SALINITY OF SEA WATER 153 



niille ; between Greece and Barca (Africa) 38.46 permille, and about 

 halfway between the islands of Rhodes and Cyprus (long. 30° 18' 

 E., lat. 35° 49' N.) it is 39.40 permille. The salinity varies strongly 

 with depth. Thus at the Straits of Gibraltar the following changes 

 occur : 



Surface 3^' -35 pcnnille The denser water flows out as an 



25 m 36- 56 pemiille undercurrent and affects the salinity 



50 m 37- 00 pemiille of the deeper strata of the Gulf of 



100 m 38 07 pcnnille Cadiz for a long distance out. The 



200 m 38 • 30 permille density of 38.46 found at 400 meters 



400 m 38.46 permille depth in the Gibraltar Straits is 



found between Malta and Pantel- 

 leria at a depth of 200 meters and south of Greece at the surface. 

 In the eastern region (Cyprus district) the surface salinity w^as 

 found in the summer to be from 0.2 to 0.4 permille greater than 

 at the bottom (2,000 to 2,950 meters). This change occurs in the 

 upper 100 meters, and is believed to be due to the rapid evapora- 

 tion on the surface. The seasonal change in the salinity of surface 

 waters, due to the influx of fresh water through the streams, is 

 well shown in the Adriatic, where in the s})ring the salinity sinks to 

 18 or even 16 permille in the neighborhood of the land, while in 

 the winter the salinity is 38 permille even at the mouths of streams. 

 This freshening of the surface waters extends, however, to the 

 depth of only about one meter. Throughout the year salt water 

 ascends the streams along their bottoms : in the Natissa River at the 

 head of the Adriatic, it ascends as far as Aquileja, 10 kilometers 

 from the coast. ( Krummel-20 : J55.) 



The Sea of JNlarmora, between the Black and Roman mediter- 

 raneans, has a surface layer, of 11 meters or more, of low salinity 

 (22 to 25 permille), followed by a rapid increase to a depth of 

 25 meters where the salinity is 28.5 permille. Beyond this follows 

 a slow increase to a depth of 200 to 300 meters, where the salinity 

 is 38.1 permille, increasing later to 38.4 permille, after which it 

 remains constant to the bottom ( 1,400 meters). 



The surface stratum of low salinity is again seen in the Black 

 Sea, where, according to Wrangell and Spindler. tlie upper 40 or 45 

 meters have a homohaline character of 18.3 permille. Downward this 

 slowly increases to 19.7 at 90 m., to 21.4 at 180 m., 22.0 at 350 m., 

 and 22.4 to 22.5 from 900 m. to 2,000 m. The Sea of Azov is an epi- 

 continental sea, being very shallow, and, as a result, it is usually 

 homohaline, with 10.5 to 10.7 (more rarely ii.o) permille. In the 



