Robert G. Young & Sarah Adamowicz University of Guelph Cathryn Abbott & Tom Therriault Department of Fisheries and Oceans

Transcription

1 Evaluating Canadian zooplankton biodiversity through DNA barcodes: assessing non-indigenous species presence to provide a framework for future monitoring Robert G. Young & Sarah Adamowicz University of Guelph Cathryn Abbott & Tom Therriault Department of Fisheries and Oceans

2 Canadian Aquatic Biodiversity Understanding Canada s aquatic biodiversity is important, especially given increasing threats from invasive species Accurate information on levels of biodiversity can be valuable to support informed conservation decisions (Sorte et al. 2010) The current level of diversity of Canadian aquatic taxa, including species in Canadian Pacific, Arctic, and Atlantic oceans, is currently underestimated significantly (Archambault et al. 2010) 2

3 Why Study Zooplankton? Represent both meroplankton and holoplankton species Important trophic level Phylogenetically diverse May contain species with large ranges due to aquatic connectivity dispersal (both natural and human influenced) 3

4 Question: What is the current level of plankton diversity in Canadian waters? 4

5 DNA Barcoding Powerful tool for monitoring Canada s aquatic biodiversity DNA Barcoding uses short standardized DNA sequences that enable species discrimination in large blocks of life Barcode sequence library Barcoding and the barcode library may be used to identify and detect the presence of indigenous and non-indigenous species 5

6 Assessing Canadian Aquatic Diversity using DNA Barcoding Must be able to extract and sequence the DNA region of interest for many different species Must have enough variation between species to allow species identifications but not be too variable within species For animal life the mitochondrial DNA 5 end of the Cytochrome Oxidase Subunit I gene (Hebert et al. 2003) 6

7 Barcode Of Life Datasystems 7

8 Barcode Of Life Datasystems 8

9 Barcode Of Life Datasystems 9

10 Barcode analysis Differences in DNA barcodes help create trees showing genetic distances between species. Distance from the root of the tree to the tips represents the genetic distance between specimens Distance across tips is arbitrary

11 Barcoding Challenges Overlap in intra-specific and inter-specific divergences Poor taxonomy, poor knowledge of species boundaries Solutions Well-populated specieslevel dataset Integrative approaches (morphology, genetics, ecology) Hybridization, recent radiation Complementary markers when needed, diagnostic characters 11

12 Plankton and the Advantages of Barcoding The ability to identify all life stages including: Larvae plankton Family:Nereididae Terebellides stroemi Juveniles Carcinus maenas Adult specimens Oikopleura labradoriensis Conchoecia sp. 12

13 Questions Using Barcode Data 1.Cryptic species Acartia tonsa (Chen 2008) 2.Biogeography Gattyana cirrhosa (Carr 2011) 3.Presence of invasive species Limnoithona tetraspina (Bollens 2012) 13

14 Question: What is the current level of plankton diversity in Canadian waters? 14

15 Methods: Collection Locations Northern Collections Churchill Iqaluit Deception Bay Steensby Inlet West Coast Nanaimo Victoria Vancouver Roberts Bank East Coast Port Hawksbury Bayside Bedford Basin Baie de Sept-Iles Great Lakes System Hamilton Montreal Nanticoke Thunder Bay 15

16 Methods All unique morpho-species were selected at each port Specimens were expertly identified, imaged, and sequenced at the DNA COI barcode region Expert identifications indicate over 90 unique species 16

17 Collected Taxonomic Diversity Arthropoda (Crustaceans) Annelida (Polychaetes) Chaetognatha Chordata (Tunicates) Cnidaria Ctenophora Echinodermata Mollusca 17

18 Barcode Support for Taxonomic Identifications Class Species Barcode Molecular Grouping Maxillopoda Skistodiaptomus oregonensis Maxillopoda Eurytemora affinis Maxillopoda Epischura lacustris Eurytemora affinis Maxillopoda Mesocyclops edax Mesocyclops sp. 18

19 Hamilton Port Results Six families from both molecular and taxonomic identifications Molecular results indicate an additional Maxillopoda group indicating possible: Cryptic species Unrecorded diversity Invasive species Branchiopoda Arthropoda Sididae Daphniidae Chydoridae Bosminidae Diaptomidae Maxillopoda 0.03? Cyclopidae 19

20 Continued work A large number of specimens have been expertly identified. Continue working on isolating and extracting viable DNA from individuals with associated vouchers for approximately 2200 specimens Obtain DNA barcode (COI region) data for all identified specimens Obtain additional molecular regions for identified specimens (including 18S and potentially two others) 20

21 Overall Significance Increase our knowledge of Canadian plankton biodiversity and biogeography and to further our understanding of invasive species in Canadian waters. 21

22 Taxonomic Breakdown Arthropoda 77% Annelida 4% Chordata 7% Coelaenterata, Nematoda, Ctenophora, Bryozoa, Echinodermata 3% Cnidaria 3% Mollusca 3% Chaetognatha 3% 22

23 Limitations of Threshold-based Approaches (Meyer and Paulay PLoS Biology) 23