JPR Advance Access published online on April 3, 2007
Journal of Plankton Research, doi:10.1093/plankt/fbm027
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Temporal occurrence of planktotrophic bivalve larvae identified morphologically and by Single Step Nested Multiplex PCR (SSNM-PCR)
,* Department of Life Sciences and Chemistry, Roskilde University, 4000 Roskilde, Denmark ** Skidaway Institute of Oceanography, 10 Ocean Science Circle, 31411 Savannah, GA, USA *** Marine Biological Laboratory, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
E-mail: bhansen{at}ruc.dk Phone: +45-4674-2406 Fax: +45-4674-3011
Received on November 27, 2006; revised on March 1, 2007; accepted on March 28, 2007
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Abstract |
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We report the application of a recently developed molecular method, Single Step Nested Multiplex PCR (SSNM-PCR) assay and microscopy to identify and investigate temporal patterns of bivalve larvae in a Danish estuary, Isefjord. All samples were collected during the SUSTAINEX program from June through November, 2001. Using the molecular assay, larvae could be categorized into six groups including; the blue mussel, Mytilus edulis, Ensis spp., species of the Myoidae superfamily (Mya spp.), the common cockle (Cardiidae family), members of the Abra and Macoma genera of the Tellinoidae superfamily, and members of the surf clam genera, Spisula spp. A seventh group was comprised of unknown larvae. Greater resolution was possible by microscopy, but only for relatively large and intact individuals (>150-200 µm). The molecular approach was capable of differentiating between larvae regardless of shell size. Where it was possible to directly compare identifications based on both methods, concordance was high for Mytilus edulis, Macoma balthica/Abra alba, and E. americanus while identification of Myoidae spp., and Cardiids were less consistent. Over the course of the study, two patterns of larval occurrence were observed. Larvae from species known to exhibit a protracted annual spawning period (Mytilus edulis, Myoidae spp., Mysella bidentata and Cardiids) were present in the water column throughout the sampling period, while larvae of Abra alba, Barnea candida, Ensis americanus, Macoma balthica, Musculus marmoratus, Scrobicularia plana and Tapes pullastra appeared at clearly defined periods.
Key Words: SSNM-PCR • bivalve larvae • planktotrophic • species identification • morphological identification
Present address Department of Biology, University of Bergen, Jahnbakken 5, 5020 Bergen, Norway
Present address Department of Science, Systems and Models, Roskilde University, 4000 Roskilde, Denmark
Present address Department of Environmental, Social and Spatial Change, Roskilde University, 4000 Roskilde, Denmark