Overcoming the Challenges of Studying Soil Nematodes: A New Approach with Implications for All (Soil) Organisms

Post provided by Stefan Geisen

(Soil) Nematodes

“…if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes…” (Cobb 1914)

He may have said it more than a century ago but we now, more than ever, realise that Nathan Augustus Cobb was right. Nematodes are by far the most abundant animals soil, freshwater and marine ecosystems. These tiny worms are barely visible to the human eye (if they’re visible at all), hundreds can inhabit a single gram of soil . Their similar shape might lead you to think that they’re all alike, but that’s not the case. More than 25,000 species have been identified and estimates put their entire species diversity in the 100,000s.

Some common nematode species found in most soils. a) Plectus sp; b) Aphelenchus sp; c) Helicotylenchus sp; d) Thonus sp; e) Mononchus sp; © Wageningen University, Laboratory of Nematology, NL; Hanny van Megen

Some common nematode species found in most soils. a) Plectus sp, b) Aphelenchus sp, c) Helicotylenchus sp, d) Thonus sp, e) Mononchus sp. © Wageningen University, Laboratory of Nematology, NL; Hanny van Megen

This taxonomic and functional diversity has boosted nematodes to become useful bioindicators for soil quality. Nematodes perform many different functions in both terrestrial and aquatic ecosystems. These are mainly defined by what they eat:

  • Bacteria/Fungi: Many nematode groups eat bacteria and fungi. They control the population of these organisms and keep them active.
  • Plants: Plant feeders are the unwanted guests in agricultural systems as well as in our gardens. They can destroy entire harvests by piercing into or infiltrating roots.
  • Omnivores/Predators: Many nematode species prey on other smaller organisms including smaller nematodes and control their abundances.
  • Parasites: These species inhabit other larger organisms and can act as biocontrol agents.

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New Associate Editors

Today we are welcoming two new people to the Methods in Ecology and Evolution Associate Editor Board. Pierre Durand is joining us from the University of the Witwatersrand (South Africa) and Andrew Mahon joins from Central Michigan University (USA). You can find out more about Pierre and Andrew below.

Pierre Durand

Pierre Durand

“My research is broadly focussed on the evolution of complexity. Many of my projects are related to the evolutionary ecology of programmed cell death (PCD) in unicellular organisms; how PCD impacts microbial communities; and how the philosophy of levels of selection informs our understanding of PCD evolution. I have also examined other aspects of complexity evolution such as the origin of life and group formation in unicellular chlorophytes in response to predation. The model organisms I typically use are phytoplankton. With specific reference to submissions to Methods in Ecology and Evolution, I have used a range of methods in my research, including general cell and molecular biology tools, biochemical assays, microscopy, flow cytometry, bioinformatics and computational algorithms.”

The most current projects in Pierre’s laboratory concern: programmed cell death evolution and complexity in microbial communities; changes in phytoplankton abundance and diversity in harmful algal blooms, led by PhD candidate Andrew Ndhlovu (“A red tide forming dinoflagellate Prorocentrum triestinum: identification, phylogeny and impacts on St Helena Bay, South Africa” in review in Phycologia); and the genomics of the four-celled chlorophyte Tetrabaena socialis, led by PhD candidate Jonathan Featherson.

Andrew Mahon

Andrew Mahon

“I’m a molecular ecologist who uses genetic and genomic tools to ask questions ranging from surveillance and monitoring to biodiversity and phylogeography.  My work includes development of novel molecular detection tools and metabarcoding applications for aquatic invasive species.  I’m also interested in applying molecular tools to ask questions related to the evolution and biodiversity of benthic marine invertebrates in Antarctica.”

Andrew has recently been published in the journal Research Ideas and Outcomes (‘DNAqua-Net: Developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe‘) and in Environmental Science and Technology (‘Influence of Stream Bottom Substrate on Retention and Transport of Vertebrate Environmental DNA‘). He also has a manuscript in press with Ecology and Evolution (‘Geographic structure in the Southern Ocean circumpolar brittle star Ophionotus victoriae (Ophiuridae) revealed from mtDNA and single-nucleotide polymorphism data‘).

We are thrilled to welcome Pierre and Andrew to the Associate Editor Board and we look forward to working with them over the coming years.