The coral lagoons of Lakshadweep have been widely reported to have luxuriant growth of seaweeds. In these coral reef ecosystems, calcareous algae form the important group in seaweeds, as they are essential in the formation of coral reefs. Though several surveys of seaweed growth have been carried out from time to time in different regions of the mainland, Lakshadweep and Andaman-Nicobar Islands, studies are lacking from the Androth island, one of the Laccadivian archipelago islands to identify seaweed growing areas in Androth. Also, there is no significant work to assess the standing crop of seaweeds in Androth. Therefore, this study was attempted to map the distribution and diversity of seaweed species in the Andrott island of Lakshadweep. In agreement with studies on the coastal distribution of seaweed fauna and flora, our study also identified extensive growth of seaweeds species like Halimeda, Chaetomorpha , Boodlea, Composita, Chaetomorpha, Enteromorpha, Padina, Sargassum wightil, Acanthophora specifera etc along the coral coast of Androth island belonging to the Lakshadweep Archipelago.
Research Article
Diversity and Distribution of Seaweeds in the Androth Island of Lakshadweep Archipelago
https://doi.org/10.21203/rs.3.rs-4267159/v1
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Seaweeds
coral island
Androth
Lakshadweep archipelago
Lakshadweep in the Arabian Sea is a part of the Indian subcontinent and is recognized as the smallest union territory of India. Lakshadweep is an archipelago of twelve atolls, three reefs and five submerged banks, with a total of about thirty-nine islands & islets(http://lakshadweep/gov.in). The Lakshadweep has rich seaweeds vegetations. Important species of seaweeds found in Lakshadweep coast includes Enteromorpha, Ulva, Caladophora cualerpa, Sargassum, Turbeneria, Gelidella, Gracillaria, & Hypnea. Altogether 62 genera and 114 species of seaweed are recorded of which 18 genera and 43 species belong to chlorophyceae, 11 genera and 14 species to phaeophyceae, 30 genera & 54 species to Rhodophyceae and 3 genera & 3 species to cyanophyceae (CSMCRI, 1979; Tripathy 2002). However, a detailed identification of the seaweed fauna and flora is lacking from the largest island of Lakshadweep namely the Androth island. The present study attempts to identify and document almost all available seaweeds, their distribution and diversity from a number of locations in the Androth island.
Study Station
Androth is one of the coastal islands of Lakshadweep lying on the Arabian sea, 220–440Kms off the Kerala coast. It lies in the east west orientation, between 10° 48’ and 10° 50’N latitude and 73° 38’ and 73° 42 E’ longitude (http://lakshadweep/gov.in). Androth is the largest island of UTL with an area of 4.90 sq, length of 4.66 km and a maximum width of 1.23 km. It stands apart from other islands of Lakshadweep in having a very small lagoon area and in the orientation. It is the most populated island among the eleven inhabited islands of Lakshadweep (Chandramohan et al., 1993; Koya et al., 2021).
The Androth island was selected as the study station (Fig. 1). A total of 4 sites (Fig. 2) namely Pandath (site 1), Chemmachery (site 2), Keechery (site 3) and Edachery (site 4) were selected and seaweeds diversity and distribution according to the nature of the coral beds were recorded (Table 1).
| Location Site | Sampling site | Site Description |
|---|---|---|
| PANDATH (1) | 1 | SEA GRASS BED |
| 2 | ROCKEY AREA | |
| CHEMMACHERY (2) | 1 | SEA GRASS BED |
| 2 | ROCKEY AREA | |
| EDACHERY (3) | 1 | SEA GRASS BED |
| 2 | ROCKEY AREA | |
| KEECHERY (4) | 1 | SEA GRASS BED |
| 2 | ROCKEY AREA |
Collection of algae and associated fauna
Macro algae samples collected mainly using random method from the submerged marine rocks, soft substratum during low tide in the intertidal regions. Five belts transact (5x50) were laid in each sampling site and whatever species encountered during the survey were also collected. For the collection of seaweeds handpicked method was used. The collected macro algae immediately photographed then washed with fresh water to remove the unwanted materials in the species. Then identified using published literatures and consultation with experts.
The seaweeds were identified along the coral coastal regions of the Androth island. A few are given below (fig 3). The diversity and distribution of seaweeds are given as table 2 and 3 respectively. Species wise distribution from individual sampling sites are given in Fig 4.
Table 2: Diversity of seaweeds in Androth island of Lakshadweep Archipelago
Table 3: Distribution of seaweeds in Androth island of Lakshadweep Archipelago
Seaweeds are large algae (macro algae) that grow in salt water or marine environment and lack true stems, roots and leaves. Seaweeds commonly grow on coral reefs or in rocky landscape or can grow at great depths if sunlight can penetrate through the water. Most of the seaweeds can be seen thriving in underwater beds floating along the seasurface attached to rocks (Sikdar et al., 2016). According to Untawale et al. (1983) Indian coast line has 844 species of marine algae belonging to 215 genera and 64 families. Gulf of Mannar stands first in terms of diversity and density (302 species), followed by the Gulf of Kutch (202 species). Totally 73 species of seaweeds were reported from the coastal region of Maharashtra of these 28.77% species belongs to Chlorophyta, 45.21% to Rhodophyta, 2.73% to Cyanophyta and 23.29% to Phaeophyta. Species of Ulva, Chaetomorpha Enteromorpha, sargassum, Padina, Amphiroa, Jania, and Gracilaria are common in this region. Species of Porphyra, Gracilaria, Gelidium, Ulva, Sargassum spp are the economically important algae occurring along this coast (Waghmode 2017). In agreement with above studies, our study also identified extensive growth of seaweeds along the coral coast of Androth island belonging to the Archipelago.
Extensive fauna and flora of Seaweeds are found in Androth Island such as Bryopsis plumose, Ulua lactuca, Halimeda macroloba, Halimeda discoidae, Halimeda opantia, Halimeda simulans, Chaetomorpha antennina, Boodlea, Composita, Chaetomorpha, Enteromorpha, Padina, Sargassum wightil, Acanthophora specifera, Ectocarpus, Gracilaria corticata, Asparagopsis taxiformis, Dermonema virens, Gelidiopsis repens, Gracilaria corticata, Gracilaria crassa, Codium tomentosum, Iyengeria stellata (Borgesen).
Author contribution: Ms. Najva conceptualize, investigated, arranged resources and written the manuscript. Dr Rekha Govindan contributed to resources and writing the manuscript. All the authors read the final draft and approved the manuscript.
- Ethical Approval: Not applicable
- Data Availability: Not applicable
- Competing Interest declaration: The authors have no competing interests to declare that are relevant to the content of this article.
- Funding declaration – None: No funds, grants, or other support was received.
- Conflict of interest - None
- Availability of data and materials: Not applicable
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- http://lakshadweep/gov.in
No competing interests reported.