Critical evaluation of marine calcareous skeletons as recorders of global climate change (CALMARS II)

Research project SD/CS/02A (Research action SD)

Persons :

  • Prof. dr.  WILLENZ Philippe - Royal Belgian Institute of Natural Sciences ()
    Coordinator of the project
    Financed belgian partner
    Duration: 15/12/2005-14/12/2007
  • Prof. dr.  ANDRE Luc - Royal Museum for Central Africa ()
    Financed belgian partner
    Duration: 15/12/2005-14/12/2007
  • Prof. dr.  BLUST Ronny - Universiteit Antwerpen (UA)
    Financed belgian partner
    Duration: 15/12/2005-14/12/2007
  • Prof. dr.  DUBOIS Philippe - Université Libre de Bruxelles (ULB)
    Financed belgian partner
    Duration: 15/12/2005-14/12/2007
  • Prof. dr.  DEHAIRS Frank - Vrije Universiteit Brussel (VUB)
    Financed belgian partner
    Duration: 15/12/2005-14/12/2007

Description :


To determine the appropriate responses to climate changes, we should improve our knowledge of the respective impacts of natural multidecadal climate variability and of human-induced climate changes. Our previous project (CALMARS 2001-2005) demonstrated that CALcareous MARine Skeletons of marine invertebrates can be used as environmental recorders, since they integrate ecological information without interruption from various time scales. Those skeletons will help reconstructing climate evolution and producing a predictable model for the future. However, because the composition of biogenic carbonates is also clearly influenced by biological factors, the correct interpretation of these chemical archives requires a precise understanding of the processes controlling the incorporation of elements, and hence, biomineralization.

Project description


Five Belgian institutions have set up a project aiming to produce a predictive mathematical model using climatic data recorded by calcareous skeletons from three different taxa of marine invertebrates. These taxa, selected for their contrasted characteristics (lifetime, growth rate, etc.), are hypercalcified sponges, bivalves, and echinoderms.
The originality of this project resides in four new perspectives:

(i) A better understanding of biomineralization and pathways of element incorporation in the skeleton that will increase the confidence in the proposed proxies.

(ii) The study of the new proposed proxies will improve the separation of salinity and temperature signals (δD in the skeleton organic matrix) and offer an insight in the levels of river discharges and the associated weathering processes (δMg in the carbonate).

(iii) A precise understanding of the barium signal in carbonates will give the keys to describe the estuarine barium cycling, an important aspect for the oceanic Ba proxy.

(iv) Our multi-specific and multi-proxies model of climatic reconstitution will clarify the reconstitutions carried out to date and, for example, allow a deconvolution of temperature and salinity signals, which commonly act on the same proxy.


CALMARS II approach is based on a combination of field work, laboratory experimentation and mathematical modelling. Field work implies regular sampling of specimens from selected sites of the North Sea and the Mediterranean Sea. Environmental conditions are continuously monitored at the same locations in order to define the influences of the seasonal variations on the skeleton formation. Specimens are also collected along environmental gradients to define relationships between proxies recording and environmental parameters. Selected proxies are analyzed by high resolution Laser-ablation ICP-MS. For each group, the influence of environmental parameters on skeletal growth rates is investigated in laboratory and on the field. In situ experiments of regeneration are carried out during the same periods. The pathways of proxy incorporation are studied in laboratory after addition of radioactive isotopes. The role of the organic matrix in the processes of biomineralization is also considered. A mathematical model will be deduced after data integration. The analysis of historical specimens from Museum collections will validate this model and lead to paleoclimate reconstitutions.

Expected results and/or products

CALMARS II aims at improving and extending the records of global change in the oceanic domain with a peculiar interest for the climate databases. Through a network of biologists and geochemists of complementary experience, CALMARS II intends to:

(1) Improve the comprehension of the mechanisms of calcification and the physiological and biological effects related to incorporation of proxies in the skeleton of hypercalcified sponges, bivalves and echinoderms;

(2) Develop a multi-proxy approach permitting to distinguish the signals from temperature and salinity and to reconstruct the evolution of these parameters on the basis of fossil specimens;

(3) Understand the specificities of the barium (Ba) proxy to reconstruct Ba inputs from estuaries back through time, contributing to a better interpretation of the oceanic paleoproductivity and paleoalkalinity;

(4) Develop a Toolbox software from a multi-species multi-proxy approach. This software will present three applications:

(i) Optimize the empirical relations between the environmental proxies and the parameters;
(ii) Infer paleoclimates on the basis of proxy data sets;
(iii) Detect artefacts (e.g. aberrant data, breakdowns, digenesis, etc.) using new mathematical tools.

Development of educational aspects from this research is planned. It implies the regular update of the web site set up during the CALMARS project (2001-2005) to describe the principal developments of this second project.



RBINSc has a long experience on Caribbean sclerosponges (ultrastructure and in situ growth rate measurement). Its implication in the CALMARS project (2001-2005) increased its expertise in the biomineralisation processes of hypercalcified sponges.
ULB has a large experience in biomineralization processes of echinoderms through morphological, biochemical, physiological and environmental approaches, both in the field and in the laboratory.
UA performs research on bioavailability, bioaccumulation and effects of metals in aquatic organisms and studies effects of environmental conditions on kinetics of metal accumulation.
RMCA & VUB-DSCH have developed together expertise for trace element analysis by Laser Ablation ICP-MS.
VUB-DGLG has a long-standing experience in stable isotope geochemistry as applied to climate change.

Contact Information

Project website:


Philippe Willenz
Royal Belgian Institute of Natural Sciences (RBINSc)
Department of Invertebrates
Rue Vautier, 29
B-1000 Bruxelles
Tel: +32 (0)2 627.42.53
Fax: +32 (0)2 627.41.41


Luc G.R. André
Royal Museum of Central Africa (RMCA)
Section Petrography-Mineralogy-Geochemistry
Leuvensesteenweg 13
B-3080 Tervuren
Tel: +32 (0)2 769.54.59
Fax: +32 (0)2 769.54.32

Philippe Dubois
Université Libre de Bruxelles (ULB)
Marine Biology Laboratory - CP 160/15
Av. F.D. Roosevelt, 50
B-1050 Bruxelles
Tel: +32 (0)2 650.28.39
Fax: +32 (0)2 650.27.96

Frank Dehairs
Vrije Universiteit Brussel (VUB)
Analytische en Milieuchemie (ANCH)
Pleinlaan 2
B-1050 Brussel
Tel: +32 (0)2 629.32.60
Fax: +32 (0)2 629.32.74

Ronny Blust
Universiteit Antwerpen (UA)
Department of Biology / Ecophysiology, Biochemistry and Toxicology Group
Groenenborgercampus, Groenenborgerlaan 171
B-2020 Antwerpen
Tel: +32 (0)3 265.03.44
Fax: +32 (0)3 265.04.97

Follow-up Committee

Guy Munhoven - Université de Liège / Département d'astrophysique, géophysique et océanographie (AGO) / Labo de physique atmosphérique et planétaire (LPAP), Belgium
Peter K. Swart - Stable Isotope Laboratory / University of Miami, Rosenstiel School of Marine and Atmospheric Science (RSMAS), Florida, USA
Yves-Marie Paulet and Laurent Chavaud - Université de Bretagne Occidentale (UBO) / Institut Universitaire Européen de la Mer (IUEM), France
Jelle Bijma - Alfred Wegener Institute for Polar and Marine Research, Germany
Anne Lorrain - CHRONOS/LASAA Centre IRD de Brest, BP 70 29280 Plouzané, France
Catherine Mertens - Federal Council for Sustainable Development (FCSD), Belgium

Documentation :

Critical evaluation of MARine CALcareous Skeletons as recorders of global climate change : final report (phase 1)    Brussels : Federal Science Policy, 2010 (SP2216)
[To download

Evaluation critique des squelettes calcaires comme enregistreurs du changement climatique global : résumé (phase 1)    Bruxelles : Politique scientifique fédérale, 2011 (SP2345)
[To download

Critical evaluation of MARine CALcareous Skeletons as recorders of global climate change : summary (fase 1)    Brussels : Federal Science Policy, 2011 (SP2346)
[To download

Critical evaluation of MARine CALcareous Skeletons as recorders of global climate change : final report  André, Luc - Blust, Ronny - Dehairs, Frank ... et al  Brussels : Federal Science Policy, 2012 (SP2511)
[To download]  [To order