BURROWING ACTIVITIES AND 
SEDIMENT IMPACT OF NEPHTYS INCISA 
Wayne R. Davis 
Don C. Miller 
Environmental Research Laboratory 
U.S. Environmental Protection Agency 
Narragansett, R.l. 02882 
ABSTRACT 
It is suggested here that benthic deposit feeders are an important faunal 
group contributing to the flux of materials, including pollutants, between the 
benthos and overlying water. The present study has documented the burrowing 
and feeding activities of one dominant deposit feeder, the polychaete worm, 
Nephtys incisa, at a series of test temperatures spanning the annual thermal 
range (0-24°C) of Narragansett Bay, R.L New burrow development and feeding 
are coupled events as the worm penetrates and ingests sediment. Each new 
burrow is usually continuous with recently abandoned burrows, which results 
in extensive perforation of the benthic sediment. Then as Nephtys ventilates its 
burrow for respiratory purposes, sediment oxygenation along the entire 
subsurface burrow network also occurs. Rate of new burrow building ranges 
from one/20 days at 0°C to one/day at 24°C. 
It is hypothesized that Nephtys burrowing, feeding and irrigation activity 
contributes significantly to substrate conditioning for development of the 
aerobic benthic compartment. Doubtless, pollutant diagenesis is also directly 
influenced by this creation of an oxidative environment, resulting in significant 
pollutant fluxes to and from the benthos. 
INTRODUCTION 
The polychaete worm, Nephtys incisa , is common in silty-clay sediments of 
the northern Atlantic estuarine and coastal waters. Its dominance in fine 
sediment is a unique departure from other Nephtys species, all reported to be 
active carnivores inhabiting poor to well-sorted sands (Clark, 1962; Clark et al, 
1962). To better understand the anomalous, silty-clay habitat preference of TV. 
incisa, information regarding its in-sediment activities was pursued, primarily 
through the use of laboratory microcosms. 
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