Geneviève Coté

Université du Québec à Rimouski
M.Sc. candidate

Supervisor: France Dufresne
Start: 2010-09-01
End: 2015-09-30

Project

ASSESSMENT OF MARINE BIODIVERSITY ON ROCKY SUBSTRATE USING DNA BARCODING AND INFLUENCE OF TWO SUBSTRATE TYPES ON THE RECRUITMENT OF ENDEMIC SPECIES AND THE INVASIVE CIONA INSTESTINALIS
In recent decades, the importance given to the conservation of global biodiversity has considerably increased due to the many stresses affecting community structure (including extinctions) and species abundance. In the marine environment, one of the most significant threats to biodiversity is the introduction of invasive species. A program has recently been developed to monitor biodiversity in four regions of the southwest Bay of Fundy, identified by Fisheries and Oceans Canada as Ecological and Biological Significant Areas (EBSAs). Under this program, we tested the use of "collectors" (91 x 61 x 15 cm with 37 mm mesh) to monitor the biodiversity of marine invertebrates that live on rocky substrates in the shallow (≤ 10 m) subtidal zone. In this study we address two objectives: 1) characterizing the biodiversity of invertebrates colonizing the collectors (settlers and “crawl-ins”) with DNA barcoding and 2) comparing the recruitment of endemic species as well as the invasive species Ciona instestinalis on naturally colonized cobble from the low intertidal and bare cobble from a quarry. For the second objective, 16 collectors filled with cobbles (diameter ≈ 10 cm) were submerged in the shallow subtidal zone in Beaver Harbour from May to October 2011, 8 of which were filled with bare quarry cobble and 8 with colonized lower-intertidal cobbles. Multivariate analyses (ANOSIM) were performed using PRIMER 6, which indicated a significant effect of substrate type on community structure when non-transformed data were analysed (Global R = 0,366; p = 0,001) but no effect of substrate type when the analysis was conducted on presence/absence data (Global R = 0,127; p = 0,074), indicating that substrate type affected the abundance but not the identity of species found in the collectors. Subsequently, an analysis of variance (ANOVA) showed a higher abundance of the tunicate Ciona intestinalis in cages with barren rocks compared to cages filled with cobbles from the intertidal zone (F(1,15) = 21.85 ; p : 0.0004). Genetic characterization of specimens (70 species) was performed in a known biodiversity hotspot of the southwest Bay of Fundy. The DNA of more than 50 species was amplified using a total of 30 primers of the conserved CO1 gene (or 18S when CO1 failed to amplify). The total sequencing success rate was 66.6%, there was high agreement in species identification done on the basis of DNA barcoding and morphology, although we did find some disagreement for cnidarians (low rates of mitochondrial evolution) and for some very young settlers.

Keywords

Biodiversité marine, Codebarre génétique, Colonisation du substrat, Recrutement, Espèce invasive, Invertébrés marins, Marine invertebrate, DNA barcoding, Biofouling, Biofilm, Settlers, recruitment