modified Go-Flo bottles, and lever-action or X-type
Niskin bottles. None of them are easy to keep
clean and handle properly, and experience is
needed in their operation depending on the type of
bottle. Hydrowire is also important, since
normal steel wire has rust and grease that can easily
contaminate the water. To avoid this, some workers
use plastic Kevler line and others use stainless-steel
wire or a titanium armored cable.
With the rapid growth of semiconductor industries
from the early 1970s, clean laboratory techniques
also become more popular in the field of marine
chemistry and helped considerably to reduce contamination from reagents, containers, and dust in the
room atmosphere. Real oceanic concentrations of
trace metals are so low that conventional analytical
techniques prior to 1970 were not normally sensitive
enough to detect them except in polluted or some
coastal waters. Thus, significant efforts were also
devoted to developing more sensitive and reliable
methods using atomic absorption spectrophotometry, chemiluminesence detection, isotope
ELEMENTAL DISTRIBUTION: OVERVIEW 9