Workshop on the Seasonal Cycle of the Carbon-Climate System in the Southern Ocean

Cape Town 23 – 25 August 2010

The seasonal cycle is not only one of the strongest modes of variability in different components of the carbon cycle in the Southern Ocean but also the mode which couples climate forcing to ecosystem responses such as productivity, diversity and ultimately carbon export.  We hypothesise that:

Evidence of adjustments in the climate forcing signal, through trends in the interannual signal, will be reflected in changes in the magnitude, the phasing and persistence of the seasonal cycle in the mixed layer physics and particularly in the biogeochemistry through changes in the carbon cycle. 

These signatures of climatic forcing could be used to better understand the influences of altered physics, iron supply (atmospheric, deep and sea-bed), stratification, and changes in trophic structures on the carbon fluxes of the Southern Ocean.  However, important gaps persist in our understanding of the sensitivity of biogeochemical processes to seasonal / mesoscale forcing of surface ocean physics. These gaps are reflected in the capabilities of observations and models to address both the seasonal and sub-seasonal as well as meso- and sub-meso scales in understanding the coupling and feedbacks of the coupled carbon–climate system in the Southern Ocean. 

Coupled physics and biogeochemistry model capabilities have been improved significantly to cope with the required resolution at the regional scale and maybe at the global scale. Similarly, our observational capabilities, especially if planned at an integrated international effort, make it possible to begin to address high resolution temporal and spatial domain at the regional system scale.

This workshop will bring together an initial small interdisciplinary discussion group comprised of physicists, biogeochemists, modellers and observationalists with the aim to:

1. Critically review our current understanding of the seasonal variability observed in the Atlantic, Indian and Pacific sectors of the Southern Ocean, particularly:
   1. Basin scale differences between the Pacific, Atlantic and Indian Oceans physics – seasonal phenology – interannual variability in the carbon cycle
   2. Role of changes in meridional advection
   3. Scaling contributions to productivity of atmospheric and bottom derived iron fluxes
   4. Critical scales of mixed layer dynamics in coupling climate to carbon
   5. Identify a series of 2 – 3 key questions on the drivers of the carbon – climate system of the Southern Ocean that can be addressed collaboratively within 3 – 5 years in order to constrain 21^st century trends in this system
   6. Discuss the need, the feasibility and the format of a coordinated international (multi-platform) experiment(s) to understand the seasonal variability of the carbon cycle in the Southern Ocean

The Workshop will be run over 3 days:

Day 1: Review our current understanding (plenary presentations followed by group discussion)

Day 2: Workshop to formulate key questions and discuss modelling experiments

Day 3: Workshop to discuss the need for experiments and coordinated observations 

Our aim in convening this workshop to is to explore ideas of scale sensitivities of the coupled carbon–climate system as a basis to bring the physics and biogeochemistry communities closer together but with a special focus on the biological pump – carbon export fluxes.

Co-conveners: Dr Pedro Monteiro (South Africa), Dr Philip Boyd (New Zealand), Prof. Tom Trull (Australia), Dr Richard Bellerby (Norway)

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Launching an effort to network Subantarctic carbon research

Welcome to Subantarctic.net, home of the SAZ Project, an effort to network Subantarctic carbon research.

Subantarctic waters lie between the Subtropical Front and the Polar Front and comprise half of the area of the open Southern Ocean. This is the region where mode and intermediate waters form, and control the uptake of heat, rain, carbon dioxide, and oxygen from the atmosphere on decadal timescales. These waters are impacted by terrestrial (such as dust flux) and tropical oceanic (eddy and boundary current transports) influences to a greater extent than polar waters. They also host important commercial, recreational, and artisanal fisheries.

The northern boundary of the Subantarctic is in close proximity to countries such as Australia, South Africa, New Zealand, Chile and Argentina. Each has active research programmes in the Subantarctic, and many also conduct other research (for example phytoplankton lab culture studies, dust sampling, remote sensing) that are pertinent to Subantarctic research concerns.

This website aims to bring together information on historic, recent and ongoing research activities in Subantarctic waters by nations bordering these waters. We hope that the existence of this site will encourage interactions among these and other researchers interested in the Subantarctic - to provide additional materials, exchange information, and promote synthesis of a circumpolar perspective on the importance of the Subantarctic to global climate and marine ecology.