THE PLANKTON ALGAE OF THE OKOBOJI REGION The lakes of Dickinson County in ...

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THE PLANKTON ALGAE OF THE OKOBOJI REGION
GILBERTM ORGANS MITH
Int rod u c tion ................................................................. 156
The waters investigated ............... .... .................................... 158
K ey to the genera ......................... ... ................................ 160
Systematic account of new or little known species ................................. 164
Table of the algae found ...................................................... 165
INTRODUCTION
The lakes of Dickinson County in Northwestern Iowa are of particular
interest since they present within a limited area all gradations from a large
deep lake to a small shallow pond. This region is generally referred to by
the name of the deepest and best-known lake, Okoboji, although there are
within a radius of ten miles from Okoboji more than a dozen bodies of
water of considerable size as well as many other smaller ones.
These lakes are located in the Wisconsin drift-region of Northern Iowa,
a region of terminal moraines formed by the Minnesota-Des Moines lobe
during the Wisconsin glacial epoch. All of the lakes studied, with the ex-
ception of Silver Lake, lie in the terminal moraines of this lobe.
The plankton flora of these lakes is of the Baltic type and contains a
considerable volume of blue-green algae, numerous Protococcales, and but
few Desmids. This would be the natural expectation, considering the
calcareous nature of the drift and the hardness of the waters. The study
of the plankton flora of this region has brought out very clearly that there
is a sharp difference between the nature of the plankton flora of small
shallow bodies of water and large lakes. The term heleoplanktonh as been
applied to the former, and the term limnoplankton to the latter. The
limnoplankton, as found in West Okoboji, East Okoboji and Spirit Lakes
has not been of particular interest since it comprises mainly the same
species of algae as are found in the lakes of Wisconsin and of other regions.
The heleoplankton, on the other hand, has been extremely interesting.
The chief feature of this plankton formation is the dominance of Proto-
coccales and the occurrence among these Protococcales of numerous species
which are not ordinarily met with in larger lakes. Its richness is shown by
the fact that during this investigation twenty one undescribed species and
varieties were discovered as well as twenty three species and varieties
which have not been reported as occurring in North America. In addition,
organisms which have been reported as occuring very sparingly at one
other station in North America were found in quantity in various of the
small permanent pools.
156
157
PLANKTON ALGAE
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IX
158 GILBERT MORGAN SMITH
The region is by far the richest in the world thus far discovered for
species of plankton algae, with the exception of the Desmids. The main-
tenance of the Lakeside Laboratory, by the University of Iowa, in the
center of this region affords an unusual opportunity to the student who
wishes to become acquainted with these organisms.
THE WATERS INVESTIGATED
Collections of plankton algae were made between the middle of June
and the first of September, 1923. In some cases repeated collections were
made from the same body of water and the progressive development of
the flora followed throughout the summer. In other cases but a single
collection was made at a station. All bodies of water from which collections
were made are shown on the accompanying map. Where exact morpho-
metric and hydrographic data are given for any body of water the informa-
tion is taken from the Report of the State Highway Commission on Iowa
Lakes and Lake Beds.1
(1)(2) Center Lake (1) lying between East and West Okoboji Lakes
has an area of 264 acres. Its banks are high and there is comparatively
little marshy land surrounding it. It is rather deeper than most of the
smaller lakes, a maximum depth of 14.8 feet being reported by the High-
way Commission survey. Collections were also made from the Northern
Arm, (2), a very shallow extension of the lake, probably less than two
feet deep. A detailed map of this lake is given on Plate 19 of the Highway
survey.
(3) Corner Pond, a mile west of the town of Spirit Lake, is one of a
group of small kettle-hole lakes. The margins of this pond are fairly free
from the swampy vegetation that characterizes the other ponds in this
vicinity. Samples were collected by wading in to where the water was a
foot and a half deep and then dipping the plankton net repeatedly. The
pond has an area of about five acres.
(4) Diamond Lake (Plate of the Highway survey) three miles north of
the village of Montgomery, is six feet deep at the center and has an area
of 111 acres. The shores are fairly steep, without trees on the western
shore and with trees on the south and eastern shore. To the north of this
lake and connected with it is a marshy slough of considerable extent.
(5)(6)(7) The Gar Lakes are shown on Plate 18 of the Report by the
Highway Commission. Through this chain of three lakes drain the waters
of East and West Okoboji. The central one of the three (6), Lake Minne-
washta, is the deepest of the small lakes of the region, having a maximum
depth of twenty feet. Upper Gar Lake (5) and Lower Gar Lake (7) must be
looked upon as expansions of the stream draining East Okoboji. Neither
of these lakes is over six feet deep.
1 DesMoines. 1916.
PLANKTON ALGAE 159
(8) Hale Pond is a small kettle-hole pond on the grounds of the Spirit
Lake Golf Club and lies near the north end of West Okoboji Lake. It is
about five acres in area; its depth is unknown.
(9)(10) Two large irregular lakes just west of Spirit Lake, which are
in reality extensions of Spirit Lake, are referred to as a single lake (Hottes
Lake) on plate 24 of the Highway Commission Report. The local custom
is to call the eastern half of this lake Hottes Lake (9) and the western half
Robinson Lake (10). I have followed this practice. Their combined area is
312 acres. Hottes Lake has a depth of 7.9 feet and Robinson Lake a
maximum depth of 5.4 feet. Both the north and south ends of Robinson
Lake are swampy. A swampy slough on the north side of Hottes Lake
is now separated from the lake by a roadway.
(11) A preliminary collection from the Little Sioux River showed so
many interesting and rare algae that this stream was visited regularly
during the investigation. The river lies west of the territory containing
most of the lakes studied. The west branch of the river receives water
from Silver Lake and a small stream extending into Minnesota. The east
branch arises in Diamond Lake. There are many algae in the stream that
are not found in either Diamond or Silver Lakes; their presence may.be
due to the small stream extending into Minnesota. The rich plankton flora
of this small stream, which is not, as a rule, over fifteen feet wide and a
foot in depth, suggests that the plankton flora of other streams in this
region may also be of interest.
(12) Little Spirit Lake lies mainly in Minnesota, a short arm of it
extends into Iowa just west of Spirit Lake. This lake is very irregular in
shape and the water is from eight to twelve feet deep. 214 of the 724 acres
of its surface lie in Iowa. Plate 25 of the Highway Commission Report
shows the topography and hydrography of this lake.
(13) Marble Lake is found on both Plates 23 and 24 of the Lake Survey.
It lies on the west shore of Spirit Lake and south of Hottes and Robinson
Lakes. Like these two lakes it is shallow, with a maximum depth of seven
feet, but its shores are relatively high. Its total area is 175 acres.
(14) East Okoboji Lake is long and narrow, extending in a general
north and south direction. Two long spits at the northern end nearly divide
it into three distinct lakes. The northern end is fairly shallow, with a
maximum depth of eight feet; the southern end is deeper, a depth of 26
feet being found near its outlet to the Gar lakes. The total area of this
lake is 1875 acres as shown by Plate 17 of the Highway Commission survey.
(15)(16)(17)(18)(19) The deepest and best-known of the lakes of the
region is West Okoboji (15). It is nearly six miles long and has an average
breadth of a mile. The maximum depth is 132 feet and the average depth
is probably in the neighborhood of fifty feet. At the south end is a shallow
extension, with shores free from swampy vegetation, known as GreenS lough
160 GILBERT MORGAN SMITH
(18). A similar extension at the north end of the lake, North Slough (19),
is quite swampy. A few years ago a real estate development company cut
a Canal from Miller's to Emerson's Bay (16). At the point where this
canal traverses the grounds of the West Okoboji Golf Club there is a broad
expansion which I have called the Golf Club Pond (17). The collections
from these four stations, all connected with West Okoboji Lake are, as an
examination of the accompanying table shows, quite different in nature
from those from the lake proper. The main lake and these outlying bodies
of water are mapped on Plate 18 of the Highway Commission survey.
(20) Pleasant Lake lies a short distance east of East Okoboji Lake.
It is fairly regular in outline and has high wooded shores. Plate 28 of the
Highway Survey shows that its maximum depth is 6.4 feet and its area
is 82 acres.
(21) Prairie Lake, four miles southwest of Pleasant Lake, is divided
by two spits into an eastern and a western half. The eastern half is the
smaller, extremely shallow, and its muddy bottom supports considerable
swampy vegetation. The western half, on the other hand, is fairly free
from vegetation and has a depth of four feet. The total area of the lake
is 105 acres. This lake is shown on Plate 27 of the Highway Commission
survey.
(22)(23) At some distance west of the Okoboji lakes and near the town
of Lake Park lies Silver Lake (22). Most of its banks are high and wooded;
the southern shore, however, is somewhat swampy. The lake is quite
irregular in outline and has several slough-like extensions. From one of
these extensions, the North Arm (23), plankton collections were made,
as well as from the main body of the lake. The main lake has a maximum
depth of 7.7 feet and covers an area of 1058 acres; Plate 20 of the Highway
Commission Report.
(24)(25) In its surface area, 5560 acres, Spirit Lake (24) is the largest
of the district. Its depth, however, is only equal to that of East Okoboji
(26 feet) and is exceeded five-fold by West Okoboji. As Plate 16 of the
Highway Commission shows, the lake is irregular in shape and a shallow
portion, the North Arm (26), lies partly in Minnesota.
(26) Welch Lake lies about three miles north of West Okoboji. It is
a small, nearly circular, body of water with high timbered banks and clear
open water. Its area is 57 acres and its maximum depth 6.1 feet; Plate 22
of the Highway Commission survey.
A KEY TO THE GENERA BASED UPON THE VEGETATIVE CHARACTERS
(1) Coloring matter not restricted to definite plastids (MYXOPHYCEAE)
(A) Cells solitary or in colonies, never in filaments
(B) Cells solitary or in small colonies
(C) Cells spherical to hemispherical
PLANKTON ALGAE 161
(D) Cells in a flat plate . ..................... MERISMOPEDIA
(D) Cells without definite arrangement ..........CHROOCOCCUS
(C) Cells greatly elongate ............................ SPIRULINA
(B) Cells in colonies of many cells
(E) Colony with cells forming a hollow sphere
(F) Center of colony with radiating gelatinous
strands ................................ OMPHOSPHAERIA
(F) Center of colony without radiating gelatinous
strands ................................ COELOSPHAERIUM
(E) Colony with cells not forming a hollow sphere
(G) Cells spherical
(H) Cells densely aggregated ............... MICROCYSTIS
(H) Cells some distance from one another.....APHANOCAPSA
(G) Cells longer than they are broad .............APHANOTHECE
(A) Cells united to form a filament
(I) Filament composed of cylindrical to subcylindrical cells
(J) Filaments solitary
(K) Sheath enclosing cells very inconspicuous. .. OSCILLATORIA
(K) Sheath enclosing cells conspicuous ......... LYNGBYA
(J) Filaments aggregated
(L) Filaments radiating from a common center. . GLOEOTRICHIA
(L) Filaments parallel to one another .......... APHANIZOMENON
(I) Filaments composed of spherical cells
(M) Filaments solitary ...................... ANABAENA
(M) Filaments parallel to one another.......... TRICHODESMIUM
(1) Coloring matter in definite chloroplasts
(2) Chloroplasts grass-green in color (CHLOROPHYCEAE)
(3) Vegetative cells ciliate
(N) Cells solitary
(0) Cells compressed ............................ PHACOTUS
(0) Cells not compressed ......................... CHLAMYDOMONAS
(N) Cells united in colonies
(P) Colony compressed .......................... PLATYDORINA
(P) Colony not compressed
(Q) Cell number 256 or less
(R) Cells in mutual contact ................... PANDORINA
(R) Cells some distance from one another
(S) Vegetative cells all the same size ......... EUDORINA
(S) Vegetative cells of different size .......... PLEODORINA
(Q) Cell number several hundred .............. VOLVOX
162 GILBERT MORGAN SMITH
(3) Vegetative cells not ciliate
(T) Cells solitary
(U) Cells free-floating
(V) Cells angular
(W) Angles without long setae or spines
(X) Body of cell large ..................... TETRAEDRON
(X) Body of cell small and continued in
processes ............................ CERASTERIAS
(W) Angles with long setae or spines
(Y) Setae or delicate spines at angles ......... POLYEDRIOPSIS
(Y) Stout spines at angles of cells ............ TREUBARIA
(V) Cells spherical, elliptic, or elongate
(Z) Length of cells not over three times the breadth
(a) Cells spherical
(b) Cells embedded in a gelatinous
envelope ........................... PLANKTOSPHAERIA
(b) Cells not embedded in an envelope
(c) Wall with ridges or very short spines.. TROCHISCIA
(c) Wall with long spines
(d) Spines gradually attenuated....... GOLENKINIA
(d) Spines thickened in basal third .....ACANTHOSPHAERIA
(a) Cells ovoid to reniform
(e) Cells reniform ....................... NEPHROCYTIUM
(e) Cells ovoid
(f) Walls without setae ................ OOCYSTIS
(f) Walls with setae
(g) Setae tapering ................... LAGERHEIMIA
(g) Setae not tapering ............... FRANCEIA
(Z) Length of cells several times the breadth
(h) Ends of cells produced into setae ......... SCHROEDERIA
(h) Ends of cells not produced into setae
(i) Chloroplast without or with one
pyrenoid . ........................... ANKISTRODESMUS
(i) Chloroplast with an axial row of
pyrenoids ........................... CLOSTERIOPSIS
(U) Cells epiphytic or epizo6tic ................... CHARACIUM
(T) Cells united to form colonies
(j) Cells spherical
(k) Colony with remains of old mother cell wall at center
(1) Wall remains forming a branching system.... DICTYOSPHAERIUM
(1) Wall remains not forming a branching
system ................. ................W ESTELLA
PLANKTON ALGAE 163
(k) Colony without remains of walls at center
(m) Cells quadrately arranged in a plane
(n) Walls with spines
(o) Cells with numerous spines ............ MICRACTINIUM
(o) Cells with few spines ................. TETRASTRUM
(n) Walls without spines ................... CRUCIGENIA
(m) Cells not quadrately arranged
(p) Walls with spines
(q) Exterior cells with several delicate
spines .............................. M ICRACTINIUM
(q) Exterior cells with a single spine........ ERRERELLA
(p) Walls without spines
(r) Cells in a hollow sphere ............... COELASTRUM
(r) Cells irregularly distributed in a gelatinous envelope
(s) Chloroplast of mature cell cup-shaped. SPHAEROCYSTIS
(s) Chloroplast of mature cell disciform... PLANKTOSPHAERIA
(j) Cells angular, ovoid, or elongate
(t) Colony a flat plate
(u) Cells quadrately arranged
(v) Walls with spines ...................... TETRASTRUM
(v) Walls without spines ................... CRUCIGENIA
(u) Cells not quadrately arranged
(w) Cells angular and in concentric rings ...... PEDIASTRUM
(w) Cells elongate
(x) Entire wall covered with spines........FRANCEIA
(x) Spines, if present, on ends or margin of
cells ............................... SCENEDESMUS
(t) Colony not a flat plate
(y) Cells forming a hollow sphere
(z) Walls without spines ................... COELASTRUM
(z) Walls with short spines . ................ SORASTRUM
(y) Cells not forming a hollow sphere
(A') Length of cells several times the breadth
(B') Cells radiating from a common center.. ACTINASTRUM
(B') Cells not radiating from a common center
(C') Colony without a gelatinous envelope
(D') Cells narrow, straight or arcuate. . ANKISTRODESMUS
(D') Cells plump, markedly curved.... SELENASTRUM
(C') Colony within a gelatinous envelope
(E') Cells straight .................. QUADRIGULA
(E') Cells curved ................... KIRCHNERIELLA
(A') Length of cells not more than three times breadth
(F') Cells straight ..................... GLOEOACTINIUM
164 GILBERT MORGANS MITH
(F') Cells curved
(G') Curvature of cells gentle
(H') A distinct envelope surrounding
each group of four or eight cells... GLOEOCYSTOPSIS
(H') All cells within a single envelope.. KIRCHNERIELLA
(G') Curvature of cells very marked ..... NEPHROCYTIUM
(2) Chloroplasts yellow-green in color (HETEROKONTEAE)
(I') Cells solitary ................................... OPHIOCYTIUM
(I') Cells in colonies ............................... BOTRYOCOCCUS
THE PLANKTON ALGAE OF THE REGION
In the following table is given the distribution of the phytoplankton
of the region. Their maximum frequency at the various stations is desig-
nated as follows: (a) abundant, (c) common, (s) scarce, (r) rare, The
species and varieties which are new to North America are marked with an
asterisk. In cases where the original publication of the species has been
given in connection with the plankton algae of Wisconsin,2 species are
cited by name only. Reference is made, however, in the discussion of new
and interesting forms to the descriptions of all species and varieties which
have not been cited in connection with the Wisconsin phytoplankton.
SYSTEMATICA CCOUNTO F NEW OR LITTLE KNOWN SPECIES
OSCILLATORIAF ORMOSAB ORY. Pl. 2, Fig. 3.
Dict. Class. d'hist. nat. 12: 474. 1827; Gomont, Ann. Sci. Nat. Bot., 7 Ser. 16: 250, pI. 7,
fig. 16. 1893. (Sep.)
Cells 4.5-5.5,.t broad.
TRICHODESMIUMLA CUSTREK lebahn. PI. 2, Fig. 4.
Schr6der3h as recently discussed this alga and thinks that it should not
be referred to Trichodesmium, a genus which, except for this species, is
exclusively marine. Since no suggestion is made as to the genus to which
the species should be transferred it is retained in Trichodesmium.
PLATYDORINAC AUDATA Kofoid. PI. 4, Figs. 4-5.
Bull. Ill. Lab. Nat. Hist. 5: 435, pl. 38,figs. 1-5. 1899.
This remarkable member of the Volvocales occurred in some quantity
in the canal connecting Miller's and Emerson's Bays of West Okoboji. The
organism has been described so fully by Kofoid that but little need be
said concerning it. In the Okoboji collections 16-celled colonies were far
more numerous than 32-celled ones. Perfect colonies were rarely met with,
2 Smith, G. M., Phytoplankton of the Inland Lakes of Wisconsin. Wis. Geol. and Nat.
Hist. Survey Bull. 57, Part 1. 1920.
3 Sitzbr. Ak. Wiss. Wien 130: 152. 1921.
Gar Lakes W. Okoboji
-?~~ . 'S~O~f. ~~.- ~g~I, ~c 2 3 191 4 'o^^1321' o .o s 2^3 ge o2 4 .ag 2 2> -^ 5
0 .~~~~~~~~ce0~ 0 a c
MYXOPHYCEAE
CHROOCOCCACEAE
Chroococcus
CC.. ldimispneertsicuuss (KVt.L KeIm1ei sms..).. Lemm. ......... ............. C.lIm23 netic rr mr .1 - - r . - r r .--- -r - r r .. ra a.r. r r r - r r
Merismopedia................................
MMC...g tluemgninudeiusti sasim( uEsaLh reL.m)e mmNmar.iNg. ................................................................... .. ...... I11 455 rr- r - - - -- --- -r-- r r --- - -r r r r r - -r -s r r -rr r - r- - - r- - - r -
MMMCo ...pe peluleuongnsacptcnatshtaAaatM.ea Mr eB.i eur.yy. m..e.e...n...n ... ...... ............................................. .1.... ............... .... ........... ... 67 rr - r - r r r r - -r r rr -r -- --- - -r -- -s r
C.KuetzingianumN g ........................ 1 - s r - - r s r - s s r r r r r r r - r
C.Naegelianum Unger .................. .... 1 9 r----- s - r- s r ss r r r
Gomphosphaeria..............................
G.lacustrisChod............................. 1 0 - r - - - r r r r - - - r r - r
M icrocystis ..................................
M . aeruginosa Ktz............................ - - - - - - r- .
var. major(Wittr) G.M. Smith.............. 1 12 c r ---- a c - - - r - ---s a - r
M . incerta Lemm............................. r- - - -- -- - - . -
M.fios-aquae(Wittr.)Kirchn.................. 2 1 c - r c - - c c r r - s r s r r r r r a r s r
A phanocapsa......................... . .......
A.delicatissimaW.&G.S. West.............. 1 11 - r - - r r r r r s r r r r r r rs rs
A elachista ...... ............................
var. conferta W. & G. S. West ................ ..- - ....r -- ----- -
var. planctonica G. M. Smith ............... - - - - r - _
A phanothece. ..... ...........................
A. clathrata W. & G. S. West.................. - - ------------- r r - -'---------
HORMOGONEALES.........................
Spirulina ....................................
S. major Ktz................................. 2 2 - - - - - - - - - - - r r - - - - - - - - - - - - -
Os cillatoria ..................................
0. formosa Bory.............................. 2 3 - c - - - - - - c - - - - - - - - - - - - - - - - -
Trichodesmium. ..............................
T. lacustreKlebh............................. 2 4 - - - - r - - - r r - - - - - - - - - - - - - - r
Ly ngbya. ....................................
L. contortaLemm ............................. 2 5-6 - - - r ----------- - - s -s - s c
L.BirgeiG. M. Smith...................... 2 7 r r - - - - - - - - - - - r r - - - - - r r s -
Anabaena...................................
A. planctonica Brunnth....................... 2 8 - - - - - - - - - - - - - - - r - - - - - - - - - -