A comparison of the fossilization potential and recycling of wood by wood-boring bivalves and isopods on the shelf and slope of the Bahamas and Gulf of Mexico.

摘要

We explored the colonization and destruction by wood-boring bivalves (teredinids and pholads) and wood-boring isopods (Limnoria) of conifer and angiosperm wood in a subtropical marine carbonate environment (Bahamas) and a marine siliciclastic and carbonate environments (Gulf of Mexico). Wood samples were kiln-dried lumber except for pieces of Quercus stellata Wang, which had decomposed in a terrestrial environment prior to deployment. Samples in weighted bags were deployed at a range of depths from 15 to 267 mbsl along two transects and retrieved after one and two years in the Bahamas, and at 18 sites (60–571 mbsl) after two years in the Gulf of Mexico.; Limnoria (gribbles) attack the surface of the wood creating shallow tunnels (2 mm diameter) initially parallel to wood grain that eventually become narrow grooves. Recovered Limnoridae include Limnoria platycaudata Menzies (15 to 73 mbsl) which produces narrow sinuous tunnels and L. pfefferi Calman (70 to 267 mbsl) which produces wider tunnels with a right-angle branching pattern. Burial of wood to a depth of more than 2 cm prohibits wood-boring isopod attack.; All of the recovered wood in the Bahamas contained Teredinid (shipworms) borings into wood creating calcite-lined tubes (5 mm diameter). Recovered Teredinidae include Teredothyra dominicensis Bartsch (15 to 88 mbsl), T. macototana Bartsch (183 to 267 mbsl) and Nodoteredo sp. (183 to 267 mbsl).; Teredinids, pholads (piddocks), and Limnoria are the dominant wood borers in the Gulf of Mexico. There was significantly more wood destruction at the shelf sites (60–183 mbsl) than the slope sites (360–570 mbsl) in the Gulf of Mexico. The amount of attack in the Gulf of Mexico was much greater than that in the Bahamas for sites of equivalent depths. At each Gulf shelf site at least one wood sample was completely destroyed; whereas we recovered all wood samples deployed in the Bahamas. Terrestrially-exposed Quercus stellata was the only wood type recovered at all sites in the Gulf of Mexico. Nonetheless, similar aspects of wood anatomy and biochemistry inhibited attack in both the Gulf of Mexico and Bahamas.