Bacteria, Carbon Dioxide and
Algal Blooms
L. E. KUENTZEL, Research Associate
Wyandotte Chemicals Corporation
Wyandotte, Michigan
INTRODUCTION
A recent literature survey on the subject of lake eutrophication, and algal
blooms and nutrients as causative factors, reveals that there is a decided lack of
published information on the role of the major nutrient carbon dioxide (C02).
Great emphasis is placed on phosphorus (P) and nitrogen (N) as causative agents in
the production of unwanted algal growths, yet a satisfactory accounting for the
source of the tremendous amounts of C02 required for massive algal blooms has not
been found in the literature. The purposes of this paper are 1) to provide some
logistics on C02 requirements for such blooms, 2) to establish the fact that such
quantities of C02 are not available from the atmosphere and dissolved salts, and 3)
to point out the role played by bacteria and decomposable organic matter (much
from man-made sources and thus controllable) in supplying the C02. Such information may permit situations to be recognized where C02 is the limiting nutrient, or
can be made the limiting nutrient, in the control of massive algal blooms. Then,
control of organic pollution as well as N and P can receive appropriate consideration
in algal bloom reduction programs.
BACTERIA AND BLUE-GREEN ALGAE - A
MUTUALISTIC SYMBIOSIS?
College textbooks reveal that blue-green algae (Phylum Cyanophyta) and
bacteria (Phylum Schizophyta) are descendents of the most ancient and primitive of
living creatures. Yet, in spite of some two bil yr of evolutionary history, they are
still the simplest and least evolved of all living organisms. If "survival of the fittest"
has any place in evolution, we are attempting to deal with a very "fit" species in
blue-green algae and should not be surprised if the task is a difficult one. Moreover,
since there are reported to be 2,500 different species of cyanophyta widely distributed in nature and capable of healthy growth under widely differing conditions,
we can expect nuisance growths at any time conditions foster a "population
explosion." Measures taken to eliminate one species may produce optimum conditions for encouraging a different species to take its place. Also, it is fundamental
that aerobic bacteria require oxygen to degrade organic matter and produce C02, that
algae require C02 to photosynthesize organic matter and produce oxygen, and that
both aerobic bacteria and algae require similar environments of temperature and
minor nutrient concentrations to grow properly. This is a nearly perfect mutualistic
symbiosis that has been going on for millions of years. Once established in a given
body of water, such a cycle would be difficult to break so long as temperatures
approach optimum and the sun continues to shine. This must nearly be the situation
in Lake Erie's western basin where, according to Harlow (1), algae produce nearly
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