Last month’s issue of Applied Spectroscopy featured a Focal Point Review article on remote Raman spectroscopy in space. This month’s issue goes to the opposite extreme with an article on Raman spectroscopy at the depths of the ocean. In a message to Congress in 1961, President John F. Kennedy wrote "Knowledge of the oceans is more than a matter of curiosity. Our very survival may hinge upon it.” In a book titled Deep Sea Challenge, H. B. Stewart wrote "As man continues to break away from his Earth, as interplanetary travel becomes a reality and we earthlings are able to view our planet from the vast reaches of space, we will realize just how much of the earth is in fact covered with the waters of the global sea … Probably the greatest enticement for those who today are devoting their lives to the study of the sea is the lure of the unknown, the challenge of the undiscovered, the thrill of discovery on what is truly the last frontier on earth.” It has been said that we know what the surface of the moon is better than we know what the surface of the sea floor is. So what better way of following last month’s review article on Raman spectroscopy in space with one on advances on deep-ocean Raman spectroscopy by Peter Brewer, Ed Peltzer and their colleagues at the Monterey Bay Aquarium Research Institute who describe experiments made at depths as great as 1 km from a remotely operated vehicle (ROV).
Robots have proven themselves to be valuable tools for both space and deep-ocean exploration. ROVs have been used for deep-sea rescue operations and to recover things from the sea floor since the 1960s, when their development was funded by the United States Navy. Almost immediately the oil and gas industry saw their potential and began building ROVs of their own to use in the development of offshore oil fields. They became especially valuable in the 1980s, when many of the deposits discovered were at depths that were impossible for divers to reach.
In their Focal Point article, Brewer and his colleagues show how the abundance of dissolved methane and sulfide in sediment pore waters can be measured and that there is a difference by as much as a factor of 30 between the amount of methane measured in situ and from recovered core samples. They discuss the feasibility of surveying sea-floor conditions associated with potential sub-sea geological CO2 disposal in abandoned oil and gas fields. Thus although this subject is one that most readers of the journal will not be involved with themselves, it is potentially one of the more important review articles we have published.
Other articles in the March issue of the journal include four others on various aspects of Raman spectroscopy and two on applications of LIBS, one on monitoring the isotopes of uranium, hydrogen and lithium using a compact probe and the other on classifying sea salts. The article with the longest title, namely “Detection of Reversible Nonlinear Dynamic Responses of Polymer Films by using Time-Resolved Soft-Pulse Compression Attenuated Step-Scan Fourier Transform Infrared Spectroscopy” by Nishikawa, Nakano and Noda, a particularly elegant way of examining the effect of interactions between the components of copolymer films is reported.
See Applied Spectroscopy, Volume 66, Number 3 (2012) for a full list of articles.