Dead trees at the bottom of the ocean host a diverse range of bacteria, fungi and molluscs (pictured; a cent is included for scale).
Craig McClain of the National Evolutionary Synthesis Center in Durham, North Carolina, and James Barry of the Monterey Bay Aquarium Research Institute in Moss Landing, California, left 18 Acacia hardwood logs at a depth of more than 3,000 metres in the northeast Pacific Ocean and retrieved them after five years.
The duo found thriving ecosystems that varied dramatically between logs, even though the wood was within an area 500 metres square: on average, the logs were only about 25% similar in terms of species composition. Key colonizers were wood-boring bivalves, which create holes for other organisms to shelter in and provide food in the form of wood chips and faeces.
Changing patterns of deforestation, river flow and hurricanes might affect the frequency and size of such 'wood falls', which could have a significant impact on deep-sea diversity, the authors say.