ABSTRACT
A BIOLOGICAL SURVEY OF A SUBTERRANEAN STREAM: SULLIVAN CAVE, LAWRENCE COUNTY, INDIANA
by David Lawrence Weingartner
Sullivan Cave, one of the largest caves in southern Indiana, con- tains a recently-discovered subterranean stream. From August, 1961, to
May, 1962, a survey was made to determine the organisms present in the stream passages, and to determine some of the physical and chemical conditions under which these organisms lived.
The cave lies under a ridge with poorly-deve10ped surface drain- age; most of the water seeps through the soil, penetrates fractures in the limestone bedrock, and combines to form the subterranean stream.
The stream flow varied from 3.5 to 1000 gallons per second during the course of the study. .
The following four stations for chemical determinations and biological collections were established: 1) a riffle and pool of the main cave stream, 2) a semi-isolated pool of the flood passage, 3) a rivulet of seepage water entering a fissure in the limestone, and 4) a surface stream overlying the cave.
Standard methods were used in the physical and chemical analyses.
The water temperature of the cave stream varied from 53 to 56 degrees
Fahrenheit during the period of the investigation. Dissolved oxygen varied from a low of 7.4 p.p.m. in the flood passage pool to a high of
11.8 p.p.m. in the seepage water. Methyl Orange alkalinity varied from 43 p.p.m. in the seepage water to 186 p.p.m. in the main cave stream. No phenolphthalein alkalinity was observed.
x I) . Pv‘ a} .I. 1 ;‘ on. . u a“ I.v U . .- .1 .LV .1.’ .rc 0, David Lawrence Weingartner
Terrestrial, planktonic, benthic, and larger aquatic organisms were collected. The terrestrial fauna was found to be similar to that of other caves of the area. The Protozoa were mostly ciliates; no
Sarcodina were found. The plankton was composed mostly of c0pepods and rotifers, and lacked Cladocera. Many aquatic insects were found which have not been reported from other caves. The isopods, amphipods, planaria, and crayfish of Sullivan Cave were typical cave Species. A few fish were found, and the sculpin, Cottus bairdi, seems to have be-
come established in the cave stream.
Ten phyla, 16 classes, and 64 families were represented. Of these, one group was keyed to phylum, one to class, 12 to family, 44 to genus, and 28 to Species; A total of 86 taxons was collected and identified.
An analysis of the drift biota of the cave stream was made during the dry period of late summer, 1961. An average of only .7 ml. of drift material was found to be carried in the 300,000-gallon daily dis- charge of the stream.
Quantitative studies of the seepage water entering a fracture in the limestone and of the water of flood passage pools demonstrated the paucity of aquatic cave life. The fauna of the seepage water lacked planktonic forms.
Seasonal changes on the surface were found to impose an annual cycle on the cave stream. Stream discharge, water chemistry, drift material, and aquatic organisms were factors affected by surface con- ditions.
Food for the aquatic cave organisms was derived from four sources —- plankton and drift material from overlying surface waters,
.1 - .. . . , . ghepasfiwux , . : .fi f a}! gust. David Lawrence Weingartner members of the terrestrial cave fauna, organic material brought in by bats and humans, and epigean animals migrating upstream into the cave.
Humans, who have been visiting the cave stream since 1957, have greatly affected the cave environment and its fauna. The residue from carbide lamps has a deleterious effect upon aquatic organisms, while the large amount of food materials brought into the cave by people has
I been beneficial to the cave community. A BIOLOGICAL SURVEY OF A SUBTERRANEAN STREAM: SULLIVAN CAVE, LAWRENCE COUNTY, INDIANA
By
David Lawrence Weingartner
A THESIS
Submitted to Michigan State University in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
Department of Zoology
1962 ACKNOWLEDGMENTS
The author wishes to eXpress his sincere thanks to Dr. Peter I.
Tack, Dr. Philip J. Clark, and Dr. T. Wayne Porter for their supervision and criticism of this study.
Grateful acknowledgment is also due the following: Dr. H. C.
Yeatman, of the University of the South, for identification of c0pepods;
Mr. D. C. Cook, of Wayne State University, for identification of water mites; Dr. E. Ferguson, of Lincoln University, for identification of ostracods; Dr. K. A. Christiansen, of Grinnell College, for identifica- tion of Collembola; Dr. L. L. Curry of Central Michigan University, for identification of Diptera; and Dr. C. H. Krekeler, of Valparaiso
University, for identification of the anOphthalmid beetle.
Gratitude is also expressed to Mrs. B. R. Henderson, secretary in the office of the Department of Zoology, who aided in many ways, and
Dr. E. C. Williams, of Wabash College, who inSpired the author's in- terest in caves.
ii TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS ...... -...... ii
LIST OF TABLES ...... vi
LIST OF FIGURES . . . . .l...... vii
INTRODUCTION ...... 1
PART I DESCRIPTION OF THE CAVE ...... 2
Location and Climate ...... 3
Surface Features and Drainage ...... 3
The Upper Dry Cave ...... 3
The Subterranean Stream Passages ...... ' 4
Stream Morphology and Substrate ...... 5
PART II PROCEDURES ...... 12
Difficulties ...... l3
Collecting MEthods ...... 13
Methods for Physico-Chemical Determinations ...... 14
PART III PHYSICAL AND CHEMICAL FEATURES ...... 15
Temperature ...... l6
Dissolved Oxygen ...... l6
Alkalinity ...... 21
PART IV BIOLOGICAL FEATURES ...... 27
Terrestrial Animals ...... 28
Caddie-Flies ...... 28 Cave Beetles ...... 28 Frogs ...... 30
iii Contents : Page
Bats ...... 30 Collembola ...... 30
Aquatic Organisms ...... 30
Fish ...... 30 Crayfish ...... 33 Aquatic Insects ...... 34 Plecoptera ...... 34 Ephemeroptera ...... 34 Megaloptera ...... '...... 34 Trichoptera ...... 35 Diptera ...... 35 ColeoPtera ...... 36 Benthic and Planktonic Organisms ...... 36 Crustacea ...... 36 Rotifers ...... 37 Nematodes and Annelids ...... 37 Hydracarina ...... 38 Planaria ...... 38 Protozoa ...... 38 Algae ...... 39
Quantitative ASpects ...... 39
Drift Material of Cave Stream ...... 39 Quantitative' Aspects of the Flood Passage Pools . . . 42 Quantitative Aspects of the Seepage Water ...... 44
Seasonal Changes ...... 45
Stream Discharge ...... 45 Water Chemistry ...... 46 Drift Material ...... 47 Aquatic Organisms ...... 47
Food Sources ...... 48
Drift Material ...... 48 Plankton ...... 48 Source of the Cave Plankton . . . . . 48 Feeding and Reproduction of the Cave Plankton . . 49 Fate of Cave Plankton ...... 49 Terrestrial Cave Fauna ...... 50 Humans and Bats ...... 50 Epigean Animals ...... 50
The Influence of Human Visitors ...... 51
SUMMARY ...... 52
iv Contents Page
SPECIES LIST . 54
LITERATURE CITED . 62 LIST OF TABLES
Table Page
Comparison of Dissolved Oxygen from Three Locations in the Cave Stream, from August 17 to September 25, 1961 18
Comparison of Dissolved Oxygen from Four Locations, from November, 1961, to May, 1962 . 20
Comparison of Total Alkalinity from Three Locations in the Cave Stream, from August 17 to September 25, 1961 22
Comparison of Total Alkalinity from Four Locations, from November, 1961, to May, 1962 . 25
Food Content of Sculpin Stomachs 32
Drift Net Results of Five 24-hour Samples Taken August 29-September 22, 1961 . 40
Quantitative Analysis of Benthic Organisms of Flood Passage Pool ...... 43
Quantitative Analysis of Plankton of Flood Passage Pool 43
Quantitative Analysis of Seepage Water . 44
vi LIST OF FIGURES
Figure Page
Diagrammatic Cross-section of Sullivan Cave .
Three-dimensional Map of Surface Topography and Sullivan Cave ......
Photograph of Point Where Water of Surface Stream Seeps into the Ground ......
Photograph of Point Where Seepage Water Enters the Cave Through a Fissure in the Limestone
Photograph of Typical Portion of the Cave Stream 10
Photograph of Cave Stream Waterfall with Drift Net in Position ...... 10
Photograph of the Flood Passage ...... 11
Photograph of Water Issuing from the Cave . . . . . 11
Comparison of Dissolved Oxygen from Three Locations in the Cave Stream, from August 17 to September 25, 1961 . 17
lCL Comparison of Dissolved Oxygen from Four Locations, from November, 1961, to May, 1962 . . . . 19
1]” Comparison of Total Alkalinity from Three Locations in the Cave Stream, from August 17 to September 25, 1961 . 23
:12. Comparison of Total Alkalinity from Four Locations, from November, 1961, to May, 1962 . . . . . 24
143. Distribution of Regional Anophthalmid Cave Beetles of the genus Pseudanophthalmus 29
144. Pr0portions of Various Components of the Drift 42
vii INTRODUCTION
Hundreds of caves occur in southern Indiana. Besides being merely points of interest, these caves play an important role in the drainage
of the region. A great portion of the run-off water descends through
sinkholes and is carried away by subterranean streams. This vast
underground system is not sterile, but contains functional communities
of organisms.
Previous investigations usually involved only a portion of the
total cave population. The terrestrial members of cave communities have
been intensively studied in Indiana. Banta's (1907) investigation of
Mayfield's Cave was a classic study. The aquatic cave fauna is less
Well known. Kofoid (1899) studied the plankton of Mammoth Cave,
Kentucky, and Scott (1909) investigated the plankton of Shawnee
(Donaldson's) Cave. These two are the only previous studies of North
American cave plankton.
The present study is an attempt to investigate the total biolog- ical community of the subterranean stream passages of Sullivan Cave.
This cave is one of the largest in Indiana, but had not previously been investigated. The study began in August, 1961, and continued until
May, 1962. PART I DESCRIPTION OF THE CAVE 3
LOCATION AND CLIMATE
Sullivan Cave is located two miles'west of Springville, Lawrence
County, Indiana (Sec. 20, 21, 28, and 29, T-6-N, R-Z-W).
The mean annual temperature of the area is 54.60 F. The average
yearly precipitation is 45.5 inches.
SURFACE FEATURES AND DRAINAGE
The cave underlies a ridge forested with beech, maple, and oak,
although a part of the land has been cleared of timber and serves as
pasture. Karst features are characteristic of the surrounding area,
but the ridge itself has only two sinkholes. Drainage of runoff water
is effected by intermittent streams in a radial drainage pattern.
There is a great amount of leakage between the surface streams
and the cave stream below. In many cases the surface streams flow only
a short distance before disappearing entirely into the ground. There
is only one surface stream with any degree of permanence, and it flows
only five hundred feet before seeping into the ground. This stream
arises fifty feet from an artifical farm pond, the only permanent pond
on the ridge. After rainfall, temporary ponds form in the sinkholes,
but: these dry up within four or five hours.
THE UPPER DRY CAVE
This part of Sullivan Cave has been known and visited for over one hundred years. These upper passages were formed by the subterranean
Stream in the geological past. The cave stream has since sunk to a
1(fiver level, leaving the passages dry. 4
THE SUBTERRANEAN STREAM PASSAGES
In 1957, a lower cave level was discovered. These lower passages contain the subterranean stream, which varies from 50 to 220 feet below the surface. The source of this stream is ground water infiltration and stream bed leakage from the ridge above. This water descends through the soil until it reaches the limestone bedrock. Water collects on the upper surface of the bedrock and flows laterally until it en- counters a fracture in the limestone. The water descends through the fracture to the main subterranean stream. .Many such tributaries flow into the main stream passage, adding to the volume of flow.
The main stream passage is large enough to be readily investigated for a length of 6000 feet. The cave, upstream from the Quarry Room, has been explored only a few times. It extends for at least 3000 feet in a north-northwest direction. This seems to indicate that the cave stream passes under and beyond the surface sinkholes, but its ultimate source is unknown. One thousand feet downstream from the Quarry Room the cave stream divides. One branch, which carries the main water flow, is blocked to exploration by a collapsed ceiling. The other branch carries off flowing water only during periods of flood. During dry seasons, the water in this branch passage forms disconnected pools which gradually dry up, although the larger pools are permanent. This flood passage connects with the upper dry cave at the Mountain Room, but the 2600 feet of dry cave passages between the Mountain Room and
the cave entrance insures the isolation of the cave stream from exter- nal influences by this route. The two branches of the cave stream rejoin downstream from.the Mountain Room, and from this junction the
stream flows for 1200 feet to the Spiral Room. From this point the 5
stream flows 500 feet through unexplorable channels and empties at three points into a surfacevalley. As a surface stream, it flows into Indian
Creek, a tributary of the East Fork of the White River.
Along most of the passages through which the cave stream flows, the water itself occupies only a portion of the passage floor. The remaining portion of the floor is occupied by emergent mud banks.
The volume of stream flow is partly dependent upon rainfall.
During a period of little precipitation in August and September of
1961, the stream flow decreased and leveled off at 3.5 gallons per second. Seepage of groundwater maintained this reduced rate of flow even during prolonged dry periods. The rate of stream flow during the first five months of 1962 was never observed to be less than 25 gallons per second, and on April 1, 1962, the rate of flow was estimated at greater than 1000 gallons per second.
Although the age of this cave can not be determined, the sinuous meanderings of the stream passages indicate that this is an old, well- established cave (Greene, 1908).
STREAM MORPHOLOGY AND SUBSTRATE
The stream gradient is moderate, and the cave stream is approxi- mately 75 per cent pools and 25 per cent riffles. The pools are between one and four feet deep and may cover up to four hundred square feet.
The width of the stream varies between five and fifteen feet. A one foot high waterfall forms the only stream barrier. The stream water is clear, except during times of heavy flood.
The substrate of riffled areas is usually limestone bedrock, and in many cases, this limestone is covered with chert gravel. 6
Usually, this gravel is not loose, but is cemented securely to the limestone. In other areas, the limestone stream-bed is pocked with numerous potholes. The substrate of pooled areas is usually a thick layer of silt and precipitated calcium carbonate.
LEGEND:
l. sinkhole 2. farm pond 3. permanent stream 4. intermittent stream 5. seepage water 6. seepage water collected on surface of limestone 7. sampling station 8. upper dry cave 9. tributary stream 0. cave stream passage 1. exit of cave stream
,limestone
permanent water
m intermittent water
Figure l.-Diagrammatic cross—section of Sullivan Cave
.I,, .,o- .i..._l_...v i .n, 1 ,1, A r, - ,1 _1 :I il,j111.LiI11U TLJ .' "E 1 ‘L;1;n““rrj'“riijl”‘1 " 'rJY‘Lr“T‘I‘1‘ ‘ Ii TJT TTLJi I;
Figure l LEGEND:
LAYER A: SURFACE TOPOGRAPHY
sinkhole farm pond
permanent stream
0.. bWNl—l surface stream issuing from cave
LAYER B: UPPER CAVE
. entrance to cave . point where seepage water enters cave . Mountain Room
LAYER C: CAVE STREAM PASSAGES
Quarry Room branching of cave stream main stream passage flood passage . Mountain Room . pools of flood passage; sampling station junction of main stream and flood passage at waterfall pool tributary streams 9. large pool; sampling station 10. stream riffle sampling station ll. waterfall 12. Spiral Room 13. cave stream exiting into surface valley
-°- uncharted water routes "’ "" temporary Streams —— permanent s treams
Figure 2.--Three-dimensional map of surface tOpography and Sullivan Cave.
1000 Feet __J
Figure 2
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8.- ..- 2 V ‘ - \ ’\.\ 3
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1000 Feet ,_J I Figure 2 Figure 3.--Photograph of point where water of surface stream seeps into the ground.
Figure 4.--Photograph of point where seepage water enters the cave through a fissure in the limestone. 3 4 Figure Figure Figure 5.--Photograph of typical portion of the cave stream.
Figure 6.-—Photograph of cave stream waterfall with drift net in position. 10
Figure 6 Figure 7.--Photograph of flood passage.
Figure 8.--Photograph of water issuing from the cave. ll
Figure 7
Figure 8 PART II PROCEDURES l3
DIFFICULTIES
This study was limited in scope because of the difficulty in
reaching the cave stream. There are 2600 feet of cave passages to be
traversed before reaching the stream, requiring 45 minutes of travel
time. It is also necessary to pass through a tunnel that is only
fifteen inches in height, limiting the size and type of equipment that
can be tranSported to the cave stream.
COLLECTING METHODS
To collect terrestrial organisms the following methods were used:
Mousetraps baited with cheese and liver were placed among
the rock rubble bordering the stream.
Fly-paper was suSpended from passage walls and laid on the
mud banks.
Pieces of liver were laid on the mud banks to attract
animals for hand picking.
The mud banks and rock rubble were closely examined and
the discovered organisms collected.
To collect aquatic organisms the following methods were used:
1. Silt substrate of the stream pools was strained with No. 20
and No. 40 bottom Sifters.
Samples of water were cultured with boiled lettuce.
Plankton was collected with a plankton net having 190 meshes
per inch.
Drift biota was collected with a plankton net having 75
meshes per inch. 14
5. Larger organisms, such as crayfish and fish, were collected
by either hand or net.
Collected organisms were either kept alive for further study or preserved in 5 per cent formalin.
METHODS FOR PHYSICO-CHEMICAL DETERMINATIONS
Temperatures of the water of the cave stream were determined with both a Taylor maximum-minimum thermometer and a Taylor pocket thermometer.
For alkalinity determinations polyethylene bottles were filled with water samples. For oxygen determinations polyethylene bottles were filled with water samples and all steps preliminary to titration were performed immediately. These water samples were tranSported from the cave to be analyzed 1 to 2 hours later. Oxygen was determined by the Alsterberg (Azide) Modification of the Winkler Method (Standard
Methods, 1955). Phenolphthalein and Methyl Orange alkalinity were determined by titration with sulfuric acid (Standard Methods, 1955).
Precipitation data were obtained from the Purdue Oolitic Experi- mental Farm, seven miles east of Sullivan Cave, and Crane Naval Depot,
15 miles west of Sullivan Cave; precipitation figures for the cave area were determined by interpolation. PART III PHYSICAL AND CHEMICAL FEATURES 16
TEMPERATURE
A Taylor maximumdminimum thermometer was placed in the cave stream. From August 17, 1961 to May 12, 1962 the temperature of the water varied between 53 and 56 degrees Fahrenheit. This range of only
3 degrees indicated that the water of the cave stream was well buffered against fluctuation of outside temperature. The temperature of water seeping into the cave was modified by the temperature of the surrounding rock and approached 54.60 F., the mean temperature of the area and the temperature maintained by the deeper layers of limestone the year round.
On May 5, 1962 the temperature of the water of the surface stream was 620 F. On the same day the temperature of seepage water that had
—just entered the cave (see Fig. l, 7) was 490 F. This low temperature indicated a seasonal or diurnal temperature lag in the soil through which the water had passed. At this point water seeping into the cave had just come in contact with the limestone, and its temperature had not yet been greatly modified.
DISSOLVED OXYGEN
Dissolved oxygen was determined by the Alsterberg Modification of the Winkler Method. During August and September of 1961, twenty deter- minations were made of the oxygen content of the cave stream. Samples were taken from three collecting stations: 1) a riffle of the cave stream (see Fig. 2, C 10), 2) the largest pool of the cave stream
(see Fig. 2, C 9), and 3) a pool of the flood passage (see Fig. 2, C 6).
Water samples from the pools were taken two feet below the surface.
The complete results are given in Figure 9, and a summary in Table 1 below. Figure 9.-Comparison of dissolved oxygen from three locations in the cave stream, from August 17 to September 25, 1961.
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TABLE 1
COMPARISON OF DISSOLVED OXYGEN FROM THREE LOCATIONS IN THE CAVE STREAM, FROM AUGUST 17 TO SEPTEMBER 25, 1961
Range in p .p.m.
No . of Mean Sampling Station samples in p .p .m. Low High
stream riffle 20 10.7 10.0 11.3
stream pool 20 10.8 9.9 11.5 flood passage pool 20 8.3 7.4 9. 9
The determinations showed little difference in the dissolved
oxygen content between pooled and riffled areas of the cave stream.
Oxygen content was high, and the water was approximately 100 per cent
saturated. Dissolved oxygen was less in the flood passage pool, and
the water was approximately 77 per cent saturated. An oxygen reduction
trend was noticeable in the flood passage pool during the month of
analysis. A noteworthy aSpect of the dissolved oxygen determinations
was the daily fluctuations. The cause of these fluctuations is un-
known. No correlation with precipitation was evident. Experimental
error probably accounted for some of this variation.
A second series of dissolved oxygen determinations was conducted
from November 22, 1961 to May 12, 1962. The flood passage pool and
cave stream riffle sampling stations were retained. Two new sampling
stations were established; one station was a riffle area of the per- manent overlying surface stream (see Fig. l, 3), and the other station was established where a rivulet'of seepage water first penetrated a
fracture in the limestone (see Fig. 1, 7). The complete results are given in Figure 10, and a summary in Table 2 below. Figure lO.-Comparison of dissolved oxygen from four locations, from November, 1961, to May, 1962.
19
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20
TABLE 2 COMPARISON OF DISSOLVED OXYGEN FROM FOUR LOCATIONS, FROM NOVEMBER, 1961, to MAY, 1962
Range in p.p.m.
No. of Mean Sampling Station samples in p.p.m. Low High
surface stream. 5 . 10.4 8.1 11.5 seepage water " 4 s 11.4 11.3 11.8 cave stream ‘3 10 i 10.8 10.3 11.1; f 100 d passage poo 1 .1 5 7 J ' 10.0 8.2 11.09 #J
The determinations showed that during this six month period the cave stream maintained a fairly constant dissolved oxygen content, with a mean of 10.8 p.p.m. The oxygen content of the flood passage pool,
however, from a November low of 8.2 p.p.m., increased steadily through
the winter months. By March of 1962 this increase had leveled off at
a value nearly approximating that of the main cave stream. There was
a great decrease in the oxygen content of the surface stream during the
month it was analyzed -- from 11.5 p.p.m. to 8.1 p.p.m. The four
oxygen.content determinations made on the seepage water during April
and May revealed a consistently high value with a mean of 11.4 p.p.m.
FExnn an extrapolation of a single temperature reading made on May 5,
1962, this seepage water apparently was 100 per cent saturated.
From these two series of dissolved oxygen determinations, the folenving conclusions were drawn: The oxygen content of the surface stream water varied greatly during the Spring months depending upon rate of flow and agitation, temperature, and organic oxygen reduction- production relationships. This surface water, upon seeping through the soil, cooled, became 100 per cent saturated, and attained the 21
highest oxygen content observed during the determinations. Upon pene-
trating the limestone, the temperature of the seepage water gradually
approached 54.60 F., the temperature of the rock. The water remained
100 per cent saturated, and the oxygen content approached 10.8 p.p.m.
This dissolved oxygen level was maintained in the main cave stream the
year round. Because of the lack of photosynthesis, oxygen is supplied
to the cave water solely through interaction with the cave atmOSphere.
This source, however, was sufficient to maintain 100 per cent saturation
of the main cave stream water, because of the dearth of aquatic cave
fauna, suSpended organic matter, and other oxygen-consuming factors.
The pooled water of the flood passage, which was isolated for
several months during the dry summer of 1961, showed a steady decrease
in amount of dissolved oxygen. These pools were stagnant, and the oxygen,
supplied only by direct diffusion from the cave atmOSphere, apparently was not sufficient to balance the oxygen-depleting processes. At its
lowest level of 7.4 p.p.m., the oxygen content was still sufficient to meet normal biological requirements (Welch, 1952). During the winter months, with an increase of precipitation, the waters of the flood
passage were reconnected with the main cave stream; this brought about a gradual increase in the dissolved oxygen level of the flood passage water.
ALKALINITY
Determination of alkalinity was by titration with sulfuric acid,
'with Methyl Orange and phenolphthalein being indicators. During
.August and September of 196l,‘alka1inity determinations were run con- currently with the dissolved oxygen determinations. The same three 22 sampling stations were used: 1) riffle of cave stream, 2) largest pool of cave stream, and 3) pool of flood passage. The complete results are given in Figure 11, and a summary in Table 3 below.
TABLE 3 COMPARISON OF TOTAL ALKALINITY FROM THREE LOCATIONS IN THE CAVE STREAM, FROM AUGUST 17 TO SEPTEMBER 25, 1961
Range in p.p.m.
No. of Mean Sampling Station samples in p.p.m. Low High
stream riffle 20 179 174 186
stream pool 20 177 172 184 i flood passage pool 20 115 110 140
At no time was phenolphthalein alkalinity observed. The Methyl
Orange alkalinity ran fairly high, especially in the main stream.
The relationship between rainfall and alkalinity of the cave water was not made clear from these determinations.
A second series of alkalinity determinations was conducted from
November 22, 1961 to May 12, 1962, concurrently with the dissolved oxygen determinations. There were four sampling stations: 1) cave stream riffle, 2) pool of flood passage, 3) surface stream riffle, and
4) a rivulet of seepage water penetrating a fissure in the limestone.
The complete results are given in Figure 12, and a summary in
Table 4 below.
The values indicate an increase in alkalinity as surface water seeped down to the cave stream. The stagnant water of the flood passage maintained an alkalinity level lower than that of the main cave stream. Figure 11.-Comparison of total alkalinity from three locations in the cave stream, from August 17 to September 25, 1961.
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‘bm .03 . 11 \ 3 ‘ .02 Figure 1 "PSepte'IhISerAIr .18 If 30 q{ A) \ 28 I POOL .01 26 ) L .35 24 .}p , .09 ° Li 1—1 22 E 8 1 Q4 J 20 .08 IFFL °\\ STREAM R r 18 0/ . Aughst 1 .13 l 190 180"- 1704 160-0- 150- 140~r 130‘ 1204 110-» 'N'd'd NI ALINITVXTV TVIOI uAIE inches , in Freelpitation from 1962. May, alkalinity to total 1961, of November, from 12.-Comparison Figure locations, four 170 «L ' 150«- “ Monthly Ar ° “ Precipitation 130 «L- SHHONI 'W'J'd Cave Streao ° #- 0 Riffle ’0 I o 110 1" ‘\ NI NI NOIIVLIJIOHHJ AIINITVNTV 90 Entering Limestone N J 30 k Surface Stream .1- Riffle ’,.—O 10 . L q V, ,,£* ., 4 l 1 L 1 ‘_ T r r DATE NOVEMBER DECEMBER JANUARY 'ITFEBRUARY MARCH APRIL MAY Figure 12 25 IFigure 11 shows that there was a gradual decline in alkalinity in both the cave stream and flood passage water from November to March. llue alkalinity increased at all four sampling stations from March to May. An inverse correlation between precipitation and alkalinity is evident. TABLE 4 COMPARISON OF TOTAL ALKALINITY FROM FOUR LOCATIONS, FROM NOVEMBER, 1961, TO MAY, 1962 Range in p.p.m. No. of Mean Sampling Station samples in p.p.m. Low High surface stream. 5 14 8 21 seepage water 4 50 43 60 cave stream 10 114 73 165 flood passage pool 8 93 72 118 From these two series of alkalinity determinations, the following conclusions were drawn: Surface water, initially low in alkalinity, seeped downward through soil and limestone to the cave stream. In this downward passage, the alkalinity of the seepage water gradually in- creased. This was brought about by a chemical reaction -— carbonic acid in the water combined with calcium carbonate to form soluble calcium bicarbonate (Folsom, 1956). This calcium bicarbonate was chiefly responsible for the alkalinity of the water. This chemical process was more effective during periods of little precipitation, when seepage proceeded at a slower rate. Thus, the cave waters were most alkaline during the dry summer of 1961, and became less alkaline during the heavy precipitation of the early months of 1962. 26 The water of the flood passage decreased in alkalinity upon isolation from the main cave stream. This was apparently caused by a shift in the chemical equilibrium of the stagnant water -- the calcium bicarbonate disassociated into insoluble calcium carbonate and carbon dioxide gas. This precipitated calcium carbonate has formed a thick bottom sediment in all the cave pools. PART IV BIOLOGICAL FEATURES 28 TERRESTRIAL ANIMALS Terrestrial and aerial collections were made in the flood and main stream passages. Mud banks and boulders are the usual substrate, and the atmosphere is very humid. In comparison with Banta's (1907) study of Mayfield Cave, there seemed to be a paucity of terrestrial organisms in Sullivan Cave. This result is partly explained by less intensive collections, but the principle factor is that Mayfield Cave is small and in intimate communication with the surface, permitting many trogloxenic animals to stray into the cave. Most of the animals ' found in Sullivan Cave were either troglophilic or troglobitic; in general, they were not unusual, being common to most of the caves of southern Indiana. Some animals worth noting are the following: Caddis-Flies The caddis-fly, Polycentropus sp., was frequently seen crawling over the mud banks bordering the stream. They have not been described‘ from other caves. Cave Beetles The cave beetle, Pseudanophthalmus shilohensis, was found. The Speciation.of this genus has been intensively studied by many investi- gators. The.re1atedness of forms endemic to a drainage system is most readily accounted for by diSpersal along stream valleys (Krekeler, 1958). The distribution patterns of the Species of group shilohensis is exceptional. These very closely related Species, separated from one another overland by seven to thirty miles, are separated by quite large distances as measured along stream courses -- from 60 to 160 miles. Krekeler (1958) prOposed three possibilities to eXplain this 29 distribution: 1) disPersal through channels not parallel to surface drainage, 2) di8persa1 overland across divides during the Pleistocene glaciation, and 3) diSpersal along ancient river valleys. Figure 13 below shows the Spatial relationship of the Sullivan Cave anophthalmid to others of the area. 1 C . 2 :4 LL] ,. s. 3 £0 E a Q‘s“ "' 4 R O o 5 O 7 00° 6 1.0%“2 “1 VER ‘ R 1. group shilohensis; P. shilohensis boonensis; Boone Cave 2. group shilohensis; P. shilohensis mayfieldensis; Mayfield Cave 3. group shilohensis; _P. shilohensis _; Sullivan Cave 4. group shilohensis; _P. shilohensis shilohensis; Shiloh Cave 5. group emersoni; P. emersoni; Donnehue's Cave 6. group eremita; P. jeanneli; Elrod's Cave 7. group eremita; _P. morrisoni; Donaldson Cave 8. group youngi; _P. youngi; Donaldson Cave Figure l3.--Distribution of regional anOphthalmid cave beetles, of the genus Pseudanophthalmus. (Modified from Krekeler, 1958) 30 Frogs Rana pipiens was seen on two occasions. One Specimen was near thetfifiral Room, and probably had recently strayed from the outside. A.second Specimen was found in the flood passage near the Mbuntain Room, nearly a half mile from the nearest entrance. This Specimen was pale and emaciated. These frogs apparently do not lead a functional life in the cave, and it is interesting how far within the cave they can stray. Bats Bats were frequent inhabitants of the stream passages. On one occasion a group of twenty—five bats was seen hanging on a wall directly over the stream. -Bat guano falling into the water is an important source of food for the aquatic organisms. Collembola Four Species of Collembola occurred in the cave. Dr. Christiansen, in a personal communication, said that ArrhOpalites whitesidei, which was found in the cave, represented the first cave record of this Species from Indiana. Swarms of Collembola were often seen on the surface of the flood passage pools. This neustonic habit of Collembola provides a constant source of food for the aquatic organisms. AQUATIC ORGANISMS Tina Sculpin, Cottus bairdi, was the principal fish of the cave. They were frequently seen in the pools of the flood passage and in the cave stream below the waterfall. On May 12, 1962, in the waterfall 31 pool, seven sculpins were seen lying within one square meter of sub- strate. They were less frequent in the cave stream above the waterfall, which apparently was a barrier to their migration. Blatchley (1938), identifying this fish as Cottus ictalogs, stated that "it was fre- quently found in streams issuing from caves, and even at some distance within caves, where there is little or no light." In the Sullivan Cave stream these fish were abundant 2000 feet within the cave. Blatchley's (1938) observations, coupled with the abundance, of sculpins deep within Sullivan Cave, seemed to suggest that Cottus bairdi was a troglophilic animal, able to maintain itself in the cave environment, and not just an accidental stray from surface streams. This assumption was weakened by three facts: 1) no Sculpin fry were observed in the cave or caught in the drift net, 2) dead sculpins were occasionally observed in the cave stream, and 3) a histological examina- tion of the eyes and Optic nerves of a cave Sculpin revealed no observ- able degeneration. To clarify this question the stomachs of a few cave sculpins, taken 'both alive and dead during August of 1961, were analyzed for food content. The results are given in Table 5 below. These results indicate that the cave sculpins were capable of finding food. The stomach of Sculpin no. 4 contained .15 c.c. of food; this was a remarkable quantity, considering that the average volume of daily drift material was only .7 ml. in the 300,000-gallon daily dis- charge of the stream. _ No parasites of the gills, liver, or alimentary tract were found in the five dissected sculpins. The cause of death of sculpins 4 and 5 is unknown. 32 TABLE 5 FOOD CONTENT OF SCULPIN STOMACHS Food Content Sculpin Condition no. at capture Stomach Intestines l alive none . none , I 2 ; alive 2 isopods 1/4 full 5 3 alive 1 collembola ' 1 mayfly nymph 3/4 full t 4 dead 2 mayfly nymphs i 1 caddis-fly adult none ; 15 iSOpods i 5 dead none none From these observations, it is concluded that Cottus bairdi is a troglophile, leading an active life in the cave. The sedentary habits of this fish have pre-adapted it to the cave environment; an actively swimming fish would require more food and blunder blindly into objects. The scalelessness of sculpins also seems to have pre—adapted them to the cave environment since Norman (1926) stated that cave fishes are commonly derived from families in which the scales are reduced or absent. Sunfish, suckers, and minnows were other fish occasionally observed in the cave stream. Most seemed emaciated and pale, and probably were accidental strays from the surface stream. A female sunfish found in the cave stream in September of 1961 was examined. The oviducts contained many eggs, but their state of maturity was not determined. A single isopod was the only food found in its alimentary tract, although many parasitic nematodes were present. These facts 33 suggest that this sunfish was capable of finding some food and remaining somewhat functional . Crayfish (kronectes pellucidus, the cave crayfish, and Cambarus bartoni 1aevis were both prominent inhabitants of the cave stream. Eberly (1960) observed that these two crayfish commonly coexist in southern Indiana caves. He stated that they are ecological equivalents, coming into direct competition over food, which is usually the cave iSOpod, Caecidotea Sp. Cambarus bartoni 1aevis is only slightly modified for the cave environment. It is considered to be a subSpecies of a common epigean crayfish, Cambarus bartoni. This crayfish was frequent in the surface stream issuing from the cave, and its migration into and from the cave was likely. On one occasion two crayfish were observed crawling out of the surface stream. These crayfish proceeded to climb four feet up a vertical bank to the source of a Spring. Such rheotaxic behavior is probably re3ponsib1e for pOpulating the cave stream.with many animals that are normally epigean. The migrating characteristic of Cambarus bartoni was also observed in the cave; while the study of drift matter was being conducted, Cambarus bartoni would frequently enter the collect- ing net. Orconectus pellucidus was never observed to do so. The smaller pools of the flood passage were commonly inhabited by only a single individual Cambarus bartoni, due to their cannibalistic, aggressive nature. Orconectus pellucidus, a smaller more delicate cray- fish, was relegated to cobble-strewn portions of the cave stream, where it could escape from the larger Cambarus crayfish. Cambarus bartoni 34 was infested with Branchiobdellidae ectoparasites. Aquatic Insects The collection of aquatic insects of Sullivan Cave was probably the most fruitful and original part of this study. Trichoptera, EphemerOptera, PlecOptera, Diptera, MegaloPtera, and the aquatic beetle, Helichus Sp., were found. With the possible exception of certain Diptera, none of these are mentioned in the principal lists of cave animals -- Chappuis (1927), Banta (1907), Packard (1886), or Nicholas (1960). Whether other cave investigators have neglected this area of study, or whether Sullivan Cave is unique, is uncertain. PlecOptera Acroneuria Sp. nymphs occurred in the main cave stream. They also were found in the seepage water entering the limestone. The Perlidae are carnivorous and feed on other aquatic insects, including mayfly nymphs and Diptera larvae (Pennak, 1953). Ephemeroptera ParaleptOphlebia Sp. nymphs were the most common aquatic organisms. They were observed during the entire study, from August, 1961 to May, 1962. They were abundant in the stream and were occasionally taken from the flood passage. Their occurrence and abundance in the cave seems unusual, since mayfly nymphs are almost entirely herbivorous (Pennak,l953). Adults were collected in the drift net, but were not observed during collection of terrestrial animals. Other Baetidae larvae were caught in the drift net, but were few in number. Megaloptera A single Specimen of Corydalus Sp. was found in seepage water 35 near the entrance to the upper cave. Its proximity to the entrance might signify that it was a stray from the outside. Trichoptera Polycentropus Sp. larvae were found living in the cave stream, and adults were frequently seen on the mud banks bordering the stream. The presence of all life stages indicated that this animal was a func- tional member of the permanent cave pOpulation. Ross (1944) found Polycentropus pentus in a surface stream emerging from a Spring at Utica, Illinois, but he did not investigate the Spring itself. A single Rhyacophila sp. adult was taken, but its larval stage was never taken in drift samples or observed living in the stream. The adult Specimen was picked up by the drift net and possibly washed into the cave from the surface. Rhyacgphila was reported by Ross (1944) as frequenting Illinois streams which were temporary, but which were rapid and clear when running. This description fits the surface Streams of the cave ridge. RhyacOphilidae larvae are also found as glacial relics in cold springs (Edmondson, 1959). Pennak (1953) stated that "caddis larvae are chiefly omnivorous, (but) the genus Rhyacophila and some Psychomyiidae, on the other hand, are thought to be generally carnivorous. Animal food consists of small crustaceans, annelids, and insect larvae." This characteristic would prediSpose these caddis-flies to a cave existence. Diptera Many Species were found; they were members of the families Psychodidae, Simuliidae, Ceratopogonidae, and Tendipedidae. Species of the Tendipedidae occurred in all three major cave environments -- main stream, flood passage, and seepage water. Chironomus sp. and 36 Psychoda Sp. adults were members of the terrestrial and aerial cave pOpulation. Coleoptera Helichus Sp. occurred in the drift biota. Pennak (1953) reported that dryOpids feed on the algal film of the stream substrate. Either this cave dryOpid was carried regularly into the cave, or its feeding habits had been greatly modified. Benthic and Planktonic Organisms Crustacea Six Species of c0pepods were found; five Species were cyclopoid and one was harpacticoid. All were Species common to surface streams of the area. They were very abundant, and many were observed carrying egg sacs. Seepage water contained only the harpacticoid copepod, Canthocamptus Sp., while the pools of the flood passage contained both forms. All copepod Species were found in the main Stream. None of the cave c0pepods were infested with the algal ecto- parasite, Characium Sp., which was commonly found on c0pepods of over- lying surface streams. Infested copepods from surface streams were placed in the cave for six days. After this length of time, the c0pepods were Still covered with the ectOparasite. This eXperiment seemed to indicate that the cave c0pepods, although the same as surface Species, had not been recently derived from them. Cypria Spp. were common in the seepage water, flood passage pools, and main stream. The cave amphipod, Crangonyx gracilis, was common. This troglobite is common to many southern Indiana caves. 37 The cave isopod, Caecidotea stygia, was abundant. As in Crangonyg, it is highly modified for the cave existence, being eyeless and white. It is an important source of food for the fish and crayfish of the cave. Caecidotea was common in all parts of the stream having a pebbly or cobble-strewn substrate and was even present in the seepage water entering the limestone. Cladocera were not found in the cave. This was unusual, Scott (1909) having found five genera in Donaldson's Cave. Rotifers The rotifer pOpulation of the cave stream was qualitatively rich; fifteen genera were identified. Only eight genera of rotifers were described from Donaldson Cave (Scott, 1909), and none were found in Mammoth Cave (Kofoid, 1899). Of the fifteen described genera, thirteen were present in the main cave stream. The pools of the flood passage contained a more meager rotifer pOpulation -- Keratella quadrata, Polyarthra Sp., Rotaria Sp., and Macrotrachela Sp. The seepage water entering the limestone contained only Habrotrocha Sp. and Macrotrachela Sp. Scott (1909) Stated the opinion that loricate rotifers were more suited to the cave environment than illoricate forms. This did not seem to be particularly true of Sullivan Cave; Six genera were loricate and nine were illoricate. Nematodes and Annelids Several Species of nematodes were common in all the aquatic environments of the cave. Only Criconema Sp., from the flood passage pools, was identified. Annelids of the family Naididae occurred occasionally in the main 38 stream and were fairly abundant in seepage water. Branchiobdellidae were very abundant on the crayfish, Cambarus bartoni. Hydracarina Halacaridae, Feltria Sp., and Aturus Sp. were found. Aturus was described as commonly inhabiting mountain streams (Edmondson, 1959), but the cave stream, in such reSpectS as temperature and water quality, is ecologically very similar to mountain streams. Planaria The troglobite, Phagocata subterranea, occurred in the main cave Stream, but not in the pools of the flood passage. It was restricted to portions of the Stream having a loose, pebbly substrate. It also seemed to have stringent current requirements, and did not live in still water or swift rapids, but only in moderate riffles. In 1959, 50 individuals of Dugesia tigrina, an epigean Species, were accidently introduced into the cave stream. None were found during the course of the present study and they apparently failed to become established. Protozoa Water from the main cave stream, flood passage pools, and seepage water entering the limestone was cultured. Many Protozoa, eSpecially ciliates, were observed. Vorticella Sp., Halteria Sp., Cyclidium Sp., and Glaucoma Sp. were identified. Kofoid (1899) re- ported Amoeba Sp., Difflugia Sp., and Centropyxis Sp. from Mammoth Cave. Scott (1909), likewise, reported two Sarcodina, Arcella Sp. and Difflugia Sp. Sarcodina, which were the principal protozoans of both Mammoth and Donaldson Cave, were not observed in Sullivan Cave. 39 flair-1 Although algae were not functional members of the cave pOpulation, they were occasionally taken from the flood passage pools and the main stream. Diatoms, Pandorina Sp. and Closterium Sp. were taken from the cave stream in viable condition. Diatoms, Ceratium Sp., and Stigeoclonium sp. were taken from the pools of the flood passage, but were in a non-functional state. No algae were found in the seepage water. Scott (1909) reported 16 genera of algae from Donaldson Cave. This abundance of algae was probably due to the fact that the Donaldson Cave Stream flows On the surface at two points because of collapsed ceilings. QUANTITATIVE ASPECTS Drift Material of Cave Stream During August and September of 1961, there was very little precip- itation. The flow of the main cave stream was reduced to 3.5 gallons per second during this dry period. This reduced rate, however, seemed very stable and was maintained by seepage water even during extended droughts. While the stream flow was reduced, it was possible to place a plankton net (75 meshes per inch) in such a position as to intercept the total water flow (see Fig. 6). The drift net was usually placed in the stream for a 24 hour period. Fourteen samples were taken from August 17 to September 23, but only five were judged to be representa- tive; many samples were destroyed by Cambarus bartoni entering the drift net. Table 6 on the following page gives the summarized results. 40 TABLE 6 DRIFT NET RESULTS OF FIVE 24-HOUR SAMPLES TAKEN AUGUST 29-SEPTEMBER 22, 1961 Mean Variation Total Volume No. Per per Total No. ' Collected Organism Sample Sample Collected in ml. ARTHROPODA Insecta: Collembola f ; Arrhopalites 47.2 3 30-72 236 1 .03 others 29.0 i 16-51 145 ‘ .02 PlecOptera nymphs 1.2 0-3 6 , .01 Ephemeroptera Paraleptophlebia , 5 adults .6 0-2 3 I 05 i nymphs 65.6 16-120 328 ‘ 3 E others 1.8 1-4 01 TrichOptera larvae 1.6 0-3 8 -— ColeOptera Helichus 6 0-1 3 .08 Carabidae larvae 6 0-2 3 -- Diptera adults 31.4 19-60 157 .2 larvae and pupae 13 9-21 65 .03 Arachnoidea: Hydracarina 1.2 0-3 6 -- Acarina Rhagida 10 5-15 50 -- others 3 1-5 15 -- Araneida 1.8 0-5 9 .01 Diplopoda: .2 0-1 1 -- Crustacea: Eucopepoda 333.8 196-523 1669 E .1 PodOCOpa 9 1-37 45 i -- ISOpoda 20.8 11-28 104 ' .2 Amphipoda 10.4 2-14 52 .3 PLATYHELMINTHES 1.4 1-3 7 .02 41 TABLE 6.--Continued Mean Variation Total Volume Vol. Per per of material Material Sample Sample in ml. Insect Exuviae -- -- .01 Guano . .02 0-.05 .1 Wood .1 .02-.3 .5 Debris .3 .2-.6 1.5 3.4 total drift in m1. The total volume of drift material for five days was 3.4 m1. From this Study and a rough estimation of stream flow, it was calculated that only .7 m1. of drift matter was carried in the 300,000-gallon daily discharge of the Stream. These figures apply only to this drought period. It would have been interesting to determine the volume of drift during the Spring floods, but no satisfactory sampling method was worked out. Figure 14 on the following page shows the proportions of various components of the drift and demonstrates that almost half of the drift volume was composed of debris. This classification included fragmented plant parts, invertebrate eggs, insect exuviae, and fibers of wool or cotton. These fibers, which made up the great bulk of drift material, were apparently from a man-made article. An attempt to judge the prOportion of drift material derived directly from the surface was futile. Even the source of wood was questionable because human visitors have tranSported many wooden objects into the cave. Guano, if it was derived from the bats, was material brought in from the outside. There is a possibility, however, that the guano came from cave mice, in which case it would be derived from within the cave. 42 AQUATIC FAUNA 29 . 47. TERRESTRIAL (“Hr-1‘35; FAUNA 8.8% DEBRIS GUANO 3% 44.1% Figure l4.--Proportions of various components of the drift. Quantitative Aspects of the Flood Passage Pools A flood passage pool was investigated on September 7, 1961. During wet seasons this pool is contiguous with adjacent pools and is 9 square meters in area. At the time of analysis, during the dry season, the pool was isolated and only 1.5 square meters in area, and a week later this pool had dried up completely. Table 7 below gives the macroscopic animals found. 43 TABLE 7 QUANTITATIVE ANALYSIS OF BENTHIC ORGANISMS OF FLOOD PASSAGE POOL Organism Number Volume in m1. Caecidotea stygia (isopod) 115 .6 Crangonyx gracilis (amphipod) 75 .4 ' ' Pentaneura larvae (Diptera) 28 .07 ”1:07 total .—u-n-_-m m— On two occasions during the Spring of 1962 the larger permanent _ WWI—‘3' 'Mee, pools of the flood passage were also investigated. Five hundred gallons 2’3. of pool water were strained through a plankton net having 190 meshes per inch. The results are given in Table 8. TABLE 8 QUANTITATIVE ANALYSIS OF PLANKTON OF FLOOD PASSAGE POOL 500 Gallons of Water Sampled Organism April 17 May 12 Cyclopoid c0pepods 8 6 Copepod nauplii 142 26 ROTATORIA Polyarthra Sp 8 0 Keratella guadrata 0 1 1 Rotaria sp. 0 l Macrotrachela Sp. 2 3 0 NEMATODA Criconema Sp. ‘ l L 0 other i 0 ‘ l ALGAE J Ceratium Sp. 1 0 Stigeoclonium Sp. 3 0 Diatoms many many plant debris none some 44 Both analyses, eSpecially the plankton study, showed a paucity of pool life. The figures of Table 7 are probably misleading, since the animals of the pool had been concentrated by the shrinking dimensions of the pool. Quantitative Aspects of the Segpage Water The seepage water, at the point where it first penetrated a fracture in the limestone (Fig. 1, 7), was strained through a plankton net having 190 meshes per inch. The rivulet of seepage water flowed at a rate of .67.8 gallons per minute. Table 9 below shows the sampling results for three separate days in the Spring of 1962. TABLE 9 QUANTITATIVE ANALYSIS OF SEEPAGE WATER Date and Volume Sampled _ April 12 April 17 1 May 11 Organism 850 gallons 1000 gallons 1 700 gallons NEMATODA 11 2 20 ANNELIDA A Lumbricidae 0 0 l l Naididae 1 2 3 Macrotrachela rotifer 0 l i 4 Crustacea: 1 Harpacticoid copepods 23 i 24 i ll Copepod nauplii 28 22 § 2 Ostracods 8 7 i 3 ISOpods 2 ‘ 2 E 3 Hydracarina 7 6 E 4 Insecta: i Plecoptera nymphs l 3 , 1 Diptera larvae 8 5 g 12 Collembola l l g 0 plant debris some some L some 45 The organisms of the seepage water seemed to be mostly bottom- living forms. Planktonic rotifers and copepods were entirely lacking. Unfortunately, no direct comparison with the drift material of the main stream can be made, because the sampling nets were of dif- ferent mesh sizes and the experiments were conducted seven months apart. SEASONAL CHANGES .2 The constancy of the cave environment has been stressed by other investigators. The darkness, temperature, and high relative humidity 'J of the cave atmosPhere are factors which are indeed highly invariable, making the terrestrial environment very stable. The aquatic environ- ment, however, is subject to changeable conditions. Stream discharge, water chemistry, drift material, and aquatic organisms are factors which are modified by surface conditions. Thus, an annual cycle is imposed upon the subterranean stream. Stream Dischargg The volume of stream flow was found to vary greatly. In the late summer of 1961, the stream flow was reduced to a low of 3.5 gallons per second, but during the Spring of 1962 it had increased over three hundred—fold, to greater than 1000 gallons per second. The discharge of the subterranean Stream was dependent upon precipitation at the surface, although the correlation was not always prOportional, eSpecially during the warmer months when the surface ‘vegetation took up a great portion of any rainfall. This was observed during the dry period of the summer of 1961; on the few occasions of 'rainfall the flow of the cave stream did not measurably increase. 46 The flood passage was subjected to extreme conditions of alternate flood and stagnation. This branch of the cave Stream occasionally flooded to the very ceiling, but this was only a short-lived condition. Usually there was no current, and the water formed stagnant, limpid pools. During prolonged isolation the water of these pools evaporated, but this was a slow process because the humidity of the cave atmoSphere ‘U was nearly 100 per cent. The isolation and shrinkage of pools imposed many hardships upon the aquatic fauna. They were isolated from an external food Supply, concentrated into a smaller volume of water, and I . ’ a _ subjected to changing water chemistry. These pools are probably never a!- EV ‘ isolated for more than four months at a time. Hawes (1939) in an investigation of Balkan caves found crayfish and amphipods living in pools that had been isolated for an estimated eight months. Many of the pools in Sullivan Cave dried up completely, creating problems of migration or aestivation for the flood passage organisms. When these dry pool beds refilled with water, they were repopulated through migra- tion, tranSportation by water current, and hatching of eggs and resting stages. Moist gravel from a dried pool bed was flooded with water and observed daily. C0pepod nauplii appeared within 24 hours, but amphipods and isopods, the dominant pool animals, did not appear and apparently repOpulate pools by migration. Water Chemistry Alkalinity was found to have seasonal variation, decreasing during the winter months. The alkalinity of the subterranean Stream is throughly discussed in Part 1. Associated factors, such as pH and hardness, must also have varied, but no measurements were made. Dis— solved oxygen was found to have seasonal variation only in the waters V: "A l . . _é" '_1_r"'~ .-_$-’-:‘ ‘ l&‘ 47 of the flood passage -- the oxygen content decreased in the late summer when the waters of the flood passage were isolated from the main stream. Dissolved oxygen is also discussed in Part I. Drift Material When the Stream flow was 3.5 gallons per second, the average inorganic drift, composed of sand and silt, was only .1 ml. per day. The molar action of the stream increased greatly during flood, and suSpended particles could be felt by placing the bare hand in the swollen stream current. Flood also caused increased turbidity and surface foam. Aquatic Organisms Many organisms, such as crayfish, isopods, amphipods, mayfly nymphs, and caddis fly larvae, occurred the year round in the cave stream. This indicated that these organisms were permanent members of the cave community. Other members of the aquatic fauna, however, seemed to occur only seasonally, eSpecially during periods of flood. Simuliidae larvae occurred in drift samples only during the Spring floods. These larvae may be normal inhabitants of the cave stream the year round, only occurring in the flood drift because of their normally firm attachment to stationary objects. Needham (1930) found this to be true in a sur- face Stream near Ithaca, New York. Naididae oligochaetes also were present in the cave Stream only during the Spring floods, and nematodes were more numerous then. The cave rotifer pOpulation changed from day to day during the Spring; Species appeared and disappeared seemingly at random. 48 FOOD SOURCES The cave ecosystem is not self-sustaining since there is no photosynthesis. Because of this lack of producers, the cave community depends upon external food sources. The food of the aquatic cave fauna is derived from four primary sources: 1) drift material and plankton from overlying surface water, 2) members of the terrestrial cave fauna, . 3) organic material brought in by bats and humans, and 4) epigean animals migrating upstream into the cave. faiwn' ‘ Drift Material sin-2.. \‘n "u. Water washing into the cave is well-Strained by the soil, and the largest drift object found was a woody stem having a volume of only .2 m1. Nevertheless, an investigation of stream drift demonstrated that Small fragments of wood, leaves and stems, and other debris made up almost 60 per cent of the total drift volume. The troglobitic planaria, isopods, and amphipods, feeding upon this debris, form the lowest trophic level of the permanent aquatic cave fauna. Plankton Source of the Cave Plankton Scott (1909) found that the plankters of Shawnee Cave were epigean forms derived directly from Surface sources. Although this conclusion is not questioned, the present study of Sullivan Cave did not wholly support this viewpoint. Examination of overlying surface waters in the Spring of 1962 revealed many organisms which did not occur in the drift of the cave stream -- the tardigrade, Hypsibius, the gastrotrich, Chaetonotus, and many algae, protozoa, and rotifers. The algal genera, Pediastrum, Nostoc, Zygnema, Cosmarium and Gonatogygon, 49 and the protozoan genera, Actinosghaerium, Stentor, Chilodonella, Stylonychia and Arcella, were common in surface waters; but they were not found in cave waters. The relationship between surface and cave rotifer pOpulations was eSpecially confusing. Only the genera Polyarthra and Sygchaeta were found in the surface farm pond. These genera also occurred in the cave, but the cave Synchaeta seemed to be a different Species, or at least much smaller than the surface form. mm The rotifers, Colurella and Adineta, were present in surface Streams, but not in the cave. With the exception of bdelloids, none of the -~m:n'3 h-AA _ .genera of cave rotifers occurred in surface streams, and seepage water an- \ .. 1“ entering the limestone contained only bdelloid rotifers. This seeming lack of relationship between surface and cave plankton is not understood. It might be explained by cave-contributing surface waters that differed markedly from those examined. Selective destruction of many planktonic Species in the cave environment might also have greatly modified its character. Feeding and Reproduction of the Cave Plankton The alimentary tracts of the copepods usually contained some food, and most of the plankters were in an active condition. Eggs were common in the ovisacs of the c0pepods and upon the rotifer, Keratella cochlearis. Copepod nauplii were abundant in all the aquatic environments of the cave. These observations demonstrated that some of the plankters were able to continue their nutritive and reproductive processes under cave conditions. Fate of Cave Plankton Scott (1909) maintained that the cave plankton does not form a part of the permanent cave fauna because the stream current in its 50 higher Stages is powerful enough to carry out of the cave all forms that are not strong swimmers. This conclusion was supported in the study of Sullivan Cave, where all the planktonic forms found in the cave waters were also found in the water issuing from the cave. Terrestrial Cave Fauna F’s: Analysis of drift material during the period of drought demon- strated that members of the terrestrial cave population were an impor- tant food source, making up almost 9 per cent of the organic drift. n— It would seem that the terrestrial fauna would be an even more important 1* m food source during periods of flood, when these organisms would be 1:112: more apt to be accidentally swept into the cave Stream. Humans and Bats Humans are becoming increasingly important as an agent for trans- porting food into the cave. Wood, paper, cans, food, excreta, and other items are left in the cave, much of which can be utilized as food. This food source has become the dominant one for the cave organisms. Bats, which rely on food they obtain outside the cave, are fre- quent inhabitants of the cave stream passages. DrOppings from these bats are a significant source of food, and composed 3 per cent by volume of the total drift material analyzed during the summer of 1961. Epigean Animals Many fish, frogs and crayfish, normally inhabitants of the surface stream which issues from the cave, migrate upstream and enter the cave itself. Some of these animals, such as the crayfish, Cambarus bartoni, and the Sculpin, Cottus bairdi, are able to function effectively under 51 cave conditions and form the highest trephic level of the cave Stream. Other animals, such as frogs, sunfish, suckers, and minnows, are unable to live actively in the cave and soon die, contributing organic material to the cave stream ecosystem. THE INFLUENCE OF HUMAN VISITORS Since 1957, the cave stream passages have been affected by a new factor -- the human visitor. The changes brought about can not be overestimated. ‘ 1 Human visitors have greatly increased the food supply of the cave. I 4.“: Since the food supply is the limiting factor for many of the cave inhabitants, this increase has undoubtedly modified the populations of many Species. Humans also have an adverse effect on the cave organisms. Many cave explorers use carbide lamps. The residue of calcium hydroxide from these lamps is often left in the caves. It is doubtful if this residue harms the terrestrial organisms and it eventually combines with carbon dioxide to form.water and calcium carbonate (Sisler g£_g1., 1949). In the cave stream, however, this residue, which has a low solubility, forms a suSpension known as "milk of lime". In this form the residue is diSpersed, forming an eSpecially thick layer next to the substrate. A limited experiment was conducted using the cave isopod, Caecidotea stygia, the most Common bottom-living animal of the cave. Isopods were subjected to different concentrations of the residue under cave conditions. Concentrations as low as .2 grams of residue in 300 c.c. of water per 20 square inches of substrate would kill the iSOpods within ten hours. The effect: of lower concentrations was not determined. SUMMARY The stream passages of Sullivan Cave were Studied from August, 1961, to May, 1962. - '1 The dissolved oxygen content of the cave water was found to be sufficient for normal biological requirements. In most cases these oxygen values indicated 100 per cent saturation. The alkalinity of the cave water was found to increase as it seeped downward. From sur- face water to main cave Stream, the alkalinity ranged from 14 p.p.m. to 114 p.p.m. No phenolphthalein alkalinity was observed. The terrestrial cave animals collected were, in general, Species common to many other caves of southern Indiana. The aquatic fauna was more unusual. Many aquatic insects were found that are not listed in the principle biOSpeleological literature. The plankton of the cave water was qualitatively rich in rotifers, but completely lacked Cladocera and Sarcodina. Cottus bairdi was the most common fish, and apparently is a functional member of the cave community. Ten phyla, 16 classes, 64 families, 71 genera, and 28 Species were represented. Of these, one group was keyed to phylum, one group to class, 12 groups to family, 44 to genus, and 28 identified to Species. This gives a total of 86 taxons represented in Sullivan Cave. Drift net investigations were conducted during the dry period of the summer of 1961. It was found that an average of only .7 m1. of drift material was carried in the 300,000-gallon daily discharge of the stream. 52 53 Quantitative Studies Of the seepage water penetrating a fissure in the limestone and of the water of flood passage pools demonstrated the great dearth of aquatic cave life. The fauna of the seepage water seemed to be limited to those forms that had well-developed clinging habits. Seasonal changes on the surface affected the cave stream and its inhabitants. Stream discharge, water chemistry, drift material and aquatic organisms were found to have seasonal variation. Food for the aquatic cave organisms was derived from the following sources: 1) plankton and drift material from overlying sur- face waters, 2) members of the terrestrial'cave fauna, 3) organic material brought in by bats and humans, and 4) epigean animals migrating upstream into the cave. During the course of this investigation it was observed that humans have greatly modified the cave environment and its fauna. The large amount of food materials tranSported into the cave by Spelunkers has been beneficial to the cave community, while the residue from carbide lamps has had a deleterious effect upon the aquatic fauna. SPECIES LIST Each lowest taxon is followed by a code. = terrestrial organism ___7 aquatic organism .m.-2}“ ’- II found in main cave stream found in flood passage pools = found in seepage water entering OJKJP‘P'H limestone ham] '- g ,.::-.-'9-v_- 1 ‘mg PLANT KINGDOM I! DIVISION ChlorOphyta Class ChlorOphyceae Order Volvocales Family Volvocaceae Pandorina Sp.; A 1 Order Ulotrichales Family ChaetOphoraceae Stigeoclonium Sp.; A 2 Order Zygnematales Family Desmidiaceae Closterium Sp.; A 1 DIVISION Chrysophyta Class BacillariOphyceae; A l, 2 DIVISION Pyrrophyta Class Dinophyceae Order Peridiniales Family Ceratiaceae Ceratium Sp.; A 2 54 ”Pi.fl1wm§i. . .1111! I’ll-11.)." 1|, 1|! 55 ANIMAL KINGDOM PHYLUM Protozoa Class Ciliata Order Holotricha Family Frontoniidae Glaucoma Sp.; A 1, 2, 3 Family Pleuronematidae Cyclidium Sp.; A 1 Order Peritricha Family Vorticellidae Vorticella Sp.; A 1 Order Spirotricha Family Halteriidae Halteria Sp.; A l, 2 PHYLUM Platyhelminthes Class Turbellaria Order Tricladida Family Planariidae Phagocata subterranea Hyman; A l PHYLUM Rotatoria Class Digononta Order Bdelloidea Family Philodinidae Macrotrachela Sp.; A 1, 2, 3 Philodina Sp.; A 1 Rotaria Sp.; A 2 Family Habrotrochidae Habrotrocha Sp.; A 3 56 Class Monogononta Order FloSculariacea Family Filiniidae Filinia Sp.; A 1 Family Testudinellidae Testudinella Sp.; A 1 Order Ploima Family Notommatidae Dicranophorus Sp.; A 1 Encentrum Sp.; A 1 Family Synchaetidae Polyarthra Sp.; A 1, 2 Sygchaeta Sp.; A 1 Family Brachionidae Brachionus Sp.; A 1 Keratella cochlearis Grosse; A 1 Keratella quadrata Mfiller; A 2 Lophocharis Sp.; A 1 Notholca Sp.; A l Monostyla Sp.; A l PHYLUM.Nematoda; A l, 3 Class Phasmidia Order Rhabditida Family Criconematidae Criconema Sp.; A 2 PHYLUM Annelida Class Oligochaeta 57 Order Prosopora Family Branchiobdellidae; A l, 2 Order PlesiOpora Family Naididae; A 1, 3 Order Opisthopora Family Lumbricidae; T PHYLUM ArthrOpoda Class Crustacea Order PodOCOpa Family Cyprinidae Cypria turneri Hoff; A 1 Cypria Sp.; A 1 Order EucOpepoda Family Cyclopidae CyclOpS vernalis Fischer; A l Macrocyclops albidus Jurine; A l Eucyclops Speratus Lilljeborg; A l Eucyclops agilis Koch; A 1 Eucyclops montanus Brady; A 1 Family Canthocamptidae Canthocamptus Sp.; A 1, 2, 3 Order Isopoda Family Asellidae Caecidotea Stygia Packard; A l, 2, 3 Order Amphipoda Family Gammaridae Crangonyx gracilis Smith; A l, 2 58 Order Decapoda Family Astacidae Cambarus bartoni 1aevis Fabricius; A 1, 2 Orconectes pellucidus Tellkampf; A l, 2 Class Diplopoda Order ASCOSpermophora Family Conotylidae Conotyla bollmani McNeil; T Class Arachnoidea Order Hydracarina Family Halacaridae; A 1 Family Feltriidae Feltria Sp.; A 1 Family Axonopsidae Aturus Sp.; A 1 Order Acarina Family Rhagidiidae Rhagida cavicola Banks; T Family Oribatidae; T Family Cunaxidae; T Order Araneida Family Linyphiidae Linyphia subterranea Emerton; T Class Insecta Order Thysanura Family Campodeidae; T Order Collembola 59 Family Entomobryidae Isotomiella Sp.; T Sinella alata Christiansen; T Family Sminthuridae ArrhOpaliteS whitesidei Jacot; T I I] :’ Family Poduridae VI r. r Onychiurus Sp.; T Wfi-_'. f Order Ephemeroptera Family Baetidae n..- Paraleptophlebia Sp.; A l, 2 uflh‘_ Ameletus Sp.; A 1 Order Plec0ptera Family Perlidae Acroneuria Sp.; A 1, 3 Order Orthoptera Family Gryllacrididae Ceuthophilus stygius Scudder; T Order ColeOptera Family Carabidae Pseudanophthalmus shilohensis Krekeler; T Family Staphylinidae Quedius Sp.; T Family DryOpidae Helichus Sp.; A 1 Order MegaIOptera Family Corydalidae Corydalus Sp.; A 3 60 Order TrichOptera Family Psychomyiidae Polycentropus Sp.; T + A l Family RhyaCOphilidae RhyacOphila Sp.; T _ .m.-nu Order Diptera -‘.'. r- MD 1.1 Family Tipulidae; T Family Tendipedidae Polypedilum Sp.; A 1 h 11 Chironomus Sp.; T + A 1, 3 Pentaneura Sp.; A 2, 3 Paratendipes Sp.; A 1 Family Simuliidae; A 1 Family Psychodidae Psychoda cinerea Banks; T-+ A 1 Family CeratOpogonidae; A l Bezzia Spp.; A 1 Family Sciaridae Sciara Sp.; T Family Phoridae 22252.5P-3 T Family Heleomyzidae; T Family Borboridae; T PHYLUM Chordata Class Osteichthyes Order Cypriniformes Family Cyprinidae I13. clifgfrlnumvé . .. . I . .. 1...... i 1.1 61 Semotilus atromaculatus Mitch.; A l, 2 Family Catostomidae; A 1 Order Perciformes Family Centrarchidae Lepomis cyanellus Raf.; A 1 Family Cottidae Cottus bairdi Girard; A l, 2 Class Amphibia Order Salientia Family Ranidae Rana pipiens Schreber; A l, 2 Class Mammalia Order ChirOptera Family VeSpertilionidae Mygtis lucifugus Le Conte; T Order Rodentia Family Muridae Peromyscus leucOpus Raf.; T Order Primates Family Hominidae Homo sapiens L.; T LITERATURE CITED Anonymous. 1955. Standard methods for the examination of water, sewage and industrial wastes. Amer. Pub. Health Assoc., New York. I55 522 pp. 3 Banta, A. M. 1907. The fauna of Mayfield's Cave. Publ. Carnegie Inst. Wash. 67:1-114. L ‘v— Blatchley, W. S. 1938. The fishes of Indiana. The Nature Publ. Co., "Mn. Indianapolis. 121 pp. .r .1" 1 Chappuis, P. A. 1927. Die tierwelt der unterirdischen gewasser. ail-T Die Binnengewasser. 3:1-176. Eberly, W. R. 1960. Competition and evolution in cave crayfishes of southern Indiana. Systematic Zool. 9:29-32. Edmondson, W. T. (ed.). 1959. Fresh-water biology. John Wiley and Sons, Inc., New York. 1248 pp. Folsom, F. 1956. Exploring american caves. Crown Publ., Inc., New York. 280 pp. Greene, F. C. 1908. Caves and cave formations of the Mitchell Limestone. Ind. Acad. of Sci. Proc. 175-184. Hawes, R. S. 1939. The flood factor in the ecology of caves. Jour. Animal Ecol. 8:1-5. Kofoid, C. A. 1899. The plankton of Echo River, Mammoth Cave. Trans. of the Amer. Mic. Soc. 21:113-126. Krekeler, C. H. 1958. Speciation in cave beetles of the genus Pseudanophthalmus (ColeOptera, Carabidae). Amer. Midl. Nat. 59:167-189. Needham, P. R. 1930. Ecology of streams. Biol. Lab., L. 1. Biol. Assoc. 2:3-6. Nicholas, B. G. 1960. Checklist of macroscopic troglobitic organisms of the United States. Amer. Midl. Nat. 64:123-160. Norman, J. R. 1926. A new blind catfish from Trinidad, with a list of blind cave-fishes. Ann. Mag. Nat. Hist. Ser. 9. 18:324-331. Packard, A. S. 1886 (1888). The cave fauna of North America. Mem. Nat. Acad. Sci. 4. 156 pp. 62 63 Pennak, Robert. 1953. Fresh water invertebrates of the United States. Ronald Press, New York. 769 pp. Ross, H. H. 1944. The caddis flies of Illinois. Bull. Nat. Hist. Surv. Div. 23:1-326. Scott, W. 1909. An ecological study of the plankton of Shawnee Cave, with notes on the cave environment. Biol. Bull. 17:386-407. Sisler, H. H., C. A. Vander Werf, and A. W. Davidson. 1949. General chemistry: a systematic approach. The Macmillan Co. 870 pp. Welch, P. S. 1952. Limnology. McGraw-Hill, New York. 538 pp. f*fl~..‘y_l‘fl§‘l , "<3 '1‘! -I’ I.Ii\l 4'." .§" ' um U311 C3: £2.le ”711171171 11’: 1171111111; 11211111111 11'“