While there are a number of publications that describe the species of shipworms present in different marine environments, few have tried to estimate the rate of wood removal as the infestation progresses from in situ observations. The dynamics of wood decay by these bivalves was quantified for the first time in this new publication.
Our new article entitled "Wood Decay at Sea", which presents some early results from a long-term wood degradation experiment is now available at the Journal of Sea Research.
This block of pine has been almost completely replaced by "shipworm" tubes
One of the biggest experimental difficulties is how to estimate the numbers of living organisms remaining as the colonization process progresses within a block of wood. Each tube is extremely fragile, and forms complex entangled three-dimensional structures as individuals tunnel and grow into the wood block.
Abstract
"The oceans and seas receive coarse woody debris since the Devonian, but the kinetics of wood degradation remains one of many unanswered questions about the fate of driftwood in the marine environment. A simple gravimetric experiment was carried out at a monitoring station located at the exit of a steep, forested Mediterranean watershed in the Eastern Pyrenees. The objective was to describe and quantify, with standardized logs (in shape, structure and constitution), natural degradation of wood in the sea. Results show that the mass decrease of wood logs over time can be described by a sigmoidal curve. The primary process of wood decay observed at the monitoring station was due to the arrival and installation of wood-boring species that consumed more than half of the total wood mass in six months. Surprisingly, in a region where there is little remaining wood marine infrastructure, “shipworms”, i.e. xylophagous bivalves, are responsible for an important part of this wood decay. This suggests that these communities are maintained probably by a frequent supply of a large quantity of riparian wood entering the marine environment adjacent to the watershed. By exploring this direct link between terrestrial and marine ecosystems, our long term objective is to determine how these supplies of terrestrial organic carbon can sustain wood-based marine communities as it is observed in the Mediterranean Sea."
Citation
Charles, F., Coston-Guarini, J., Guarini, J-M, Fanfard, S. 2016. Wood decay at sea. J. of Sea Research, v. 114, 22-25; http://dx.doi.org/10.1016/j.seares.2016.05.002.
All images (c) by J. Coston-Guarini.