A.D. Hasler – författare

Chance Favors Only the Prepared Mind How does a scientist go about the task of pushing back the curtains of the unknown? Certainly the romance of tackling the mysteries of nature provides the motivation, for who would not be inspired by the remarkable life history of this romantic beast, the salmon. After living in the Pacific Ocean for several years, salmon swim thousands of kilometers back to the stream of their birth to spawn. I have always been fascinated by the homing migration of salmon. Noone who has seen a 20-kilogram salmon fling itself into the air repeatedly until it is exhausted in a vain effort to surmount a waterfall can fail to marvel at the strength of the instinct that draws the salmon upriver to the stream where it was born. But how does it find its way back? I was puzzling over this problem during a family vacation in 1946. Inspired by the work of the great German Nobel Laureates, Karl von Frisch and Konrad Lorenz, I had been conducting research with my graduate student Theodore Walker, since 1945, on the ability of fishes to discriminate odors emanating from aquatic plants. Von Frisch had studied schooling minnows and discovered that, if broken, their skin emitted a con specific chemical substance, termed Schreckstoff, which caused other members of its school to disperse and hide.

Chance Favors Only the Prepared Mind How does a scientist go about the task of pushing back the curtains of the unknown? Certainly the romance of tackling the mysteries of nature provides the motivation, for who would not be inspired by the remarkable life history of this romantic beast, the salmon. After living in the Pacific Ocean for several years, salmon swim thousands of kilometers back to the stream of their birth to spawn. I have always been fascinated by the homing migration of salmon. Noone who has seen a 20-kilogram salmon fling itself into the air repeatedly until it is exhausted in a vain effort to surmount a waterfall can fail to marvel at the strength of the instinct that draws the salmon upriver to the stream where it was born. But how does it find its way back? I was puzzling over this problem during a family vacation in 1946. Inspired by the work of the great German Nobel Laureates, Karl von Frisch and Konrad Lorenz, I had been conducting research with my graduate student Theodore Walker, since 1945, on the ability of fishes to discriminate odors emanating from aquatic plants. Von Frisch had studied schooling minnows and discovered that, if broken, their skin emitted a con specific chemical substance, termed Schreckstoff, which caused other members of its school to disperse and hide.

This volume is concerned with many kinds of links between terrestrial and aquatic ecosystems. Ecological systems on land interact with water in many ways that have been treated throughout the Ecological Studies series. Volume l''s chapters 16 through 18, on Hydrologic Cycles, provide background that leads directly into the description of nutrient-hydrologic interactions in Chap­ ter 1 ofthe present volume. Volume 2 treats further aspects of water in forests, grassland, and crops. Volume 3 summarizes biological and environmental aspects of the whole Indian Ocean as a marine ecosystem that is notably influenced by upwelling of water and nutrients along several of its shorelines. Volumes 4 and 5 provide a closer look at the movement of water in crops and other woody or herbaceous systems and their soils, from viewpoints ranging from that of physics to that of practical agriculture. These volumes, especially Volume 7 on the evolutionary adaptation of ecosystems to mediter­ ranean types of climates, are concerned with the ecosystem''s strategies of using water, which nature provides on a very seasonal basis. Volume 8 treats many aspects of seasonality in a variety of ecosystem types, including en­ vironmental signals that turn growth on and off at times that are generally appropriate for organisms'' survival and for effective use of landscapes by mankind.