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. KaveriappaDepartment 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 investigatedby 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 regionof the spring and the rivulet (site II) and the spot where the spring joins the rivulet (site III). The numberof species of hyphomycetes encountered at the three sites were 1, 14 and 20, respectively. The sulphidecontent of the spring ranged between 0.1-3.1 mg 1- ' and the temperature between 26.5-36.5 C. Inanother experiment submerged coffee leaves from a fresh water stream were collected and incubated inspring water, stream water and well water at different temperatures (16-40 ° C). A maximum of 18 speciesof hyphomycetes sporulated at 22 C followed by 17 species at 28 ° C, irrespective of the source of waterin which the leaves were incubated. Based on these studies, we conclude that the presence of only onespecies 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 tooccur in streams and rivers of different parts ofthe world (Ingold, 1975; Subramanian, 1971).These organisms live in fast flowing, well aeratedstreams where they colonise submerged leaves(Ingold, 1942). Most studies on the occurrence ofthese organisms have been confined to regionswhere the water temperature ranges between0-25 C (Barlocher, 1982; Suberkropp & Klug,1981). In recent years, these fungi have also beenreported from tropical regions, where water tem-perature ranges between 20-29 °C (Padgett,1976; Sridhar, 1984; Sridhar & Kaveriappa,1984; Subramanian & Jayarama Bhat, 1981;Swart, 1986). This is the first investigation on theoccurrence of hyphomycetes in a sulphur spring.

The spring 'Bendre Thirtha' originates in a placecalled Panaje and connects to a tributary of theriver Nethravathi. It is surrounded by trees suchas Banyan, Jack, Mango, Coconut and Areca.The water level of the spring is around two feetthroughout the year.

The materials for this study were collected fromthree sites: the spring proper (site I), the connect-ing region of the spring and the rivulet (site II) andthe spot where the spring joins the rivulet(site III), (Fig. 1). Collections were made duringDecember 1985, February and April 1986.

The foam and water samples and submergedleaves from the three sites were collected in poly-thene bags. The materials were analysed in thelaboratory for the presence of fungal conidia by

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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 sul-phide of water from the three sites were analysedat the time of collection.

To study the sporulation of hyphomycetes atdifferent temperatures and in different sources ofwater, sulphur spring water and stream water wascollected in plastic cans and stored in the labora-tory. Submerged leaves of coffee were collectedfrom the Sampaje stream as these leaves arereported to be colonized by different species ofaquatic hyphomycetes (Sridhar, 1984). Thewaters from the sulphur spring, stream, and well

were filtered through millipore filters (Pore size,0.45 pm diam) before use. Ten coffee leaves werecut into small pieces (1.5 x 3 cm) and transferredto three separate sets of 15 Petri dishes, contain-ing the three types of water. While transferring thematerial, care was taken to see that all the threesets of Petri dishes received leaf sections fromeach leaf uniformly. The three Petri dishes fromeach set were incubated at 16, 22, 28, 34 and40 C. On alternate days the Petri dishes wereexamined under a low power microscope for thedevelopment and sporulation of different speciesof hyphomycetes. After each observation thewater in the Petri dishes was replaced. Observa-tions were continued for 30 days and the various

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Table 1. Aquatic hyphomycetes recorded from the sulphur spring Bendre Thirtha.

Fungi Sampling sites

Site I Site II Site III

Methods* 1 2 3 4 1 2 3 4 1 2 3 4

Alatospora acuminata - - - - - - - - - - +Anguillospora longissima - - - - + - - - + + +Anguillospora sp. - - - - + + - - + + +Beltrania rhombica - - - - + - + - +Camposporium pellucidum - - - - - - - - - - +Flabellospora verticillata - - - - - - - - - - +Flagellospora curvula - - - - + - + + + + + +Flagellospora penicillioides - - - - + + + + + + + +Helicosporium sp. - - - - + - - - - - + +Lunulospora curvula - - - - + + + + + + + +Lunulospora cymbiformis - - - - + + - +Phalangispora constricta - - - - + - + - - - +Speiropsls pedatospora - - - - + - - +Tetraploa sp. - - + - - - - - - + +Tetraploa aristata - - - - + - - +Tricladium brunneum - - - - - - - - - - +Triscelophorus acuminatus - - - - + - + - - - - +Triscelophorus monosporus - - - - + + + - + + + +Triscelophorus sp. - - - - + + + - + + + +Wiesneriomyces javanicus - - - - + - + + +

Total no. of species recordedunder each method 0 0 1 0 13 6 8 5 9 11 15 10

Total no. of species recordedfrom each site 1 14 20

* 1. leaf litter incubation2. foam induction3. foam analysis4. water filtration

species of hyphomycetes appearing on the leafsections of different Petri dishes were recorded.

Results

The aquatic hyphomycetes observed in the sul-phur spring are listed in Table 1. F. penicillioides,and L. curvula were found with all four methodsat site II and III. F. curvula, T. monosporus andTriseclophorus sp. were recorded in all the meth-ods of observations only at site III.

The data on temperature, pH, dissolved oxygenand sulphide concentration at the three sites are

Table 2. Temperature, pH, dissolved 02 and sulphide con-tent of the sulphur spring at the three collection sites (averageof three samples).

Site I Site II Site III

Temperature (°C) 36.5 35.5 26.5pH 5.9 6.1 7.3Dissolved oxygen (mg ') 3.2 3.8 8.2Sulphide (mg 1 ') 3.1 1.2 0.1

given in Table 2. The data on the sporulation ofhyphomycetes on coffee leaves in different typesof water and at different temperatures are given in

'+' present'-' absent

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Table 3. Sporulation of aquatic hyphomycetes on coffee leaves incubated in stream water, tap water and spring water at differenttemperatures.

Fungi Incubation 16 22 28 34 40temperature (C)Source of water* S T B S T B S T B S T B S T B

Alatospora acuminata - - +Anguillospora longissima - - - + +Anguillospora sp. + +- - - -

Flabellospora crassa - - - + - + + + Flabellospora multiradiata + - - + + +

Flabellospora verticillata + + + + + + + + + - + - - -Flagellospora curvula + + + + + - - +Flagellospora penicillioides - + - + + - + + + + +Helicosporium sp.1 + + + + + + + + + + +Helicosporium sp.2 + - + + + + + + +Isthmotricladia laeensis - - - + + - +Lunulospora curvula - - + - -+

Phalangispora constricta + + + + + + + +Speiropsis hyalospora - - - + +Speiropsis pedatospora - - + + -+ +Tetraploa sp. - - - - +Tetracladium sp. - + - - ++ +Triscelophorus acuminatus - + - + -Triscelophorus monosporus - - + - + + + Triscelophorus sp. - - + - - + + + Wiesneriomyces javanicus + + + + + + + + +

* Qfrem *t-r ' ' nrnt

T Well waterB Sulphur spring water

Table 3. A. longissima, I. laeensis, S. hyalospora,Tetraploa sp. and Triscelophorus sp. were recordedon leaf sections incubated in well and streamwater but not in spring water. On the other hand,A. acuminata and L. curvula which were recordedon leaf sections incubated in spring water were

Table 4. The number of species encountered on submergedcoffee leaves incubated at different temperatures.

Source of Incubation temperature Total numberwater ( C) of species

recorded16 22 28 34 40

Stream 8 15 11 2 - 17Well 8 12 15 2 - 19Spring 10 8 9 1 - 16

Total number ofspecies recorded 14 18 17 3

absent on leaf sections incubated in well andstream water. Within each type of water the num-ber of species recorded varied with temperatures(Table 4). At 40 C no species were recorded. At34 C only three species were found. At 28 °Cand below many species of hyphomycetes weredetected. The three species recorded at 34 °Cwere 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, Radha-krishna (1971) investigated some physical andchemical aspects of the spring water. Field &Webster (1985), found a tolerance limit of5 mg 1- of sulphide for the growth of aquatic

'-' absent

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hyphomycetes. In the present investigation, thesulphide content of the spring water recorded wasnot more than 3.1 mg 1- '. Therefore it is believedthat the sulphide concentration of the spring wasnot high enough to produce any adverse effect onthe fungi recorded in the three sites.

Barlocher & Rosset (1981) in a comparison oftheir own results with those of Conway (1970),Willoughby & Archer (1973), Brlocher &Kendrick (1974) and Iqbal & Webster (1977) con-cluded that the number of fungal species occurringin a stream is a function of pH and forms aunimodal curve with a maximum at pH 6.7.Sridhar (1984) recorded a pH between 7-8.0 inthe three streams investigated in the WesternGhat Forest region where several species ofaquatic hyphomycetes were reported. The pH ofthe spring water recorded in this study was closeto neutral. Therefore, the difference in the numberof species recorded in the three sites of the springis probably not due to pH.

Sridhar (1984) reported a dissolved oxygenlevel ranging from 7-11 mgl - ' in the threestreams of Western Ghat forests. In the presentstudy the maximum number of species wererecorded at site III, where the dissolved oxygenconcentration was 8.2 mgl - '. But at site IIwhere the oxygen concentration was 3.8 mg 1- ',as many as 14 species were recorded while at site Iwhere the oxygen concentration was 3.2 mg 1- 'only one species was recorded. Therefore it isunlikely that the lower number of species recordedat site I is due to the low oxygen concentration.

Suberkropp & Klug (1981) found 15-25 C asthe optimum temperature range for the growth ofaquatic hyphomycetes. Sridhar (1984) recorded atemperature range of 20-29 C in the threestreams of the Western Ghat Forest region. In theseasonal occurrence studies of the two streams(Chandrashekar, 1987) a temperature range of19-32 ° C was recorded. Thus, the temperature ofspring water at site III, where maximum numberof aquatic hyphomycetes was recorded was com-parable to the water temperatures recorded forother streams of this region.

Initial observations indicated that the higherconcentration of sulphide at site I adversely

affected the occurrence of these fungi at that site.But the studies on sporulation of aquatic hypho-mycetes in different types of water, including sul-phur spring water, showed that it was the highertemperature and not the sulphide content of site Iwhich was responsible for the presence of onlyone species at that site.

Acknowledgements

We thank the Chairman & members of the staffof Dept. of Biosciences, Mangalore University forencouragement throughout this investigation.

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