1922.] 



Fauna of the Chilka Lake : Observations in Rambha Bav. 



685 



reverse of that seen by them, because, as I have already pointed out, the water at 

 the head of the bay in 1919 had a lower density than that in the centre. 



At the same time I found that the density of the lower layers of water near the 

 bottom showed a considerable diminution below what had been found in correspond- 

 ing situations previously, the bottom water at a depth of 10 feet being now only a 

 little over 9*0 in density in situ or a little over 10 - o at standard temperature of 25°C, 

 whereas previously in sections 2 and 4 I had found that at this depth it was io-o or 

 over in situ, or 11 o and over at standard temperature. Furthermore, the temper- 

 ature of the water at this depth showed an increase of more than io°C above that 



is. 



29-o'C 



16. 



17. 



Z9-S' 



jg. Salinity. 

 30:0 Temperature. 



Fig. i. — The vertical distribution of temperature (t) and salinity 

 (s) at station 23, August 18, 1919. 



previously noted. The cause of these changes is by no means obvious, and it 

 is probable that more than one factor has contributed towards their production ; the 

 purely mechanical effect of the waves raised by the storm must have caused a con- 

 siderable amount of admixture between the various layers and would thus tend to 

 cause a fall in density and rise in temperature, but if this had been the sole cause the 

 temperature at 5 feet depth would have been higher than that at 10 feet depth which 

 is not the case. It seems, therefore, that it must be due to an influx along the bottom 

 of water having a higher temperature than that of the mid-water. It is possible that 

 this flow may be merely an increase in the inflowing deep current that we have already 



