Chemical Oceanography Element Fluxes in the Sea

The study of radioisotopes provides the added dimension of time to the chemical perspective of oceanography. Stable elements and isotopes (Chapter 6) are useful tracers of the sources and transformations of marine materials, but they carry no direct information about the rates and dates of their associated processes. However, such temporal distinctions are made possible by many different, naturally occurring radioactive isotopes with their wide range of elemental forms and decay rates. These highly dependable atomic clocks decay by nuclear processes that are insensitive to temperature and pressure and that allow them to be detected at very low concentrations. A fanciful analogy of how these tracers are used is an experiment in which you attach hundreds of clocks that operate only at pressures less than one atmosphere to helium-filled balloons and release them to float in the atmosphere. After the helium leaks out of the balloons, the clocks would fall to the Earth scattered across the landscape. Because each clock records only the time spent aloft, their position and time would convey information about the direction and speed of local winds.