International Journal of Engineering & Science Research

IJESR/October 2013/ Vol-3/Issue-10/555-562 e-ISSN 2277-2685, p-ISSN 2320-9763 International Journal of Engineering & Science Research

STUDIES OF MANGROVES AND IDENTIFICATION OF VARIOUS SALT RESISTANCE SPECIES AT SOUTHERN KRISHNA DELTA K.Sasidhar 1, Ch.Tirupathi 1, R Hema Krishna*2, Z Vishnuvardhan 3, AVV S Swamy 1, P Brahmajirao 1 1Department of Environmental Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur (A.P), India. 2Department of Chemistry, University of Toronto, Ontario, Canada. 3Department of Botany , Acharya Nagarjuna University, Nagarjuna Nagar, Guntur (A.P), India. ABSTRACT This research has been designed to study the salinity in bay of Bengal and identification of various species of mangroves at southern Krishna delta. Mangroves are obligatory halophytes grown in high salinity areas in the estuarine regions. Mangrove ecosystems are highly productive ecosystems and are found all along the coastal regions of India. Andhra Pradesh is having, a second longest coast line in India, of about 974 km. Andhra Pradesh is richly endowed with biodiversity as well as perennial rivers. Mangroves are trees that inhabit the intertidal zones with high salinity, while salt tolerance competence of different species varies. Even congeneric species usually occupy distinct positions of intertidal zones due to differential ability of salt tolerance. Some species have different ecotypes that adapt well to littoral and terrestrial environments, respectively. These characteristics of mangroves make them ideal ecological models to study adaptation of mangroves to salinity. By integrating all information from mangroves and performing comparisons among species of mangroves ,we could give a general picture of adaptation of mangroves to salinity, thus providing a new avenue for further studies on a molecular basis of adaptive evolution of mangroves.

Keywords: Mangroves, Salinity, ecosystems , Bay of Bengal, southern Krishna delta. 1. INTRODUCTION Mangrove forests, together with their adjacent intertidal environments are among the most productive ecosystems on the earth. Continuing loss of mangrove systems has, among other causes, been attributed to erosion of delicate coastal wetlands. The continued decline of the forests is also caused by conversion to agriculture, aquaculture, tourism, urban development and overexploitation .Mangroves are tropical and subtropical forests occurring in the intertidal areas of coastal shorelines protected from wave action. Mangrove forests provide a plethora of ecosystem services and products and play an important socio-economic as well as ecological role [1-5]. World-wide disappearance of mangrove forests is undoubtedly mainly caused by large-scale clear cutting and land conversion [6-7]. However, changing environmental conditions, in particular salinity, can also lead to mangrove degradation and die-off [8-9]. Changes in soil water salinity can be influenced by climate [10] as well as by human impacts caused by leakage from salt extraction pans or by the damming or redirection of rivers [11-12]. Nevertheless, relating mangrove degradation to changes in soil water salinity is still impeded by a lack of local, long-term environmental data .Mangroves are trees inhabiting the intertidal zones of tropical and subtropical coasts [13]. They fall into two groups according to their habitats in nature: true mangroves and mangrove associates. True mangroves refer to species that specifically grow in intertidal zones, such as Rhizophora apiculata , Kandelia candel , Ceriops tagal , Bruguiera gymnorrhiza , Aegiceras corniculatum , Sonneratia caseolaris ; while mangrove associates are capable of occurring in both littoral or terrestrial habitats, such as Hibicus tilisaceus and Excoecaria agallocha [14-15]. Mangrove species possess a common characteristic of tolerating high-salinity seawater, implying convergent adaptation of these species. Nevertheless, different mangrove species may adopt distinct strategies for adaptation to high salinity due to their differential ability of salt tolerance. Performing salinity measurements on a long-term basis is impractical as the spatial and temporal variations in the mangrove habitat [16-19]would require a high sampling intensity. Therefore, there is an urgent need for proxies of environmental conditions and in particular of salinity. In this present research by integrating all information from Data on the distribution of salinity in the offshore waters of the Bay of Bengal and mangroves and performing comparisons among species of mangroves ,we could give a

*Corresponding Author www.ijesr.org 555

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general picture of adaptation of mangroves to salinity, thus providing a new avenue for further studies and The diversity of the species, have been also studied for all the four stations of the study area . 2. METHODOLOGY 2.1 Sample Collection Species samples were collected from different areas of the southern Krishna delta mangrove ecosystem (Lat, 15° 54’0 N; Long 80° 40’0 E) situated along the south coast of Andhra Pradesh, India. The sample was taken and transferred to a sterile bag and transported immediately to the Acharya Nagarjuna University Environmental Laboratory. 2.2 Study sites The present study has been carried out the Southern Krishna delta on the effect of salinity on mangroves in post monsoon and pre monsoon seasons on mangroves at four stations

Fig 1: Location map of the study area The study has been carried out post monsoon and pre monsoon seasons and the thrust is given for mangroves and a general picture of the others associate species were present in the Results and discussion chapter. The plant species are identified using [20] Flora of East Godavari [21] and Flora of Andhra Pradesh [22] . A herbarium is prepared for future reference and kept in the division of ecology and wild life management, Department of Environmental Sciences, Acharya Nagarjuna University. 2.3 Salinity Surface water samples were collected by using a cleaned plastic bucket, and the bottom water samples at different depths (10, 30, 50, 75, 100, 150, 200, 400, 600, 800, 1000, 1500, 2000 meters) were collected by using C.T.D.Salinity was record on board through the pre calibrated C.T.D system (Sea- Bird Electronics Inc., USA) with a precision of ± 0.001 0C, ± 0.003 PSU respectively. 3. RESULTS AND DISCUSSION 3.1 Salinity studies Data on the distribution of salinity in the offshore waters of the Bay of Bengal during southwest monsoon and

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premonsoon seasons at four stations, viz., Nizampatnam, Palarevu, Dindi and Nakshatranagar of Krishna estuary were given in Table 1. The salinity of the sea surface waters varied from 28.8 to 33.62 PSU with an average of 32.33 PSU during southwest monsoon and from 33.23 to 34.36 PSU with an average of 33.92 PSU in the premonsoon season. In the subsurface waters, it varied from 28.80 to 34.98 PSU with an average of 33.71 PSU, and from 33.40 to 35.07 PSU with an average of 34.44 PSU respectively for monsoon and premonsoon seasons. In the intermediate depths, the salinity values varied from 34.56 to 35.04 PSU with an average of 34.97 PSU and from 34.90 to 35.06 PSU with an average of 34.99 PSU for the respective seasons. In the bottom waters, the salinity values varied from 34.60 to 34.87 PSU with an average of 34.76 PSU, and from 34.76 to 34.97 PSU with an average of 34.84 for the respective seasons. Distinct spatial and temporal variations were observed in the distribution of salinity in the present study, showing lower concentrations in the northern region and gradually increased towards southern region during monsoon and premonsoon seasons. Table 1: Salinity (PSU) distribution in the offshore waters of Bay of Bengal Southwest monsoon (Aug. - Sept., 2012)

Depth St.1 St.2 St.3 St.4 0 28.80 30.70 32.15 33.22 10 28.80 31.76 32.68 33.34 30 31.20 31.82 32.86 33.46 50 32.60 33.25 33.41 33.86 75 33.40 33.75 33.82 34.01 100 34.25 34.28 34.57 34.86 150 34.56 34.92 34.91 34.99 200 34.86 34.97 34.98 34.99 400 34.99 34.98 35.01 35.01 600 35.00 35.01 35.02 34.96 800 35.01 34.97 34.97 34.98 1000 34.93 34.90 34.74 34.92 1500 34.82 34.83 34.62 34.85 2000 34.72 34.63 34.60 34.62

Premonsoon (May – June, 2012)

Depth St.1 St.2 St.3 St.4 0 33.23 33.36 33.73 34.36 10 33.40 33.47 33.75 34.36 30 33.51 33.68 33.85 34.42 50 33.71 33.81 34.27 34.65 75 34.01 34.45 34.54 34.75 100 34.76 34.79 34.87 34.98 150 34.90 34.96 34.97 34.99 200 34.94 34.98 34.99 35.01 400 35.01 35.02 35.02 35.02 600 35.01 35.03 35.03 35.00 800 34.99 34.98 35.98 34.97 1000 34.97 34.91 34.91 34.92 1500 34.88 34.93 34.83 34.89 2000 34.98 34.76 34.76 34.76

St.1=Nizampatnam,St.2Dindi,St.3Palarevu,St.4Nakshatrapuram Higher salinities were observed during premonsoon season than that of southwest monsoon season, which may be attributed to low land runoff from the Krishna and other rivers and higher evaporation due to higher temperature. During

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southwest monsoon, surface salinity decreases to 28.80 PSU at head of the Bay due to the influence of increased river runoff from the Krishna and other rivers. An influx of freshwater about 2.81 x 103 M3 S-1 flows in to the Bay annually and aqiit 50% of this covers during southwest monsoon months [23]. The higher salinities in the southern region (south of 15°N) are caused by the northward extension of the Indian Monsoon Current. [24] also observed a similar pattern of surface salinity distribution in these waters during summer monsoon. [25] also reported higher surface salinities in the southern Bay around 4°N. [23] also found that the diluted surface water off the mouths of rivers along the central east coast of India was transported to offshore in a southeasterly direction by the northern part of the anticyclic gray in the southern Bay. Thus the large scale gradient (4.82 PSU) of surface salinities were observed from north to southern Bay during monsoon season are only a result of the wide flocculation in river runoff and surface currents. Distribution of salinity in the offshore waters of the Bay of Bengal is shown in Table .1 for southwest monsoon and premonsoon seasons. The variation of salinity with depth is more pronounced in the upper 200 m when compared with intermediate (200 - 800 m) and bottom (1000 - 2000 m) waters. Based on the observed salinities in the upper layer upto 100 m, a strong halocline was observed in both seasons may be attributed to estuarine type of distribution. 3.2 Species Diversity at Various Stations Species diversity is a measure of the diversity within an ecological community that incorporates both species richness (the number of species in a community) and the evenness of species' abundances. Species diversity is one component of the concept of biodiversity. Mangroves are the coastal forest resource known for their high productivity. They are often referred to as ‘ sentinels of coastal areas ’ as they form very strong shelterbelt and protect the coastal regions by reducing the impacts of cyclones, hurricanes and tsunamis. In India, about 55 mangrove species are reported and are found in all places where the inland river systems empty themselves into the Bay of Bengal or Arabian Sea or Indian Ocean. Godavari and Krishna river systems are rich in mangroves next to Sundarbans of West Bengal and Mahanadi Estuary of Orissa on the East Coast of India. Coringa is a very popular and large mangrove habitat of Godavari estuarine system in Andhra Pradesh. Krishna Estuary forms two pockets of mangroves. The Krishna River divides into two main branches after leaving Vijayawada. One branch goes to north and enters Bay of Bengal near Diviseema in Krishna District. Another branch runs to south and enters into Bay of Bengal at Nizampatnam in Guntur District. Both Nizampatnam and Diviseema form two important hubs of mangrove forests in the Krishna Estuary. The present study has been conducted at the southern fringes of the Krishna estuary at four stations, viz., Nizampatnam, Palarevu, Dindi and Nakshatranagar. The study area includes vast expanses of submerged lands, elevated inner fringes of backwaters, and landward marshy lands, which form typical mangrove habitats. The diversity of the species, have been studied through boat trip (see photo .1) for all the four stations of the study area were tabulated below [26].

Photo 1: Mangroves research at krishna estuarine region

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Table 2: Species Diversity Of Nizampatnam [26] S.No. Family Name of the Species Stature 1 Acanthaceae Acanthus ilcifolius L. Shrub 2 Myrsinaceae Aegiceras corniculatum (L.) Blanco Shrub 3 Plumbaginaceae Aegialitis rotundifolia Roxb. Shrub 4 Avicenniaceae Avicennia officinalis L. Tree 5 A. alba Blume Tree 6 A. marina (Forsk.) Vierh. Tree 7 Rhizophoraceae Bruguiera gymnorrhiza (L.) Savigny Tree 8 B. cylindrica (L.) Bl. Tree 9 Ceriops decandra (Griff.) Ding Hou Shrub 10 Rhizophora apiculata Bl. Tree 11 R. mucronata Poir. Tree 12 Verbenaceae Clerodendrum enerme (L.) Gaertn. Shrub 13 Papilionaceae Dalbergia spinosa Roxb . Shrub 14 Derris heterophylla (Willd.,) Back and Shrub Bakh. 15 Euphorbiaceae Excoecaria agallocha L. Tree 16 Combretaceae Lumnitzera racemosa Willd . Tree 17 Chenopodiaceae Salicornia brachiata Roxb. Herb 18 Suaeda fruticosa Shrub 19 S. maritima (L.) Dum . Shrub 20 S. monoica (Forsk.) Ex. Gmel. 21 Aizoaceae Sesuvium portulacastrum L. Herb 22 Sonneratiaceae Sonneratia apetala Buch. Ham. Tree 23 Meliaceae Xylocarpus granatum Koen. Tree Table 3: Species Diversity At Dindi [26] S.No. Family Name of the Species Stature 1 Acanthaceae Acanthus ilcifolius L. Shrub 2 Myrsinaceae Aegiceras corniculatum (L.) Blanco Shrub 3 Plumbaginaceae Aegialitis rotundifolia Roxb. Shrub 4 Avicenniaceae Avicennia officinalis L. Tree 5 A. alba Blume Tree 6 A. marina (Forsk.)Vierh. Tree 7 Rhizophoraceae Bruguiera gymnorrhiza L. Savigny Tree 8 B. cylindrica (L.) Bl. Tree 9 Ceriops decandra (Griff.) Ding Hou Shrub 10 Rhizophora apiculata Bl. Tree 11 R. mucronata Poir Tree 12 Verbenaceae Clerodendrum enerme (L.) Gaertn. Shrub 13 Papilionaceae Dalbergia spinosa Roxb. Shrub 14 Euphorbiaceae Excoecaria agallocha L. Tree 15 Combretaceae Lumnitzera racemosa Willd. Tree 16 Chenopodiaceae Salicornia brachiata Roxb. Herb 17 Aizoaceae Sesuvium portulacastrum L. Herb 18 Chenopodiaceae Suaeda fruticosa Shrub 19 S. maritima (L.) Dum Shrub 20 S.monoica (Forsk.) Ex. Gmel. Shurb

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Table 4: Species Diversity Table Of Palarevu[26] S.No. Family Name of the Species Stature 1 Acanthaceae Acanthus ilcifolius L. Shrub 2 Myrsinaceae Aegiceras corniculatum (L.) Blanco Shrub 3 Plumbaginaceae Aegialitis rotundifolia Roxb . Shrub 4 Avicenniaceae Avicennia officinalis L. Tree 5 A. alba Blume. Tree 6 A. marina (Forsk.) Vierh . Tree 7 Rhizophoraceae Bruguiera gymnorrhiza (L.) Savign y Tree 8 Ceriops decandra (Griff.) Ding Hou Shrub 9 Rhizophora apiculata Bl. Tree 10 R. mucronata Poir. Tree 11 Verbenaceae Clerodendrum enerme (L.) Gaertn Shrub 12 Papilionaceae Dalbergia spinosa Roxb. Shrub 13 Euphorbiaceae Excoecaria agallocha L. Tree 14 Combretaceae Lumnitzera racemosa Willd. Tree 15 Chenopodiaceae Salicornia brachiata Roxb. Herb 16 Aizoaceae Sesuvium portulacastrum L. Herb 17 Chenopodiaceae Suaeda maritima (L.) Dum . Shrub 18 Suaeda fruticosa Shurb Table 5: Species Diversity At Nakshatrapuram[26] S.No. Family Name of the Species Stature 1 Acanthaceae Acanthus ilcifolius L. Shrub 2 Avicenniaceae Avicennia alba Blume. Tree 3 A. marina (Forsk.) Vierh Tree 4 Verbenaceae Clerodendrum enerme (L) Gaertn. Shrub 5 Rhizophoraceae Rhizophora apiculata Bl. Tree 6 R. mucronata Poir Tree 7 Aizoaceae Sesuvium portulacastrum L. Herb 8 Chenopodiaceae Suaeda maritima (L.) Dum. Shrub 9 Suaeda fruticosa Shurb 3.3 Diversity of The Vegetation The vegetation in the study area included twenty species belonging to eleven families, fifteen genera and twenty species .Members of Avicenniaceae, Rhizophoraceae, Chenopodiaceae are represented by three (Avicennia officinalis, A. alba and A. marina), five (Rhizophora apiculata, R. mucronata, Bruguiera gymnorrhiza, B. cylindrica and Ceriops decandra) and three (Salicornia brachiata, Suaeda fruticosa and S. maritima) species, respectively. All strata of the vegetation are represented in the study area. The vegetation included ten species of trees (Avicennia officinalis, A. Alba, A. marina, Bruguiera gymnorrhiza, B. cylindrica, Rhizophora apiculata, R. mucronata, Excoecaria agallocha, Lumnitzera racemosa, and Sonneratia apetala), eight species of shrubs (Acanthus ilicifolius, Aegiceras corniculatum, Ceriops decandra, Clerodendrum inerme, Dalbergia spinosa, Derris trifoliata, Suaeda fruticosa, S. maritima) and two species of herbs (Salicornia brachiata and Sesuvium portulacastrum) .The vegetation in the study area is not homogeneous. It is distributed in all the zones of submergence, zone of occasional submergence, zone of rare inundation and landward zones. Mangrove species are known for their distribution patterns and are very specific to certain zones. Large creeks & channels, small creeks & channels, elevated banks, mud flats, and transition lands are clearly observed in all the stations of the study area. Some of the species are distributed along the water line i.e. in the zone of submergence, some are found away from the banks but well within the occasionally submerged mud flat zones while some are found along the marshy open lands & transition lands on the land ward side. Mostly the zones of continuous submergence and zones of occasional submergence harbours tree strata in different associations and the distant lands i.e. marshy open or transition lands are armored with shrubs and herbs. The zones of occasional submergence were found to contain more number of species as well as individuals were shown in Table .6 [26].

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Table 6: Diversity of The Vegetation Along the creeks & Along the elevated banks and Marshy open lands or transition channels : mud flats: lands Avicennia alba Salicornia brachiata Rhizophora apiculata A. officinalis Suaeda maritima R. mucronata Excoecaria agallocha S. fruticosa Avicennia officinalis Aegiceras corniculatum Sesuvium portulacastrum A.marina Acanthus ilicifolius Clerodendrum inerme Bruguiera gymnorrhiza Lumnitzera racemosa Avicennia alba A.cylindrica Dalbergia spinosa Ceriops decandra Derris trifoliata (creeping shrub) Sonneratia apetala Bruguiera gymnorrhiza Excoecaria agallocha Clerodendrum inerme Ceriops decandra Sonneratia apetala

4. CONCLUSION In this research Salinity exhibited an increasing trend from north to south. Vertical distribution of salinity revealed the well developed halocline in the upper 200 m water column. Even inter specific variations in the salinity of bay of Bengal water, the common species of mangroves having the tolerance towards the salinity was confirmed from their existence. Mangrove species are known for their distribution patterns and are very specific to certain zones. In the present study area large creeks & channels, small creeks & channels, elevated banks, mud flats, and transition lands are clearly observed. In this research paper we summarize some of the progress made in mangroves adaptation to salinity in terms of their existence . To confirm this hypothesis Further research is required to describe How do mangroves adapt to high- salinity seawater . Acknowledgement Authors would like to thank Dr. A. V. V. S. Swamy Head of the Department of Environmental sciences, Acharya Nagarjuna University for providing the infrastructural support to carry out research activity in this area. The authors also gratefully acknowledge the co-faculty members of the Department of Environmental sciences, Acharya Nagarjuna University. REFERENCES [1] Ronnback P. The ecological basis for economic value of seafood production supported by mangrove ecosystems. Ecological Economics 1999; 29: 235–252. [2] Dahdouh-Guebas F, Mathenge C, Kairo JG, Koedam N. Utilization of mangrove wood products around Mida Creek (Kenya) amongst subsistence and commercial users. Economic Botany 2000; 54: 513–527. [3] Dahdouh-Guebas F, Jayatissa LP, Di Nitto D, Bosire JO, Lo Seen D, Koedam N. How effective were mangroves as a defense against the recent tsunami? Current Biology 2005; 15: R443–R447. [4] Kairo JG, Dahdouh-Guebas F, Bosire J, Koedam N. Restoration and management of mangrove systems—a lesson for and from the East African region. South African Journal of Botany 2001; 67: 383–389. [5] Moberg F, Ronnback P. Ecosystem services of the tropical seascape: interactions, substitutions and restoration. Ocean and Coastal Management 2003; 43: 27–46. [6] Valiela I, Bowen JL, York JK.. Mangrove forests: one of the world’s threatened major tropical environments. BioScience 2001; 31: 807–815. [7] FAO. State of the world’s forests. Mangrove conversion and conservation. Rome: Food and Agriculture Organization of the United Nations. 2003. [8] Spalding M, Blasco F, Field C. World mangrove atlas. Okinawa: The International Society for Mangrove Ecosystems 1997. [9] Kathiresan K. Why are mangroves degrading? Current Science 2002; 83: 1246–1249.

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