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Sodium, Potassium and Sulphate Composition in Some Seaweeds Occurring along the Coast of Gulf of Mannar, India

S.R. Sivakumar and K. Arunkumar
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Minerals such as sodium (Na+), potassium (K+) and sulphate were analyzed in red, brown and green abundant seaweeds found along the Coast of Gulf of Mannar, India, during July 2005. A high mean amount of Na+ was recorded in Chlorophyceae followed by Rhodophyceae and Phaeophyceae. The mean value of K+ in the brown and red algae were higher when compared to green seaweeds. A less Na+/K+ ratio indicated high K+ and low Na+ in brown and red algae and a high Na+/K+ ratio in green seaweeds indicated high Na+ and low K+. The sulphate content was variable in the algae studied; the maximum concentration was found in red alga Grateloupia lithophila (162.8 mg g-1 alga dry wt.) and minimum in brown alga Chnoospora implexa (0.88 mg g-1 alga dry wt.).

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S.R. Sivakumar and K. Arunkumar, 2009. Sodium, Potassium and Sulphate Composition in Some Seaweeds Occurring along the Coast of Gulf of Mannar, India. Asian Journal of Plant Sciences, 8: 500-504.

DOI: 10.3923/ajps.2009.500.504



All the essential minerals are provided by seaweeds and these essential minerals may be some time absent from freshwater and food crops grown on mineral-depleted soils. Seaweeds contain 20-50% minerals in their dry weight (Kazutosi, 2002). This figure was obtained by burning off seaweed’s organic material and weighing the remaining ash. The elements abundant in seaweeds include: potassium, sodium, calcium, magnesium, zinc, copper, chloride, sulfur, phosphorous, vanadium, cobalt, manganese, selenium, bromine, iodine, arsenic, iron and fluorine. Besides, seaweeds are rich in cell wall polysaccharides, vitamins and protein, of which brown algae tend to contain more minerals per unit weight than the red (Mabdau and Fleurence, 1993). Sodium, potassium and sulfur are found relatively in high quantities in marine algae and utilized directly for the cellular building blocks (De Boer, 1981). The mineral constituents of different species of marine algae around the world and Indian coast have been investigated (Rao Kesava, 1987; Rao Kesava and Indusekhar, 1987, 1989; Oza et al., 1983; Harold, 1977). The mineral constituents such as Ca, Na, K, P, Fe, Mn, Mg and Cl were analyzed in seaweeds (Rajasulochana et al., 2002; Vasanthi and Rajamanickam, 2003). The amount of K+ was higher than Na, P and Cl contents in marine algae (Tewari and Rao, 1988). But in edible red seaweed Porphyra vietnamensis reported high Na and less K (Subba Rao et al., 2007). Though the seaweeds living in ocean containing predominantly Na and their salts, some seaweeds accumulated more K and their salts than Na. Potassium is an essential macronutrient required for the growth and metabolic activities of plants in general and seaweeds in particular. However, some seaweeds sequested more of Na+ than K+ (Dickson and Kirst, 1897). Sulphate is an important anion incorporated in commercially important cell wall hetero-polysaccharides of most of the seaweeds. The Gulf of Mannar located in the southeast coast of India declared as a biosphere reserve with an area of 10, 500 km2 considered as biodiversity hot spot supported with 3600 species of corals, crustaceans, mollusks, fin fishes, seaweeds, sea grasses, mangroves and other marine animals. Seaweeds occurring abundantly in the 21 islands of this Gulf region are exploited for their commercial utilization (Kumaraguru, 2006). The present investigation was aimed to study the Na+, K+ and sulphate content in some red, brown and green seaweeds abundantly occurring along the coast of Gulf of Mannar, Rameswaram, Tamil Nadu, India and the proportion of Na+ and K+ was expressed as Na+/K+ ratio because it is a good index to indicate the level of Na+ and K+ salts in the seaweeds.


Collection of material: Ten red seaweeds such as Gelidiella acerosa (Forsskal) J. Feldmann and G. Hamel, Cheilosporum spectabile Harvey, Grateloupia lithophila Boergesen, Gracilaria corticata var. corticata (J. Agardh) J. Agardh, G. corticata (J. Agardh) J. Agardh var. cylindrica Umamaheswara Rao, G. canaliculata Sonder (G. crassa), G. pudumadensis V. Krishnamurthy and Rajendran, Hypnea valentiae (Turner) Montagne, Acanthophora spicifera (Vahl) Borgesen and Laurencia poitei (Lamour.) Howe.; 10 brown seaweeds such as Dictyota dichotoma (Huds.) Lamour., Stoechospermum marginatum (J. Ag) Kuetz., Padina boergesenii Allender and Kraft, Hydroclathrus clathratus (C. Agardh) Howe., Chnoospora implexa J. Agardh, Hormophysa cuneiformis (J. Gmelin) P. Silva (Hormophysa triquetra), Sargassum longifolium J. Agardh, Sargassum myriocystum J. Agardh, Sargassum wightii Greville and Turbinaria conoides (J. Agardh) Kutzing; and 5 green seaweeds such as Enteromorpha compressa (Linn.) Nees, Ulva lactuca Linn., Ulva reticulata Forsskal, Valoniopsis pachynema (Martns) Boergsen and Helimeda gracilis Harvey ex J. Agardh were collected from the inter-tidal and sub-tidal regions along the Coast of Gulf of Mannar region during July 2005. After hand picking, the seaweeds were cleaned with seawater and then thoroughly with fresh water (3 to 4 times) to remove the extraneous matters such as associated fauna and pebbles. The samples were dried in shade for 5 days and then in an oven at 60°C for 12 h till getting constant weight. The algae were identified with the help of Check list of Indian Marine algae (Oza and Zaidi, 2001).

Flame photometric detection of sodium and potassium (Jackson, 1971): One gram of each dried seaweed sample was digested in 10 mL of triple acid mixture of H2SO4: HNO3: HCl (9:3:1 v/v/v). Liquid ammonia was added into the digested sample to adjusted the pH 7 and the volume was made up to 100 mL by using distilled water. Then it was filtered through Whatman No.40 filter paper and the filtrates were stored in clean glass bottles till analysis made. The analysis of Na+ and K+ were done by using a Flame photometer (Elico, India) by selecting suitable filter against deionised water as a blank.

Estimation of sulphate (Verma et al., 1977): The sulphate content of all seaweeds except 3 Red seaweeds (Cheilosporum spectabile, Gracilaria crassa and G. pudumadensis) and 3 Green (Enteromorpha compressa, Ulva reticulata and Valoniopsis pachynema) was made. One gram of each algal sample was subjected to 10 mL of triple acid mixture for digestion. To a 10 mL of aliquot prepared by triple acid mixture digestion, 1 mL of 6 M HCl followed by 5 mL of 70% sorbital solution and 1 g of BaCl2. 2H2O crystals were added. The content was shuck vigorously to dissolve the barium chloride and allowed to stand for at least 5 min. Then the turbidity of the suspension was read in a colorimeter at 470 nm, along with standards prepared in the same way and covering the sulphate concentration range 0-50 ppm. If the suspensions were left to stand for long time, it was advisable to shake the tubes gently before taking the reading. Triplicates were maintained for each experiment and mean values were expressed as mg g-1 alga dry wt.

Mean and Duncan Multiple Range Test (DMRT) were analyzed using SPSS14 statistical package and results expressed.


In the present study, analysis on Na+ and K+ content of 10 red, 10 brown and 5 green seaweeds; and sulphate content of all seaweeds except 3 red seaweeds (Cheilosporum spectabile, Gracilaria crassa and G. pudumadensis) and 3 green (Enteromorpha compressa, Ulva reticulata and Valoniopsis pachynema) occurring along the coast of Gulf of Mannar were made and the following results are recorded.

In the present study, 7 red seaweeds such as Gelidiella acerosa, Cheilosporum spectabile, Gratelooupia lithophila, Gracilaria corticata var. cylindrica, G. crassa, Hypnea valentiae and Laurencia poitei were accumulated more Na than K, however the mean K content was higher than Na in the members of Rhodophyceae (Table 1). This is due to very high amount of 140.5, 119.12 and 114.54 mg g-1 dry wt. of K recorded in the red seaweeds such as Gracilaria corticata var. corticata, G. pudumadensis and Acanthophora spicifera, respectively. The mean Na/K ratio of red algae was 0.91. Unlike red algae, the ratio of Na/K in brown was decreased to 0.73 and this decrease in the mean value of Na/K ratio indicated as high K accumulation in brown seaweeds than in red (Table 2). Of the 10, 7 brown seaweeds contained more K than Na where as the rests were accumulated more Na. Based on the K+ accumulation, the seven brown algae were arranged in decreasing order: Sargassum longifolium, Turbinaria conoides, Stacheospermum marginatum, Padia boergesenii, Hydroclathrus clathratus, Dictyota dichotoma and Sargassum myriocystum. Less Na/K ratio indicated high K and low Na content (Table 1, 2). A maximum amount of 121.41 mg g-1 alga dry wt. of K and 68.63 mg g-1 alga dry wt. of Na was recorded in Sargassum longifolium and Turbinaria conoides, respectively. Compared to red and brown, mean Na/K ratio was very high (1.79) in green seaweeds which indicate increasing level of Na+ and decreasing level of K+ (Table 1). Though a maximum Na+ accumulation of 172.85 mg g-1 dry wt. was recorded in green alga Valoniopsis pachyniema,high proportionate accumulation of Na over K was observed in Helimeda gracibis, Enteromorpha compressa, Valoniopsis pachynima, Ulva reticulata and U. lactuca which was clearly indicated in Na/K ratio as an order of hierarchy (Table 1).

Table 1: Na+, K+ and Na+/K+ ratio of seaweeds collected along the Coast of Gulf of Mannar, Rameswaram region, Tamil Nadu, India during July 2005 (*mg g-1 dry wt.)
Image for - Sodium, Potassium and Sulphate Composition in Some Seaweeds Occurring along the Coast of Gulf of Mannar, India
Mean values not followed in the same letter significantly differed within the class of algae at 5 % level

Table 2: The mean Na+, K+ and Na+/K+ ratio of seaweeds collected along the Coast of Gulf of Mannar, Rameswaram region, Tamil Nadu, India during July 2005 (*mg g-1 alga dry wt.)
Image for - Sodium, Potassium and Sulphate Composition in Some Seaweeds Occurring along the Coast of Gulf of Mannar, India
Mean values not followed in the same letter significantly differed within the class of algae at 5% level

In the present study, sulphate content of 19 seaweeds such as red, Gelidiella acerosa, Grateloupia lithophila, Gracilaria corticata var. corticata, Gracilaria corticata var. cylindrica, Gracilaria crassa, Acanthophora spicifera and Laurencia poitei; brown, Dictyota dichotoma, Stoechospermum marginatum, Padina boergeseni, Hydroclathrus clathratus, Chnoospora implexa, Hormophysa triquetra, Sargassum mariocystum, Sargassum longifolia, Sargassum wightii and Turbinaria conoides and green Ulva lactuca and Helimeda gracibis was made. Generally two green algae contained high sulphate. However, of all the seaweeds studied, a maximum sulphate content was registered in red seaweed Grateloupia lithophila (168.2 mg g-1 dry wt.) while minimum sulphate content was recorded in brown seaweeds Hormophysa triquetra, Chnoospora implexa and Sargassum wightii (0.88 mg g-1 dry wt.).

Table 3: Sulphate content of seaweeds collected along the Coast of Gulf of Mannar, Rameswaram region, Tamil Nadu, India during July 2005
Image for - Sodium, Potassium and Sulphate Composition in Some Seaweeds Occurring along the Coast of Gulf of Mannar, India
Mean values not followed in the same letter significantly differed within the class of algae at 5% level

Among the green seaweeds a high sulphate content of 66.4 mg g-1 dry wt. was recorded in Ulva reticulata (Table 3).


In the present study, 7 red algae were accumulated more Na than K, however the red algae Gracilaria corticata var. corticata, G. pudumadensis and Acanthophora spicifera contained high K as in 7 brown algae, whereas very high level of Na than K was recorded in green algae. As like in the present study, high potassium and low sodium were recorded in the brown algae Macrocystis integerifolia and Nereocystis luetkeana (Vinogradov, 1953; Sitakara and Tipnis, 1967). Bio-deposited concentration of elements such as Ca, K, Na, Mg, Mn and P showed high K and low Na in brown and red algae whereas high Na and low K were recorded in green seaweeds (Sivalingam, 1978). The salt inclusion and/or exclusion mechanisms in operation to avoid or tolerate the high salinity condition in marine organism. Accumulation of high concentration of Na as salt inclusion mechanism was toxic to biological systems. To lessen this toxic effect, Na was sequestered in side the vacuoles and the vacuolar osmotica was counter balanced by synthesizing non-toxic organic osmotic substances in the cytosol. Operation of this mechanism requires less expenditure of energy (Raven, 1980). High Na and low K recorded in green seaweeds in the present investigation may adopt the salt inclusion mechanism to withstand the saline condition. Most of the brown algae (7 out of 10) and few of the red algae (3 out of 7) accumulated more K than Na. This indicated that red and brown algae may sustain in seawater by operating Na exclusion mechanism. Active accumulation of K in their cell sap against osmotic gradient operating as salt exclusion mechanism at the expenditure of photosynthates and/or membranes with a lower permeability to (toxic) Na than K to lower the intracellular Na content below the (equilibrium) value from the interior negative membrane potential (Harold, 1977; Raven, 1980). Osmoregulation in marine algae are mainly maintained by Na+ and K+ pump operating between seawater and cell sap and the turgor pressure changes are caused by variable ionic composition of vacuoles (Eisler, 1980). Accumulation of more K than Na in brown and red algae against salt gradient of seawater indicated that they thrive in salinity by operating salt exclusion mechanism whereas high Na in green tolerate the salinity with salt inclusion principle. Variation in sodium, potassium, calcium and magnesium content observed among the different genera of seaweeds showed that high Na and low K were recorded in green seaweeds where as high K and low Na were recorded in brown and red algae (Ramavat et al., 1986).

Sulphate is an essential macronutrient required for the growth and development of algae. It is constituted in commercially important cell wall polysaccharides of red and brown seaweeds. However, Craigie (1990) reported low quality of agar in Gracilaria sp. due to high sulphate content. Studies of Craigie et al. (1984) and Cote and Hanisak (1986) showed that gel strength is one of the factors to determine the quality of agar which is inversely proportional to sulphate content. Carrageenans are highly sulphated polysaccharides found in some red seaweeds and its gel strength was inversely proportional to the sulphate content (Doshi et al., 1968; Ramalingam et al., 2003; Chandrasekhara and Kaladharan, 2003). The cell wall hetero-polysaccharide, fucoidan displaying various bioactivity mainly constituted with L-fucose sulphated at 2 and 4 position was extracted from brown algae (Percival and Ross, 1950; Black, 1954; Boisson-vidal et al., 1995). As like the earlier findings, in the present study, two green algae and some red and brown algae which are not potentially viable for the extraction of commercial cell wall hetero-polysaccharides (Agar, algin, carrageenan, fucoidan etc.,) contained high sulphate. So, those algae which are not commercially important for the extraction of cell wall polysaccharides but contained high sulphate recorded in the present study may opt as a source of sulphate.


Some algae contain high quantity of Na, K and Sulphate. Accumulation of more Na in majority of red seaweeds and a few brown seaweeds and accumulation of more K in few red seaweeds and majority of brown seaweeds shows that both groups sustaining in salinity by operating either Na inclusion and/or exclusion mechanism whereas all green seaweeds may defend salinity only by Na inclusion mechanism. Some red and brown algae are not commercially important for the extraction of cell wall polysaccharides sequestering high K and sulphate they may serve as a source of essential macronutrients (K and sulphate).


The authors are grateful to The Principal and Prof. P. Chandrasekaren, Head of the Department of Botany, Alagappa Government Arts Collage, Karaikudi, Tamil Nadu, India for permission and facilities provided for carrying out this study. I extremely thankful to Prof. Rengasamy, Director, Centre for Advanced Studies in Botany, University of Madras, Chennai-600 025, India for constructed suggestion while writing the articles.

1:  Black, W.A.P., 1954. The seasonal variation in the combined L-fucose content of the common British Laminariaceae and fucaceae. J. Sci. Food Agric., 5: 445-448.
CrossRef  |  Direct Link  |  

2:  Boisson-vidal, C., F. Haroun, M. Ellouali, C. Blondin, A.M. Fischer, A. De Agostini and J. Jozefonvicz, 1995. Biological activities of polysaccharide from marine algae. Drugs Future, 20: 1237-1249.
Direct Link  |  

3:  Chandrasekhara, R.A. and P. Kaladharan, 2003. Improvemebnt of yield and quality of agar from Gracilaria edulis (Gmelin.) silva. Seaweed Res. Utiln., 25: 131-138.

4:  Cote, G.I. and M.D. Hanisak, 1986. Production and properties of native agars from Gracilaria tikvahiae and other red algae. Bot. Mar., 29: 359-366.

5:  Craigie, J.S., Z.C. Wen and J.P.V. Meer, 1984. Interspecific and nutritionally determined variations in the composition of agar from Gracilaria sp. Bot. Mar., 27: 55-61.

6:  Craigie, J.S., 1990. Cell Walls. In: The Biology of the Red Algae, Cole, K.M. and R.G. Sheath (Eds.). Cambridge Univ. Press, Cambridge, pp: 221-257.

7:  De Boer, J.A., 1981. Nutrients. In: The Biology of Seaweeds, Lobban, C.S. and M.J. Wynne (Eds.). Blackwell Scientific Publications, Oxford, pp: 359-391.

8:  Dickson, D.M. and G.O. Kirst, 1987. Osmotic adjustment in marine eukaryotic algae: The role of inorganic ions, quaternary ammonium, tertiary sulphonium and carbohydrate solutes II. prasinophytes and haptophytes. New Phytol., 106: 645-655.
CrossRef  |  Direct Link  |  

9:  Doshi, Y.A., P.V. Raju and P.S. Rao, 1968. A relation between sulphate content in red seaweeds and the gel strength of agar. Curr. Sci., 34: 493-493.

10:  Eisler, R., 1980. Accumulation of Zinc by Marine Biota. In: Zinc in Environment Part 2: Health Effects, Nriagu, J.O. (Ed.). Jhon Willey, New York, pp: 259-351.

11:  Harold, F.M., 1977. Ion currents and physiological functions in micro-organisms. Annu. Rev. Microbiol., 31: 181-203.
CrossRef  |  PubMed  |  Direct Link  |  

12:  Jackson, M.L., 1971. Soil Chemical Analysis. Prentice Hall of India, New Delhi, India, ISBN: 1-893311-47-3, Pages: 574.

13:  Kumaraguru, A.K., 2006. Bibliography of Gulf of Mannar-Executive Summary. In: National Research and Monitoring Moderation Workshop, Melkani, V.K., V. Naganathan, R. Uma and R. Maheswari (Eds.). Gulf of Mannar Biosphere Trust, Ramanathapuram 623501, Tamil Nadu, India, pp: 1-5.

14:  Kazutosi, N., 2002. Seaweeds Kaiso: Bountiful harvest from the seas. Sustenance for Health and Wellbeing.

15:  Mabdau, S. and J. Fleurence, 1993. Seaweeds in food products: Bio-chemical and nutritional aspects. Trends Foods Sci. Technol., 4: 103-107.

16:  Oza, R.M., H.V. Joshi, R.G. Parekh and V.D. Chauhan, 1983. Preliminary observations on a Monostroma Sp from Okha coast, Gujarat. Indian. J. Mar. Sci., 12: 115-117.

17:  Oza, R.M. and S.H. Zaidi, 2001. A Revised Checklist of Indian Marine Algae. Central Salt and Marine Chemicals Research Institute, India, pp: 296.

18:  Percival, E.G. and A.G. Ross, 1950. The isolation and purification of fucoidin from brown seaweeds. J. Chem. Soc., 3: 717-720.

19:  Rajasulochana, N., M. Baluswami, M.D. Vijayaparthasarathy and V. Krishnamurthy, 2002. Chemical analysis of Grateloupia lithophila. Boerg. Seaweed Res. Utiln., 24: 79-82.

20:  Ramalingam, J.R., N. Kaliaperumal and S. Kalimuthu, 2003. Commercial scale production of Carrageeenan from red algae. Seaweeds Res. Utiln., 25: 37-46.

21:  Ramavat, B.K., Y.A. Doshi, R.G. Parekh and V.D. Chauhan, 1986. Concentration of polyvalent metals by seaweeds from Okha coast. Phykos, 30: 44-50.

22:  Rao Kesava, C.H., 1987. Studies on seaweeds variation in the important chemical constituents of some seaweeds and seawater along the Saurashtra coast. Ph.D. Thesis, Bhavanagar University.

23:  Rao Kesava, C. and V.K. Indushekhar, 1987. Carbon, nitrogen and phosphours ratios in seawater and seaweeds of saurashtra northwest coast of India. Indian J. Mar. Sci., 16: 117-121.
Direct Link  |  

24:  Rao Kesava, C.H. and V.H. Indushekher, 1989. Seasonal variation in chemical constituents of certain brown seaweeds and seawater from Saurashtra coast. I. Carbon ,Nitrogen and phophorus. Mahasagar, 22: 63-72.

25:  Raven, J., 1980. Nutrient transport in microalgae. Adv. Microbiol. Physiol., 21: 226-247.
PubMed  |  Direct Link  |  

26:  Sivalingam, P.M., 1978. Bio-deposited Trace metals and mineral contents studies of some Tropical marine algae. Bot. Mar., 21: 327-330.

27:  Sitakara, R.V. and U.K. Tipnis, 1967. Chemical composition of some marine algae from Gujarat coast. Proceedings of the Symposium on Sea, Salt and Lands, (SSL'67), Bhavnagar, India, pp: 227-228.

28:  Subba Rao, P.V., V.A. Mantri and K. Ganesan, 2007. Mineral composition of edible seaweed Porphyra vietnamensis. Food Chem., 102: 215-218.
Direct Link  |  

29:  Tewari, A. and M.P. Rao, 1968. Chemical composition of a species of Porphyra from Vishakhapatnam. South India Curr. Sci., 5: 138-139.
Direct Link  |  

30:  Vasanthi, H. and G.V. Rajamanickam, 2003. Variations in the chemical constituents present in Hypnea valentiae at Tuticorin and Manadapam coast-an environmental impact. Seaweed Res. Utiln., 25: 115-121.

31:  Verma, B.C., K. Swaminathan and K.C. Suel, 1977. An improved turbidometric procedure for the determination of sulphate in plants and soils. Talanta, 24: 49-50.
PubMed  |  Direct Link  |  

32:  Vinogradov, A.P., 1953. The Elementary Chemical Composition of Marine Organisms (Efron and Setlow, Translators). Yale Univ. Press, New Haven, USA., pp: 463-566.

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