INTRODUCTION: MARINE CHEMISTRY AND
GEOCHEMISTRY
The field of marine chemistry and geochemistry has developed dramatically since the end of World War II.
Mainly this spurt of refinement was the consequence of the development of novel techniques of measurement
of both radioactive and radiogenic isotopes as well as the light stable isotopes. These new approaches were
accompanied by the refinement of elemental analytical techniques for the determination of element concentrations, resulting in large part from the war effort.
The saltiness of the oceans was well known from ancient times and salt was used for domestic uses. But the
major composition of sea water was yet to be determined. As early as 1820 William Wollaston, the discoverer
of palladium and rhodium, predicted the presence of potassium in sea water and then proceeded to determine
its concentration using gravimetric analytical techniques, based on the newly discovered platinum group
elements and the formation of potassium-platinum compounds.
Both deep sea deposits and sea water were sampled first by the Challenger expedition (1872–1876).
William Dittmar analyzed sea water from around the oceans collected by the Challenger expedition and
showed the composition was fairly constant so far as the major components of the dissolved salts were
concerned.
Over the past 60 years refined techniques of analysis have shown the patterns of distribution of the trace
elements in ocean water profiles in all the oceans. These results are summarized by the late Yoshiyuki Nozaki
in this volume. Similarly the understanding of the stable isotopes of oxygen, carbon and nitrogen in the
oceans have played important roles in deciphering both the ancient temperature history of the oceans and the
biological pathways of nutrient elements in the marine system.
The carbon system, tracked by radiocarbon has important consequences for both the study of ocean
circulation and the ultimate fate of anthropogenically released carbon dioxide to the atmosphere.
Other forms of pollution are impacting the oceans resulting in enhanced anoxia especially in some coastal
zones. The impact of trace metals from anthropogenic sources provide both tracers and in some cases health
hazards for those relying on marine resources.
Some anthropogenically introduced radionuclides and synthetic compounds are useful as ocean circulation
tracers. These include tritium, bomb radiocarbon and CFCs.
The role of hydrothermal vents in modifying the composition of sea water, as well as adding to deposits on
the sea floor, has been explored since the 1970s. Especially the role of the high temperature reactions of sea
water and hot basaltic rock have been shown to influence not only the chemistry of sea water but also the
isotopic composition of oxygen as well as certain other isotope systems.
Extensive sampling of the oceans and the sediment piles provide information on nutrient cycling and the
history of climate. The several organized efforts in these areas starting with GEOSECS (Geochemical Ocean
Section Studies) and the Ocean Drilling Program have expanded our knowledge of how the ocean circulates
and the reactivity of biological and other particles in the ocean column as well as the long-term history of the
oceans. There are clearly secrets yet to be revealed using these methods of exploration.
Karl K. Turekian
Editor
ix
GEOCHEMISTRY
The field of marine chemistry and geochemistry has developed dramatically since the end of World War II.
Mainly this spurt of refinement was the consequence of the development of novel techniques of measurement
of both radioactive and radiogenic isotopes as well as the light stable isotopes. These new approaches were
accompanied by the refinement of elemental analytical techniques for the determination of element concentrations, resulting in large part from the war effort.
The saltiness of the oceans was well known from ancient times and salt was used for domestic uses. But the
major composition of sea water was yet to be determined. As early as 1820 William Wollaston, the discoverer
of palladium and rhodium, predicted the presence of potassium in sea water and then proceeded to determine
its concentration using gravimetric analytical techniques, based on the newly discovered platinum group
elements and the formation of potassium-platinum compounds.
Both deep sea deposits and sea water were sampled first by the Challenger expedition (1872–1876).
William Dittmar analyzed sea water from around the oceans collected by the Challenger expedition and
showed the composition was fairly constant so far as the major components of the dissolved salts were
concerned.
Over the past 60 years refined techniques of analysis have shown the patterns of distribution of the trace
elements in ocean water profiles in all the oceans. These results are summarized by the late Yoshiyuki Nozaki
in this volume. Similarly the understanding of the stable isotopes of oxygen, carbon and nitrogen in the
oceans have played important roles in deciphering both the ancient temperature history of the oceans and the
biological pathways of nutrient elements in the marine system.
The carbon system, tracked by radiocarbon has important consequences for both the study of ocean
circulation and the ultimate fate of anthropogenically released carbon dioxide to the atmosphere.
Other forms of pollution are impacting the oceans resulting in enhanced anoxia especially in some coastal
zones. The impact of trace metals from anthropogenic sources provide both tracers and in some cases health
hazards for those relying on marine resources.
Some anthropogenically introduced radionuclides and synthetic compounds are useful as ocean circulation
tracers. These include tritium, bomb radiocarbon and CFCs.
The role of hydrothermal vents in modifying the composition of sea water, as well as adding to deposits on
the sea floor, has been explored since the 1970s. Especially the role of the high temperature reactions of sea
water and hot basaltic rock have been shown to influence not only the chemistry of sea water but also the
isotopic composition of oxygen as well as certain other isotope systems.
Extensive sampling of the oceans and the sediment piles provide information on nutrient cycling and the
history of climate. The several organized efforts in these areas starting with GEOSECS (Geochemical Ocean
Section Studies) and the Ocean Drilling Program have expanded our knowledge of how the ocean circulates
and the reactivity of biological and other particles in the ocean column as well as the long-term history of the
oceans. There are clearly secrets yet to be revealed using these methods of exploration.
Karl K. Turekian
Editor
ix