Effects of Fluid Mud on Bottom Boundary Layer Dynamics and Sediment Fluxes at Mudflats

2007 ◽  
Author(s):  
Tian-Jian Hsu ◽  
Alex Sheremet ◽  
Arnoldo Valle-Levinson ◽  
Ashish Mehta
Keyword(s):  
Boundary Layer ◽  
Bottom Boundary Layer ◽  
Fluid Mud ◽  
Bottom Boundary ◽  
Sediment Fluxes ◽  
Boundary Layer Dynamics

Water masses and bottom boundary layer dynamics above a sediment drift of the Antarctic Peninsula Pacific Margin

2003 ◽  
Vol 15 (4) ◽  
pp. 537-546 ◽  
Author(s):  
ALESSANDRA GIORGETTI ◽  
ALESSANDRO CRISE ◽  
ROBERTO LATERZA ◽  
LUCIANO PERINI ◽  
MICHELE REBESCO ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Bottom Boundary Layer ◽  
Bottom Current ◽  
Mean Flow ◽  
Bottom Boundary ◽  
Current Regime ◽  
Sediment Drift ◽  
Pacific Margin ◽  
Boundary Layer Dynamics ◽  
The Antarctic

Data from eight CTD casts and two one-year long current time series collected at 8 and 60 m above the seafloor of a sediment drift, off the Pacific Margin of the Antarctic Peninsula are presented, with special emphasis on bottom boundary layer dynamics and processes relevant to sediment settling and re-suspension. The water masses over the drift are characterized, including also a comparison with other measurements available from that region. The south-westward flow along the continental rise exhibits a strong topographic (bathymetric) control in the near-bottom current regime. A consistent mean flow deflection between an upper and lower current regime suggests that only the lower regime falls within a bottom (turbulent) Ekman layer. The bottom current regime is not energetic enough to maintain the coarse sediment fraction in suspension. The absence of evidence for a nepheloid layer justifies the assumption that most sediment was supplied to the margin during glacial periods. Two events, with peak velocities of up to 20 cm s−1, are associated with barotropic eddies shown as negative (cyclonic) mean sea level anomalies detected by ERS/TOPEX satellite altimeters. These energetic bottom current pulses may give way to episodic sediment re-suspensions of the sortable (non-cohesive) part of the sediment, thus exerting a minor role in redistributing fine sediments through the mean flow regime.

Sign in / Sign up

Export Citation Format

Share Document