Tamil Nadu Coast Research Articles

Distribution of Marine Puffer and Porcupinefishes (Order: Tetraodontiformes) from Tamil Nadu Coast, Southern India

The marine pufferfishes (Family: Tetraodontidae) and porcupinefishes (Family: Diodontidae) were collected from major fish landing centres viz. Royapuram (station I), Cuddalore (station II), Nagapattinam (station III), Mandapam (station IV) and Kanyakumari (station V) along the Tamil Nadu coast, Southeast coast of India. Monthly sample collections were carried out for a period of 1 year from August 2014 to July 2015 from these five major fish landing centres. Overall, 12,112 fishes were collected which belongs to 15 species, 9 genera and two families Tetraodontidae and Diodontidae under the order Tetraodontiformes. It was also found that all the 15 species were not available in all the five stations. The collected 15 species were identified as Arothron immaculatus, A. reticularis, A. hispidus, A. stellatus, Arothron sp., Lagocephalus guentheri, L. sceleratus, L. lunaris, Takifugu oblongus, Torquigener brevipinnis, Chelonodon patoca, Canthigaster solandri, Diodon holocanthus, cyclichthys orbicularis and Chilomycterus reticulatus. The maximum distribution of pufferfishes was observed in Mandapam followed by Cuddalore, Nagapattinam, Royapuram and Kanyakumari. The present study clearly showed that 15 species of pufferfishes and porcupinefishes were reported which includes 6 additional distribution records as compared with previous literature. The study also presented the distributional updates of pufferfishes and porcupinefishes along with taxonomic features and figures for identification of species.

Mass Mobilization: Salt Satyagraha in the Coastal Tamil Nadu (1930-1931)

Mass Mobilization: Salt Satyagraha in the Coastal Tamil Nadu (1930-1931)

Understanding the characteristics of rapid intensity changes of Tropical Cyclones over North Indian Ocean

North Indian Ocean (NIO), which comprises of Bay of Bengal (BoB) and Arabian Sea (AS) basins, is one of the highly potential regions for Tropical Cyclones (TCs) in the world. Significant improvements have been achieved in the prediction of the movement of TCs, since the last decade. However, the prediction of sudden intensity changes becomes a challenging task for the research and operational meteorologists. Hence, the present study focuses on finding the climatological characteristics of such intensity changes over NIO regions. Rapid Intensification (RI) is defined as the 24-h maximum sustained surface wind speed rate equal to 30 knots (15.4 ms−1). The results suggest that the TCs formed over the NIO basin are both seasonal and basin sensitive. Since 2000, a significant trend is observed in RI TCs over the basin. At least one among three cyclones getting intensified is of RI category. More number of RI cases have been identified in the BoB basin than the AS. The post-monsoon season holds more RI and rapid decay cases, with 63% and 90% contribution. Most of the TCs are attaining RI onset in their initial stage. Further, India is receiving more landfalling RI TCs, followed by Bangladesh and Oman. The east coast of India, Tamil Nadu, and Andhra Pradesh are the most vulnerable states to these RI TCs. The cyclogenesis locations associated with RI cases hold higher moisture, and sea surface temperature as compared to the Non-RI cases.

Recently Discovered Iron Anchors from Tamil Nadu, East Coast of India

In maritime archaeological studies, anchors made of stone, wood, or metal have played a significant role in shipping, not only acted as a proxy during the period of their use but also suggesting maritime connections with other countries. Anchors of different types have discovered all over the world which used in the vessels engaged in carrying cargo, passengers as well as warships. Iron anchors were introduced in India by the European rulers, and later on, were manufactured in different parts of India. Like the stone anchors, different types of iron anchors have been recorded during onshore explorations as well as underwater sites with and without shipwreck remain along the Indian coast. In recent past, coastal explorations along Tamil Nadu coast brought to light two iron anchors at Tuticorin harbour while other two anchors displayed at the Government Museum, Egmore, Chennai. Both the iron anchors of Tuticorin harbour belong to Trotman type. In contrast, the iron anchors of the Government Museum, Egmore, belong to Old plan Long shanked Anchor (Admiralty Long Shanked) and Admiralty pattern anchor. This paper details a comprehensive study of these iron anchors and a comparative survey of the iron anchors of Tamil Nadu as well as India.

First record of Seamoths Eurypegasus draconis (Teleostei: Pegasidae) in the Tamil Nadu coast, India

In the present study a single individual (64 mm SL) of Seamoths Eurypegasus draconis Linnaeus, 1766 was recorded from the Kasimedu fisheries harbour, Chennai coast. This is the first record of the species from mainland of India Chennai, Tamil Nadu coast and third record from Indian waters. After three decades the species were documented in the Indian coast. A systematic account of the species and distributions are provided. The species has been compared with earlier studies and similar species of E. papilio .

Influence of nutrient management practices for relay cropped maize (Zea mays)

Plant nutrition is one of the important factors that manipulate the growth and yield of maize crop. It will be suboptimal when the bio-available soil pools of these nutrients are insufficient. Therefore, along with chemical fertilizers the crop plants are also vastly dependent on root-associated microbes and foliar applied liquid manures to enhance nutrient availability. This field experiment was conducted during 2018 at Annamalai University Experimental Farm, Annamalainagar, Chidambaram, Tamil Nadu, India to find out the effect of integrated nutrient management practices for maximizing the yield of maize under relay cropping system. The experiment was laid out in randomized block design with three replications. A total of thirteen treatments comprised of three doses of fertilizer i.e., 100, 75 and 50% in combination with and without seed treatment of microbial consortium and foliar application of panchagavya @ 3% at knee high and pre-tasseling stages along with absolute control. The maximum growth characters, yield attributes and yield, were registered with integrated application of 100% RDF along with seed treatment with microbial consortium and foliar application of panchagavya at knee high and pretasseling stages. However, based on the economic benefits, it can be concluded that integrated application of 75% RDF (187.50: 56.25: 56.25 kg/ha N, P2O5 and K2O, respectively), seed treatment with microbial consortium (20 mL/kg) and foliar application of panchagavya @ 3% at knee high and pre-tasseling stages is economically feasible agrotechnology as it provides better returns to the small and marginal maize growing farmers under relay cropping system in Cauvery Deltaic region of Coastal Tamil Nadu, India.

Identification of Suitable Aquaculture Sites Using Large-Scale Land Use and Land Cover Maps Factoring the Prevailing Regulatory Frameworks: A Case Study from India

Identification of a suitable site is a crucial step for the sustainability of an aquaculture venture. This study shows a framework for identifying areas suitable for freshwater and brackishwater aquaculture in India while integrating the governing regulations. Land use and land cover (LULC) maps at 1:10,000 scale derived from high-resolution imagery were used as base maps, along with allied layers. Site selection criteria were identified through review. Multi-criteria evaluation technique was used to select the technically suitable sites. Coastal regulation zone and coastal aquaculture authority guidelines, which form the regulatory framework governing brackishwater aquaculture in India, were spatially applied on the technically suitable sites to locate sites complying with regulations. The analysis was carried out using layers in the vector geographical information system format. The study was done in one coastal block each from two coastal states along the east coast of India, viz. Odisha and Tamil Nadu. The study identified areas suitable for brackishwater aquaculture in the selected blocks of Odisha (Ersama block: 86 ha) and Tamil Nadu (Pattukottai block: 343 ha). Areas suitable for freshwater aquaculture in Ersama and Pattukottai were 4286 ha and 6265 ha, respectively, while the areas suitable for freshwater aquaculture with interventions, in the respective blocks, were 487 ha and 2467 ha. In context of scarce land availability for aquaculture and stringent laws governing it, we demonstrate utility of large-scale LULC maps for identifying sites suitable for freshwater and brackishwater aquaculture, through a multi-criteria approach.

Estimating the fractional abundance of coral reef benthic compositions using linear spectral unmixing

The present work is focused on providing the application of linear spectral unmixing technique to Landsat-8 images of Operational Land Imager (OLI) bands in coral reef environment at Gulf of Mannar (GoM) islands along the coast of Tamilnadu, India. The spectral characteristics of benthic compositions namely sand, seagrass, branched corals and mass corals in the GoM are recorded in-situ using RAMSES-TriOS Hyperspectral radiometer and the signatures recorded from in-situ have been used as input for linear spectral unmixing technique. The results of linear spectral unmixing provide the fractional abundances of coral reef benthic communities in the Islands of GoM region. Such maps can be used to characterize the landscape structure and composition of reefs, which can in turn be linked to environmental and human impacts. This kind of approaches is cost-effective and acts as a valuable tool for the evaluation and periodical monitoring of coral reef community.

Impact of hydrogeochemical processes and its evolution in controlling groundwater chemistry along the east coast of Tamil Nadu and Puducherry, India.

The present study area falls beside the coastal zone of Tamil Nadu, and Puducherry is characterized by varied geological formations that mostly contain groundwater resources that are primarily utilized for domestic, agricultural, industrial, and other utilities. The study aims to differentiate various hydrogeochemical processes responsible for disparities in water chemistry. Groundwater samples were collected from 66 sites during the two major seasons: pre-monsoon and post-monsoon. The analytical data were separated into terrain vice and utilized for preparing graphical plots as well as mathematical calculations to obtain the existing relationship among chemical constituents and water quality. The Ca-HCO3, Na-Cl, Ca-Na-HCO3, mixed Ca-Mg-Cl, Ca-Cl, and Na-HCO3 are the main hydrochemical facies observed from the groundwater samples. The ionic relationship among the samples indicates the control of direct and reverse ion exchange in the concentration of Ca2+, Mg2+, Na+, and K+ in groundwater. Moreover, silicate weathering contributes more in comparison with carbonate and evaporite dissolution. Gibbs plots reveal that water-rock interaction and evaporation processes are the main mechanisms controlling the water chemistry. The saturation index of different mineral phases indicates groundwater to be oversaturated with silicate mineral phases irrespective of the terrain. Statistical methods like correlation and principal component analysis were also performed to differentiate the specific association and possible source of the dissolved constituent in the groundwater. The study concludes the influence of multiple processes such as silicate weathering, direct and reverse ion exchange, secondary dissolution, saline water intrusion, and anthropogenic sources as the main reasons responsible for variation in groundwater chemistry.

Hydrogeochemical investigations to assess groundwater and saline water interaction in coastal aquifers of the southeast coast, Tamil Nadu, India.

Groundwater and saline water interaction is the most common processes in the coastal aquifers that alters the quality of aquifer waters. The quaternary alluvium aquifer system is a significant water resource of southeast coastal Tamil Nadu that provides water supplies for industrial, agriculture, and domestic utilities. Hydrogeochemical investigations were attempted to analyze groundwater-saline water interactions for which a total of three hundred and sixty samples representing surface water, pore water, and groundwater samples collected from three significant locations (location A, B, and C) and analyzed for major ion concentrations. Piper plot infers surface and pore water samples representing saline water type (Na-Cl) in all the three locations due to tidal variation and sand dominant surface layer. Groundwater samples represent (Ca-HCO3) type at location A due to fresh groundwater discharge, mixed or subterranean estuary (Ca, Mg-Cl, HCO3) at location B due to conversion of freshwater (Ca-HCO3) at low tide to saline water (Na-Cl) at high tide, and saline (Na-Cl) water at location C due to proximity and influence of tides. The Cl-/HCO3- vs. Cl- plot represents two water types, such as fresh groundwater (0.5) and strongly affected by seawater intrusion (6.6). The plot (Ca2++Mg2+)/(K++Na+) vs. log Cl- represents freshwater in location A, mixing in location B, and saline water in location C. Groundwater samples observed to be fresh in location A (20.0 km away from the coast), recirculated in location B (9.0 km away from the coast), and saline in location C (0.5 km away from the coast).

Microbial contamination and its associations with major ions in shallow groundwater along coastal Tamil Nadu.

Microbes in groundwater play a key role in determining the drinking water quality of the water. The study aims to interpret the sources of microbes in groundwater and its relationship to geochemistry. The study was carried out by collecting groundwater samples and analyzed to obtain various cations and anions, where HCO3-, Cl- and NO3- found to be higher than permissible limits in few samples. Microbial analysis, like total coliform (TC), total viable counts (TVC), fecal coliforms (FC), Vibrio cholera (V. cholerae) and total Streptococci (T. streptococci) were analyzed, and the observations reveal that most of the samples were found to be above the permissible limits adopted by EU, BIS, WHO and USEPA standards. Correlation analysis shows good correlation between Mg2+-HCO3-, K+-NO3-, TVC- V. cholerae and T. streptococci-FC. Major ions like Mg+, K+, NO3, Ca2+ and PO4 along with TS and FC were identified to control the geochemical and microbial activities in the region. The magnesium hardness in the groundwater is inferred to influence the TVC and V. cholerae. The mixing of effluents from different sources reflected the association of Cl with TC. Population of microbes T. streptococci and FC was mainly associated with Ca and Cl content in groundwater, depicting the role of electron acceptors and donors. The sources of the microbial population were observed with respect to the land use pattern and the spatial distribution of hydrogeochemical factors in the region. The study inferred that highest microbial activity in the observed in the residential areas, cultivated regions and around the landfill sites due to the leaching of sewage water and fertilizers runoff into groundwater. The concentrations of ions and microbes were found to be above the permissible limits of drinking water quality standards. This may lead to the deterioration in the health of particular coastal region.

Occurrence of fine scale to massive green tides in coastal waters of Palk Bay and Gulf of Mannar regions, southeast coast of Tamil Nadu, India

Occurrence of fine scale to massive green tides in coastal waters of Palk Bay and Gulf of Mannar regions, southeast coast of Tamil Nadu, India

Current biodiversity of Mandapam group of Islands in Gulf of Mannar Marine Biosphere Reserve, Southeast coast of Tamil Nadu, India

The global climate change is known to involve in the decline of biodiversity from different ecosystems, including coral reefs worldwide. The spatial distribution of reef associated flora and fauna in the Gulf of Mannar (GoM) Marine Biosphere Reserve (GOMMBR) are declined due to damage of coral reefs by three major global problems observed in coral reefs, pertaining to frequent bleaching events, sedimentation and overwhelming algal communities. The occurrence of rich biodiversity in reef areas indicates the healthy condition of an iconic reef ecosystem. In this study, to assess the health status of coral reefs in Mandapam group of Islands under GoM, the diversity and distribution patterns of species composition assembled in reefs at seven Islands were analyzed. In 2019, summer temperature range was exceeded between 32 to 36 °C than usual range 28 to 30 °C, which resulted again massive coral bleaching in GoM. Statistical analysis revealed the high diversity of macroalgae in all the reef sites at Mandapam group Islands. Considerably, dead reefs in Mandapam group Islands represent 90% of algal communities and very less to scarce faunal diversity. While, faunal diversity was well diversified in the live coral cover areas and reefs with less macroalgal assemblage. This assessment provides current reef biodiversity data for gaining further insights into complex spatial distribution patterns of reef biota in GoM, and this will support the authorities to plan conservation efforts and to support livelihood of local fisher folk community.

Assessment of heavy metals and radionuclides (238U, 232Th and 40K) concentration of beach sands collected from East Coast of Tamilnadu, India with multivariate statistical approach

ABSTRACT This paper discusses the relation between the heavy metal and radionuclide activity concentration in beach sand samples collected from East Coast of Tamilnadu. The elemental composition in beach sands is determined by EDXRF technique. The mean concentrations of elements followed in the order of Si > Ca > Fe > Al > Mg > K > Ti > Mn > Zr > Sr > Zn > Pb > Ni > Cu > Cd > Co in the study area. A NaI(Tl) gamma-ray spectrometer has been used to determine activity concentration of 238U, 232Th and 40K in sand samples. The measured activity in the sand samples ranged from 3.0 to 1766.8 Bqkg−1, 3.0 to 8326.88 Bqkg−1 and 11 to 1434.9 Bqkg−1 for 238U, 232Th and 40K, respectively. The measured natural radioactivity concentration was compared with worldwide average values as reported by UNSCEAR. The interrelation between the natural radioactivity and heavy metal concentration is determined using Pearson correlation coefficient, factor and cluster analysis for finding existing relation between them. The results showed that there is a significant relation of heavy metals for heavy minerals which can contribute radioactivity concentration based on the correlation and factor analysis.

BIOSYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM MARINE MACROSCOPIC RED SEAWEED HALYMENIA PORPHYROIDES BOERGESEN (CRYPTON) AND ITS ANTIFUNGAL EFFICACY AGAINST DERMATOPHYTIC AND NON-DERMATOPHYTIC FUNGI

Objective: The current study illustrates the biosynthesis of economically scalable and energy efficient colloidal silver nanoparticles (AgNPs) from marine red seaweed Halymenia porphyroides Boergesen (Crypton) collected from Southeast coast of Tamil Nadu, India, and their antifungal efficacy against dermatophytic and non-dermatophytic fungi was evaluated.
 Methods: The biosynthesis of silver nanoparticles from marine macroscopic red seaweed H. porphyroides Boergesen were synthesized by green synthesis method and characterized by UV–Vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), scanning electron microscope (SEM), and transmission electron microscopy (TEM). The efficacy of silver nanoparticles against dermatophytic and non-dermatophytic fungi was performed by disk diffusion method.
 Results: The presence of silver nanoparticles with an average size between 34.3 and 80 nm and exhibiting face-centered cubic structure was confirmed. SEM revealed the morphology of the nanoparticles as spherical and TEM exhibited the nanoparticle distribution. The FT-IR spectra confirmed the presence of potential biomolecules in the seaweed crude extract which is responsible for reducing and capping the bioreduced silver nanoparticles. The UV absorption spectra at 430.5 nm revealed the characteristic spectra of the silver nanoparticles. The purity and the thermal stability of silver nanoparticles were revealed by TGA. Silver nanoparticles showed significant efficacy against dermatophytes and Rhizopus microsporus among non-dermatophytes.
 Conclusion: Intermediate efficacy was observed against dermatophytes and among non-dermatophytic fungi R. microsporus exhibited better efficacy, whereas Aspergillus flavus were resistant to the biosynthesized silver nanoparticle.

Spatial and heavy metal assessment in beach sands of east coast of Tamil Nadu, India

Beach sand samples were collected from the East Coast of Tamil Nadu and the concentration of major and trace elements in them were determined using the Energy-dispersive X-ray Fluorescence (EDXRF) technique. The concentration of elements such as Mg, Al, Si, K, Ca, Ti, Fe, Cr, Mn, Co, Ni, Cu, Zn, Pb, Cd, Zr & Sr was determined to assess the contamination status and the degree of pollution level. The abundance of elements in the samples was found to occur in the order: Si > Ca > Fe > Al > Mg > K > Ti > Mn > Zr > Sr > Zn > Pb > Ni > Cd > Cu > Co. The mean concentration of the elements in the beach sand was compared with those in the Earth's Crust, Sandstones, and Ultrabasic Rocks to see if there were any anomalies. The assessment of pollution was carried out by computing the Enrichment factor (EF). The enrichment factor of Fe & Mn indicates that they are possibly from the anthropogenic sources. XRD analysis was carried out to study the influence of heavy metals in the sand samples collected from the study area. SEM-EDX analysis was utilized to reveal the morphology and elemental composition of the selected sand samples. The distribution of metal concentration in the study area was identified by plotting the spatial map. The inter-relationship between the elements was analyzed using the Pearson Correlation Matrix to differentiate between the origin of metals namely anthropogenic or geogenic sources.

Signature of buried channels as deduced from subsurface GPR survey at Southwest coast of Tamil Nadu, India

Buried channels are the subsurface geomorphic features, which illustrate the pattern and evolution of paleodrainage system in an area. Old topographical map (1967) of Kottumangalam coast of southwest Tamil Nadu, India, revealed that surface channel was directly drained into the sea, but in the present situation the same channel is not depicted on maps which indicate the channel has buried. The present study is focused to identify the location and architecture of modern buried channels through ground-penetrating radar (GPR) technology in study area. The study place is highly influenced by natural events (tsunami, high tide flood, and storm), southwest monsoon, and high waves. A 200-m-long subsurface profile was generated using GPR survey parallel to the coast. Geophysical (amplitude, attenuation, magnitude), geological (channel bed, channel bank, erosional surface, volume of sedimentation), and geographical (old topographical map) evidence were considered to identify and locate the paleochannels and to understand their developments at different stages. Two buried channels (at 120–136 m and 184–200 m in the GPR profile) were traced in between 0.5 and 3.2 m depth and it portrays three stages of evolution. High amplitude reflection and dipping of sedimentary beds in the channel banks are the notable signatures of paleochannel in the study area. Flat attenuation curves and velocity differences in the zone of the buried channels disclosed the presence of buried channels. The channels were buried due to changing conditions of marine, aeolian, and fluvial processes. Five distinct sedimentary layers, as shown by variance of reflections of radar wave from subsurface sand material at various depths are recognized as (i) saturated, (ii) semi-saturated, (iii) compact, (iv) transition, and (v) recent upper layer, besides that two erosional surfaces (around 0.8 and 1.5 m depth) were identified. The current study provides a better understating of mapping and identifying the occurrences of paleochannels in coastal environment using GPR technology.

Sustainability assessment for coexistence of afforested mangroves and aquafarms upon existing and predicted scenarios: a case study in Southern Tamil Nadu coast

Coastal stretches abode different features and activities. Among them, mangrove ecosystem is prominent. Mangrove colonies flourishing along the coast stand as the barrier against natural calamities and support the coastal communities by providing livelihood opportunities. Economic benefits from aquaculture trigger its rapid development near the coast in the recent decades. This paper evaluates the present status of mangroves and aquafarms in the coast and harbingers the effects of aquafarm growth in close vicinity of mangroves. The prediction study indicates the increasing pattern of afforested mangroves and the aquafarms in the next decades and elucidates the negative impacts of aquaculture expansion over the flourishing mangroves. Development should be in a sustained way so that the resources will not be affected. Coastal Regulation Zone should be imposed strictly in the sensitive areas like mangroves in order to achieve balance between the conservation of resources and strategic development. Remote sensing and GIS technique were used to assess temporal changes of the features.

Seasonal studies on in situ coral transplantation in the Gulf of Mannar Marine Biosphere Reserve, Southeast coast of Tamil Nadu, India

Since past three decades, coral reefs of the world are degrading at large scales due to climate change and through combination of anthropogenic and natural disturbances. Coral reefs in the 21 islands of Gulf of Mannar Marine Biosphere Reserve, Southeast coast of Tamil Nadu, India are also greatly damaged by frequent bleaching events, destructive fishing, invasive algal assemblage, sedimentation, diseases, and destructive waves and currents. To facilitate the restoration of these habitats, an extensive artificial restoration of corals has been implemented as a counter measurement. This conservation practice will help to increases the live coral covers, rebuild the destroyed coral reefs, and protect the reef biodiversity. The present study underwater experiments were revealed that profuse growths of transplanted corals are dependent on coral species and the study sites. There was significant differences in seasonal growth rate at northern side of Hare Island (p = .03), where the maximum mean Acropora coral growth rate around 11.75 cm was observed during summer from initial mean growth 7.65 cm. Similarly, significant variation in growth rate was observed during monsoon between naturally recruited and transplanted corals (p = .02), where naturally recruited coral colonies, and transplanted coral colonies were displayed the maximum mean growth rates as 11.5 cm, and 7.5 cm respectively in two months,. Significance seasonal influence on growth rates of transplanted coral was observed (p = .01). Relatively, Acropora corals have showed faster growth rates and also resistance to environmental influences such as algal invasion, sedimentation, turbidity, and bleaching events.

Antioxidant status of selected sea weeds of Manamelkudi coast, Pudukkottai district

Manamelkudi, located along the Palk Strait of East coast of Tamil Nadu serve as treasure houses for valuable marine resources like sea grass and sea weeds. A study was undertaken at Agricultural College & Research Institute, Kudumiyanmalai during 2016-17 to evaluate the nutritional composition of the seaweeds in order to use them as potential food ingredients. Sea weed samples were collected from Manamelkudi village of Pudukkotai district and were identified as Gracilaria salicornia (C.Agardh) Dawson and Gracilaria edulis (S.G. Gmel.) P.C. Silva Gracilariaceae at Botanical Survey of India, Coimbatore. The samples were washed in sea and fresh water to remove associated organisms and other extraneous matters. The sea weeds were dried, powdered and used for assessing the antioxidant status. G. edulis showed higher activities of enzymic antioxidants superoxide dismutase (312.03 U/g) and catalase (50.1U/g) when compared to G. salicornia (SOD:266.27U/g and CAT:37.1U/g). Maximum levels of the non-enzymic antioxidants, (total phenol and flavonoid) was found in G. edulis when compared to G. salicornia (5.8 and 3.43mg/g; 5.23 and 3.3mg/g respectively). The extent of lipid peroxidation assessed revealed 70.5 and 32.1 percent inhibition by the ethanolic extract of G. edulis and G. salicornia respectively. The results were comparable with that of the standard antioxidant BHT. Phytochemical analysis revealed the presence of alkaloids, carbohydrates, saponins, proteins, aminoacids, phytosterols, phenolic compounds, flavonoids, terpenoids and tannins except saponins and terpenoids in G. salicornia. Thus it can be concluded from the present investigation that both the seaweeds are potentially rich in natural antioxidants and could be used as nutrient supplements in food industry.