Cook Plant preoperational studies 1970 / John C. Ayers ... [et al.].

Research Reports

Ilypnodinium-like Algal Blooms
in Georgia Lakes
Since 1968, we have observed each June
an algal bloom of varying intensity lasting
7-10 days in Lake Sidney Lanier. The lake,
the largest in Georgia, is a young, man-made
reservoir 72.4 km north of Atlanta, measuring
about 150.2 km2 with a maximum depth of
54.9 m. In 1969, the surface of the lake
turned milky white (Fig. IA). In 1970, the
white bloom was of a low intensity in Lake
Lanier, but of heavy density in lakes Jackson
(5 June), Cardinal (22 June), and Buckhorn
(25 June). These lakes are situated on different river systems in northwest Georgia.
The alga was seen in 1970 in Lake Lanier
on 19 June, reached maximum concentrations
around 23 June, and almost had disappeared
by 28 June. Dense surface floes (105-109
protoplasts/ml) covering 3 to 20 m patches
were found only in the embayment area of
Flat Creek. This region of Lake Lanier
receives sewage effluents, a phenomenon common to all the 1970 bloom sites. Prior to,
during, and after the bloom, hydrographic
conditions in the Flat Creek area were
monitored. The bloom occurred shortly after
the water stratified with a thermocline near
9 m. The surface water temperature was 28 C,
the pHt 9.1, and the dissolved oxygen
8.2 mg/liter. At the thermocline the water
temperature was about 17 C, the pH 8.3, and
the dissolved oxygen 3.4 mg/liter. Four days
prior to the recording of the bloom the fecal
coliform density increased from <4/100 ml to
>240/100mL By 30 June, the coliform
density was <3/100 ml. An increased amount
of untreated sewage appeared to precede the
bloom.
The milky white surface scum from all
four lakes was composed primarily of tan to
orange-brown, oval to spheroidal bodies
ranging on the longest axis from 32 to
approximately 75 g (Fig. 1B). The bodies
were surrounded with a clear envelope which
stained light blue to purple with chloriodide
of zinc, which suggested the presence of
cellulose. The envelope contained one or a
few distinct, large protoplasmic bodies of
varying size. A single dark protoplasmic body
was present within most envelopes. Occasionally, one or two light, thick-walled

macrospores were also found within the
envelope. The dark protoplast matured into a
dark macrospore with a definite cell wall
which also stained blue with chloriodide of
zinc. This macrospore subdivided and produced from 2 to 15 or more bi-pored microspores (Fig. IC). The wall of the mature dark
macrospore ruptured, with the subsequent
release of mature microspores. The microspores were spheroidal, ranging in diameter
from 9.1 to 15.6 p, averaging 11.7?. Each
microspore possessed two circular pores
directly opposite each other (Fig. ID). Each

envelope. The zoospores swam with a
spiraling motion and appeared to have a short
anterior tinsel flagellum and a trailing
posterior whiplash flagellum. We are attempting to determine the complete life cycle
and to grow the organism in axenic culture.
This alga grossly resembles Hypnodinium
sphaericum Klebs, 1912, an ill-defined species
only once previously reported from the United
States (Thompson, 1949). However, the bipored cells of this alga make it distinct from
H. sphaericum. A taxonomic description will
appear elsewhere. The alga has not been
directly associated with any fish kills. A
disagreeable odor accompanies the bloom and
the thick surface floes interfere with recreational activities. The significance and longterm effects of this alga on the lakes are
unknown. Considering the capacity of the
alga to produce rapid and massive blooms, we
recommend intensive monitoring of lake
ecology following detection of this
Hypnodinium-like species.
Acknowledgments
Supported in part by a contract from the
U.S. Army Corps of Engineers, Mobile
District, and by the State Water Quality
Control Board of Georgia. We thank Mr. G. N.
Smith for technical assistance.
References
Thompson, R. H. 1949. Immobile
Dinophyceae. 1. New records and a new
speciesAmer. J. Bot., 36: 301-308.
DONALD G. AIEARN
Department of Biology
Georgia State University
Atlanta, Georgia
EDWARD T. HALL, JR.
Georgia Water Quality Control Board
47 Trinity A venue, S. W.
Atlanta, Georgia
DONALD J. REINHARDT
Department of Biology
Georgia State University
Atlanta, Georgia
(Accepted for publication 11/19/70)

C _

S

Fig. 1. Aerial view of surface bloom of
brown alga on Lake Sidney Lanier, Georgia,
in June 1969. The trail in the water is the
displacment of the bloom by the boat's
wake. (A) Protoplasts enclosed in envelopes.
(B) Immature and matured dark macrospores. (C) Mature bi-pored microspores.
(D) B, C, and D are unstained live material;
scale bars, 10 A.
spore contained a single protoplasmic body
(about 5.8 p in diameter) located next to one
of the pores. In older preparations the microspores appeared to be empty. Although movement within microspores occurred, no exit of
the protoplasmic body through the pores has
been observed. Bi-flagellated zoospores
resembling the protoplasmic bodies of the
microspores occurred in large numbers in the
microscope preparations. In several instances,
zoospores swam within the apparently intact

February 1, 1971

BioScience vol. 21, no 3

115

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