Understanding how mycorrhizal fungi move resources from point A to B

The paper

Antunes, P.M. (2025). Fluid mechanics within mycorrhizal networks: exploring concepts, traits, and methodologies. New Phytologist, 248: 1180–1191. https://doi.org/10.1111/nph.70509

Dr. Beatrice M. Bock interviewed me about this paper for the Mycorrhizas YouTube channel.

Why the networks matter

Most land plants on Earth depend on mycorrhizal fungi; fungi that live in symbiosis with plant roots. From the root, these fungi send out thread-like hyphae that explore the soil far beyond the plant's reach, moving water, nutrients, and carbon compounds between the plant and its neighbours. That network, the extraradical mycelium, is the largest part of the fungus. But it is also the part that has been studied least.

For decades, mycorrhizal research has focused on what happens inside the root or on spores in the soil. The network itself, how it is built, how fluid moves through it, what it trades off, has largely been a black box.

Borrowing from fluid mechanics

The paper makes a simple case: hyphal networks are biological vascular systems. They are pipelines that grow dynamically as they explore the soil. And there is already a mature toolkit for studying pipelines, fluid mechanics. Flow rate, pipe diameter, pressure gradients, branching geometry, these are all well-defined, quantifiable traits that transfer cleanly from engineering to biology.

Thinking about mycorrhizal networks this way fits with a broader push in the field toward trait-based ecology, where species are characterised by what they do. Fluid-mechanics traits give mycorrhizal biologists a new set of tools for asking evolutionary and ecological questions: Why do some fungal species invest in thicker, more conductive hyphae? When does it pay off to build dense networks versus sparse ones? How do networks respond when soil moisture shifts?

Methods, in and out of the lab

The paper also reviews how to actually measure fluid-mechanical traits in systems as messy as real soil. Some approaches use transparent microfluidic devices in the lab, where flow can be watched directly. Others work in opaque soil using imaging and tracer techniques. Each has trade-offs, and the paper maps them out; hopefully a useful thing for anyone planning new experiments in this space.

Why this matters beyond the lab

If we can describe fungal networks in quantitative, fluid-mechanical terms, we can model them, predict how they respond to stress, and compare them across ecosystems. That has real consequences for agriculture, how mycorrhizas move water under drought, how they connect crops in intercropping systems, and for carbon accounting, since a substantial fraction of soil organic carbon ends up in or around these networks. For ecological restoration, where soil biota are often the slowest part of a recovering system to come back, quantitative network traits would give us a way to measure whether the plumbing is actually working.