BIOLOGICAL CARBON PUMP ASSESSMENT USING THE TRANSPORT MATRIX METHOD AND GLOBAL NUTRIENT DISTRIBUTIONS (BATMAN)

Lead Research Organisation: National Oceanography Centre
Department Name: Science and Technology

Abstract

Marine life plays a key role in the Earth's climate. To grow, marine algae extract almost as much carbon dioxide from the atmosphere annually as all plants on land. This 'primary production' fuels the marine ecosystem. The resulting waste sinks, as 'export', sequestering large amounts of carbon at depth, away from the atmosphere. Atmospheric carbon dioxide levels can be very sensitive to small changes in the depth at which recycling (or 'remineralisation') of this waste back into nutrients takes place. We have sufficient observations of sinking material to investigate the process of remineralisation but far from enough to produce a global map that could be used to test climate models. We do have such maps for nutrient distributions, that are the consequence of the remineralisation, but traditionally models take too long to run to allow such comparisons. A new technique (the Transport Matrix method) provides a means of running models much faster. In tandem with this technical development, the mechanisms controlling the process of export have become much better understood in recent years. It is timely therefore to unite these recent advances to ensure that climate models accurately capture this key process of the Earth system.

Planned Impact

The following will benefit from this work:

i-MarNet & ESM Strategy:
The NERC and Met Office Strategy for Earth System Modelling states as a priority for future development: "The UK ocean biogeochemistry community needs to develop a common model for ESM activity building on the strengths of the existing UK models." The NERC ESM i-MarNet project has been planned to address this. However, each of the models under consideration in i-MarNet has a different representation of remineralisation. None of the models will be assessed on the accuracy and consequences of this key process as i-MarNet will not be able to run the models long enough for nutrient fields to reach equilibrium. This project will therefore contribute significantly to i-MarNet and ESM strategy, both directly, through providing recommendations on remineralisation parameterisations, and indirectly, through allowing future studies to run models quickly to equilibrium. Communication to i-MarNet and ESM strategy is facilitated by the lead PI of i-MarNet also being involved in this project.

The Met Office:
The extraction of a Transport Matrix for NEMO will provide a powerful tool that the Met Office and future partners can use for many aspects of climate modelling. The involvement of the Met Office (Totterdell) in the project will specifically involve Met Office implementation of the TMM, its transfer to the study of marine biogeochemistry and other dissolved tracers. The Met Office are also interested in the ability to easily downgrade the circulation from higher-resolution to coarser resolution in the TMM, which addresses goal two of this call.

Economists, social scientists and government:
The project and the Transport Matrix Method have considerable potential for those interested in putting an economic value on the biological carbon pump (BCP), e.g. Valuing Nature Network and The Economics of Ecosystems and Biodiversity. The BCP performs a major service to mankind by storing large quantities of carbon dioxide that would otherwise be in the atmosphere. Modelling studies have shown that the amount of carbon dioxide stored by the ocean is very sensitive to the manner in which organic material is remineralised in the ocean - the focus of this project. This project would therefore be of considerable interest for those looking to assess the magnitude (and uncertainty) of the BCP to put a value on it and the economic consequences of its change under various future scenarios.

The impact of this project on the academic community can be found described in Academic Beneficiaries

Publications


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Description Phytoplankton, the microscopic plants of the ocean, are a key component of the Earth system. In particular they are important in the global cycles for carbon and elements such as nitrate, silicate and phophate which form nutrients, essential for phytoplankton growth. When they die, the carbon they have converted from carbon dioxide to living material sinks from the surface where they grow into the ocean interior. Some of these phytoplankton develop spiky exteriors, made out of silicate, potentially to deter organisms that want to eat them. Consequently when they die and sink they also take silicate to depth as well as the carbon and nutrients used to build their living cell. High concentrations of silicate in waters over several thousand metres deep have been observed coming out of the Southern Ocean, linked to a region of high concentrations near the surface in the north Pacific. Our work has shown that the depth to which phytoplankton sink before they degraded back into their chemical components is the primary control on this global pattern of silicate. We have also shown that the constant rain of organic material sinking down in to the deep ocean currents means that to understand how quickly organic matter decays as it sinks it is necessary to take a global perspective as much of what is found at 1000m at one location originated from the surface possible thousands of kilometres away.
Exploitation Route The UK Earth System Model wants to use one of our outputs (the Transport Matrix for NEMO) to spin-up their biogeochemistry
Sectors Aerospace, Defence and Marine,Energy,Environment,Government, Democracy and Justice
 
Description EGU conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk at EGU Conference: "Evaluating our understanding of the biological carbon pump using the transport matrix method and global nutrient distributions"
Year(s) Of Engagement Activity 2015
 
Description Ocean Sciences talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk at Ocean Sciences conference, New Orleans,: "Using Preformed and Remineralized Nutrients to Map Spatial Variation in Remineralization"
Year(s) Of Engagement Activity 2016
 
Description Poster at Ocean Carbon Biogeochemistry workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster at Ocean Carbon and Biogeochemistry summer workshop, WHOI,: The local and remote influences of remineralization in setting global nutrient distributions
Year(s) Of Engagement Activity 2016
 
Description Poster at Ocean Carbon and Biogeochemistry summer workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster at Ocean Carbon and Biogeochemistry summer workshop at WHOI: "Relative roles of dissolution lengthscale and uptake ratio on the global distribution of silicate "
Year(s) Of Engagement Activity 2016
 
Description Talk at Challenger conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Talk at Challenger conference, Liverpool: "Is satellite-derived export production consistent with the global distribution of nutrients? "
Year(s) Of Engagement Activity 2016