Hydrobiologia 218: 151-156, 1991. © 1991 Kluwer Academic Publishers. Printed in Belgium.
151
Aquatic hyphomycetes of a sulphur spring K. R. Chandrashekar, K. R. Sridhar & K. M. Kaveriappa Department of Biosciences, Mangalore University, Mangalagangotri,Mangalore - 574 199, India Received 5 January 1988; in revised form 3 October 1990; accepted 10 November 1990
Key words: aquatic hyphomycetes, sulphur spring, temperature
Abstract Aquatic hyphomycetes of a sulphur spring in the Western Ghat region of Karnataka were investigated by the following methods: leaf litter observations, water filtration, analysis of natural and induced foam. The samples were collected and studied from three sites, the spring proper (site I), the connecting region of the spring and the rivulet (site II) and the spot where the spring joins the rivulet (site III). The number of species of hyphomycetes encountered at the three sites were 1, 14 and 20, respectively. The sulphide content of the spring ranged between 0.1-3.1 mg 1- ' and the temperature between 26.5-36.5 C. In another experiment submerged coffee leaves from a fresh water stream were collected and incubated in spring water, stream water and well water at different temperatures (16-40 ° C). A maximum of 18 species of hyphomycetes sporulated at 22 C followed by 17 species at 28 ° C, irrespective of the source of water in which the leaves were incubated. Based on these studies, we conclude that the presence of only one species in the spring proper (site I) was not due to the higher sulphide content, but to the high temperature.
Introduction
Materials and methods
The aquatic hyphomycetes have been reported to occur in streams and rivers of different parts of the world (Ingold, 1975; Subramanian, 1971). These organisms live in fast flowing, well aerated streams where they colonise submerged leaves (Ingold, 1942). Most studies on the occurrence of these organisms have been confined to regions where the water temperature ranges between 0-25 C (Barlocher, 1982; Suberkropp & Klug, 1981). In recent years, these fungi have also been reported from tropical regions, where water temperature ranges between 20-29 °C (Padgett, 1976; Sridhar, 1984; Sridhar & Kaveriappa, 1984; Subramanian & Jayarama Bhat, 1981; Swart, 1986). This is the first investigation on the occurrence of hyphomycetes in a sulphur spring.
The spring 'Bendre Thirtha' originates in a place called Panaje and connects to a tributary of the river Nethravathi. It is surrounded by trees such as Banyan, Jack, Mango, Coconut and Areca. The water level of the spring is around two feet throughout the year. The materials for this study were collected from three sites: the spring proper (site I), the connecting region of the spring and the rivulet (site II) and the spot where the spring joins the rivulet (site III), (Fig. 1). Collections were made during December 1985, February and April 1986. The foam and water samples and submerged leaves from the three sites were collected in polythene bags. The materials were analysed in the laboratory for the presence of fungal conidia by
152
Fig. I. Map showing the location of sulphur spring along with the sampling sites.
four methods: Leaf litter analysis, Foam analysis, Water filtration and Foam induction (Sridhar & Kaveriappa, 1984; Chandrashekar et al., 1986). Temperature, pH, dissolved oxygen and sulphide of water from the three sites were analysed at the time of collection. To study the sporulation of hyphomycetes at different temperatures and in different sources of water, sulphur spring water and stream water was collected in plastic cans and stored in the laboratory. Submerged leaves of coffee were collected from the Sampaje stream as these leaves are reported to be colonized by different species of aquatic hyphomycetes (Sridhar, 1984). The waters from the sulphur spring, stream, and well
were filtered through millipore filters (Pore size, 0.45 pm diam) before use. Ten coffee leaves were cut into small pieces (1.5 x 3 cm) and transferred to three separate sets of 15 Petri dishes, containing the three types of water. While transferring the material, care was taken to see that all the three sets of Petri dishes received leaf sections from each leaf uniformly. The three Petri dishes from each set were incubated at 16, 22, 28, 34 and 40 C. On alternate days the Petri dishes were examined under a low power microscope for the development and sporulation of different species of hyphomycetes. After each observation the water in the Petri dishes was replaced. Observations were continued for 30 days and the various
153 Table 1. Aquatic hyphomycetes recorded from the sulphur spring Bendre Thirtha. Fungi
Sampling sites Site I Methods* 1
Site II
Site III
2
3
4
1
2
3
4
1
2
3
Alatospora acuminata Anguillospora longissima Anguillospora sp. Beltrania rhombica Camposporium pellucidum Flabellospora verticillata Flagellosporacurvula Flagellosporapenicillioides Helicosporium sp. Lunulospora curvula Lunulospora cymbiformis Phalangisporaconstricta Speiropsls pedatospora Tetraploa sp. Tetraploa aristata Tricladium brunneum Triscelophorus acuminatus Triscelophorus monosporus Triscelophorus sp. Wiesneriomyces javanicus
-
-
+ -
-
+ + + + + + +
+
-
-
+ +
+ + +
+ + +
-
-
-
-
-
+
+ +
+ +
+ +
+ +
-
-
-
-
-
+
+
+
+ +
-
+
-
+ + -
+ + +
+ + + + + + +
-
-
-
-
-
+
-
-
-
-
-
+
+ + +
+ + +
Total no. of species recorded under each method
0
0
1
0
5
9
11
Total no. of species recorded from each site * 1. 2. 3. 4.
leaf litter incubation foam induction foam analysis water filtration
1
-
-
-
-
+ + +
+ + +
+ + + -
13
6
8
14
4
+
+ + + + +
+ + +
+
-
+ +
+ + +
15
10
20
'+' present '-' absent
species of hyphomycetes appearing on the leaf sections of different Petri dishes were recorded.
Table 2. Temperature, pH, dissolved 02 and sulphide content of the sulphur spring at the three collection sites (average of three samples).
Results The aquatic hyphomycetes observed in the sulphur spring are listed in Table 1. F. penicillioides, and L. curvula were found with all four methods at site II and III. F. curvula, T. monosporus and Triseclophorus sp. were recorded in all the methods of observations only at site III. The data on temperature, pH, dissolved oxygen and sulphide concentration at the three sites are
Temperature (°C) pH Dissolved oxygen (mg Sulphide (mg 1 ')
')
Site I
Site II
Site III
36.5 5.9 3.2 3.1
35.5 6.1 3.8 1.2
26.5 7.3 8.2 0.1
given in Table 2. The data on the sporulation of hyphomycetes on coffee leaves in different types of water and at different temperatures are given in
154 Table 3. Sporulation of aquatic hyphomycetes on coffee leaves incubated in stream water, tap water and spring water at different temperatures. Fungi
Incubation
16
22
28
34
40
temperature (C)
Source of water* S Alatospora acuminata Anguillospora longissima Anguillospora sp. Flabellosporacrassa Flabellosporamultiradiata Flabellospora verticillata Flagellosporacurvula Flagellosporapenicillioides Helicosporium sp.1 Helicosporium sp.2 Isthmotricladialaeensis Lunulospora curvula Phalangisporaconstricta Speiropsis hyalospora Speiropsis pedatospora Tetraploa sp. Tetracladium sp. Triscelophorus acuminatus Triscelophorusmonosporus Triscelophorus sp. Wiesneriomyces javanicus *
Qfrem
+ + + + + + + +
T Well water B Sulphur spring water
B
S
T
-
+ -
+
+
-
-
+ + + + + +
+ + + + + + + +
+ + + + + + +
+ + + + + +
-
-+
+ + + + + +
+ + -+ + ++ +
-
+ '
*t-r
T
'-'
+
S
T
+ + + + +
+ + + + + + -
-++ + + + + + + +
+
+
B
-
S
T
B
S
T
-
-
-
B
-
+
-
+
+ + +
+ +
+ +
+
+ + + + +
+ + +
+ + +
+ +
' nrnt absent
Table 3. A. longissima, I. laeensis, S. hyalospora, Tetraploa sp. and Triscelophorus sp. were recorded on leaf sections incubated in well and stream water but not in spring water. On the other hand, A. acuminata and L. curvula which were recorded on leaf sections incubated in spring water were Table 4. The number of species encountered on submerged coffee leaves incubated at different temperatures. Source of water
B
Incubation temperature ( C)
Total number of species recorded
16
22
28
34
40
Stream Well Spring
8 8 10
15 12 8
11 15 9
2 2 1
-
Total number of species recorded
14
18
17
3
17 19 16
absent on leaf sections incubated in well and stream water. Within each type of water the number of species recorded varied with temperatures (Table 4). At 40 C no species were recorded. At 34 C only three species were found. At 28 °C and below many species of hyphomycetes were detected. The three species recorded at 34 °C were also found at lower temperatures.
Discussion A reference to the thermal spring 'Bendre Thirtha' was made as early as 1882 by Oldham (cf. Radhakrishna, 1971). Subsequently, Radhakrishna (1971) investigated some physical and chemical aspects of the spring water. Field & Webster (1985), found a tolerance limit of 5 mg 1- of sulphide for the growth of aquatic
155 hyphomycetes. In the present investigation, the sulphide content of the spring water recorded was not more than 3.1 mg 1- '. Therefore it is believed that the sulphide concentration of the spring was not high enough to produce any adverse effect on the fungi recorded in the three sites. Barlocher & Rosset (1981) in a comparison of their own results with those of Conway (1970), Willoughby & Archer (1973), Brlocher & Kendrick (1974) and Iqbal & Webster (1977) concluded that the number of fungal species occurring in a stream is a function of pH and forms a unimodal curve with a maximum at pH 6.7. Sridhar (1984) recorded a pH between 7-8.0 in the three streams investigated in the Western Ghat Forest region where several species of aquatic hyphomycetes were reported. The pH of the spring water recorded in this study was close to neutral. Therefore, the difference in the number of species recorded in the three sites of the spring is probably not due to pH. Sridhar (1984) reported a dissolved oxygen level ranging from 7-11 mgl - ' in the three streams of Western Ghat forests. In the present study the maximum number of species were recorded at site III, where the dissolved oxygen concentration was 8.2 mgl - '. But at site II where the oxygen concentration was 3.8 mg 1- ', as many as 14 species were recorded while at site I where the oxygen concentration was 3.2 mg 1- ' only one species was recorded. Therefore it is unlikely that the lower number of species recorded at site I is due to the low oxygen concentration. Suberkropp & Klug (1981) found 15-25 C as the optimum temperature range for the growth of aquatic hyphomycetes. Sridhar (1984) recorded a temperature range of 20-29 C in the three streams of the Western Ghat Forest region. In the seasonal occurrence studies of the two streams (Chandrashekar, 1987) a temperature range of 19-32 ° C was recorded. Thus, the temperature of spring water at site III, where maximum number of aquatic hyphomycetes was recorded was comparable to the water temperatures recorded for other streams of this region. Initial observations indicated that the higher concentration of sulphide at site I adversely
affected the occurrence of these fungi at that site. But the studies on sporulation of aquatic hyphomycetes in different types of water, including sulphur spring water, showed that it was the higher temperature and not the sulphide content of site I which was responsible for the presence of only one species at that site.
Acknowledgements We thank the Chairman & members of the staff of Dept. of Biosciences, Mangalore University for encouragement throughout this investigation.
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