Why study microfossils?

Most sediments contain microfossils, the kind
depending largely on the original age, environment of
deposition and burial history of the sediment. At their
most abundant, as for example in back-reef sands,
10 cm3 of sediment can yield over 10,000 individual
specimens and over 300 species. By implication, the
number of ecological niches and biological generations
represented can extend into the hundreds and
the sample may represent thousands if not hundreds
of thousands of years of accumulation of specimens.
By contrast, macrofossils from such a small sample are
unlikely to exceed a few tens of specimens or generations.
Because microfossils are so small and abundant
(mostly less then 1 mm) they can be recovered from
small samples. Hence when a geologist wishes to know
the age of a rock or the salinity and depth of water
under which it was laid down, it is to microfossils that
they will turn for a quick and reliable answer. Geological
surveys, deep sea drilling programmes, oil and
mining companies working with the small samples
available from borehole cores and drill cuttings have
all therefore employed micropalaeontologists to learn
more about the rocks they are handling. This commercial
side to micropalaeontology has undoubtedly
been a major stimulus to its growth. There are some
philosophical and sociological sides to the subject,
however. Our understanding of the development and
stability of the present global ecosystem has much
to learn from the microfossil record, especially since
many microfossil groups have occupied a place at or
near to the base of the food web. Studies into the
nature of evolution cannot afford to overlook the
microfossil record either, for it contains a wealth of
examples. The importance of understanding microfossils
is further augmented by discoveries in Precambrian
rocks; microfossils now provide the main
evidence for organic evolution through more than
three-quarters of the history of life on Earth. It is also
to microfossils that science will turn in the search for
life on other planets such as Mars.