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The flora of Monument Lake, Colorado

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THE FLORA OF MOMUMEMT LAKE, COLORADO
A Thesis
Presented to
the Faculty of the Department of Botany
The University of Southern California
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
W
Ellen Permelia Donnelly
June 1941
UMI Number: EP41411
All rights resewed
INFORMATION TO ALL USERS
The quality of this reproduction is dependent upon the quality of the copy submitted.
In the unlikely event that the author did not send a complete manuscript
and there are missing pages, these will be noted. Also, if material had to be removed,
a note will indicate the deletion.
UMI EP41411
Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author.
Microform Edition © ProQuest LLC.
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unauthorized copying under Title 17, United States Code
ProQuest LLC.
789 East Eisenhower Parkway
P.O. Box 1346
Ann Arbor, Ml 4 8 1 0 6 - 1346
T h is thesis, w r i t t e n by
...
u n d e r t he d i r e c t i o n o f h&JC. F a c u l t y C o m m i t t e e ,
a n d a p p r o v e d b y a l l i t s m e m b e r s , h as b e e n
p r e s e n t e d to a n d a c c e p t e d b y t h e C o u n c i l on
G ra du a te S tu d y a n d Research in p a r t i a l f u l f i l l ­
m e n t o f the r e q u ir e m e n ts f o r the degree o f
MASTER..M...SQimGE
D ean
Secretary
D a te
...
F a c u lty C om m ittee
C hairm an
TABLE OF CONTENTS
CHAPTER
PAGE
ACKN 0WLEDGM3NT
I*
II.
I N T R O D U C T I O N ..........................
I
GEOGRAPHY AND METEOROLOGY OP THE REGION
A. Description of the Lake
...
............
3
3
B. Chemical Composition of the Water of
Monument Lake
4
C. Precipitation
.........
D. Seasonal Changes In Water Temperature . . .
III*
GEOLOGY OF THE R E G I O N
A. Structural
11
.
.................. . . . # •
B. H i s t o r i c a l ..........
IV.
16
16
19
RELATED I N V E S T I G A T I O N ...............
22
A. FIoristic Composition • • • • • • • • • • .
22
B. C l a s s i f i c a t i o n ..........
S3
• •
..........
Cm Ecological Aspects
D. Periodicity . . . . . . .
V.
9
METHOD OF PROCEDURE
84
..........
26
. . . . . . . . . . . . . .
28
A. Means of Collecting
..........
B. Collection Statistics
28
• • • • .
29
Cm Methods of Preserving • • . • • • • • • . ♦
30
VI. RESULTS AND DISCUSSION
...........
38
A. Florist!c Composi t Ionian d Distribution . . .
38
1. Benthos
• • • • • • • •
...............
39
CHAPTER
PAGE
2. Plankton
•
•
•
•
•
•
•
•
«
•
•
•
•
•
»
41
B* Altitudinal donation and Classification of
the Lake
...........................
C. Physico-Chemical Aspects
TLT.
..........
46
• *
48
D. P e r i o d i c i t y ..................
54
CONCLUSION
60
..............
. . . . . . . .
B I H L I O G R A P H T ................................
63
LIST OF TABLES
TABLES
II#
III#
Water Inlets
to Monument L a k e .........
6
.
I*
PAGE
Water Analysis of Monument Lake • • • • • • ♦
EE-ion Concentration of Monument Lake Water
7
•
8
IT# • Annual and Monthly Precipitation and Distri-
V#
VI*
VII*
hution of the Monument Lake Region, Colorado
10
Temperature Range of Monument Lake Water
• •
12
« *'.
35
FIoristic Composition of Monument Lake
Collection Data ..........
VI I I * . Occurrence of Flora in
• « • • « • • • •
Monument Lake
55
• _ • • ' # ■ 57
LIST OF FIGURES
FIGURE
PAGE
1*
Topographical Map of Monument Lake* Colorado • •
2*
'Topographical Map of the Spanish Peaks
Quadrangle* Colorado « • « • • « • « • • • • »
3*
...........
34
Altitudinal Areas of the Littoral Zone* Monument
Lake* Colorado • • • • •
5#
15
Floristic Composition and Areas of Plant Distri­
bution* Monument Lake*Colorado
4*
5
.......................
45
Graph Showing the Correlation between the Temper­
atures of the Lake Water*, and the Types of
Plants Pound.... ..............................
49
ACKNOWLEDGMENT
The author of this investigation is deeply indebt­
ed to Dr# George R. Johnstone, Head of the Department of
Botany, The University of Southern California, under whose
guidance this investigation was made.
From time to time
during the investigation Dr. Johnstone has made very help­
ful suggestions and criticisms, and has carefully aided in
the identification of specimens.
Credit is due L.V. Wilcox of the Rubidoux Labora­
tory, Riverside, California, for the chemical analysis of
the water sample.
Also, the author is greatly indebted to Harold
W. Sohns who aided in the collection of specimens and typed
the manuscript during its preparation.
Records concerning the physical and meteorological
conditions of the lake were made available by the Water
Department and the City Engineer of Trinidad, Colorado.
The identification of Limosella aquatioa L. was
made by Miss Bonnie Templeton of the Los Angeles Museum.
The identification of the Diatoms was made by
Mr. H.E. Sovereign, 7227 Sixth Avenue, Seattle, Washington.
To the above mentioned persons, the author wishes
ho express her deep appreciation and to make a grateful
acknowledgment of their kind assistance in this investi­
gation*
CHAPTER I
IHTRCDUCTXOH
Monument Lake , Colorado, at an altitude of 8,500
feet, Is a cold water lake which has been artificially made
by building a dam across a depression and turning spring and
stream water from melting snows into it*
Located at the edge
of San Isabel National Porest in south-central Colorado, it
is in the region at the foot and west of the perpetually snow­
capped Sangre de Cristo Range, and to the south of the twin
Spanish Peaks*
The lake is covered by a layer of ice, vary­
ing in thickness from a very thin sheet to two feet, from the
month of November to the month of March*
It is during the re­
maining months of the year that most of the plant growth in
the lake occurs*
In the late summer and early autumn months the plant
growth in the lake is by far the most abundant, a wide margin
of the submerged shore line being almost entirely covered b y
macroscopic plants around and among which is a rich plankton
growth*
The lake during the early autumn becomes a character­
istic blue-green oolor because of the vast numbers of freefloating algae —
a condition known as nwater bloom”*
The purpose of this investigation was to determine
to what extent the following physico-chemical factors of
Monument Lake, Colorado, such as:
wide seasonal variations of
water temperature; chemical composition of the water; p E of
the water; amount of rainfall; and length of time the lake was
covered by ice; which interacting, tended to serve as deter­
mining factors upon the biotic population of the lake as in­
dicated by the flora found thriving in the lake at different
periods of the year*
A more detailed account of the geography of the region,
the meteorological conditions and the geologic features will
be helpful in the interpretation of the results of this study*
CHAPTER XI
GEOGRAPHY AND METEOROLOGY OF THE REGION
A* Pe script ion of the L ake*
Monument Lake * which
has been so named because of a large sandstone boulder stand­
ing in the lake* is located in Monument Lake Park at the foot
of the eastern slope of the Sangre de Cristo Range lust out­
side San Isabel National Forest in the south-western part of
Las Animas County* forty miles west of Trinidad* Colorado*
and is owned by the City of Trinidad*
The latitude Is 3?°12#
the longitude 105°; the altitude is 8*500 feet above sea
level*
The lake lies in an almost north and south direction
is approximately 4,500 feet long, 1,100 feet wide* and has a
shore line of about two and one-half miles.
the lake covers 89*49 acres*
At high water
The average depth of the water
is twenty feet*
There was originally a swampy depression or wet
weather lake a little north of the center of the present lake
which was surrounded by dry land*
The construction of a dam
at the south end of the present lake site was started in 1926
and completed in 1936*
The only purpose for which the dam
was built was to create a reserve water storage for city
Irrigation*
Constructed of native stone* the dam measures
40 feet in height* 700 feet in length, 20 feet in width
across the top and 175 feet in width across the bottom#
As
shown in Figure 1 the shore line slopes rather stpeply*
The
bottom of the lake is covered by fine red sand interspersed
with sandstone rocks as might be expected from th,p character
of the soil, and rocks of the region which are red sandstone
and Permian red conglomerate, the geology of which will be
discussed in a later chapter#
Seasonal rain water, springs and melting: snow feed the
six ditches which supply the lake with a more or less constant
flow of water#
These ditches are;
D-ditch, carrying 30*88
second feet of water; C-ditch, carrying 57*2; Brown's Creek,
10; Monument No# 1, 34; Monument No# 2, 15; and Cherry Creek,
4#8#
There are only two outlets:
one through the fish
hatchery which has a continuous flow, and^the other through
the spillway at the west end of the dam the only purpose of
i1
which is to prevent an overflow of the lake#
At high water
the volume of water in the lake is 16 71 acre-feet, or 549,524,497
gallons#
1
B * Chemical Composition of the Water of -Monument
Lake#
An analysis of the water was made "by the ^Bureau of
Plant Industry, United States Department qf Agriculture, at
the Rubidoux Laboratory, Riverside, California, from a sample
collected 30 feet from shore on September
1940*
*
is shown in Table II#
The report
F i y m l - T o p tfQ p k ffllM Q p o f M m m f h iis
Elmfm im w M
S53S
m
Mop ty wittf City Errtjwt, City of Tri M>
TABLE I
WATER INLETS TO MONUMENT LAKE
SOURCE
SECOND FEET OF WATER
D-ditch
30 #88
C-ditch
57# 20
Brown*s Creek
10#00
Monument No# 1
34.00
Monument No# 2
15.00
Cherry Creek
Total
4.80
151.88
TABLE II
WATER ANALYSIS MONUMENT LAKE, COLORADO
Report made by the Bureau of Plant Industry, United States Department of Agriculture,
Rubidous Laboratoryf Riverside,. Californiaf from ,a BamX.e. collected 30. feet from shore. September 8, 1940
Specific
electrical
conductance Boran
(Kx 105 at
(B)
25°C.)
n.n.m.
MILLIGRAM EQUIVALENTS PER LITER
Percent
Na
Cl
CATIONS
ANIONS
Calcium Magnesium Sodium Carbonate Bicarbonate Sulphate Chloride Nitrate
Ca
Mg
Na
CQr,
HCOt
SO,.
Cl
N0?
18.7
0.03
7
1*
1.21
0.57
O.H
trace
1.73
Total Dissolved Solids: 0.16 tons per acre foot
♦Less than 1$
0.18
trace
trace
TABLE III
H-ION CONCENTRATION MONUMENT LAKE WATER
(Determinations made at the University of Southern California)
Sample No. Date of Collection With CHoO
Water Temperature
pH
1
3-26-39
none
6°
C.
7.0186
2
3-26-39
yes
6°
C.
6.5567
3
3-26-39
none
6°
C.
7.3029
Three samples of water collected March 26, 1939
and examined for H-ion at the University of Southern Calif­
ornia, yielded results as given in Table III*
All tests made by alk-acid testing paper at the
time plant collections were made indicated that the water
was slightly alkaline regardless of the time of day when the
tests were made*
C. Precipltation*
Table IV shows the monthly,
annual, average monthly and average annual precipitation for
a seven year period beginning January 1, 1934 and ending Dec­
ember 31, 1940.
The average monthly rainfall for the region
was 1*561 inches.
The average annual rainfall was 18.738
inches which was 3.182 inches below the government standard
yearly average of 21.92 inches.
The table further shows
that 1934 was the driest year of the period, only 11.86
inches of rain falling that year.
age of 0.988 inches.
This was a monthly aver­
The year 1938 was the wettest year of
the period having a total of 25.06 inches which was only
slightly above the total for 1940 of 25.05 inches*
The
monthly average of 1938 was 2*088; for 1940 It was 2.087
inches.
August had the highest average monthly precipita­
tion for the seven year period of 2*821 inches, which was
only slightly above the average for July which was 2*704
inches.
December had the lowest, the monthly average being
only 0.531 inches*
TABLE IV
ANNUAL AND MONTHLY PRECIPITATION AND DISTRIBUTION
FOR THE MONUMENT LAKE REGION, COLORADO
FROM RECORDS OF THE TRINIDAD WATER DEPARTMENT
Amount of Precipitation
Month
M
221S
1936
1937
1938
1939
1940
Average
Precipitation
January
0.25
0.32
1.04
0.32
1.18
1.25
1.80
.880
February
1.76
0.80
0.66
0.89
0.62
1.00
2.07
1.115
March
0.54
0.54
0.14
3.43
2.54
0.68
1.70
1.368
April
1.21
0.93
1.41
2.61
2.19
1.31
1.33
1.570
May
2.27
2.61
1.06
1.93
2.35
1.67
2.24
2.019
June
0.37
0.55
2.45
3.28
3.77
0.36
2.01
1.826
July
2.07
2.93
3.65
1.93
2.96
2.50
2.89
2.704
August
0.82
4.72
4.41
0.38
2.23
2.81
4.38
2.821
September
1.61
1.74
2.68
11.52
2.72
1.54
2.55
2.051
0.00
1.10
2.13
0.92
1.99
0.47
0.34 -
0.993
0.38 ‘ 0.42
1.48
0.58
2.42
1.005
October
i
November
0.75
December
0.22
0.00
0.45
0.47
1.03
0.23
1.32
0.531
11.86
16.24
20.46
18.10
25.06
14.40
25.05
18.738
Annual Precipitation
Average Monthly
Government Standard
Yearly Average
0.988
1.353
1.705
1.508
2.088
1.20
2.087
1.561
21.92
11
No figures on atmospheric temperature or temperature
range are available.
Seasonal Changes in Water Temperature♦
During
the months of luly, August and September, the temperature of
the lake water reaches its highest point which is slightly
above 19°C* as shown in Table V*
From November to the latter
part of March the lake is usually covered with ice which
ranges in thickness from a very thin sheet to two or two and
one-half feet*
Twice a year, once in the spring and once in the fall,
the water in the lake undergoes a seasonal "turn-over"*
This
"turn-over" usually occurs during the latter part of Septem­
ber or the early part of October, and again during the latter
part of March or the early part of April, though no records
on exact dates on which the "turn-over" takes place are
available*
At the time of these "tum-overs" the temper­
ature of the water lies between 4°C. and 6°C** The water,
which is normally almost clear, becomes very turbid and
muddy, and seems almost to be churning*
The "turn-over" is
usually completed within 24 hours after which the mud and
sediment settle and the water again becomes almost clear*
According to Tiffany (1938) the influence of the
spring and fall "turn-over" largely explains the spring and
fall maxima*
The temperature of the deeper water, or
TABLE V
TEMPERATURE RANGE OF MONUMENT LAKE WATER
Date of Collection
Temperature of Water
November 13, 1937
0° C.
September 25, 1938
12° C.
October 9, 1938
10° C.
November 6, 1938
0° C.
February 12, 1939
0° C„
March 26, 1939
6o c.
September 10, 1939
13° C„
October 8, 1939
12° G»
November 26, 1939
0° C,
May 19, 194-0
June 16, 1940
15° C.
July 11, 1940
17° G*
July 18, 1940
August 13, 1940
19° C.
September 7, 1940
15° C.
13
hypolimnion, remains approximately at 4°C. as it has no
circulation#
As the air temperature changes during the
spring and fall there are corresponding changes in the tem­
perature of the water and also a change in the density of the
water at different depths*
This results in almost complete
turbination of the upper layers of water or epilimnion during
the spring and fall.
Usually the transition region, or
thermocline, is quite sharp*
Oxygen, carbon dioxide and
mineral salts which are essential to algae in the synthetic,
respiratory and assimilatory processes are more equally
distributed for the time being as a result of the "turn­
over"*
Water possesses the peculiar property of being
most dense at 4°C. and not at freezing temperature*
To this
property of water the spring and fall "turn-over" may be
attributed*
The temperature of the upper layers of the
water in the fall becomes lower in correspondence with the
lowering air temperature and as a consequence the density
of the water is increased.
Immediately below the surface
are the warmer and less dense layers of water which are then
replaced by the more dense, cooler water from the surface*
*
This process continues until the temperature becomes lower
and ice is formed, the density is less and the ice remains
on the surface.
If the greatest density of water were at
zero rather than at 4°Q., lakes would become solid cakes of
*
Ice in the winter time and only the surface would melt dur­
ing the summer#
C O LO R A D O
i
S P A N IS H P E A K S Q U A D R A N G L E
.
\ft
104*30'
(Walsenbu
L. U )I ' // k -AlYJF'30'
Crotoni
•
'T 30J
jfir'i
A S ISABEL
rsrw^t*.
J'l
M a r t i*
IU430'
(Brilliant it-dm
)
Llovfl,.
Scale ffisbito
Edition o f June !897, reprinted 1923.
CHAPTER III
GEOLOGY OE THE REGION
A* Structural Geology#
The structural geology of
the region in the vicinity of Monument Lake influences the
mineral composition of the water and to some extent the
supply of water#
■ Monument Lake is situated east of the Sangre de
Cristo Mountains in the Spanish Peaks Quadrangle, the
latitude of which is 37°12t and the longitude 105°, as
shown in Figure 2#
According to Burbank and Goddard (1937)
the entire region lying east of the Sangre de Cristo Mountains
*
includes what is probably one of the most complexly folded
**
*
sedimentary beds in Colorado# There are also excellent
£'■*
examples of various types of mountain and valley structures
b
in the region#
r
A
f
-There has been
much debate about
thestructural
origin of the Southern Rocky Mountains, different theories
i
3
having been advanced#
i
v
:The Sangre
deCristo Mountains extend
from the
Arkansas River in Colorado in a southeasterly direction intoNew
•
•
Mexico#*
The two divisions of this range to the Blanca Peak
massifa are sometimes called by separate names:
the
<
northern division being called the Sangre de Cristo, and the
southern division the Culebra#
Here, however, the entire
range will be considered the Sangre de Cristo*
The
characteristic feature of the range is its small width ,
ranging from less than 10 to 20 miles•
It also is charac­
terized by a regular arc-like form which is convex toward
the east*
The central peaks whose regularity is broken
only by a few comparatively low passes average a little above
12,000 feet*
The San I»uis Talley depression which bounds
the range on the west is separated from the range by profound
fault lines as some of the principal structural divisions of
the range are cut by this physiographic boundary*
The Wet
Mountain Valley and the Huerfano River Basin bound the range
on the east*
The linear boundary between the east flank of
the range and the Wet Mountain Valley seems to be controlled
by uniform easterly dips of the sedimentary formations that
form the flank*
A prominent fault bounds the east side of the
range north of the Wet Mountain Valley*
This fault probably
continues southeastward under the alluvial deposits and Joins
a similar steep fault separating Huerfano Park from the south­
ern Wet Mountains*
Thrust faults, upturned and prominent
hogbacks of the steeply tilted beds characterize and control
the physiography of the east boundary*
Extending eastward
some distance into the Great Plains region from the mountains
are folds, minor flexures and igneous intrusion incident to
the range development*
The comparatively shallow blanket of
sedimentary beds overlying the basement rocks are thought to
28
be affected chiefly by the folds#
Along the west border of the Sangre de Cristo
Mountains schist, gneiss, and pregmatite form the greater
part of the massifs, although local bodies of granite and
diorite exist#
The bulk of sedimentary rocks that make the Sangre
de Cristo Mountains are beds of Pennsylvanian and Permian
formations#
Both marine and terrestrial facies comprise the
beds which vary in degree of consolidation and other physi­
cal properties#
The development of shallow marginal phases
of deformation are thought to be greatly influenced by these
beds, which have been estimated to range in thickness from
2,000 to more than 13,000 feet#
According to Hills (1901) in the immediate region
east of Monument Lake the dominant sedimentary layers are
the Garlile shale and the Laramie formation#
The Carlile shale is* characterized by a layer about
200 feet thick of dark gray shale which is almost black to
the middle, and grades upward to 10 feet of sandy shale and
rotten yellowish sandstone#
It is capped by a layer of
purplish, bituminous limestone which is from one to two feet
thick#
Many marine fossils, the most numerous of which
is the coiled ammonite, are found in this limestone layer#
Occasionally sharks* teeth are present#
The shale is easily
eroded as it is very soft, but appears as a steep slope as
1-9
it isprotected
by higher strata which are much harder*
In the Laramie formation there is an alternation of
thick bedded gray sandstone with shaly beds which are found
toward the base, with the sandstone found toward the top*
The upper half of the shale beds consists of clay shale, and
the lower half of sand shale, which are interrupted by bands
of sandstone and beds of clay shale with seams of coal*
From a few miles east of Monument Lake and continuing
westward
toward the mountains, these formations are overlain
by beds of red conglomerate*
Historical Geology*
The historical geology of
the region gives an insight into the origin and complexity of
the structure of the region*
Hills (1901) states that the region was a land mass
till the middle of the Cretaceous when it was succeeded by a
subsidence and an invasion of the ocean*
According to Burbank and Goddard (1937), a
Paleozoic mountain range, called the San Luis Range, existed
approximately in the present position of the San Luis Talley
from which the red conglomerate beds were derived*
Boulders
several feet in diameter are common in these beds.
From the
front of a high landmass which faced a trough of the sea be­
tween the San Luis Range and the Wet Mountain Landmass, these
beds were derived in the form of coalescing fans*
The
so*
deposits in this trough after the retreat of the sea, were
mostly terrestrial fana. From the amount of shortening by
thrusting and folding during the Laramide orogeny, may be
obtained an estimate of the original width of deposits at the
narrowest part of the troughs which were possibly 15 or 18
miles*
Adjoining the belt of marginal deformation are Precambrian crystalline massifs which range in width from the
tapered end of a wedge up to 10 or 15 miles*
massifs are distinguishable:
Two separate
(1) the Sierra Blanca, irregu­
lar in shape and 48 miles long, extending northward; and (2)
the Culebra, about 48 miles long and extending southward into
Hew Mexico*
Little is known about the nature and structure
of the southern part of the Culebra, except that the massif
is composed chiefly of Pre-cambrian rocks, partly concealed
in some places by Tertiary lavas*
Faults which were active till late Tertiary or
Quaternary times separated the Sierra Blanca and Culebra from
the San Luis Range.
Intrusive bodies of the eastern margin of
the range, ranging in composition from granite and syenite to
basalt and noteworthy for the abundance of lamprophyric types,
extend from the Huerfano formation as far south as the
Purgatoire River*
The beds beginning with the rocks of the Benton age
upward to the top of the Pierre shale show an unbroken
21
sequence of Upper Cretaceous Marine formation*
The Trinidad
sandstone in the Walsenburg quadrangle and south along the
eastern border of the range covers the Pierre shale and is
the last phase of the Cretaceous marine deposition*
Since the ages of the intrusive bodies in the older
formations are not known, it is difficult to determine the
extent to which igneous magma was involved in deformation
during the early stages.
Minor volcanism before mid-Eocene
times is indicated by the presence of some igneous fragments
in the Cuchara formation*
The presence of volcanic substance
in other parts of Colorado during the late Cretaceous and
early Tertiary is contrasted by its absence in the Sangre
de Cristo Mountains*
This would seemingly be explained by
the restriction of magmas by the abnormally thick and strongly
deformed sedimentary beds*
It has been concluded that
blanketing of the magmas has resulted in restricted volcan­
ism*
In the Spanish Peaks area is found a much more strongly
contrasted series of differentiates than exhibited by the
intrusive bodies of the mountain ranges belonging, probablyr
to an older group*
CHAPTER IV
RELATED INVESTIGATIOHS
The literature which has bearing on the study of
plant life in Monument Lake emphasized the importance of
floristic composition, classification on the basis of gener­
al distribution and altitudinal zonation, the physical and
chemical composition of the water and finally, periodicity#
Andersen and Walker (1920) in a study of some sand­
hill lakes in Nebraska found growing in some of the lakes
macroscopic plants such as Chara» Zizanla, Scirpus. Myrlophyllum and Potomogeton, which formed more or less dense beds,
A rich plankton growth was found among these plants some
being attached to the plant bodies of Potomogeton,
Other plants found Included Rivularia, Nostoc,
Merismopedium, Oscillatoria, Pictyosphaerium» Gloeocystis#
Soenedesmus, Chaetophora» Microcystis and Anabaena#
Robbins (1912) made a preliminary list of the algae
of Colorado,
There are 143 species included in this list#
From the 49 habitats where collections were made, 36 were
from an altitude above 7,000 feet.
According to Eggleton (1939) fresh-water habitats
are classified as Lotic series, including:
and rivers; and Lentic series, including:
and marshes#
brooks, creeks
lakes, ponds, bogs
Springs and subterranean waters may be of either
23
series*
In standing, permanent fresh waters, the associations
can be divided into limnetic and benthic communities.
In a
limnetic community are to be found nekton, plankton, and
neuston*
Of these, the plankton is of major importance*
Smith (1933) states that in lakes and ponds algae
that have drifted from the benthos may be included in the
plankton*
Usually plankton algae are so scant that special
means must be employed to obtain enough for microscopical
examination, although they frequently occur in such quantities
as to give the water a characteristic color*
Of the species
of plankton algae, the majority are usually unicellular
rather than colonial, though the colonial may exist in a
greater number of individuals*
Morphological features
which tend to give buoyancy to and adapt plankton algae to
a pelagic life are:
long gelatinous bristles, wide gelatin­
ous sheaths, flattened colonies, or coiled filaments*
The plankton flora of small and relatively shallow
ponds and lakes may be more varied and distinctive than much
larger bodies of water.
It has been found that the plankton
flora of permanent and semipermanent pools and ditches is
much richer and more varied than any other type of habitat*
Zygnemataceae and Oedogoniaceae of the floating
filamentous Chiorophyceae occur often in abundance*
Myxophyceae, Baclllarieae and Chlorococcales occur inter-
24
mingled with the filamentous Chlorophyoeae, but are much
more abundant among and attached to the macrophytes which
are submerged*
The plankton species present determine whether the
lake is of a Caledonian type or of a Baltic type.
Desmlds
are predominating in the Caledonian type which, while rich in
species and small in bulk, has relatively few species of
Chroococcales and Hormogonales.
Chlorophyoeae and Myxo-
phyoeae are predominating in the Baltic type which, while
having fewer species, possesses them in large quantity and
conspicuously lacks Pesmidiaceae.
Lakes rich in Desmids
are usually found in geologic areas older than the carbonif­
erous although the hardness of the water has a great influence
on the type of flora found growing in the lake.
A flora of
the Caledonian type is found in waters poor in calcium#
In a benthic community, the lake bottom from the
shore line to the deepest part of the lake can be divided
into the littoral, sublittoral and profundal zones.
An
"abyssal" zone has been suggested by some workers in the
fieldbut has found little
favor as
it would be applied only
to lakes greater than 600 meters in depth#
The limits of these zones which have been quoted by
Eggleton (1939) have been accepted as follows:
"The littoral zone of the bottom is . . . •
that region lying between the shore line and
approximately the lakeward limit of rooted
aquatic vegetation. The produndal zone extends
Z5
from the greatest d e p t h ............ up the slope
toward shore to a point (it would be better to say
isobath) somewhat above that corresponding to the
average upper limit of the hypolimnion. The sub­
littoral lies between these two"*
Eggleton (1959) says that the physical and chemical
nature of the water above them very strongly affects the
benthio communities on the lake floor*
Only those lakes
having thermal stratification have a profundal zone*
Such;
stratification and the accompanying chemical stagnation fre­
quently wipe out the whole benthic fauna beneath it*
lakes have only the littoral zone*
Many
Where lakes are deep
enough to have a produndal and sublittoral zone the sublittoral
is always a transition zone*
The Nebraska Sandhill Lakes investigated by Andersen
and Walker (1920) were all alkaline, some more so than others.
Such alkalinity seemed in these cases to be more or less of a
limiting factor.
In the less alkaline lakes there seemed to
be a more abundant algal flora both as to species and indi­
viduals*
The depth of these lakes varied from two to a
maximum of fifteen feet.
Temperature of the water of Hack-
berry Lake, where water conditions were studied averaged
between 70° and 80° Fahrenheit*
Because of the shallowness
of the lake and the rather continuous wind the water was
well stirred and aerated.
They also studied the effect of
light penetration to depths at which the algae lived by means
26
of the common solio paper photometer#
Records of forms occurring at the various periods of
collection were kept in an effort to determine their periodi­
city*
Of these the Oscillatoriaceae were found only during
the early summer, Merismopedium and Coelosphaerium only in
July#
The green algae reached their maximum during midsummer
but were also found most of the other months of the year#
The Desmids, likewise, reached their maximum in July*
Algologists have, investigated the seasonal succession
of algae.
Transeau (1913, 1916J shows by studies that the
algae fall into six natural groups:
1* Winter annuals— vegetative in autumn, fruit in
early spring*
2. Spring annuals-rvegetative in autumn, fruit In
May*
3. Summer annuals-rgerminate in spring, fruit in
July and August*
4. Autumnal annuals— vegetative in spring, fruit in
autumn*
5* Perennials— vegetative cycle continuous from
year to year*
6* Ephermerals-rappear in numbers any season for a
short time*
According to Smith (1933) there is a maximum of Diatoms
in the spring and sometimes a second maximum in the fall*
The
maximum of Chlorophyoeae is early summer, while the maximum of
Myxophyoeae is late summer or early fall*
27
According to Eggletom (1939), present day invest!gations seem to be of two types:
basic fundamental limnology#
applied limnology and
Biotic investigations which
have long been only qualitative have now become also quanti­
tative#
One phase of these investigations is extensive and
the other is intensive*
The present qualitative investigation, and to some
extent quantitative, is of the floristic composition of
Monument Lake and the physico-chemical conditions of the
water as determining factors in periodicity of vegetative
and reproductive activities#
CHAPTER V
METHOD OF PROCEDURE
Means of Collecting-
When collections of plant
specimens were made, the water of Monument Lake was usually
very clear which made it possible to see without any difficulty
the submerged plants, even though some of them were growing
where the water was fairly deep-
The only times when the
water was murky or not clear was during the "turn-over” of
the lake water which occurred twice a year as a result of
temperature changes in the fall and again in the spring-
Part
of the specimens could be collected from shore, but some
could only be collected from a row boat because of the depth
of the water in which they grew and because the distance from
shore was too great for the plants to be reached by a rakeShore collections of submerged macroscopic plants
were made either by reaching a hand into the water, catching
hold of the plants and pulling them out, or by using a garden
rake to dislodge the plants and then drag them to shore In making hand collections where the water was shallow, it was
often necessary to use a small sharp knife to dislodge or
scrape the plants from the sandstone rocks, and submerged
logs and twigsCollections of macroscopic plants from a row boat were
made by reaching a hand over the side of the boat, firmly
grasping the submerged stems of the plants and pulling them
up and into the boat.
The stems were thickly covered by small
plant f o m s growing attached to them, around and among which
was a very rich plankton growth.
in three ways.
The plankton was obtained
The first method was to put the entire
macroscopic plant which usually had a very long stem thickly
surrounded by plankton foims into a jar, then filling the jar
with water from the same locality where there was usually a
dense bed of the same kind of macroscopic plants.
The second
method was to submerge an empty jar fitted with the lid or
cork into the center of a dense bed of macroscopic plants
which were thickly surrounded by plankton forms, then to re­
move the lid or cork allowing the jar to fill with water con­
taining the plankton forms andjreplacing the lid or cork.
The
third method was to submerge an empty jar fitted with a lid or
cork, into water not near a bed or beds of macroscopic plants.
When the jar was completely submerged, the lid or cork was
removed allowing the jar to fill with water containing the
plankton forms.
As soon as the jar was filled the lid or cork
was replaced before bringing the jar to the surface of the lake.
No nets of any type were used in collecting the plankton forms,
as they were so thick an ample collection could b e made by one
of the above methods.
B. Collection Statistics.
Collections were made
30
every month of the year with the exception of December,
January and April*
During the months of December and January
the ice was too thick to make collections possible*
Only
meagre collections could be made during February, March, May
and November*
Better collections were made during June, vitlile
by far the best and most abundant collections were made during
July, August, September and the early part of October#
The temperature of the water was taken at a depth of
between three and six inches below the surface where the
collections were made*
A centigrade thermometer, which had
been calibrated, was used for the temperature determinations*
In order to determine the pH of the water, three
samples were sent to the University of Southern California
where they were tested for H-ion concentration*
At other
times, and at different times of day when collections were
made the water was tested by dipping a piece of Alk-acid
testing paper into it*
Each time the paper turned slightly
green indicating that the water was slightly alkaline*
C* Methods of Preserving Material*
1* By far the
largest proportion of specimens collected were preserved in
a 3 to 5 per cent solution of foimalin*
Calculations were
made before the collections were made to determine what
quantity of a 40 per cent solution of formalin should be
added to completely fill each Jar and produce a 3 to 5 per
31
cent solution of formalin in the Jar*
In each case where
the specimens were preserved in formalin, the formalin was .
added immediately after the specimens were put in the Jar be­
fore the lid was screwed on or the cork replaced, except in
the case where plankton collections were made below the surface
of the water and the lids or corks replaced before the Jar
was brought to the surface.
In these cases the lid or cork
was removed as soon as the Jar was brought to the surface and
the formalin was added.
Then the lid or cork was replaced#
The addition of formalin to the specimen Jars proved
to be by far the most satisfactory method of preserving the
specimens for later examination#
2# Another method of preserving which was used was
to drain the water from the Jar containing the specimens
through muslin cloth to prevent loss of plankton forms, then
to refill the Jar with a solution composed of 50 per cent
glycerine and 50 per cent alcohol#
While specimens pre­
served In the 50 per cent alcohol and 50 per cent glycerine
solution kept very well, they were not as satisfacotry Tor
later examination#
3# In a few cases after the specimen Jars were
completely filled with water the lid was screwed on tightly
and no preservative of any kind was added.
This method did
not prove satisfactory for later examination of specimens#
4. for the purpose of making dried or pressed
herbarium mounts of macroscopic plants, two methods were used*
In each, however, the plants were washed in lake water to re­
move any sand that might be on them, especially those that
were collected from shore by means of a rake*
The first of
the two methods was to carefully wrap the plants in waxed
paper and place in a box from the florists.
Then the box
was sent to the Herbarium of the University of Southern
California immediately where herbarium mounts were made of'
them.
The second method was to place the specimens very
carefully between sheets of newspaper which had been taken
to the lake for that purpose.
in this way at one time.
Many specimens were pressed
The stack of newspaper containing
the specimens were weighted down and dried over a register
from a hot air furnace.
It was necessary to change the papers
from time to time until the plants were completely dry to pre­
vent them from molding.
After the plants were completely dryt
they were sent to the University of Southern California
Herbarium#
5.
In order that plankton forms could be preserved
and yet could be examined from time to time permanent
microscopic mounts were made of them.
This was done by
adding a small amount of material to glycerine Jelly on a
microscope slide, and then covering the Jelly containing the
material with a cover glass and sealing it with Canada Balsam.
This proved to be the most satisfactory method of any which
was tried#
HO stains of any Kind were used at any time*
All of the specimens collected were examined under
both low and Jiigh power of a compound microscope#
of plankton specimens were made on 3x5 inch cards#
Drawings
These cards
were later mounted on 11 1/4 x 16 X/Z inch herbarium paper for
.
-
.
?
•
use in making photostat copies#
In £ll cases the specimen Jars were immediately
labeled after the collections were made.
Each label contained
the place and date of the collection, temperature of the
V
water and nagie of the collector#
Then the labels were sealed
on with paraffin in order to prevent the ink on the labels
§
from becoming wet and smearing, or coming off the jars#
■ %
The| microscope mounts were also labeled with the
u
place and dsjjte of the collection, temperature of the water
and name of ^ h e collector#
A number of these microscopic
mounts were^also sent to the University of Southern Californiat
Department of Botany for examination*
t
[Imh ok/s&q M
TABLE VX
FX.ORISTIC COMPOSITION: OF MONUMENT LAKE
Algae
A. Myxophyceae
1# Anabaena
2. Gloeotrichia
3. tyngbya
4* Merismopedla
5# Osclllatorla
B. Bacillarieae
Aohnanthes mlnutissima Kutz (type)
Aohnanthes mlnutlssima var. cryptocephala
8# Coceoneis placentula Ehr. var. euglypta (Ehr.)
9* Qymbella affinis
10. Qymbella clstula (Hemp.) Grim*
11. Qymbella microoephala Gruiw
Qymbella turglda (Greg.)
Qymbella ventricosa Kutz.
14. Dlatoma elongatum Ag.
15. Fragilaria crotonensis Kit ton
16. Gomphonema acuminatus Ehr. Var. coronata
17* Gompbonema constrictum Ehr.
18# Gomphonema intricatum Eutz
19. Gomphonema parvulum (Kutz.) Grun*
TABLE VI
CONTINUED
FLORISTIC COMPOSITION OF MONUMENT LAKE
20. Navicula cryptocephala
21* Navicula cryptocephala Kutz* var* intermedia Grun.
22* Navicula cryptocephala Kutz* var* veneta (Kutz.)
Grun*
23* Navicula cuspidata Kutz*
24. Nltzschla. Sp* fragment
25. Sururella Sp* fragment
26* Syne dr a minuscula Ag*
27• Synedra ulna (Nitz.) Ehr.
28* Synedra vaucheriae Kutz*
29* Synedra vaucheriae Kutz. var. eapitellata Grun*
Chlorophyoeae
30. Bulbochaete
31* Chaetophora
32* Cladophora
33* Cosmarium
34* Cruoigenia
35. Desmidlum
36* Gloeotaenjum
37* Mougeotia
38* Nephrocytlum
39. Oedogonlum
40* Fediastrum
TABLE VI
CONTINUED
FLORISTIC COMPOSITION OF MONUMENT LAKE
41# Pithophora
42. Planlctosphaerla
43* Scenede sinus
44. Sorastrum amerioanum
45. Sphaerocystis
45. Splrogyra
47* Staurastrum
48. Stigeoolopeum
49. Tetraedrop
50. Ulothrlx
51. Zygnema
D. Chara
52. Chara
Spermat ophyt e s
53. Limosella aquatloa L.
54. My r1ophyllum ve rtioolllaturn L.
55. Polygonum amphlblum L.
56. Potomogeton follosus Raf.
57. Ranunculus purshil Rich.
CHAPTER TL
RESULTS AND DISCUSSION
A. Floristic Composition and Distributl on«
As
shown in Figure 3 the flora found growing in Monument Lake
represents two distinct types:
benthos and plankton*
Dur­
ing the months of luly, August and September the plant
growth was found to be by far the most luxuriant, comprising
the greatest number of species and th© most frequent indi­
viduals of each separate species.
It is at this time that
very dense beds of macroscopic plants are found beginning
just enough below the shore line to be completely submerged,
and extending to a depth of about ten feet into the lake in
a band completely surrounding the lake with the exception of
the south end where the dam is located*
The band of seed
plants growing at a depth range from about ten to twenty
feet are attached to the lake bottom and have long slender
stems extending to the surface of the water*
The rather
thickly distributed leaves float on the surface of the water
and the small blooms which are either pink or white in color
are borne above the surface*
In some regions of the lake
the band of plants with the floating leaves is wider than in
other regions.
These variations in width are determined by
the corresponding width of the lake bottom in any particular
area between the ten and twenty
foot depth contours.
It is
mon and around the stems of these plants that an extremely
luxuriant and abundant growth of plankton occurs; many small
forms are attached to the stems of seed plants.
In the water
toward the center of the lake are to be found free~f1oating
plankton forms.
The attached algae are species of Chaetomorpha,
growing Just submerged
on the rocks of the dam for its
complete length and on
the monument in the lake.
BENTHOS
The spermatophytes. Myriophyllum verticillatum L . f
Polygonum amphibium I*., Ranunculus purshii Rich. f Limosella
aquatic a L. , grew completely submerged in dense beds beginning
at a depth of about six inches to a depth of nearly ten feet
in a band completely surrounding the lake with the exception
of the south end where the dam occurs.
The growth of.
apparent till late June.
these plants did not become at all
Prom that
time, however, they made
a rapid growth forming the dense luxuriant beds of late July
and August.
The growth of Potomogeton foliosus Raf ♦ t as with the
other Spermatophytes did not become apparent until late June;
however it seemed to make a fairly rapid growth.
By the
middle of July the leaves which were rather thick and numer­
ous were floating on the surface of the water.
In early
40}
.
August the flower buds had appeared sticking up above the sur­
face, and by the middle of August they were blooming.
Some of
the blossoms were pink in color while others were white#
These Spermatophytes all flourished till late Septem­
ber or early October.
The same plants reappeared at approxit
mately the same time the following year, repeating the same
cycle#
The green alga, Chara. was also growing in dense beds
in a band completely around the lake with the exception of
the south end#
This stonewort, Chara. was found at the shore
line just submerged, and continued to a depth of about three
or four feet#
Ohara, which is frequently found in habitats
containing calcium carbonate, seemed to begin its new growth
about the middle of June, and also reached its greatest growth
in late July and early August#
Ohaetophora, an alga, made its appearance also about
the middle of June on the rocks of the dam,which were just
submerged#
It was found on the rocks the entire length of the
dam where it flourished abundantly until the lake was
completely frozen over#
After the "turn-over" of the lake water and the
onset of colder weather the benthic plants seemed to be in
either a dead or dying condition, and a new growth did not
became apparent until the following June#
PIAMETOET
Because of the occurrence of plankton In such large
numbers of species and also individuals, the plankton is of
particular importance#
The plankton was of two different
types according to the place collected:
either from water
not close to macroscopic* plants, or from water close to or
around macroscopic plants.
During the latter part of August
and early part of September the lake had a condition known
as "water bloom", which will be discussed more in detail a
little later.
color#
The entire lake became a distinctive green in
Samples of water examined showed the blue-green alga,
Anabaena, existed in almost pure culture and in such
quantities as to give the water of the lake its characteris­
tic color#
When cooler weather began, the "water bloom"
condition disappeared from the lake and Anabaena was found
rather infrequently until late the next summer when the
"water bloom" condition again became apparent#
By far the greatest variety and number of species
of'plankton forms were to be found growing in the water
around and among the macroscopic plants.
These forms were
found fairly evenly distributed with the macroscopic plants
around the entire lake.
A few species of Myxophyceae. meaty
Bacillarleae and many Chlorophyoeae were found#
The species
of Bacillarleae occurred in large numbers in the late
summer collections and comprised the chief specimens found
42
after the lake "turn-over" when cold weather had begun.
Species
of Chlorophyceae were dominant in the late summer collections#
Myxophyceae♦
The Myxophyceae or Cyanophyceae are
typically blue-green in color#
This coloring is due to a
mixture of two pigments, chlorophyll and phycocyan, and in
addition to accompanying carotinoids.
They are distinguish­
ed from other algae in that they do not possess a "definite"
nucleus and chromataphores.
orders:
They are divided into two
the Ooocogonales and Hormogonales:
always asexual#
reproduction
Hew colonies are formed by hormogones in
the second order, Hormogonales♦
Myxophyceae» according to Smith (1933), occur in a
wide variety of habitats.
The plants may be found in salt,
brackish, or fresh water; mineral or hot springs; streams,
ponds or lakes; terrestrial situations or as endophytes#
They may occur in such large quantities in the plankton of
ponds or lakes during certain seasons of the year as to
produce in the water what is known as "water bloom" which
is particularly undesirable if the water is used for drink­
ing purposes#
The Myxophyceae found in Monument Lake were
Merismopedia, Oscillatoria and Anabaena.
Species of the genus
Anabaena occurred in such vast numbers throughout the entire
lake as to produce the ’fwater-bloom" of late August and early
September#
43
Bacillarieae.
The Bacillarieae are one-celled
plants which differ markedly from other algae in the struc­
ture of their cells.
symmetrical.
They may be radially or bilaterally
A silicified cell wall is always present and
yellow or golden brown chromatophoras are present within the
cell.
Reproduction is chiefly asexual although some groups
show a special type of sexual fusion between the protoplasts
of the ordinary individuals according to Pritsch (1935}.
Diatoms are widely distributed in the sea and all kinds of
fresh water, also in the soil and other terrestrial habitats.
In Monument Lake the Bacillarieae occurred in
great abundance, both in the number of species and varieties,
as well as individuals.
tion from May until
They were present in every collec­
November, and in such great numbers
that every microscopic mount made from the collections was
loaded with them.
In the July and August collections alone
there were twenty-two species and varieties present.
Chiorophyceae.
The class Chlorophyceae. includes
algae which possess grass green plastids.
This color is
due to the same four pigments which are found in higher
plants and also occur in about the same proportions as they
do in higher plants.
The storage product of photosynthesis
in such plants is usually starch.
the cell wall.
Cellulose is present in
Some unicellular algae are motile and have
a number of flagella of equal length.
Reproduction may be
44'
vegetative, asexual or sexual ranging from isogamy to oogamy*
In Monument Lake the Chlorophyoeae might be divided
into three groups:
Chara and Chaetophora which were presented
in the benthos and have already been discussed, forming the
first group; the filamentous forms making the second group;
and the unattached forms making the third group*
In July,
August and early September the filamentous forms which in­
cluded:
Glothrix* Mougeotia«Bulbochaete» Oedogonium*
Zygnema» Splrogyra. Cladophora, Pithophora. and Stigeocloneum were so abundant that the stems of Potomogeton to which
they were attached or surrounding were completely covered
by the dense mass*
Among the filamentous forms in late July,
August and September were found the representatives of the
third group or unattached forms#
They included:
Scenedesmus * Cosmarium* Planktosphaeria * Sphaerocystls *
STephrocytium* Staurastrum* Pediastrum* Sorastrum* Gloeotaenlum* Desmidium* Tetraedron and Qrucigenia*
The Chlorophyoeae were dominant in the late July,
August and September collections*
TJlothrix* Oedogonium and
Mougeotia were especially abundant while Spirogyra appeared
rather infrequently in only the July and August collections*
Most of the filamentous types were in a fruiting condition
in either August or early September collections*
This was
especially true of Zygnema, nearly every specimen of which
in the August collection was in a fruiting condition*
F / c ju r e F
A/f/fua///7aI A r e a s o f f/? e L f f f o r a / F o r e
M o re /m e n '/’ A a /re
C j
<rr* c p
-
/o
-Po/o/7?o^eAon
- /3 feel
2 0
Feet
46
Fresh water Chlorophyoeae outnumber the combined
fresh water species of other classes*
They may be found in
almost any fresh water collection*
Floristie composition and areas of plant distri­
bution may be directly correlated with the altitudinal
zonation of the lake*
B.
Plants *
Altitudinal Zonation and Classification of the
As shown in Figures 3 and 4 the flora of Monument
Lake was found growing in definite areas according to the
depth of the water*
According to Eggleton (1939) the
littoral zone of the lake extends from the shoreline to the
approximate limit of rooted vegetation toward the center of
the lake*
In Monument Lake the littoral zone itself shows
very definite zonation which in this discussion will be
called areas in order to avoid confusion which would result
in the repeated use of the word zone*
The first area extend
ed from the shoreline just submerged and continued to a
depth of about three or four feet*
The plant found in this
area was Chara which occurred in very thick dense beds*
Also at the lower limits in this area were a few scattered
individuals of Myriophyllum verticillatum
The second
area extended from the lower limits of the beds of Chara to
a depth of about ten feet.
In this area was found the
largest number of different kinds of Spermatophytes♦
These
47
included:
Myriophyllum verticlllatum L. , Polygonum amphibium
* Ranunculus purshll Rich., and Limosella aquatica L.
This second area, like the first, was also made up of thick,
dense beds of the plants.
The third area which extended
toward the center of the lake from the lower limits of the
second included depths approximately between ten and twenty
feet.
In this area were found the dense beds of Potomogeton
foliosus R a f .
The lower limits of this area coincided with
the lower limits of the littoral zone, beyond which no rooted
aquatic vegetation was found.
The lake bottom possesses the three zones as
described and defined by Eggleton (1939).
Beyond the lake-
war d limit of the littoral zone was the sub-littoral or
transition zone between the lakeward limit of rooted aquatic
vegetation and the deepest part of the lake or profundal
zone.
The width of the sub-littoral zone is not known.
The
profundal zone includes the largest area of the lake being
most of the area of the lake bottom with the exception of
the littoral zone.
Monument Lake also possesses thermal stratification
as demonstrated by its spring and fall wturn-overs% in
which the more dense surface water at a temperature of
4°C displaces the less dense water at a greater depth re­
sulting in an almost complete turbination of the water
48
twice a year as discussed by Tiffany (1938) •
Fggleton (1939)
states that only lakes having thermal stratification have a
profundal zone, and that often the chemical stagnation
accompanying the thermal stratification frequently wipe out
the entire benthic fauna beneath it.
These facts probably partially account for the
sharply defined lake ward limit of the wide marginal band
of benthic flora completely surrounding the lake with the
exception of the south end where the dam is located.
Monument Lake, because of its recent age, its large
numbers of diatoms, the presence of Chara, a lime loving
plant and the relatively few species of Desmids, might be
classified as a Baltic type rather than •-* Caledonian
according to Smith*s (1933) classification#
^ • Physico-chemical Aspects and Periodicity.
As
shown in Figure 5 the floral growth in Monument Lake is
directly correlated with the temperature changes.
During
the period when the temperature is the lowest viz. 0° C.
early in March to 15° €♦ during the middle of June, an
abundant growth of Diatoms in the plankton becomes evident
during the latter part of May and most of June •
As the
temperature continues to rise through July to the middle of
August when it reaches its peak of slightly above 19° 0*,
the greatest plant growth in the lake takes place.
Large
m 'o:: viirnoavotHa “oo Ksaziaia ?Nsan3
&
.
<0
<0
i
_
M
p
l
Te/vperafe/re
G iG
of
Wafer
- Deoraes
Ce/?f'ara<f&
numbers of individuals of Myxophyceae and large numbers of
individuals of Chlorophyoeae in addition to the Diatoms
which comprise most of the plankton*
During this same
period also, vast numbers iii rooted aquatic vegetation make
their greatest growth and flourish abundantly#
After the
latter part of August new floral growth is not apparent,
and there seems to be a gradual tapering off of floral
growth through the month of September and the early part of
October, coinciding with a decline in water temperature
until the "turn-over" is reached#
Following the "turn-over"
the macrophytes present seem to be in either a dead or dying
condition while in the plankton the Diatoms are the forms
that are found during late October and early November#
According to these results it appears that the
temperature influences the rate of growth, and acts more or
less as a determining factor upon the types of flora found
growing within a particular temperature range.
The long
period during which the temperature is at a minimum of 0° 0.
would seem to cause the plants or the seeds of the
Spermatophytes to remain dormant without killing them#
Otherwise, the plants would not reappear at approximately
the same time and at about the same temperature the follow­
ing season#
The rapidity of development and the abundance
of the late summer floral growth while the water temperature
ranged between 15° C and 19° C. would seem to indicate that
51
that this temperature range is more favorable for a rapid
plant growth, and acts as a determining factor in as much
as it does not inhibit plant growth or cause its dormancy
which seens to be the case in the gradually lowering in the
temperature
autumnAaccompanied by the decline in floral growth until
the long period during which the lake is frozen over*
The pH of the water as determined by the University
of Southern California from samples sent there was approxi­
mately 7*3*
At all periods of the year and during different
times of day including early morning, late morning, nooht
early afternoon and early evening, when the water was tested
with Alk-acid testing paper the water was slightly alkaline.
Water slightly alkaline seems to be favorable for floral
growth as indicated by the abundance and variety of the
summer flora of Monument Lake.
It is interesting to compare
the flora found growing in Monument Lake with that found in
some Sandhill Lakes of Nebraska, the study of which was
made by Andersen and Walker (1920)*
Plants found in the
slightly alkaline Sandhill Lakes of Nebraska which were also
found in Monument Lake included:
Chara, Myriophyllum.
Potomogeton. Merismopedium. Osclllatorla, Scenedesmus.
Chaetophora and Anabaena.
The pH of the water seems to have a large influence
on the plant growth as a determining factor in the growth
52
of vegetation*
Andersen and Walker (1920) found that in
strongly alkaline lakes plant growth was almost entirely
inhibited, and in lakes less alkaline the plant growth was
increased both in numbers and in species*
According to Smith (1955) the greater abundance of
algae in hard water lakes is due to the utilization of
dissolved bicarbonates in photosynthesis*
The chemical composition of the water, then, is
important as a determining factor on the plant growth of
the lake*
Smith (1933) states that the presence of calcium and
magnesium is important as their bicarbonates furnish carbon
dioxide for photosynthesis.
It will be seen from the report
of the water analysis of Monument Lake as shown in Table II,
that Monument Lake water contains 1*21 milligram equivalents
per liter of calcium and 0*57 milligram equivalents per liter
of magnesium; 0*14 of sodium; a trace of carbonate and 1*73
of bicarbonate;
0*18 of sulphate; a trace of chloride and
a trace of nitrate*
According to Smith (1933) silicon is
necessary for the growth of Diatoms.
The great abundance and
variety of Diatoms found in Monument Lake indicate the
presence of silicon which would be expected from the type
of soil*
The soil of the entire region is Permian red
conglomerate and sandstone as discussed in Chapter II*
.53
As evidenced by the abundant and varied plant growth
of the lake, the pH of the water, 7*3, and the presence of
calcium, magnesium and silicon in their respective amounts
are favorable for floral growth.
Seemingly the relatively high altitude of the lake
does not affect the plant growth, and as no tests were made on
light intensity its influence on the flora of Monument Lake
is not known.
However, in the region there are but few days
during the year v/ithout sunshine#
There seemed to be some correlation between the
amount of rainfall during the summer and the appearance of
nwater bloom".
During late August and early September of
1939, a blue-green alga, Anabaena. which was free floating,
occurred in such vast numbers in the water of the entire
lake that the lake itself became a characteristic green color,
a condition known as "water bloom"*
It was practically im­
possible to get a sample of water in which Anabaena was not
present.
This condition persisted for three or four weeks and
then disappeared, after which Anabaena appeared in collections
only very infrequently*
During the month of July, 1939, the
rainfall amounted to 2.59 inches, and during August, 1939,
it amounted to 2.81 inches, a total for the two months of
5.40 inches.
During the summer of 1940, however, the rain­
fall was greater.
In the month of July the rainfall was
2.89 inches, and in the month of August 4.38 inches, a total
54'
for the two months of 7.27 inches.
The total amount of rain­
fall during July and August, 1940, was 1.87 inches greater
than for the same period of 1939*
As a result the lake
was very full of water and high on the banks during the
latter part of August, 1940, and the "water bloom" condition
was only scarcely apparent.
While Anabaena did occur rather
infrequently throughout the lake, it did not occur in the
vast numbers that it did in late August, 1939.
At no time
during August, 1940, did the lake become the characteristic
green of the "water bloom" condition*
These results would seem to indicate that definite
relationship exists between the amount of water flowing into
the lake, the amount flowing out, the evaporation rate, and
the late summer appearance of a "water bloom" condition.
During late August, 1939, when the amount of water in the lake
and the height of the shore-line remained relatively constant
the "water bloom" condition, caused by Anabaena. appeared.
During late August, 1940, when the amount of water in the
lake was considerably increased, and the shore line raised,
because of increased rainfall over the same period of time,
the "water bloom" condition did not become apparent and
Anabaena appeared only infrequently.
D. Periodicity*
In-Monument Lake the characteristic
species of the flora exhibit very definite and marked
periodicity by their appearance at approximately the same
Table Y E ~ Collection
Types
D a te
\
| Condition o f
of
of
Do/a
P la n ts
L i l l ora/ Zone
Found and Re/olive Numbers
Center 0/ la /e
- Shoreline /o Twenty Fed Depth t/aor
Surface
%A
L a k e Water
f,H 0
P ta n k ton
B en th o s
Plankton
Algae
Sptrmolopkyles MwopAvceae Baci/hr/ege Cf/orophyceae Myrop/?(/c2Q<2
Species fnJJu'/fitoli Spacias btdrWaOg/sSptcfts tnd/V/Jads Species kffafcVetOh Spec/as InllWlutf Spades /uli/fut/s
f 1H/- $carcf fewy scarce
yevtf
CVeaW (c/taj (deoc/ nom none
November 13, O’C. Ice form!no (Jttef
tnfragrtf wore m re
none none
or
or
or
fgvV
cf<ff*tf) dylry) dyfnf)
/ 3$7
/erg
very
yery
vtry /try very
very
September 2 3, 0 C. 'W afer bloom far/ obuadanl s ^ m l obandan’i ftW
many obandan! ore dunJvot
a M t f may ebunJrit
/9 3 B
wry
very very
i/ery very
$ m rd
O d o b e r 3, IO ‘ c.
ram
ftW
fa
fV
ld
C le a r
tberltrW
bony abanJn/t wry etv/ndaf none
cdbardarl few
Collection
/9 3 8
tiwtmbtr 6j
0‘C. Ice forming fen/
1938
February /2, OX. Ice /wo P e l
Jh/ck
1939
March 2.6,
6 ‘C. T u r b id
September /O,
1939
8,
1939
!3 °c.
lA /ofer
6/oowf' few
/2 ‘C. C /z o r
few
C lear
non
C /cor
/940 IJ*C.
-ft*/
/940
/§
none
none
/try
abuudml
seven!
I 7‘C,
1940
/Q,
C har
C har
1940
13,
I 9X. C h ar
S940
September 7
,
ISX. C har
very
hw
freyvtW
rare
Hore
none
/tone. rd/ve rare rare none
very very very very
very
few
durian! many abundant many
ohtwefed
very
ont
ohundt/ff
cdeacf
•fen/
rare
none
very
tbunJotf
none
very
fragut/ft m n t MWL none. non2
few
Sdyt'a/
aytny
very very very
mfryrtb rone none
now none m/ee none none.
may freguant few
very very very
imfnpMiit y W *>fr9ftKnl lew freyuiti
infnfrtd non now
many abundant fe w
or
several
mm none
/try
Ju ly II,
1940
runt now
rone
very vary
very very
szvend
freyvtff!
ferf ahur/rd
many ddtinJa/fl nary abundant rare
ohundtf law
Mat/ / 9,
Auyusf
n o rt
deal
OX. Tb/r? /c e
1939
July
dying
dy/ny
M/ft
/fry
/Forember 26,
June
6r semi or
ft/rm n y oise/*"
1939
O de her
none
lead
Jt*J
SQvw! r r , few
(refjed
Inyuvff
very Very very
very
/nary
{reyua/f! /nary abundin'1
fre g m t none none
vary
very
very Very very very
few abundant' semi abundaf few obunlad
none none
/ram / nhv/fd&jf wry abundad
/try
vary
very very very very
fzw abundantseven! thanJant few ab/M mm/ tbardani ntary fbnnlrW one ebvndod
vary
very
very very Very very
one hfrtf"*
ftw abendtdmm! tbunion 1 few tkd/fJaf
nxw y tbvndi/f! /very abunAd
56
time each year; their disappearance at approximately the same
time each year; their complete absence during certain periods
of the year; and the abundance with which they occur during
certain other periods of the year*
From Figure 5 it can be seen that there is a
definite correlation between the temperature of the water and
the occurrence and abundance of the flora, as has been dis­
cussed in a previous section*
Table VII shows that the plant growth in the lake
occurs between the middle of May and the early part of
September, different forms occurring during different times
of the period*
From May until November * the Diatoms are
very numerous, both is species and in individuals.
Every
collection made during this period and every microscopic
mount from these collections were loaded with Diatoms.
In
the May and November collections the Diatoms were the only
plants that seemsd to be living with the exception of Scenedesinus, vhich was present in the May collection*
Of the Myxophyceae. Oscillatoria was fairly fre­
quent in the June and early July collections*
Gloeotrichla
and Merismopedia were abundant in late July, August and
September collections*
Very few individuals of Lyngbya
were present In the August collection*
-During late August
and early September the free-floating Anabaena occurred in
such vast numbers as to cause the Mwater bloom” condition*
TABLE VIII
OCCURRENCE OF SEASONAL DISTRIBUTION OF THE FLORA IN MONUMENT LAKE
Locality
Date of Collection
0s
O
cr\»
- .
w O'
w>
O
' to to
-
Flora Occurring in Monument Lake
ca §
o
a
§ H
-a. ja*.
I. Algae
A. Myxophyceae
1. Anabaena
2. Gloeotrichia
x
3* Lyngbya
4-. Merismopedia
5* Oscillatoria
• Bacillarieae
6* Achnanthes minutissima (types)
7. Achnanthes minutissima
var. Cryptocephala
8. Cocconeis placentula
9* Cymbella affinis
10. Cymbella cistual
11. Cymbella microcephala
12. Cymbella turgida
13 • Cymbella ventricosa
14. Diatoma elongatum
15* Fragilaria crotoneusis
16. Gomphonema acuminatum
17* Gomphonema constrictum
18. Gomphonema intricatum
19* Gomphonema barvulum
20. Navicula cryptocephala
21. Navicula cryptocephala var.
intermedia
22* Navicula cryptocephala var.
veneta
23. Navicula cuspidata
24* Nitzchia
25* Surirella
26. Synedra minuscula
27* Synedra ulna
28• Synedra vaucheriae
29* Synedra vaucheriae var*
capitellata
X
O'
OOOQO
-4- -vt -v
4
- -5- -4-
0'r-toO'
rxcr\0'0''rHc<^0'-si-0'0'0'0'0'''
H
O' rH rH
O' rH O' rl rl r| r) rl
•*rH r—
I
* rH
rH
v\
^ «0
^
^ ^ «k •»
rH
c\i
•
* »k
(VvOH
*vO »
k
v
Orl to C
^
\C
^
O' v
OrH C
V
C
OO
J
HH H H
-P *
•
•
* -4-5
•
•
<D i>> t>» • -p
> P«-P l>rO PL,-p P> >>g H r j ttOFU
oa>ooa>aj Q) t ) Oa} 3 pdsJa)
SWOg!li.aWOi2!Sh»bb<JtO
X
X
X
X
x
x
X
X
X
X
X
X
X
X
X
X X X
X
X
X
X
X X
X X X
X
X X X
X
X X X
X
X X X
X
X X X
X
X X
X
X X
X
X X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X X
X
X X X
X
X X X
X
X X X
TABLE VII CONTINUED
OCCURRENCE OF SEASONAL DISTRIBUTION OF THE FLORA IN MONUMENT LAKE
Locality _____ Date of Collection
Flora occurring in Monument Lake
_
O ' O ' CO
ON O '
O ' O ' rH £ \
rH
O ' rH
O'
^ rH
•» t f\
•»
Of *hvO Of VO
tO
rH Of
rH
O'
OH
o
o
-P
x
i
.
M
p
q
G
3
<D
rH
PQ
C. Chlorophyoeae
30. Bulbochaete
31* Chaetophora
3 2 . Cladophora
33. Cosmarium
3 k * Crucigenia
35* Desmidium
36* Gloeotaeniura
37. Mougeotia
3S. Nephrocytium
3 9 * Oedogonium
40. Pediastrum
41. Pithophora
42. Planktosphaeria
43. Scenedesmus
k k * Sorastrum americanum
45. Sphaerocystis
46. Spirogyra
-47. Staurastrum
4S. Stigeocloneum
49* Tetraedron
50. Ulothrix
51. Zygnema
D. Chara
52.
Spermatophytes
53* Limosella aquatica
54* Myriophyllum verticillatum
55* Polygonum amphibium
56. Potomogeton faliosus
57. Ranunculus purshii
Ph
ON
to
E"- cr\
to
n O 'to cn
•
• -p
t>
co
o o o o o
O'
"Nf -<}■ "Sf
CO O *'4‘
O ' ->t ON ON ON ON ON
rH O ' r l H H H H
rH
O
rH ^.*"
0
Of
•
P«-P
•
l>
s0 w0)00
o s
*» n O
r-j tO C'f'XOrH H
0) t>»>> *P
•
•
P*-P
>
0)0 0 cO £ ^■3 S’®
co o s S3 *-a •-a Pa «*J CO
•P
X X X
X
X
X X X
X X
X
X
x -
X
X
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X X
X X
X
X
X
X X
X
X
X
X
X X
X
X X
X
X X
X X
X
X
X X
X X
X
X
X
X X
X
X
X
X
X
X
X X X X
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X
X
X X
X
X X
X X
XX X X X
X
X X X
X
X X
■X X
X X X X X
X
X
X X
X X
X X
X X X X X
X X
X X X X X
X
X X
X X
X X X X X
X
X X
X
X X
X X
X
X
X
X
58
Of the Chlorophyoeae» Chara, the stonewort, appeared
during the middle of June attached to the lake bottom#
It
continued its growth, forming dense beds till about the middle
of August when it seemed to have reached its maximum growth*
It was present in evidently a living condition till late
October#
In the November collections it seemed to be in
either a dead or dying condition#
Chaetophora, which grew in such numbers as to cover
almost completely the submerged rocks of the dam, became
apparent about the middle of June and continued to be present
until the lake was completely frozen over#
The other filamentous Chlorophyoeae began to appear
in the early July collections, and became much more numerous
in species and individuals until they were dominant in the
late July and August collections#
Ulothrix# Bulbochaete#
Oedogonium and Mougeotia were present in the early July
collections#
In addition to these Zygnema« Spirogyra#
Cladophora, Pithophora and Stigocloneum were present in the
late July and August collections.
ium
Ulothrix, Mougeotia, Oedogon­
were present in the September collections#
Scenedesmus was present in collections from May to
October#
Of the other plankton Chlorophyoeae, Cosmarium#
Planktosphaeria, Sphaerocystis and Nephrocytium appeared in
July#
In addition to these Staurastrum, Pediastrum#
Crloetaenlum and Desmidium appeared in August, while
59
Tetraedron and Cruoig.enia appeared in early September*
These
plankton forms were also present in early October collections
and completely absent in November collections*
The Spermatopfxytes:
Limosella aquatica. Myriophyllum
verticillatum L . , Fotomogeton foliosus R a f .t Polygonum
amphibium- a n d
Ranunculus purshii Rich., became apparent
during the latter part of June and continued their growth*
forming very dense beds during July, August and early Sept­
ember.
They seemed to reach their maximum during late August
and early September*
until late October.
They remained in a living condition
Pram November till June the only Sper-
matophytes found were either dead or dying*
During the period from November to February when the
lake was covered by a thick layer of ice, it was impossible
to make collections.
No plant growth at all was evident until
about the middle of May when the Diatoms appeared*
Prom these results it would seem that in Monument
Lake the Bacillarieae are abundant during the entire growth
period from May until November*
abundant in. late summer.
The Myxophyceae are most
The filamentous Chlorophyoeae are
dominant in late July and August, and the plankton
Chlorophyoeae are -most abundant in late August and September.
The Spermatophytes are apparent from late June to late
October.
Prom November to early May plants are either
dormant or entirely absent.
CHAPTER VII
CONCLUSION
The results of this investigation show that during
a period of a year an abundant and floristlcally diversified
flora occurs in Monument Lake , fifty-seven species and
varieties having been collected.
and 52 were Algae.
Of the Algae:
Of these, 5 were Spermatophytes
5 were Myxophyceae» 24 were
Bacillarieae» 22 were Chiorophyceae and 1 was Chara.
The results further show that a definite altitudinal
zonation occurs, ranging from Chara and Chaetophora at and
slightly below the shore line to Potomogeton at a depth of
from ten to twenty feet in the lake, beyond which no rooted
vegetation was collected.
The results also show that the flora of Monument Lake
exhibit definite periodicity.
no plant growth is apparent.
From late November to early May
Bacillarieae occur in great
abundance from the middle of May to early November.
A few
scattered individuals of Myxophyceae occur in collections from
June to early October.
During late August and early September,
one species of Anabaena occurs in such vast numbers as to
cause "water bloom".
A few individuals of Chlorophyoeae,
appear in June;(lnan^more appear in June; many more appear
in early July, August and early September.
Then gradually
disappearing until only a few individuals are found in late
October, after which they disappear entirely.
A definite
correlation seems to exist between growth rate and water
temperature ♦
At temperatures from 0° C. to 6° C., no plant
growth was evident.
As the temperature reached 18° C.
Bacillarieae appeared; as it reached 15°
Spermatophytes.
a few Myxophyceae and a fev; Chlorophyoeae appeared; as it
reached 17°
the growth rate seemed to be greatly acceler­
ated until it reached 19° C. when the population was the. great­
est*
From 19° C the growth rate slowly tapered off corres­
ponding to a gradual temperature decline till 0° C. was
reached and the lake became covered by a layer of ice ranging
from a thin sheet to two feet in thickness, and no plant
growth was evident.
Plant growth again became evident as 18°
C. was reached the following spring#
These results would indicate that the temperature,
rather than being a determining factor on the kinds of flora
occurring in the lake, would chiefly affect the growth rate*
causing dormancy inllife-cycles o f . t h e plants during the
period that it remained at 0° C. or slightly above.
As the
temperature rises, plants appear, and as it continues to rise
the growth rate is greatly accelerated and a very large
population occurs at the peak of 19° C*
The chemical composition of the water is determined
to a large extent by the character of the soil of the sur­
rounding region which is Permian red conglomerate and sand­
stone •
62
The p H of the water, ?»3, and the presence of
calcium, magnesium and silicon in their respective amounts
are favorable for plants as evidenced by the abundant and
varied plant growth#
The constant flow of water into and out of the lake
prevents an accumulation of dissolved salts which would
change the p H and greatly affect the flora#
BIBLIOGRAPHY
Anderson* Emma N . * and El da R. Walker
1920 "Ah Soologioal Study of the Algae of Some Sandhill
Lakes#
Trans. American Microsc. Soc#
39: 51-85
Burbank*
193?
W.S#.and E.N. Goddard
Thrusting in Huerfano P a r k # Colorado# and Related
Problems of Orogeny In the Sangre de Cristo Mountains.
New York: Bulletin of the Geological Society of
America 48: 931-976
Coulter*
1930
John Merle* Charles Reid Barnes and Henry C. Cowles
A Textbook of Botany# Vol. 1#
Eggleton* Prank E#
1939 Presh Water Communities#
Notre Dame* Ind.: The American Midland Naturalist
21: 56-71
Pritsch*
1935
P.E#
Structure and Reproduction of the Algae#
New York: Macmillan Company, pp# 1-28
Hills*
1901
R#C#
Geologic Atlas of the United States#
Peaks Folio#
Washington* D*C# pp# 1^7
Robbins *
1912
Spanish
w#w.
Preliminary List of the Algae of Colorado#
Moulder, Colorado* University of Colorado Studies
9: 105-118
Smith*
1933
Gilbert M#
Presh Water Algae of the United States# New York: Mc&raw-Hlil Rook Co.* Inc# pp# 1-533
Tiffany,
1938
Lewis Hanford
Algae# the Grass of Many Waters#
Tilden*
1935
Josephine
The Algae and Their Life Relations#
M n h e a p o l i s * Minn#: Univ. of Minn. Press
pp# 1-99; 352-471
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