122 Alfred C. Redfield 



temperature of the surface water of the Outer Gulf is at a maximum of 28-2° C in 

 October, and falls to a minimum of 25-3° C in February. In December the mean 

 value is 27-0° C, corresponding closely to the present observations. The high tempera- 

 ture of the deeper water of Calabozo Bay may be considered to have been acquired 

 some months previously, when this water was formed in the mixing zone over the sill. 

 The distribution of phosphorus and oxygen also shows the stratification arising 

 from the estuarine circulation of Calabozo Bay, the similarity of the water in the Outer 

 Gulf to that in the Caribbean, and the independence of the deeper water of Calabozo 

 Bay from that east of the sill. These properties are dependent on biological processes 

 as well as on the physical circulation, and will be considered in more detail below. 



The Horizontal Circulation 



The distribution of properties in the several sections across the Gulf (Figs. 3-6) 

 and in the surface diagrams (Figs. 8-11) shows no evidence that the brackish outflow 

 from Lake Maracaibo is deflected to the right by the Corioli force, as is so frequently 

 the case in the estuaries of higher latitudes. The water of low salinity formed at the 

 outlet of Lake Maracaibo occupies a crescentic band along the western margin of 

 Calabozo Bay (Fig. 8). The eastward extent of this band along the southern shore of 

 the Gulf is not defined by the data. Along the northern shore it terminates abruptly 

 in a convergence at 71° 30' W. The Secchi disk showed an abrupt change in the 

 transparency of the water across this convergence. This general distribution is reflected 

 by the temperature and phosphorus content of the surface water. 



Observations by the Corps of Engineers, U.S. Army (1938) show a northwesterly 

 set of the alongshore currents off" the outlet of the Lake, supporting the view that 

 surface water is being transported at that point toward the western end of the Bay. 

 The Saihng Directions for the West Indies (U.S. Navy Hydrographic Office, 1949) 

 on the other hand state that a current, which sets south-westerly along the coast of 

 the Peninsula of Guajira, turns eastward to flow along the southern coast of Calabozo 

 Bay as far as Punta Penas (70° 30' W), where it turns northward and is dissipated in 

 the middle of the Gulf. A south-westerly set is described along the eastern shore of 

 the Outer Gulf. This account indicates a convergence on the side of the Gulf opposite 

 to that inferred from the Atlantis observations. 



It seems probable that the north-east trade winds drive the brackish water formed 

 at the outlet of Lake Maracaibo into the western end of the Bay, and tend to hold it 

 against the shore. Escape is affected by alongshore currents, as discussed by Living- 

 stone (1954). These currents appear to follow the coast of the Peninsula of Guajira 

 until it turns northward, where they meet water moving into the Gulf along that shore, 

 and both currents are deflected toward the middle of the Bay. Doubtless complex 

 eddies exist throughout the Bay, but no pattern is revealed by the observations, nor 

 any special path by which the fresh water works its way seaward. It may be that, as 

 the trade winds slacken in summer, the brackish outflow from the Lake turns eastward 

 under the Corioli influence, and sets up the pattern described in the Sailing Directions. 



Although the water in the Outer Gulf resembles that in the Caribbean closely, 

 small differences in temperature and salinity reveal the final steps in the escape of lake 

 water to the Sea. Upwelling appears to occur along the Paraguana coast, as shown by 

 the slope of the isohalines in Sections I and III, Fig. 3. This gives rise to a band of 

 surface water having salinities higher than that found off'shore, which extends north- 



