The application of electrochemical tools for in situ measurements in aquatic systems

Since the 1970's, when the first in situ measurements of oxygen in the ocea ns were reported the development of electrochemical sensors for in situ mea surements in aquatic systems has significantly intensified. A synthesis of the progress made in limnology and oceanography to measure chemical species in situ is presented. From amperometric and potentiometric sensors that ca n measure a single analyte to voltammetric sensors that can measure several species during the same scan, a variety of electrodes have been used in si tu to better understand the nature of the biogeochemical processes occurrin g in aquatic systems. The advantages and disadvantages of each technique, t he technical improvements over the years, and some recommendations are pres ented together with representative data reported in the literature over the last two decades.