Institution

The silicate values plotted against potential tempera-
t u r e fall very n ear 1 y on a s t r ai g h t 1 i n e (+ 2 p g - a t / 1 ) from
1.9008, 34 pg-at/i, to 1.55°8,59 pg-at/i (Fig. 6.6). Below
148
1.7508 the values are identical to the plot of Metcalf (1969)
for the western Atlantic between the Equator and about lOoN,
an indication that the AABW over the Greater Antilles Outer
Ridge is not strongly affected by mixing below about 1.708~
Silicate values from water warmer than 1.75°8 over the outer
ri dge form a ti ghter curve wi th lower mean val ues than
Metcalf's curve.
Dynamic Calculations
The geostrophic method (Lafond, 1951) was used to
ca1 cul ate vol ume transports through all si x secti ons (Table \ )
6.2) and between six pairs of stations bracketing the current
meters. Additional calculations between the end stations of
the sections were made to determine total transports into
and out of the region. Since the region is characterized by
acti ve currents, the reference surface is probably nei ther
level nor fixed in time. Calculations were made for two
di fferent reference 1 evel s, at 4300 m and
4700 m, to deter-
mine representative flow around the Greater Antilles Outer
Ridge.
The s hall owe r depth i s at the 1 eve 1 of both m i n i mum
hori zontal and mi ni mum verti cal densi ty gradi ents and is
thus a level of minimum shear. However, it is not a level of
zero shear since indications of the deeper temperature )