Food web: evaluate the relationship between postlarval biodiversity and plankton communities (phyto- and zooplankton), in Northwest Mediterranean sea.

Transcription

1 Food web: evaluate the relationship between postlarval biodiversity and plankton communities (phyto- and zooplankton), in Northwest Mediterranean sea. Garsi L.H. 1, Rossi A. 1, Pasqualini V. 1, Garrido M. 1,Bisgambiglia, P.A. 1, Agostini S. 1 garsi@univ-corse.fr 1 University of Corsica, Science for Environment, UMR 6134 CNRS-UCPP, Corte (France) Colloque DIRVER/SUBLIMO, Institut Océanographique Paul Ricard Ile des Embiez avril 2015

2 Introduction Life+ Sublimo = PL fish biodiversity Some parameters influence the survival of post-larvae Location : Corsica Evaluate relation between PL and food

3 Primary site: 9 CAREs/night 8 night/month 12- Sept 14 Secondary sites: 5 CAREs/night 4 night/month - Oct 12 June - Sept 13 June - Sept 14 Study area Main currents BASTIA SAINT FLORENT BONIFACIO SANTA SEVERA Additional sites: 3 CAREs/night 4 night/month - Oct 13 Aug 14 CALVI LUCCIANA

4 Sampling design «CARE» Post-larvae : Life + Sublimo Identification and Counting Getting breeding pond Apstein net 50 l 100 ml Phytoplankton Identification and Counting Uthermöl method Filet WP2 Numerical identification and Counting by ZOOSCAN equipment Zooplankton 200 ml Stella mare

5 Chla (µg.l-1) Results : Phytoplankton communities in Bastia Diatomophyceae Dinophyceae Prymnesiophyceae Cyanophyceae others Chl a (previmer) Chl a (sonde) 1% 11% 4% 32% 53% 100% 1,00 90% 0,90 80% 0,80 70% 0,70 60% 50% 40% Stella mare Stella mare 0,60 0,50 0,40 30% 0,30 20% 0,20 10% 0,10 0% 0,00 Majority of Diatomophyceae (53%) & Dinophyceae (32%) Phytoplankton bloom in early spring : 13 and February 14 was missed Previmer data 5

6 Results : Phytoplankton communities in Bastia June February January November November February January Transform: Square root Resemblance: D1 Euclidean distance Transform: Square root 2D Stress: 0,07 Resemblance: D1 Euclidean distance 2D Stress: 0,07 year year February January November February January November February November November February January January June June Temporal variability : composition and abundance February 2013 January November February 2014 : missed Transform: Square root Resemblance: D1 Euclidean distance November February January 2D Stress: 0,07 y

7 Zooplankton biovolume (mm/m3) Results : Zooplankton communities in Bastia 2% Appendicularians Chaetognaths Cladocerans Copepoda Curstacean larvae Crustacean nauplii Curstacean eggs Fish eggs Fish larvae Echinoderm Jellyfish Siphonophora Salps Molluscs Ostracods Pteropods Radiolaria Annelids Biovolume 95% 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0,80 0,70 0,60 0,50 0,40 0,30 0,20 0,10 0,00 Zooplankton peak in spring : 13 and 14 Majority of Copepods (95%) and Cladocerans (2%)

8 Results : Zooplankton communities in Bastia January January January February January February November February November November February November June June June June Transform: Fourth root Resemblance: S17 Bray Curtis similarity Transform: Fourth root 2D Stress: 0,16 Resemblance: S17 Bray Curtis similarity 2D Stress: 0,16 year year Temporal segregation for spring peaks Sub-segregation for winter months

9 Total abundance Results : Post-larvae communities in Bastia Ammodytidae Atherinidae Blenniidae Carangidae Clupeidae Gadidae Mugillidae Mullidae Pomacentridae Sparidae others Total abundance 67% 11% 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% in 2013 & 2014 : S. salpa + P. acarne in June 2013 & 2014 : S. smaris Sparidae (67%) & Mugilidae (11%) most abundant

10 Results : Post-larvae communities in Bastia June June Transform: Square root Resemblance: D1 Euclidean distance (+d) Transform: Square root Resemblance: D1 Euclidean distance (+d) 2D Stress: 0,07 2D Stress: 0,07 year June January June February November November January January February November November January February February year Temporal variability in composition and abundance for : Summer peak (June 2013 & 2014) and Winter peak ( 2012 & 2013)

11 -12 Aug-12 Sept-12 Oct-12 Nov-12 Dec-12 Jan-13 Feb-13 Mar-13 Apr June Aug-13 Sept-13 Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr June Aug-14 Sept-14 Biovolume (ml.m3) et Chl a (µg.l-1) Post-larves (Abondance totale) Results : Temporal monitoring in Bastia chl a post-larves 1,00 0,90 biovolume , ,70 0,60 0,50 0,40 0,30 0,20 0,10 0, Observation of trophic succession : T C = ± 1 - In 2013 : Phyto/zoo (R²=0.780), Zoo/PL (R²=0.856) - In 2014 : Phyto/zoo (R²=0.872), Zoo/PL (R²=0.948) 1 month in advance in 2014 compared to 2013!

12 Results : Interactions Phyto/Zooplankton Diato/Echinoderm (R²= 0.665) Diato/Cladocerans(R²=0.994) /Crustacean larvae (R²=0.986) Stella mare Dino/Annelid (R²=0.811) Stella mare Stella mare Dino/Cladocerans(R²=0.997) /Copepoda (R²=0.928) /Crustacean larvae (R²=0.996) Stella mare

13 Results : Interactions Zooplankton/PL Jellyfish larvae Jellyfish larvae Carangidae Cladocerans Radiolaria Sparidae Crustacean eggs Copepoda Gadidae Copepoda Crustacean eggs Mugilidae Crustacean nauplii Annelid larvae Mullidae Significative correlations : 5 families Molluscs Molluscs Differences in zooplankton compositions between 2013 & 2014 Food composition : Majority of crustaceans Cladocerans

14 Conlusion Preliminary results of oriental coast dynamic (Bastia) Phyto / Zooplankton and Post-larvae communities other 2 years (jul.12 sept.14) First observation of Trophic Succession on 3 levels on the Corsican coast Summer 2013 & 2014 Perspectives Compare with other Corsican sites Verify with gut contents Analysis over several years (verify adaptation)

15 Thank you