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Dutch title: Rol van de PElagische cAlcifiering en van de export van de CarbonaatproductiE in de klimaatverandering
Parent project: Science for a Sustainable Development, more
Reference no: SD/CS/03A
Period: December 2005 till January 2010
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- Université Libre de Bruxelles; Faculté des Sciences; Département des Sciences de la Terre et de l'Environnement; Unité Modélisation Biogéochimique Système Terre; Laboratory of Chemical Oceanography and Water Geochemistry (LoCGE), more, co-ordinator
- Universiteit Gent; Laboratorium voor Protistologie en Aquatische Ecologie (PAE), more, partner
- Université de Liège; Faculté des Sciences; Département d'Astrophysique, Géophysique et Océanographie; Unité d’Océanographie Chimique, more, partner
- Alfred Wegener Institute for Polar- and Marine Research (AWI), more, partner
- Belgian Science Policy (BELSPO), more, sponsor
Carbon dioxide (CO2) is one of the most important greenhouse gases. Due to human activities, the atmospheric CO2 concentration has recently been increasing at an alarming rate, leading to global warming. The oceans, covering two-thirds of the earth surface, play an essential role in the global carbon cycle, and have been shown to absorb more than one-third of the anthropogenic CO2. The uptake of excess CO2 not only disrupts the marine carbon cycle and ecosystems, but also leads to acidification of the seawater. This process has adverse effects on various important groups of marine organisms such as coccolithophores and corals that form calcareous skeletons (CaCO3). There is an urgent need to understand the interaction between the functioning of marine calcifiers and climate change in the light of altering ocean chemistry, in particular ocean acidification.
The overall objective of the PEACE project is to evaluate the role in climate regulation of calcification, primary production and export processes during blooms of coccolithophores, an important group of calcifying phytoplankton. We aim specifically
- To study the net ecosystem dynamics during these blooms;
- To unravel the link between the bacterial community, grazing, transparent exopolymer particle (TEP) dynamics, carbon export and dimethyl sulphide (DMS) cycling;
- To assess the effects of ocean acidification on coccolithophore metabolism and TEP production and
- To model coccolithophore dynamics and their impact on ocean dissolved inorganic carbon (DIC) chemistry.
We will use a transdisciplinary approach that combines process-oriented field investigations with laboratory experiments and modelling tools.
Field investigations, supported by remote sensing data, will be conducted in the Northern Bay of Biscay (one of the main coastal European marine areas) where coccolithophore blooms are regularly observed. This region has been visited by the Belgian biogeochemistry community since the late 1980s within the framework of the PPS Science Policy “Global Change” and SPSD-II “Climate” programmes, and the EU OMEX I and II projects. Long-term series of physical, biological and chemical variables are available for model validation. A suit of fundamental physico-chemical variables will be measured in the water column. In addition, during both field and laboratory studies, attention will be paid to determine key parameters of calcification and associated processes such as algal characterization and bacterial community structure and diversity, rate of organic and inorganic carbon production, degradation and export, and air-sea exchange of CO2 and DMS. The role of TEP in CO2 sequestration during coccolithophore blooms will be evaluated as well.
Synthesis of the acquired data and future projections in relation to increasing pCO2 and ocean acidification will be achieved through a biogeochemical model that will explicitly describe the DIC and coccolithophore dynamics (primary production, calcification, CaCO3 and organic carbon export). The model will be specifically tuned with the newly and previously acquired field and laboratory data and will be coupled with a hydrodynamic model of the region.
Interaction between the different partners
All partners participate in field investigations in the Northern Bay of Biscay and are involved in laboratory culture experiments designed to study the impact of ocean acidification on coccolithophore metabolism and TEP production. They all contribute to the modelling work.
The coordinator, ULB-LOCGE, will focus its efforts on studying processes controlling primary production and calcification, as well as pelagic CaCO3 dissolution. In addition, attempts will be made to evaluate the DMS cycling. It is also responsible for batch culture experiments and organisation of cruises.
ULg-COU will devote its activity