GEOTRACES WORKING GROUP 11-12 September 2007 ATLANTIC OCEAN TROPICAL-SUBTROPICAL REGION Chair Bill Landing Raporteur Eric Achterberg Group members: Bill Jenkins Peter Croot Peter Sedwick Simon Ussher Walter Geibert Armando Ramirez Pere Masque Tom Church Jana Friedrich. Overall plan
GEOTRACES WORKING GROUP 11-12 September 2007
ATLANTIC OCEAN TROPICAL-SUBTROPICAL REGION
Chair Bill Landing
Raporteur Eric Achterberg
We propose to undertake 2 transects:
Transect one will form part of a dust/Fe plume study cruise (possibly TEI-microbial)
Transect two will be part of a western boundary cruise
Stations are proposed at 2 degrees intervals. Not all stations will be full depth (1800 m).
We will undertake high resolution shallow casts and lower resolution deep casts to characterize deep water masses.
Cruise track 1
-The dust cruise should take place in a period of year with enhanced atmospheric dust concentrations.
-We envisage the deployments of LIDAR on the cruises for ship-board aerosol observations.
-UK GEOTRACES proposal will have to be hypothesis driven, with consideration for linking micronutrient distributions and supply-removal to microbial processes and distributions. Consequently such a programme will consider a north-south transect.
Cruise track 2
-We will undertake a cross transect in the western basin to characterize deep water masses.
-It is envisaged that stations will be occupied in the Amazone river plume and in the Cariaco Basin region (to study isolated suboxic basin system).
-Seamounts will be included in the cruise track to study the impact of the nephloid layer on water column TEI concentrations and undertake proxy studies.
-Stations over hydrothermal vents on the mid-Atlantic ridge will be included to investigate dissolved and particulate TEI signatures
Links to other Transect
-Germans run north-south cruises on 23ºW. Peter Croot is contact person.
-Low oxygen studies (1 funded and 1 under review) Peter Croot is contact person.
-Extended W transect out of Cape Cod, via Bermuda to Barbados will form ideal link-up transect for our region.
-Cruise transect into the Angolan Basin will form ideal link-up for our region.
-We will attempt to re-occupy TTO and GEOSECS stations
-We envisage that the influence of the Romanche Fracture zone on deep waters will be investigated in other group proposals (Angolan Basin work).