AMT - The Atlantic Meridional Transect. Steve de Mora. POGO-14 Cape Town January AMT - The Atlantic Meridional Transect 23/01/2013

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1 AMT - The Atlantic Meridional Transect Steve de Mora POGO-14 Cape Town January 2013 AMT - The Atlantic Meridional Transect Transect that runs from 50 N 50 S Started in 1995 with funding for annual expeditions until at least 2014 Coherent set of repeated biogeochemical measurements low temporal frequency, extensive spatial coverage, over decadal time period. A unique observing system co-ordinated by PML in collaboration with NOC,S which offers unique datasets and collaborative opportunities to the international community. To provide a sustained open ocean in situ observing system to enable early warning of any fundamental change in ecosystem functioning and to better forecast the marine environment for society s needs 1

2 Historical context Phase ; Funding - PML, NERC, NASA, EU, MST (Spain) Phase ; Funding - NERC Consortium Grant Phase ; Funding NERC Oceans 2025 Phase onwards; Funding NERC National Capability AMT will continue to deliver: Sampling over 100 latitude including through the rarely visited South Atlantic Gyre Long-Term in-situ observations Inter-Hemisphere differences Basin scale observations Progress towards a predictive capability Modelling In-situ sampling Remote Sensing AMT has completed 22 research cruises between the UK and either the Falkland Islands, Cape Town or Punta Arenas: A total distance of approximately 176,000 miles. RRS James Clark Ross RRS Discovery RRS James Cook 2

3 22 research cruises; 223 scientists from 18 countries has generated more than 220 refereed publications and contributed to over 60 PhD Theses. Long Term Trends 1) Looking at Phytoplankton biomass across the Atlantic Gyres : - The concentration depth (DCM) varies by Province. - 1 st optical depth: satellite observation, surface to 50m - What is the longer term trend? AMT 1-20 DCM across the Longhurst Atlantic provinces Deep Chlorophyll-a Max Depth [m] Latitude degn 3

4 Long Term Trends 2) The AMT transect reveals changes to the Atlantic marine ecosystem over two decades through in situ observation. AMT observations in parallel with remote sensing and modelled data are being interrogated within the EU Green Seas programme to distinguish longer term (decadal) climatology from short term (inter annual) variability in order to assess the ecosystem response to environmental and climate changes. J. Bruun (PML) 2012 ICES ASC R10/11 Novel discoveries Significant CO 2 fixation by the smallest algae in the northeast Atlantic and in the oligotrophic Atlantic. But, in the North Atlantic subtropical gyre bacterioplankton control direct phosphate uptake, whilst algae play a minor role. Yet, >50% of feeding on bacterioplankton is carried out by the smallest algae. The above advances the basic understanding of biogeochemical cycling in oceanic oligotrophic ecosystems, which cover >40% of the Earth and are increasing with climate change. M. Zubkov (NOC) 4

5 Societal Concerns Approximately 25% of anthropogenically produced CO 2 has been removed from the atmosphere by the oceans and has resulted in a profound change to ocean carbonate chemistry and the resultant phenomenon of ocean acidification. Current evidence indicates that predicted large and rapid changes to ocean ph will have adverse effects on marine calcifying organisms and biogeochemical cycles. AMT provides an excellent opportunity to monitor natural and forced changes to ocean carbon chemistry. V. Kitidis (PML) International collaboration During AMT22 (2012) NASA performed overflights of the ship for instrument seatruthing Research Scanning Polarimeter High Spectral Resolution Lidar 1 Azores Wallops P3-B Increase capability the airborne HSRL 1 for science applications related to Ocean Ecosystems Air sea gas (CO 2 ) exchange Ocean Aerosol Interaction Cloud extinction and cloud droplet number density Improve the functionality and reliability of the (RSP) 5

6 Autonomous observations 1) Argo float deployments during AMT-22 Laboratoire d'océanographie de Villefranche Bio Argo floats (Temp, salinity + flor., backscatter, irrad., att n coeff) 4 simultaneously around NAG centre 4 simultaneously around SAG centre UK Met Office 6 standard Argo floats (Temp, salinity) Various points in the SAG Autonomous observations 2) Rutgers University deployed Gliders to complement AMT cruise tracks 6

7 Training AMT provides excellent opportunities to the next generation of oceanographers, has contributed to more than 60 PhD theses and hosts the POGO AMT fellowship 2008 Mario Vera 2009 Charissa Ferrera 2010 Barbora Hoskova 2011 Alaa Younes 2012 Priscila Lange Universidad de la Republica Uruguay University of Phillipines Institute of Microbiology, Czech Republic Institute of Oceanography & Fisheries, Egypt Federal University of Rio Grande, Brazil Being on the AMT cruise is like being in an atmosphere ocean interaction class with the subject of my training as my special project and with the other components of the programme as other topics comprising the course. This is the most extensive study on the biogeochemistry of the surface oceans that I know of and it s amazing how the components of the programme are interrelated. AMT: Combines ship and satellite observations to assess the health and function of the Atlantic Ocean Provides collaborative opportunities to the national and international scientific community Trains the next generation of oceanographers Inputs to schools curriculum Sponsors participation of developing countries Web site: uk.org Cruise blog: Contact: Dr Andy Rees (Programme Manager) apre@pml.ac.uk 7