PROSPECTS FOR THE FUTURE 93 



At great depths thermal gradients in the water occur, suggest- 

 ing instabihty in the density field. Heat flow from the earth's 

 interior is suspected as the cause of these gradients, but why 

 they are not continuously dissipated by convection is obscure. 

 Indeed, the presence of a layer of suspended material has been 

 detected widely which may make the waters stable. In addition 

 to the questions about thermal structure, those few observations 

 of movement near the bottom now available indicate that the 

 bottom waters are far from being at rest; in fact, evidence of 

 the result of currents is found in many bottom photographs. 



The ecology of animals dwelling just above, on, or just below 

 the boundary layer is a field of study of the deep sea into which 

 man has had little more than glimpses. With the undersea 

 research vehicles now available this field should advance 

 strongly. 



SEA FLOOR TOPOGRAPHY 

 AND SEDIMENT STUDIES 



The importance of the shape of the sea floor to the Navy 

 scarcely needs to be stressed again. Its study is a developing 

 art which has long been on the plateau created by the nearly 

 simultaneous invention of the sonic echo sounder and the 

 graphic recorder about 48 years ago. Improvements in accuracy 

 and resolution of vertical soundings, and even the exciting 

 side-looking sonar, all represent little steps beyond the original 

 invention. Means are greatly needed to increase the speed and 

 resolution of bathymetric surveying. These developments will 

 require a considerable parallel program of research accompany- 

 ing them if they are to be both successful and useful as soon 

 as possible. 



Continued physiographic research into the relationship among 

 topography, process, and structure is important to both sonar 

 and deep-sea technology. It will be continued using the best 

 available instruments — acoustic, photographic, and other. The 

 pressures created by unanswered scientific questions may well 

 provide the impetus and insight for the needed inventions 

 discussed above. 



