Biodiversity Journal, 2016, 7 (4): 923–934 Diversity and distribution of seaweeds in the shores and water lagoons of Chennai and Rameshwaram coastal areas, South-Eastern coast of India Iswarya Bhagyaraj & Vijaya Ramesh Kunchithapatham* Department of Plant Biology and Plant Biotechnology Quaid-E-Millath Government College for Women, Chennai 600 002, Tamil Nadu, India *Corresponding author, e-mail: [email protected] ABSTRACT Seaweeds are floating and submerged plants of shallow marine meadows. Seaweeds belong to a group of plants known as algae. Seaweeds are classified as Rhodophyta (red algae), Phaeophyta (brown algae) or Chlorophyta (green algae) depending on their mode of nutrients, pigments and chemical composition. Many of the rocky beaches, mudflats, estuaries, coral reefs and lagoons along the Indian coast provide ideal habitats for the growth of seaweeds. The present study was conducted at shores and water lagoons of Chennai and in Ramesh- waram, formed of different inter-tidal rock shores with algal vegetation. A total of 25 algal taxa were collected during the study period (Dec 2014–Feb 2016), including 10 Chlorophyta, 8 Phaeophyta and 7 Rhodophyta. Among them, Enteromorpha compressa L., Ulva lactuca L., Sargassum polycystum C.Agardh, Padina pavonica L. were the commonly occurring sea- weeds in all the monsoon periods. Interestingly, Ectocarpus siluculosus (L.) Kjellman be- longing to the family Phaeophyceae was found in the post monsoon period–Oct 2015 at Pulicat lake, Chennai, Tamil Nadu. This study is the first report of macro algal diversity along Ennore, Thiruvottiyur and Royapuram coasts. KEY WORDS Seaweed diversity; Chennai shores; Rameshwaram coastal areas. Received 18.11.2016; accepted 20.12.2016; printed 30.12.2016 INTRODUCTION 90% of the species of marine plants are algae and about 40% of the global photosynthesis is contrib- The marine ecosystem provides a vast habitat uted from algae (Andersen, 1992). Due to their for macro algal communities as they occupy the habitat and biology, seaweeds are relatively easy to rocky shores and submerged intertidal zone. The observe, manipulate and measure. Therefore, they coastline of Tamilnadu has a length of about 1076 have been widely used as model organisms for kms, whereas Chennai covers 19 km of coastal area, studying biogeographic patterns and testing various Thiruvallur and Ramanathapuram covers 27.9 km ecological theories, both in intertidal and subtidal and 236.8 km respectively (Ramesh et al., 2008). habitats (Murray & Littler, 1984; Bolton et al., Seaweeds are intercommuting with other organisms 2004; Prathep, 2005). The marine ecosystem is in marine environment and they are hallmarks in changing simultaneously due to the natural pro- the coastal biodiversity. It is estimated that about cesses and anthropogenic causes like over-exploit- 924 ISWARYA BHAGYARAJ & VIJAYA RAMESH KUNCHITHAPATHAM ation of resources, land use changes and alteration Long 80° 17' 38 E), Covelong beach (Lat 12° 78' of habitats. Taking into account the change in envir- 70 N, Long 80° 25' 04 E) and Thiruvottiyur shore onment and resources, it is necessary to study their (Lat 13° 9' 28 N, Long 80° 18' 15 E), Pulicat lake effect on the seaweed diversity and to ensure their water lagoon (Lat 13° 34' 46.056, Long 80° 11' regular distribution in the ecosystem. Therefore in 2.616) - Thiruvallur and in Keezhakarai (Lat 9° 14' our present study we investigated the diversity and 25 N, Long 78° 50' E) and Mandapam rocky shores distribution of seaweeds in rocky coastal areas of (Lat 9° 27' 70 N, Long 79° 12' 52 E) - Ramesh- Chennai and water lagoons and Rameshwaram waram, Ramanathapuram district, Tamil Nadu. The shores. algal samples were collected in three months inter- val during the study period. Fresh samples were brought to the laboratory at Department of Plant MATERIAL AND METHODS Biology and Plant Biotechnology, Quaid-E-Millath Government College for Women, Chennai for The present study was conducted for a period of further studies. The samples thus collected were 15 months (December 2014 to February 2016) to washed thoroughly in running water and preserved evaluate the seaweed diversity. Habitats chosen for in 4% (v/v) formalin. The parameters like nature of sampling seaweeds included the Chennai coastal substratum, habit of seaweed and abundance of areas, Royapuram shore (Lat 13° 6' 25 N, Long 80° species were observed. The identification of taxa 17' 43 E), Ennore rocky shore (Lat 13° 6' 26 N, was done by keys (Umamaheswara Rao, 1987; Figure1. Map showing the study area in Chennai coastal areas (courtesy Santhiya et al. 2010, modified). Seaweeds in the shores and water lagoons of Chennai and Rameshwaram coastal areas, S-E coast of India 925 Desikachary et al., 1990, 1 998; Krishnamurthy, LOCATION. Royapuram (Lat 13° 6' 25 N, Long 1999) and the nomenclature was updated using Ap- 80° 17' 43 E); Ennore (Lat 13° 6' 26 N, Long 80° peltans et al. (2012). 17' 38 E). BIOLOGy. Thalli found attached to intertidal rocks or any floating structures. RESULTS 3. Enteromorpha intestinalis (Linnaeus) Nees A total of 25 algal taxa were collected during the study period (Dec 2014–Feb 20 16). They included DESCRIPTION . The mature thallus is a ho llow 10 Chlorophyceae (16.6%), 8 Pha eophyceae tube, wrinkled and convoluted, intestine-like and up (41.6%) and 7 Rhodophyceae (41.6%) (Fig . 24). to 11 cm long. Branching is from the base. The wall Among these, Enteromorpha sp., Ulva lactuca Lin- is one cell thick and the plant appears yellow green naeus, Sargassum polycystum C. Agardh, Padina to dark green. The young pla nt is attached to the pavonica Linnaeus were the commonly occurring substratum by a basal rhizoidal cell (Fig. 8). seaweeds throughout the collection periods. Inter- LOCATION. Covelong (Lat 12° 78' 70 N, Lon g estingly, the Brown algaEctocarpus siliculosuswas 80° 25' 04 E). found in Pulicat Lake and is reported from this area for the first time. BIOLOGy. Thalli found attached to intertidal rocks. Systematics 4. Enteromorpha prolifera (Müller) J. Agardh Phyllum CHLOROPHyTA DESCRIPTION. Plants are green to dark green in Subphyllum CHLOROPHyTINA colour with tubular branches that have numerous Classis ULvOPHyCEAE slender branchlets, up to 10 cm long, attached by Ordo ULvALES means of a disk-like holdfast. Fronds tubular, pro- Familia ULvACEAE fusely branched with numerous slender branches (Fig. 2). 1. Enteromorpha compressa (Linnaeus) Nees LOCATION. Covelong (Lat 12° 78' 70 N, Long 80° 25' 04 E); Thiruvottiyur (Lat 13° 9' 28 N, Long DESCRIPTION. Thalli slightly yellowish green in 80° 18' 15 E). colour, up to 7 cm long; fronds profusely branched from the stalk-like base, narrow, tubular at the base BIOLOGy. Thallus found attached to intertidal and gradually expanded and compressed above with rocks. obtuse or round apices. 5. Ulva lactuca Linnaeus LOCATION. Royapuram (Lat13° 6' 25 N, Long 80° 17' 43 E); Thiruvottiyur (Lat13° 9' 28 N, Long DESCRIPTION. Thallus 2–5 cm long, soft, leafy, 80° 18' 15 E); Ennore (Lat13° 6' 26 N, Long 80° 17' membranous, foliaceous, bright green, blades lanceol- 38 E); Mandapam (Lat 9° 27' 70 N, Long 79° 12' 52 ate to broadly ovate to rounded, often irregularly E); Keezhakarai (Lat 9° 14' 25 N, Long 78° 50' E). and deeply incised to form lobes, lettuce type mor- phology, margins of lobes ruffled and wavy or un- BIOLOGy. Thalli found attached to intertidal dulate, membrane thick near the base (Fig. 7). rocks, found growing throughout the year. LOCATION. Covelong (Lat 12° 78' 70 N, Long 80° 2. Enteromorpha flexuosa (Wulfen) J. Agardh 25' 04 E); Royapuram (Lat 13° 6' 25 N, Long 80° 17' 43 E); Pulicatlake (Lat 13° 34' 46.056, Long 80° 11' DESCRIPTION. Pale green in colour, up to 30 cm 2.616); Mandapam (Lat 9° 27' 70 N, Long 79° 12' 52 long, grown throughout the year, attached by a small, E); Keezhakarai (Lat 9° 14' 25 N, Long 78° 50' E). round basal disk, fronds simple or branched, tubular BIOLOGy. Attached to floating substances, found with cylindrical stalks below and expanding blades in shallow waters, found growing in post monsoon above, becoming flexuous, ending in an obtuse apex. periods. 926 ISWARYA BHAGYARAJ & VIJAYA RAMESH KUNCHITHAPATHAM Ordo CLADOPHORALES LOCATION. Keezhakarai (Lat 9° 14' 25 N, Long Familia CLADOPHORACEAE 78° 50' E). BIOLOGy. Attached to Intertidal rocks and cal- 6. Chaetomorpha antennina (Bory) Kützing careous stones, found growing during Nov–Feb. DESCRIPTION. Algal thallus dark green in colour, 9. Halimeda tuna (Ellis et Solander) Lamouroux grows brush-like tufts; filaments erect, unbranched, cylindrical or barrel-shaped, up to 10 cm tall; cells DESCRIPTION. Dark green in colour, 8–10 cm 200–250 μm at the upper parts, 2–4 times longer than tall, generally tufted, moderately calcified and at- broad with a thick cell wall; chloroplasts reticulate tached by compressed conical holdfast, branching or free, but close together, filaments attached by in one plane, dichotomous or trichotomous upper irregularly branched rhizoidal basal cell; cell walls segments, cuneatereniform discoid, 6–13 mm high, of the basal cells thick with annular constrictions. 5–23 mm broad, margins entire, entangled, fusing 2–3 together at the nodes, dichotomously branched LOCATION. Thiruvottiyur (Lat 13° 9' 28 N, Long above the fused filaments (Fig. 10). 80° 18' 15 E); Ennore (Lat 13° 6' 26 N, Long 80° LOCATION. Keezhakarai (Lat 9° 14' 25 N, Long 17' 38 E). 78° 50' E). BIOLOGy. Found attached to rocks and calcare- BIOLOGy. Attached to Intertidal rocks and cal- ous stones, found growing in post monsoon periods. careous stones, found growing during Nov–Feb. 7. Chaetomorpha linum (O.F. Müller) Kützing Ordo BRyOPSIDALES DESCRIPTION. Free floating, sometimes attached Familia CAULERPACEAE to rocks and shells; plant body filamentous, less than 20 cm long, bright green to yellowish green in colour, 10.