Blue mussel bouchot culture in Mont-St Michel Bay: potential mitigation effects on climate change and eutrophication?

Transcription

1 Blue mussel bouchot culture in Mont-St Michel Bay: potential mitigation effects on climate change and eutrophication? Joël Aubin, Caroline Fontaine, Myriam Callier, Emmanuelle Roque d orbcastel INRA UMR SAS Rennes France IFREMER UMR MARBEC Montpellier/Sète France Joel.aubin@inra.fr

2 Goal and Scope Mont Saint Michel: - Abbaye from the 13th century - A bay with a particular marine ecosystem - An area for the production of 12, tonnes of blue mussels (Mytilus edulis) with a protected designation of origin..2

3 Goal and scope: Characteristics of biophysical context A tidal range of 15 m which sweeps the bay (no accumulation of organic matters) mussels are dewatered twice a day 3 production zones A: Center B: East C: Far East Current Oysters A B C.3

4 Goal and scope: Why to study environmental impacts of mussel culture? An increasing demand for aquatic products (+8-1% /year) A common activity on the sea shore in Europe: 28 k tonnes A specific relationship with the environment: Filtration of plankton and organic matter results in water epuration Production of a calcarous shell may stock carbon from the environment Plankton Drawing water Expelled water Excurrent siphon Incurrent siphon Byssal thread Foot.4

5 Goal and scope Operational objectives To help the producers organization to understand environmental impacts of mussel production To prepare the environmental labelling of aquatic products in France Scientific objectives To evaluate the potential influence of the extractive activity on eutrophication and climate change To evaluate the potential role of mussel production in regional nutrient balance (N and P).5

6 Production system.6

7 System boundary Introduction of shell s end of life to consider carbon sequestration.7

8 Life Cycle Inventory Taking into account the end of life of mussel shells Based on national statistics on management of domestic waste (28) Only 58% of the mussel shells account for C sequestration.8

9 Life Cycle Inventory Survey of 6 farmers having 2 to 3 areas of production (materials, practices, energy, productivity ) Background data from ecoinvent v3 Modelling of nutrient uptake using mass balance approach and data from literature and measurement of dry matter on mussel samples Element in shell or flesh C in shell from ingested C (Brigolin et al. 29) C in shell from dissolved C (Chairattana et al. 212) N in flesh (Brigolin et al. 29) P in flesh (Brigolin et al. 29) Per tonne of harvested mussels 198 kg C 18 kg C 4.17 kg N.38 kg P Estimated C content in the shell, and N and P contents in the flesh, per tonne of blue mussels in the life cycle inventory..9

10 Life Cycle Impact Assessment Impact categories : Eutrophication (CML2 Baseline 2) Acidification (CML2 Baseline 2) Climate change (CML2 Baseline 2) Water dependence (CML2 Baseline 2, Aubin et al. 29) Total cumulative energy demand (Frischknecht et al. 24) Functional Unit : 1 tonne of bags of ready to sell mussels Calculations with SimaPro 7. software.1

11 Contribution analysis.11

12 Location effect Total cum. energy demand (MJ) Acidification (kg SO2-eq) *** 2,5 2 1,5 1,5 *** Center East Far East Center East Far East -,5 Eutrophication (kg PO4-eq) Center East Far East Climate change (kg CO2-eq) -1-1,5 5-5 * Center East Far East

13 Comparison with Livestock For 1 tonne of protein Acidification (kg SO2 eq) Climate change (kg CO2 eq) Mussel Mt St Michel Salmon (UK) Chicken (Fr) Porc (Fr) Beef (UK) 4 2 Mussel Mt St Michel Salmon (UK) Chicken (Fr) Porc (Fr) Beef (UK) Eutrophication (kg PO4 eq) Total cum. Energy demand (MJ eq) Mussel Mt St Michel Salmon (UK) Chicken (Fr) Porc (Fr) Beef (UK) Mussel Mt St Michel Salmon (UK) Chicken (Fr) Porc (Fr) Beef (UK).13

14 Conclusion An improvement of the methodology through the mass balance of C, N and P of mollusks and the consideration of the end of life of shells. This methodology has to be applied in different contexts and on different species (oysters) Potential and limited effect of mitigation of eutrophication effect of agriculture by mussel production A carbon neutral production (if taking into account the bouchot), pointing out the large use of fuel for the rearing activities. Farmers have to be sensitive to the distance they cover each day and to the land based location of the material Relevance of spatial differentiation in LCA.14

15 Thank you for your attention.15