EFFECTS OF PETROLEUMS ON THE GROWTH OF
FRESHWATER ALGAE
J. C. Coffey, Graduate Student
C. H. Ward, Professor and Chairman
J. M. King, Research Associate
Department of Environmental Science and Engineering
Rice University
Houston, Texas 77001
INTRODUCTION
Natural oil seeps have been contributing unknown quantities of petroleum to aquatic
ecosystems for centuries, while anthropic introduction of petroleum hydrocarbons into
the aquatic environment is relatively recent and parallels utilization of liquid fossil fuels.
The complex chemical compositions of petroleums and their highly variable behavior on
entry into aquatic habitats has resulted, in part, in a deficiency in our knowledge and
predictive ability regarding the toxicity of petroleums to aquatic organisms.   However,
problems which may be associated with petroleum pollution were emphasized dramatically by the wreck of the "Torrey Canyon" and oil spillage from platform "A" in the
Santa Barbara Channel.   Effects of these acute spills and ones of smaller proportions on
marine organisms have been reviewed by several investigators [1-3].
Acute biological effects of petroleum hydrocarbons on marine algae have been well
investigated but few general conclusions can be drawn.   The sensitivity of marine algae to
petroleums is species-dependent [4-6], and toxicity depends on the stage of refinement
of the petroleums [7-9].   Nonpersistence of petroleum components in aquatic habitats
allows recovery of most algal populations after oil spills [6,10,11].   Low concentrations
of petroleums may stimulate photosynthesis in algae [12], while high concentrations of
petroleum hydrocarbons inhibit photosynthesis [12,13].
Few investigations have explored the toxicity of petroleum hydrocarbons to freshwater algae, even though 35% of the tonnage moving over inland waterways consists of
petroleums [14].   Storrs [15] showed that significant quantities of petroleums enter
freshwater, and he identified the following as major sources of these pollutants:   (a) oil
refinery wastewater; (b) petrochemical industry wastewater; (c) steel processing plants;
(d) urban storm drainage, and (e) disposal of used lubricants.   Pure aromatic fractions of
petroleums inhibit growth of some freshwater algae and naphthalene is highly toxic to
the photosynthetic system of Chlamydomonas angulosa [16].   Hellebust et al. [17] found
no adverse effects of a crude-oil spill on diversity and abundance of freshwater algae.
Likewise, Dogadina [18] showed no inhibition of growth in Chlorella vulgaris and Scenedesmus obliquus on exposure to crude oils.
This chapter presents the results of an investigation of the effects of petroleum hydrocarbons on the growth of 5 freshwater algae in batch culture systems.   Naphthalene was
also tested for possible use as a simple model of complex petroleums.
MATERIALS AND METHODS
Organisms and Experimental Culture Systems
Three species of green algae (Ankistrodesmus falcatus, Chlorella pyrenoidosa, Selenas-
trum capricornutum) and two species of blue-green algae (Anabaena flos-aquae, Microcystis aeruginosa) were used as test organisms.   The cultures of green algae were freed of
contaminating bacteria [19] and were tested periodically for bacterial contamination [20].
Basic microbiological techniques were employed throughout experiments in order to maintain axenic systems.
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