Some ideas for coordinated studies Katya Popova + FAMOS biogeochemical group National Oceanography Centre, UK 1

Well-defined ideas AO productivity in observations and models (P.Matrai) Role of the subsurface Chl-a maximum (J-E.Tremblay, P.Matrai – observations; K.Popova – global models; Nadja Steiner, Molly Palmer – 1D) Well-defined ideas lacking critical mass (minimum 2 modelling groups) Time series stations (biogeochemistry) Light vs nutrient limitation Shelf control of primary production Vague ideas but with critical mass and a lot of enthusiasm IPCC CMIP recommendations (model requirements, metrics, outputs)

1. Subsurface Chl-a maximum From Carmack and McLaughlin, 2011 25m 100m Chl-a Nutrients

1. Sub-surface Chl-a maximum (Model estimate) Subsurface contribution to primary production Subsurface contribution to Chl-a About 43% of Total AO primary production is fuelled by SCM Popova et al., 2010, Biogeosciences

2. Shelf control of AO primary production ?

2. Shelf control of AO primary production ?

Numerical experiment: no bottom remineralisation (5 years run) Control run (Control-exper)/control 20% reduction of total AO primary production after 5 years 20% reduction of total AO primary production after 5 years

3. Light vs nutrient control Winter Summer Winter 3. Light vs nutrient control Light –limited system Nutrient –limited system Half-saturation for nutrient uptake Nutrient-limited system