28 January 2009

Nodules on roots of alder (Alnus glutinosa)

On a walk around the Coneyburrow Wood part of Brede High Woods, I noticed some clustered, orange brown objects uncovered in a scuffed up patch of marshy earth.

20090128 alder root nodules 001

These are nodules on the roots of alder trees caused by the nitrogen-fixing actinobacterium (or actinomycete), Frankia.

The nitrogen provided by the bacteria in these nodules enable alders to grow well in nutrient-poor, waterlogged soils.  Much of the nitrogen arriving in temperate forests comes from Frankia bacteria on this and other tree species.

This soil enrichment helps to establish and maintain woodlands and other habitats, particularly where climate change or human activity disrupts ecosystems.

Who would think that the tiny organisms inside these bobbly conglomerations could help to save the planet?

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