The effect of food composition on feeding, growth and reproduction of bivalves

1. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Sofia SARAIVA1,3, Jaap VAN DER MEER1,2, S.A.L.M. KOOIJMAN2, T. SOUSA3 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. RoviscoPais, 1, 1049-001, Lisboa, Portugal April 2009 April 2009

2. 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 www.mohid.com Set of couple models Hydrodynamic, eulerian and lagrangian advection-diffusion, sediment transport and biogeochemical/ecological models Dynamic Energy Budgets theory Integrated Modelling Tool To simulate properties evolution in estuaries and coastal areas where bivalves are abundant (natural or cultured populations) Bivalve activity over the pelagic system Influence of different climate scenariosin the production and distribution of different bivalve species DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium April 2009

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

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

5. The effect of food composition on feeding, growth and reproduction of bivalves DEB Model Standard DEB Model Variable Composition FILTRATION FOOD Zooplankton Phytoplankton Organic Matter Sediments PSEUDOFAECES Variable Composition INGESTION FAECES FOOD ASSIMILATION FAECES RESERVES SOMATIC MAINTENANCE MATURITY MAINTENANCE MOBILIZATION k 1-k INORGANIC COMPOUNDS CO2 H2O O2 NH3 PO4 REPRODUCTION GROWTH MATURITY STRUCTURE REPRODUCTION BUFFER • structures/ reserves • isomorph • k-rule • maturity concept • maintenance SPAWNING GAMETES DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

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

7. The effect of food composition on feeding, growth and reproduction of bivalves Parameters in Feeding Processes FILTRATION INGESTION ASSIMILATION FILTRATION ASSIMILATION Maximum surface area-specific filtration rate, m3d-1cm-2 Maximum surface area-specific filtration rate, m3d-1cm-2 Maximum surface area-specific uptake rate, molCd-1cm-2 Maximum surface area-specific uptake rate, molCd-1cm-2 Yield coefficient of reserves on food, molC(reserves)/molC(food) Yield coefficient of reserves on food, molC(reserves)/molC(food) Maximum surface area-specific property i ingestion rate, m3d-1cm-2 One more parameter for each type of food “measure” of the bivalve selectivity for each type of food DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

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

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

10. 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 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

11. 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 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

12. 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 • Lowconcentration (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 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

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

14. 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 DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

15. The effect of food composition on feeding, growth and reproduction of bivalves Conclusions Food quality and quantity is a key factor for mussels growth/performance To simulate food quality an extension of the standard DEB model is needed The model presented is based on: Filtration/Ingestion/Assimilation as different processes Synthesizing units mechanism Pseudofaeces and Faeces production Several types of food 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) 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 Useful model and conceptually a good approach to deal with the bivalves food quality changes at the ecosystem scale DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium

16. DEB Theory: 30 years of research for metabolic organization DEB2009 Symposium The effect of food composition on feeding, growth and reproduction of bivalves Thank you!! Sofia SARAIVA1,3, Jaap VAN DER MEER1,2, S.A.L.M. KOOIJMAN2, T. SOUSA3 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 April 2009