Linking Arenicola marina irrigation behavior to oxygen transport and dynamics in sandy sediments
Authors: Timmermann, Karen; Banta, Gary T.; Glud, Ronnie N.
Source: Journal of Marine Research, Volume 64, Number 6, November 2006 , pp. 915-938(24)
Publisher: Sears Foundation for Marine Research
Abstract:In this study we examine how the irrigation behavior of the common lugworm Arenicola marina affects the distribution, transport and dynamics of oxygen in sediments using microelectrodes, planar optodes and diagenetic modeling. The irrigation pattern was characterized by a regular recurring periods of active irrigation lasting approximately 15 min separated by a 15 min rest period. The mean pumping rate during irrigation was 52 ml h−1. Oxygen dynamics and distribution around the tail shaft was closely related to irrigation pattern but independent of pumping rate. During irrigation the oxygen concentration in the burrow was high (>80% air saturation) and oxygen was detected at distances up to 0.7 mm from the burrow wall. Volume specific oxygen consumption rates calculated from measured oxygen profiles were up to 4 times higher for sediments surrounding worm burrows as compared to surface sediments. Model results indicated that oxygen consumption also was higher in the feeding pocket/funnel compared to the activity in surface sediments. An oxygen budget revealed that 49% of the oxygen pumped into the burrow during lugworm irrigation was consumed by the worm itself while 23% supported the diffusive mediated oxygen uptake of the burrow wall. Approximately 28% of the oxygen was consumed by the feeding pocket/funnel characterized by advective porewater transport. Model simulations indicated that oxygen injected into the sediment was usually consumed in a very narrow zone around the feeding pocket and only in rare situations with very high pumping rates (>200 ml h−1) and/or a narrow feeding funnel (<5 cm2) was oxygen advected back to the overlying water.
Document Type: Research article
Publication date: 2006-11-01