1 Introduction
A chain of backwater systems connects the southwestern coast of India, bordering the state of Kerala. The backwater system is the largest and the most important inland water resource of Kerala. The backwater system consisting of the estuaries of the rivers, the lower reaches within the tidal influx, the brackish water lakes and backwater along with their estuaries comprises about 68% of the inland water resources of the state. Sharing the characteristics of both freshwater and marine habitats makes the backwater system a unique ecosystem. The backwater of Kerala, sprawling the entire coastal length of Kerala, is rich in biodiversity of fauna and flora [1].
The biodegradation of the dead remains of plants and animals in the backwater system is carried out by an immense variety of microorganisms. Marine fungi are one such microbiota, which play a crucial role in the breakdown of organic matter and transfer the energy to the higher trophic level. The present paper deals with the marine fungal diversity of selected backwater and brackish water of the Kerala. Although there are earlier reports [2–8] about the marine mycology in the Kerala coast, it is not so exclusive with the coastal regions; therefore, in the present investigation, we have tried to explore the marine fungal diversity of selected backwater and brackish water habitats of the North Malabar region of Kerala, India.
2 Materials and methods
Wood materials were collected from the Nadal and Katampally brackish water and Kavvai and Chettuva backwater systems of North Malabar (Kerala) India. A total of 197 wood samples were collected (93 from backwater and 104 from brackish water). The collected decaying wood materials, of sizes in the range 8–12 cm × 1–1.5 cm, were thoroughly washed and transferred into a sterile polythene bag. Preliminary screening for marine fungi was carried out within a weak. The wood samples were incubated at room temperature in the laboratory. Periodical isolation of the wood materials was carried out for six months. The fungi thus isolated were tabulated and recorded (Table 1).
List of marine fungi isolated
| Name of marine fungi | Backwater | Brackish water | ||
| FO | RA | FO | RA | |
| Aigialus grandis Kohlm. et Schatz | 4.67 | 3.23 | ||
| Aigialus mangrovei Borse | 2.20 | 1.98 | ||
| Aigialus parvus Schatz et Kohlm. | 1.10 | 0.99 | ||
| Aniptodera chesapeakensis Shearer et Mill | 12.50 | 8.60 | ||
| Aniptodera salsuginosa Nakagiri et Ito | 4.40 | 3.96 | ||
| Dactylospora haliotrepha (Kohlm. et Kohlm) Hafellner | 3.30 | 2.97 | ||
| Halosarpheia abonnis Kohlm. | 2.20 | 1.98 | ||
| Halosarpehia ratnagiriensis Patil et Borse | 3.13 | 2.15 | ||
| Halosarpheia viscosa (I. Schmidt) Shearer et Crane ex Kohlm et Volkm. Kohlm, comb nov. | 3.30 | 2.97 | ||
| Leptosphaeria australiensis (Cribb et Cribb) Hughes | 4.67 | 3.23 | 4.40 | 3.96 |
| Lignincola longirostris (Cribb et Cribb) Kohlm. | 6.60 | 5.94 | ||
| Lignincola tropica Kohlm. | 6.25 | 4.30 | ||
| Lulworthia grandispora Meyers | 7.70 | 6.93 | ||
| Marinosphaera mangrovei Hyde | 4.67 | 3.23 | ||
| Pleospora pelagica Johnson | 6.25 | 4.30 | ||
| Savoryella lignicola Jones et Eaton | 10.94 | 7.53 | 8.80 | 7.92 |
| Savoryella paucispora Cribb et Cribb) Koch. | 9.38 | 6.45 | 7.70 | 6.93 |
| Salsuginea ramicola Hyde | 7.81 | 5.38 | 5.50 | 4.95 |
| Verruculina enalia (Kohlm.) Kohlm. et Volkm. Kohlm. | 12.5 | 8.60 | 8.80 | 7.92 |
| Halocyphina villosa Kohlm. | 9.38 | 6.45 | 5.50 | 4.95 |
| Ascochyta sp. | 1.56 | 1.05 | ||
| Cirrenalia macrocephala (Kohlm) Meyers et Moore | 2.20 | 1.98 | ||
| Cirrenalia pygmea Kohlm. | 7.81 | 5.38 | 6.60 | 5.94 |
| Clavatospora bulbosa (Anast) Nakagiri et Tubaki | 10.94 | 7.53 | ||
| Cumulospora marina I. Schmidt | 6.25 | 4.30 | ||
| Dendryphiella salina (Sutherland) Pugh et Nicot | 3.13 | 2.15 | 4.40 | 3.96 |
| Periconia prolifica Anastasiou | 14.06 | 9.68 | 12.09 | 10.89 |
| Phoma sp. | 3.13 | 2.15 | ||
| Trichocladium achrasporum (Meyers et Moore) Dixon | 6.25 | 4.30 | 7.70 | 6.93 |
| Trichocladium alopallonellum (Meyers et Moore) Kohlm. et Volkm. Kohlm. | 6.60 | 5.94 |
3 Results and discussion
Altogether 30 marine fungi were isolated during the course of this study (Figs. 1, 2). Among these, 19 were ascomycetes, one was a basidiomycete, and 10 were mitosporic fungi. Twenty marine fungi were obtained from brackish waters, and twenty others from backwaters. Maximum ascomycetes (up to 13) were obtained from brackish water. More mitosporic fungal diversity was found in backwater. Basidiomycete was represented only by a single isolate from each water body. Ten species that were found common in both water bodies include Leptosphaeria australiensis, Savoryella lignicola, Savoryella paucispora, Salsuginea ramicola, Verruculina enalia, Halocyphina villosa, Cirrenalia pygmea, Dendryphiella salina, Periconia prolifica, and Trichocladium achrasporum.
Isolated backwater and brackish water marine mycoflora of North Malabar (Kerala) India.
Isolated backwater and brackish water marine mycoflora of North Malabar (Kerala) India.
Periconia prolifica showed maximum percent frequency of occurrence and percent relative abundance from backwater as well as from brackish water. Percent frequency of abundance above 8 was shown by seven and three species from backwater and brackish water, respectively. Three and five species from brackish water and backwater, respectively, showed percent relative abundance above 7. Aigialus parvus and Ascochyta sp. were the species that were represented by an only single isolate each.
In terms of overall percent frequency and percent relative abundance, backwater mycoflora emerged dominant with respect to brackish water mycoflora. This might be due to various environment conditions like salinity fluctuation, availability of host, temperature, pH, dissolved oxygen, etc., which support the distribution of marine fungi.
Acknowledgements
The authors are thankful to the Principal and Management of Sir Syed College, Taliparamba, for providing facilities. One of the authors (G.R.N.) is grateful to K.S.C.S.T.E. for providing financial support.