1. The effect of food composition on feeding, growth and reproduction of bivalves Sofia SARAIVA 1,3, Jaap VAN DER MEER 1,2, S.A.L.M. KOOIJMAN 2, T. SOUSA 3 Sofia.Saraiva@nioz.nl 1. Royal NIOZ, P.O. Box 59, 1790 AB Den Burg, The Netherlands 2. Free University Amsterdam, Amsterdam, The Netherlands 3. Instituto Superior Técnico. Environment and Energy Section, Av. Rovisco Pais, 1, 1049-001, Lisboa, Portugal April 2009 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium April 2009

2. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Aim Couple a size-structured population model for several bivalve species to a hydrodynamic and biogeochemical model Individual Based Population Model Integrated Modelling Tool To simulate properties evolution in estuaries and coastal areas where bivalves are abundant (natural or cultured populations) Set of couple models www.mohid.com Dynamic Energy Budgets theory Hydrodynamic, eulerian and lagrangian advection-diffusion, sediment transport and biogeochemical/ecological models Bivalve activity over the pelagic system Influence of different climate scenarios in the production and distribution of different bivalve species

3. April 2009 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Why do we need an ecosystem Model? Estuaries and Coastal Areas Ecological Processes Ecosystem Model Organisms Tide, Wind Fresh Water Discharges Density driven currents Food Temperature Predation Hydrodynamics Food Availability Particulate Matter Erosion/Deposition Residence Time Light Nutrients (N/P) Temperature

4. BIVALVE POPULATION MODULE DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Bivalve model AND Ecosystem Model DEB Cohorts ECOSYSTEM MODEL Phytoplankton Zooplankton Particulate Organic Matter Sediments Nutrients (N and P) FILTRATION INORGANIC FLUXES FAECES PSEUDOFAECES Bivalve Structure Bivalve Reserves Bivalve Reproduction Buffer Bivalve Maturity INGESTION ASSIMILATION FOOD QUALITY FOOD QUANTITY

5. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Standard DEB Model FOOD GROWTH k 1-k FAECES MOBILIZATION MATURITY MAINTENANCE SOMATIC MAINTENANCE REPRODUCTION BUFFER RESERVES STRUCTURE REPRODUCTION SPAWNING GAMETES MATURITY INORGANIC COMPOUNDS CO 2 H 2 O O 2 NH 3 PO 4 structures/ reserves isomorph k-rule maturity concept maintenance ASSIMILATION FILTRATION FAECES FOOD PSEUDOFAECES INGESTION Zooplankton Phytoplankton Organic Matter Sediments Variable Composition DEB Model Variable Composition

6. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Feeding Processes in Bivalves FILTRATION INGESTION ASSIMILATION RESERVES … PSEUDOFAECES FAECES Zooplankton Phytoplankton Organic Matter Sediments Synthesizing Units Sequential Substitutable Sequential Substitutable ZOOPLANKTON STRUCTURE RESERVES Yield Coefficient PHYTOPLANKTON STRUCTURE Yield Coefficient RESERVES Parallel Complementary DETRITES Yield Coefficient -Any property can be processed independently from the others -The binding of each property is affected by the presence of others -A specific ratio N/C is needed -No interaction at binding level

7. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Parameters in Feeding Processes FILTRATION ASSIMILATION FILTRATION INGESTION ASSIMILATION Maximum surface area-specific filtration rate, m 3 d -1 cm -2 Maximum surface area-specific uptake rate, molCd -1 cm -2 Yield coefficient of reserves on food, molC(reserves)/molC(food) Maximum surface area-specific filtration rate, m 3 d -1 cm -2 Maximum surface area-specific uptake rate, molCd -1 cm -2 Yield coefficient of reserves on food, molC(reserves)/molC(food) Maximum surface area-specific property i ingestion rate, m 3 d -1 cm -2 One more parameter for each type of food “measure” of the bivalve selectivity for each type of food

8. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Model vs. Observations Mussels - 6cm Temperature – 6.5 o C Several lab experiments with increasing silt and detritus concentration in the water Measurements in filtration and pseudofaeces

9. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Model vs. Observations

10. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Model vs. Observations -Filtration, Ingestion and Pseudofaeces computed by the model follow the main patterns of observations - Some differences can be found but many assumptions had been made -Not all the model capacities were tested -More work in the calibration and validation of the model has to be done

11. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves “Playing with the model” Test the influence of food quantity and quality in the bivalve feeding, growth and reproduction -2 Types of food (A and B) -Same concentration, constant -High concentration (1mgC/l) -Constant temperature No selection (same affinity) Selection for food A (different affinity) -At high food concentration the ingestion of each type of food is only limited by the bivalve selectivity -Without selectivity there is no production of pseudofaeces but with selectivity some of the “less selected” type of food will be rejected -If concentrations are the same in the water column, selectivity can lead to lower growth rate and lower length -Low food, low growth, low reproduction buffer, less spawning events

12. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves “Playing with the model” -2 Types of food (A and B) -Same concentration, constant -Low concentration (0.05mgC/l) -Constant temperature No selection (same affinity) Selection for food A (different affinity) -The ingestion is limited by filtration and there is no selectivity by the bivalve -The bivalve ingestes everything that is filtered and there are no production of pseudofaeces

13. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Still “playing with the model”: a more realistic scenario Temperature and Food Algae N/C ratio? Nutrients Light Temperature Nutrients Uptake Light α Temperature CarbonUptake

14. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Constant vs. Seasonal N/C algae ratio -Seasonal changes in algae N/C ratio => difference in the nitrogen uptake => differences in assimilation => differences in growth -Algae N/C ratio changes could be important to explain bivalve performances in different places

15. The model presented is based on: DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Conclusions To simulate food quality an extension of the standard DEB model is needed Food quality and quantity is a key factor for mussels growth/performance Filtration/Ingestion/Assimilation as different processes Synthesizing units mechanism Pseudofaeces and Faeces production Several types of food Food quality (ex. algae N/C ratios) can have significant influence in bivalve’s growth and variations should be consider when comparing different populations in different locations Model results globally agree with patterns described in literature but more work could be done in calibrating/validating the model using more data sets (if available) Useful model and conceptually a good approach to deal with the bivalves food quality changes at the ecosystem scale

16. The effect of food composition on feeding, growth and reproduction of bivalves Sofia SARAIVA 1,3, Jaap VAN DER MEER 1,2, S.A.L.M. KOOIJMAN 2, T. SOUSA 3 Sofia.Saraiva@nioz.nl 1. Royal NIOZ, P.O. Box 59, 1790 AB Den Burg, The Netherlands 2. Free University Amsterdam, Amsterdam, The Netherlands 3. Instituto Superior Técnico. Environment and Energy Section, Av. Rovisco Pais, 1, 1049-001, Lisboa, Portugal April 2009 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium April 2009 Thank you!!