Breathing Water in a Warming World: an Overview of the Gill-Oxygen Limitation Theory (GOLT)

There is less oxygen in the best aerated sea or freshwater water than on top of Mount Everest. Fish and other water-breathing ectotherms (WBE) deal with this through a number of adaptations shaped by physical and dimensional constraints. These constraints are the key components of the Gill-Oxygen Limitation Theory (GOLT), presented here to provide mechanisms for key aspects of the biology (growth and its response to temperature, the timing of maturation, migrations, and others) in fish and other WBE. The GOLT’s basic tenet is that the surface area of the gills or other respiratory surfaces WBE cannot, as 2-dimensional structures, supply them with sufficient oxygen to keep up with the growth of their 3-dimensional bodies, and with the spontaneous denaturation of their bodies’ proteins, which is extremely temperature sensitive. Notably, the reduced oxygen supply per body weight induces sexual maturation, and later a slowing and cessation of growth, all accompanied by an increase of physiological processes relying on glycolytic enzymes and a declining role of oxidative enzymes. Because the ‘dimensional tension’ underlying this argument is widely misunderstood, emphasis is given to a detailed, point-by-point presentation of the various component of the GOLT. Aside from having a wide theoretical scope, the GOLT has many potential practical applications, e.g., in optimizing the way fish farmers aerate their ponds, and in predicting how fish populations will react to the warming and deoxygenation of the oceans and freshwater bodies.

Speaker: Daniel Pauly, University of British Columbia

Attend in person at Hopkins Marine Station, or attend livestream at Mitchell Hall 350/372, Stanford.