Bioerosion is the "erosion of substrate by means of biological procedures" (Neumann, 1966). This website has images, texts and links to serve as an introduction to marine bioerosion, with an emphasis on bioerosion by larger organisms (that is, greater than microscopic in size). This site will be continually corrected and amended. Please send any comments and suggestions to: mwilson@wooster.edu

A fragment of limestone bored by clams and sponges while exposed on a Holocene seashore in the Dominican Republic.

A piece of a wharf piling thoroughly bored (and virtually destroyed) by clams known as "shipworms".

The best place to start on this website is with an introduction to the processes and characters of marine bioerosion. If you have not already done so, please review this bioerosion slide presentation, which has numerous illustrations with captions. All the images at this site are indexed on a thumbnail page. If you are interested in bioerosion produced by microscopic organisms, you may want to visit the website maintained by Stjepko Golubic and the one currently being constructed by a German team devoted to microbioerosion. Bioerosion is not yet well represented on the Web. Check out our growing Bioerosion Links page. If you're interested in bioerosion of the Ordovician, see Jessica Lazzuri's "Keck Ohio" project page, as well as Woody Fischer's related page.

Bioerosion appears to us as a slow process of removing hard substrate, especially when compared to the way storms and floods remove soft sediment, but over time the effects are extraordinary. On tropical carbonate rock coastlines, bioeroding organisms can reduce the substrate by 2 to 15 millimeters per year. Over tens, hundreds, and thousands of years, these coastlines are substantially modified and even destroyed. The English Channel may have resulted from bioerosion, augmented by wave and current destruction, of the underlying chalk. Even wood-boring organisms have had a dramatic effect on history: the Spanish Armada was practically destroyed in part because the wooden ships were greatly weakened by bioeroding clams!

A mytilid bivalve peeks out of the hole it bored in a limestone exposed along the coast of Florida. The hole is approximately two centimeters in diameter.

Geologists and paleontologists are particularly interested in patterns of bioerosion preserved in the rock record. Such evidence can tell us a great deal about prehistoric sealevels, climatic conditions, and community evolution. Bioerosion traces in ancient limestones of the Bahamas, for example, have given us a direct indication of a rapid global sealevel change about 125,000 years ago (see image below). The Wooster Independent Study page of Allison Cornett has more information on this event.

The holes and other excavations left by ancient organisms are called "trace fossils". Here is a list of the most common hard substrate trace fossil ichnogenera:

Entobia Radulichnus Gnathichnus Gastrochaenolites Trypanites Palaeosabella Rogerella Teredolites

To demonstrate that not all holes in hard substrates are borings, check out Catellocaula.

After visiting each illustration, you may return to this page by clicking on your browser's "back" button. There are more illustrations of these ichnotaxa in the bioerosion slide presentation. For a convenient index of all the images on this website, see our thumbnail page.

We have a growing bioerosion bibliography, available here as a PDF or Microsoft Word file. While it is now over 114 action-packed pages, it is not yet comprehensive (although very close to being so!). If you have references you think should be included, please send them to mwilson@wooster.edu.

Please also visit our carbonate hardground page, which has its own illustrations and links. Hardgrounds are often bioeroded; indeed, it is the borings which usually lead to their recognition. We have compiled a related Bibliography of Lithologic Substrates (PDF format or Microsoft Word) which has numerous references to bioerosion of rocks.

Dr. Marcos Gektidis of Germany has a growing webpage on bioerosion you may also want to visit. It presently emphasizes microbioerosion.

Finally, Paul Taylor and I have recently published a lengthy paper in Earth-Science Reviews entitled, "Palaeoecology and Evolution of Marine Hard Substrate Communities". The publishers generously allow a free download of the paper from our website as a PDF file. It is a long one! We also have a 2006 Geology paper on predatory borings in Devonian hederellids available as a pdf.