dr.ir. CW (Casper) Quist

Research

BE-Basic aims at making a major contribution towards a bio-based economy in The Netherlands, and - at the same time - delivers the tools needed to carefully monitor the impact of the production and use of these novel biochemicals, bio-materials and bio-fuels on local soil and water environments. In this way we want to ensure the ecological safety of these new bio-based processes and products, and optimize the chances of public acceptance of these new genomics-based solutions. We will develop a tool for monitoring of the ecological condition of soil soil life with relevance for ecosystem services and their stability. As generally known, soil is one of the most bio-diverse and competitive biological environments on our planet. Apart from this, soils play an essential role ecosystem services such as in carbon, nitrogen and phophorous cycling, water retention and anthropogenic waste breakdown.

Due to its extreme biodiversity (up to 10,000 genotypes per g soil!), it is not possible to monitor soil life in its full complexity. Groups of organisms that are represented in multiple levels in the soil food web could be most informative as indicators for ecological soil condition. Nematodes are such a group; they are represented in all trophic levels in soil, and - as such - they do not only reflect their own condition, but also the condition of their food sources (bacteria, fungi, protozoa, other nematodes). Use of nematode communities as bio-indicators has been hindered severely by their conserved morphology - nematodes very much look alike. To circumvent this problem, the research group of Hans Helder developed a database linking species to Small Subunit ribosomal DNA (SSU rDNA: length = 1,700 bp) sequences, which is currently world wide the largest database of its kind (see e.g. Van Megen et al. 2009). The resolution of this database allowed us to design PCR primers for all major North Western European nematode families. This has led into a robust quantitative-PCR-based nematode community analysis tool for all major terrestrial nematode families.
Of course nematode communities respond to changes in temperature and humidity, and different soil types harbour distinct nematode assemblages. An applicable tool for the monitoring of ecological soil condition should be able to distinguish natural fluctuations from structural, anthropogenic activity-related changes. To address this, we will establish so-called Normal Operating Ranges (NORs) for nematode assemblages for the three major Dutch soil types, namely marine clay, river clay and sandy soils (four locations for each soil type). To the best of our knowledge this will be the most intensive ecological soil survey worldwide ever. The locations were selected from the RIVM BoBI ("Biologische Bodemindicator") network on the basis of optimal ecological stability. Seasonal fluctuations in nematode assemblages will be monitored during three consecutive years, and the resulting extensive dataset will result in an ecologically robust ERA (Environmental Risk Assessment) tool to assess the impact of novel bio-based processes and products on soil life. Finally, the sensitivity of this tool will be established by exposing nematode communtities to increasing gradients of relevant stressors.