Accelerating the molecular/morphological bioinventory of meiofauna: Marine nematodes of Mexico’s threatened Gulf of California

Marine nematodes (phylum Nematoda) arguably are the most abundant, diverse component of meiofauna and represent one of the largest gaps of knowledge when assessing global biodiversity. Addressing this gap, an international team proposes a novel approach to inventory one of Earthís most biodiverse and threatened seas, Mexicoís Gulf of California, where preliminary sampling assures abundant nematode species, including many new to science. Approaches first implemented in the Gulf are designed to ultimately accelerate marine nematode diversity inventories worldwide.

Collection of 500 diverse samples, each with thousands of individuals, is proposed at five ecologically and geographically divergent Gulf localities. These localities are designated as urgent priorities for biodiversity research by Mexican and international agencies based on abundant endemic species and unprecedented loss of unique habitats, exacerbated by diversion of Colorado River runoff, over-harvesting, agricultural discharge, mining and tourism. Mass collections and microscope slides/types from this inventory will be curated in established systematic collections in Mexico and the US using synchronized on-line databases. These museum databases will be linked to a complementary morphological/molecular database managed by a bioinformatics specialist. All databases are designed to provide worldwide access to specimens and data generated by the survey.

Conventional surveys of marine nematodes are confounded by inadequate taxonomic infrastructure. We will therefore employ combined morphological and molecular methods, while our databases will be designed to allow application of up-to-date phylogenetic species concepts and development of versatile identification tools. For 5000 specimens selected to represent Gulf diversity, morphological characters will be recorded prior to molecular analysis. This will be accomplished through multifocal digital video clips (VCE) that electronically represent each captured specimen. The resulting virtual vouchers will be linked to nucleotide sequences from the same individual and placed in an on-line archive, accessible to worldwide marine nematode taxonomic expertise. Mass collections, microscope slides, VCE files, DNA extract and sequences will all be linked to collection sites and samples through a bar-coding system. Sequencing methods are designed to balance the goals of maximizing inventory at approximate species level against cost- and time effectiveness, to attain meaningful breadth in the survey. Thus, in combination with morphology, the D3 expansion segment of the large subunit rDNA gene is proposed as a ìfirst cutî locus for species level molecular inventory, with sufficient DNA extract remaining for further resolution with additional loci (most notably the Internal Transcribed Spacer region). The on-line archive of light microscopy and DNA sequences will be further enhanced by judicious use of scanning electron microscopy also linked to VCE and relevant to taxonomic resolution. Through cooperation with an independent Nematodes- Assembling the Tree of Life (NemATOL) project, these specimens will simultaneously support the emerging ATOL phylogenetic framework.

Products of the proposed survey supporting related research include on-line databases, new identification aids for non-specialists, new species descriptions, revisionary systematics, museum support and a new generation of trainees in marine nematology. The proposed survey also provides the ìraw materialî for ecological/conservation work and is a source for key representatives of previously missing components for phylum-based phylogenies of the NemATOL. By bringing together international expertise in the full range of approaches to marine nematode diversity we can begin to characterize a uniquely rich, threatened and nearly unexplored region, the Gulf of California, while maximizing data output for outreach and support for a geographically and scientifically much broader range of future high priority investigations.

1) Intellectual merit is underscored by the novel methodology we propose to apply to a greatly understudied segment of biodiversity within a seriously threatened geographic region. The approach integrates the PIsí strong connections with diverse disciplines, institutions and international expertise. The proposed infrastructure will stimulate worldwide research in ecology, conservation, systematics and evolution. 2) Broader impacts are mediated by database resources and directly accessible-images available worldwide to scientists, the public, teachers and policy-makers. We also propose to build upon our demonstrated track record for involving underrepresented groups in research and training. Outreach is further extended through workshops including those developed for nonspecialists.