantic, Oct-Nov '05.
NP co-limitation observed at high N:P input ratios in N. Atlantic.
N:P (mol mol-1) at 200m
S. Atlantic
Low N:P input ratio…

3. AMT-17
N2 fix
Tricho N S
Data M Woodward

4. Polarstern Anreise cruise 2000
Sarthou, Achterberg et al., Deep Sea Res. 2003

5. N2 fixation along transect
Total
<20m S N S N

6. Surface water (1000 m) dissolved iron and aluminium (nmol/kg) in the Atlantic along CLIVAR A16 (2003; Chris Measures and Bill Landing)

7. Hypothesis
Bioactive trace elements control productivity from 30ºN to 30ºS in the Atlantic Ocean.
The bioactive trace elements are intimately involved in various physical-biogeochemical feedback loops that influence our climate

8. Objectives
Determine atmospheric inputs of bioactive trace metals through aerosol collection
Determine deep water TEI supply from diapycnal mixing and upwelling (incl. turbulence measurements)
Identify sources of TEI to the region through tracer measurements (Al, Ti, Mn)
Establish natural microbial community structure
Determine ammonium and nitrate uptake rates
Determine nitrogen fixation rates
Establish trace elements and nutrient streams through modelling