Butman, C. Woods Hole Oceanographic Institution, cbutman@whoi.edu
Starczak, V. Woods Hole Oceanographic Institution, vstarczak@whoi.edu
Grassle, J. P. Rutgers University, jgrassle@imcs.rutgers.edu
Snelgrove, P. V. Memorial University, psnelgrove/fishcons@gill.ifmt.nf.ca

 
SEDIMENT SELECTION AND LARVAL AVAILABILITY IN A COASTAL EMBAYMENT
 
Field experiments were conducted at 13 m depth in Buzzards Bay, MA, to determine if (1) settling invertebrate larvae are selective with respect to sediment type and (2) larval availability predicts settlement. Trays buried flush with the sediment surface contained either defaunated ambient (muddy) or sandy sediments (3 replicates per treatment). During three 24-hr experiments, larval availability was determined using a time-series plankton pump that sampled every hour. The pump and an S4 electromagnetic current meter were moored 1 mab. There was no significant selection by larvae for sediment type. Physical or chemical differences between the two sediments may have been obscured by a fine layer of flocculent material observed drifting across the bottom. Postlarvae contained within these flocs were similar to those collected in the tray sediments, suggesting that transport via flocs may be an important colonization mechanism at this site. Larval availability varied by at least an order of magnitude within each 24 hr experiment, and mean larval concentration in the water column did not predict mean settlement on the bed. Moreover, no larvae were collected in the water column for one worm species that was very abundant in both the colonization trays and on the seafloor.
 
Day: Thursday, Feb. 4
Time: 11:30 - 11:45am
Location: Eldorado Hotel
 
Code: SS26TH1130E