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CAPRICORN: Constraining Arctic PRimary production: Impacts and Contributions of ORganic matter and inorganic Nutrients


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Arctic Interaction stakeholders

CAPRICORN: Constraining Arctic PRimary production: Impacts and Contributions of ORganic matter and inorganic Nutrients


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A group of 20+ UK marine scientists from the Universities of East Anglia, Southampton, Exeter and Northumbria, Plymouth Marine Laboratory and the National Oceanography Centre are currently preparing a proposal to the NERC Changing Arctic Ocean programme to undertake a combined observational, experimental and numerical simulation study of the cycling of organic and inorganic nutrients in the Arctic Ocean in order to improve predictions of how the Arctic marine ecosystem may function under future 
scenarios of increased river runoff and melting sea-ice.

 

We would welcome interaction with regional stakeholders with an interest in Arctic marine ecosystem functioning.

 

The ocean plays a central role in the storage and cycling of carbon, through the uptake of CO2 by phytoplankton during photosynthesis, and the subsequent ‘packaging’ of particulate carbon in the form of dead phytoplankton cells and the faecal pellets of zooplankton which slowly sink. In addition, the activity of phytoplankton, bacteria, viruses and zooplankton produces a rich soup of dissolved organic carbon (DOC) compounds in the surrounding seawater, most of which can be rapidly respired to CO2 by bacteria, but a significant proportion of which cannot. Sunlight can also alter the chemical composition of the DOC, changing its availability to bacteria. Production of this ‘recalcitrant’ DOC, which cannot be rapidly used by bacteria to grow, means that it can be stored together with the sinking particulate carbon in the deep ocean for thousands of years. If the ocean did not play this vital storage role, the concentration of CO2 in the atmosphere would be almost double what it currently is, with hazardous consequences for global temperatures. The environmental factors which influence how much carbon is stored in the ocean are those which influence the type of plankton community which occurs in a particular place. These include temperature and sunlight, together with the quantity and quality of dissolved organic material (DOM) and inorganic nutrients such as nitrate and phosphate which can be supplied to surface waters from rivers or mixing with deep waters. These environmental factors are exactly those which are changing at an unprecedented rate in the Arctic Ocean. Increasing temperatures are causing increased melting of sea- and land based ice producing increased freshwater input to the ocean. Reduced sea-ice increases the amount of sunlight experienced by the phytoplankton and the potential for mixing of subsurface waters into the surface.

The aim of this proposal is therefore to investigate how current and predicted changes in DOM and inorganic nutrient supply, through river run-off, sea-ice melt and hence changing water column mixing, will alter the composition of the plankton foodweb and thus the cycling of nutrients and storage of carbon within the Arctic Ocean.

 

If you are interested in working with us or if you would like to find out more then please contact us.

Posted by on Mon, 30 Oct 2017



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