Next-generation biodiversity assessment and environmental monitoring of benthic communities using high-throughput DNA metabarcoding

Marine sediments constitute the largest single ecosystem on earth and their communities of benthic organisms significantly influence major ecological processes. Current marine management policies are strictly based on the maintenance of biological diversity, but our knowledge of marine benthos is lacking, especially in the deep sea and at higher latitudes. There is also an urgent need to monitor benthic biodiversity in the face of human impact and environmental change. Traditional methods for identification of benthic organisms are exceedingly labour-intensive and time-consuming, and therefore, expensive. The current project contributes to cost effective and representative monitoring of benthic organisms by developing methods based on so called DNA barcoding. We used samples with known species composition to establish a method that can be applied directly to sediment samples. The approach is used to analyse the benthic communities at various depths in a northern Norwegian fjord, Saltenfjorden. In addition, we analyse samples that were collected close to a salmon farm. These investigations adds to our knowledge of benthic biodiversity in northern waters and how it is affected by aquaculture.

There is a need to expand our knowledge of marine ecosystems in north Norwegian waters. This project specifically focuses on the demand for cost effective and representative mapping and monitoring of benthic communities in habitat types of particular conc ern, as a basis for sustainable ecosystem management. Marine sedimentary habitats constitute large ecosystems worldwide and their benthic communities significantly impact major ecological processes, such as geochemical cycling, secondary production, pollu tant distributions, and stability of sediments. Current marine management policies are strictly based on the maintenance of biological diversity, but our knowledge of marine benthos is lacking in geographic range, especially in the deep sea and at higher latitudes. In addition, there is an urgent need to monitor marine ecosystems in the face of environmental change. Traditional methods for identification of benthic organisms are exceedingly labour-intensive and time-consuming, and therefore, expensive. Al so, diversity assessments require extensive taxonomic expertise, and are usually limited to a part of the existing biodiversity, typically the macro fraction of the biota. As a result, there is an obvious mismatch between the need for representative biodi versity assessments and the resources at hand. DNA based methods offer the beginning of a possible solution to these shortcomings. The current project applies DNA barcoding and high-throughput sequencing technologies to analyze the benthic communities fro m bulk sediment samples, from a natural depth gradient in a fjord basin, and from environments influenced by aquaculture and oil production. We will further contribute to holistic and coherent methods for biodiversity assessment and monitoring. We aim to significantly expand our knowledge on the benthic biodiversity in boreal waters and contribute to molecular reference databases, in particular focusing on an important taxonomic group, the marine nematodes.