April Book Review - Entangled Life

Date: Tuesday 13 April

What is the largest organism that has ever existed on the Earth, probably?  My first thought was a bull elephant.  No, no, it must be one of the dinosaurs, Brontosauras I guessed.  But then what about a blue whale?  The unexpected answer, as revealed in Merlin Sheldrake’s remarkable first book Entangled Life, is a soil-living mycorrhizal fungus living in the forests of New England, and there may well be larger ones.  This fungus covers an area of around 2 square miles and is thought to be around 2,400 years old.  Sheldrake’s book covers both ‘normal’ fungi and mycorrhizal fungi but it is these latter organisms which obviously fascinate the author the most.

Mycorrhizal fungi are one of the world’s great hidden biological resources but what, you might well ask, have they got to do with the Climate Change agenda and, indeed, other problems caused by our over exploitation of the environment? First thing is that mycorrhizal fungi are intimately associated with plant roots, indeed they ‘feed’ plants by delivering phosphorus and nitrogen to them. Next, this feeding was very significant  500 million years ago when our climate was much warmer.  In theory, trees could grow faster but their growth was limited by, amongst other things, phosphorous: mycorrhizal fungi helped deliver this and the trees did indeed grow faster.  This increased the rate of extraction of CO2 from the atmosphere and the climate cooled.  As Sheldrake explains, this is only a hypothesis but it fits with the known facts.

Moving to the present day, mycorrhizal levels in soil are being lowered by intensive farming methods.  Does this matter?  Well, in addition to providing nutrients to plants, mycorrhizal fungi hold soil together, producing better growing conditions by allowing the water holding capacity of soil to maximise.  These fungi are also great for soil remediation both by taking up heavy metals and by producing water filtration systems composed of mycelial networks.  Indeed, a company in Finland is using this ‘microfiltration’ to reclaim gold from electronic waste.

So, you may never have knowingly seen a mycorrhizal fungus but they are all around us as, indeed, are all the other types of fungi.  A crazy statistic from “Entangled Life’ – fungi produce 50 megatonnes of spores each year.  This is equivalent to the weight of 500,000 blue whales.

For anyone interested in one of the most fascinating, and least known, facets of the natural world Merlin Sheldrake’s ‘Entangled Life’ is a joy to read.  If fungi sound dull and boring to you, except perhaps as culinary items, this book will open your eyes to a whole new world of biology.

Review provided by John Palfreyman.

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