The only reported observation of an in situ egg mass of jumbo squid was in the Gulf of California at a depth of 16 m near the pycnocline (Staaf et al.
If hatchlings promptly swim from near the pycnocline up to warmer near-surface water, where food may be more readily available, an ontogenetic increase in temperature optima would be advantageous.
and the asymmetry of the flow [epsilon] = 2djh, where h is the shear layer thickness and d is the displacement of the location of the centre of the pycnocline from that of the shear layer (Fig.
These two layers are separated by a well-defined pycnocline that has an average thickness of 2 m (Fig.
During falling tide, the echosounder images revealed the presence of solitonic waves identified by their leading waves at the pycnocline (Fig.
Soon after the disappearance of these solitonic waves (which occurred at the beginning of maximum velocity shear at 20:29) a downward dip of the pycnocline began to occur at distinct locations, where the bathymetry shoals then deepens (Fig.
Abbreviations are as follows: SAL = salinity, TEM = water temperature, OXY = dissolved oxygen; the fourth and fifth digits: 04 = April-May, 07 = June-August; the sixth character: L = lower bay, M = middle bay, U = upper bay; The last character: S = layer above the pycnocline
, B = layer below the pycnocline
Farr and Best (1998) reported that DSL distributions are related to mesoscale oceanographic features, defined by flow and temperature variability, and are most commonly observed at the pycnocline
For example, in Chesapeake Bay, USA, water beneath the pycnocline in the deepest channel becomes anoxic most summers when the level of bacterial respiration, supported by the carbon produced during the spring phytoplankton bloom, exceeds the rate of oxygen resupply from the surface (Kemp & Boynton 1992, Diaz & Rosenberg 1995).
Thus, in eutrophic waters, consumption of particulate organic matter (POM) by abundant stocks of bivalve suspension-feeders in shallow and well-oxygenated conditions will directly reduce the amount of POM remineralized by bacteria beneath the pycnocline where oxygen resupply is restricted.
3]) at sites 1 and 2 indicated that the thermocline, halocline, and pycnocline
occurred at depths < 10 m.
The water column was highly stratified throughout the region, in some cases with several pronounced pycnoclines
, consistent with isolation of deep waters from atmospheric refreshment.