Now showing items 1-20 of 24
Next Page| Abstract: | The distribution and accumulation of the rare earth elements (REE) in the sediments of the Cochin Estuary and adjacent continental shelf were investigated. The rare earth elements like La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and the heavy metals like Mg, V, Cr, Mn, Fe, Cu, Zn, U, Th were analysed by using standard analytical methods. The Post-Archean Australian Shale composition was used to normalise the rare earth elements. It was found that the sediments were more enriched with the lighter rare earth elements than the heavier ones. The positive correlation between the concentrations of REE, Fe and Mn could explain the precipitation of oxyhydroxides in the study area. The factor analysis and correlation analysis suggest common sources of origin for the REEs. From the Ce-anomalies calculated, it was found that an oxic environment predominates in all stations except the station No. 2. The Eu-anomaly gave an idea that the origin of REEs may be from the feldspar. The parameters like total organic carbon, U/Th ratio, authigenic U, Cu/Zn, V/Cr ratios revealed the oxic environment and thus the depositional behaviour of REEs in the region |
| Description: | J. Earth Syst. Sci. 121, No. 5, October 2012, pp. 1215–1227 |
| URI: | http://dyuthi.cusat.ac.in/purl/4623 |
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| Behaviour of RE ... vidence from anomalies.pdf | (606.6Kb) |
| Abstract: | This study gave the first report on the biennial metal divergence in the sediments of Cochin Estuarine system (CES). Surface sediments from 6 prominent regions of CES were sampled in 2009 and 2011 for the geochemical and environmental assessment of trace metals (Cd, Co, Cr, Cu, Pb Fe, Mg, Mn, Ni and Zn).Besides texture, total organic carbon (TOC) and CHNS were also done. The contamination and risk assessment were performed by determining geochemical indices. Comparison with sediment quality guidelines were done to assess the probability for ecotoxicological threat to the estuary. Results showed that the measured heavy metals had varied spatial distribution patterns, indicating that they had complex origins and controlling factors |
| Description: | International Journal of Recent Scientific Research Vol. 4, Issue, 9, pp.1365- 1369, September, 2013 |
| URI: | http://dyuthi.cusat.ac.in/purl/4621 |
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| Biennial Metal ... ochin Estuarine System.pdf | (496.1Kb) |
| Abstract: | Sediments are the reserve of environmental variation and analysis gives the diverse nature of the environmental chemical pattern. Present attempt provides an insight on the biogeochemistry (BGC) of sediment in selected stations of Kerala coast, India. Sampling along the Kerala coast was done during May – June 2009 in cruise no: 267 of Fishery and Oceanographic Research Vessel, Sagar Sampada. Eleven samples were collected from four stations - Cape, Trivandrum, Kollam and Cochin. Study of organic matter (OM) is significant as it exerts a strong control on the diagenic alterations in the sediment. Samples were analyzed for their Texture; OM- Protein, Carbohydrate, Tannin and lignin, Lipid; Trace metal; Total phosphorus and CHN. Among the eleven analyzed sediment, sample from Cochin station has high clay (>30%) and silt (>40%) content. The rest of the stations showed elevated amount of sand content. Generally the investigation reveals an inverse relation between lipid with other OM- Protein, Carbohydrate, Tannin and lignin. The order of relative distribution of OM were Protein > Carbohydrate > Tannin and Lignin > Lipid. High concentration of trace metal, Fe was found at Kollam and Cochin. Trace metal concentration was directly related to OM distribution. But C/N and Fe/P ratios were inversely related to OM and trace metal. |
| Description: | INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 3, No 1, 2012 |
| URI: | http://dyuthi.cusat.ac.in/purl/4612 |
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| Biogeochemical ... iments in Kerala coast.pdf | (415.0Kb) |
| Abstract: | Sedimentary biomarker pigments around Cochin estuary situated in the southwest coast of India were determined by HPLC. Fucoxanthin, an indicator of diatom was observed to be the most abundant carotenoid pigment in the estuary. Dinoflagellate derived carotenoid pigment peridinin was confined in the southern part of estuary and zeaxanthin pigment indicative of cyanobacteria were more found in sites influenced by anthropogenic activities. One compound having close similarity to fucoxanthin was also detected. Alloxanthin (cryptophyceae), chl b (green algae), canthaxanthin, neoxanthin, lutein and peridinin isomer were also detected by spectra and corresponding algal class were identified. The highest concentration of chl a (11.01 mg g 1) found near to the anthropogenic affected area while the lowest chl a (0.65 mg g 1) was recorded in industrial area. Degradation products of chl a, such as pheophorbide and pheophytin were observed and principal mode of mechanism of degradation were derived. Higher pheopigments content than chl a, reflects a density trapping of dead cells and early degradation of phytopigments from grazing activities |
| Description: | Estuarine, Coastal and Shelf Science 99 (2012) 182-190 |
| URI: | http://dyuthi.cusat.ac.in/purl/4618 |
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| Biomarker pigme ... th west coast of India.pdf | (961.9Kb) |
| Abstract: | Concentration levels of Cr, Ni, Zn, Pb and Cu in relation to those of the nutrients - total phosphates, exchangeable nitrates, total organic carbon, etc. have been investigated in the sediments of Nagapattinam beach after the 2004 tsunami. The maximum values in the study area were 3204, 75, 71, 57 and 18.5 ug g-l for Cr, Ni, Zn, Pb and Cu respectively; Cd was below detectable level. All the trace elements were relatively high in the near-shore sediments and the distribution pattern of the metals in the study area was in the order: Cr > Ni > Zn > Pb > Cu. The present study shows that the tsunami has brought the clayey sediments from the sea-bottom that were settled for years together in inland areas as well as from the offshore sediments. The event has changed the chemical composition of the beach sediments and is threatening fishing grounds even in trace concentrations |
| Description: | CURRENT SCIENCE, VOL. 95, NO.3, 10 AUGUST 2008 |
| URI: | http://dyuthi.cusat.ac.in/purl/4607 |
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| Chemical assess ... after the 2004 tsunami.pdf | (3.147Mb) |
| Abstract: | The distribution and accumulation of trace metals in the sediments of the Cochin estuary during the pre-monsoon, monsoon and post-monsoon periods were investigated. Sediment samples from 14 locations were collected and analysed for the metal contents (Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb), organic carbon, total nitrogen, total sulphur and grain size. The data were processed using statistical tools like correlation, factor and cluster analysis. The study revealed an enrichment of Cd and Zn in the study area particularly at station 2, which is confirmed by enrichment factor, contamination factor and geoaccumulation index. The factor analysis revealed that the source of Cd and Zn may be same. The study indicated that the spatial variation for the metals like Mg, Cr, Fe, Co, Ni, Cu, Zn, Cd and Pb were predominant unlike Mn which shows a temporal variation. The strong association of trace metals with Fe and Mn hydroxides and oxides are prominent along the Cochin estuary. The anthropogenic inputs of industrial effluents mainly control the trace metals enrichment in the Cochin estuary |
| Description: | Environ Monit Assess (2012) 184:6261–6279 |
| URI: | http://dyuthi.cusat.ac.in/purl/4608 |
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| Chemometric stu ... outhwestcoast of India.pdf | (395.9Kb) |
| Abstract: | Geochemical composition is a set of data for predicting the climatic condition existing in an ecosystem. Both the surficial and core sediment geochemistry are helpful in monitoring, assessing and evaluating the marine environment. The aim of the research work is to assess the relationship between the biogeochemical constituents in the Cochin Estuarine System (CES), their modifications after a long period of anoxia and also to identify the various processes which control the sediment composition in this region, through a multivariate statistical approach. Therefore the study of present core sediment geochemistry has a critical role in unraveling the benchmark of their characterization. Sediment cores from four prominent zones of CES were examined for various biogeochemical aspects. The results have served as rejuvenating records for the prediction of core sediment status prevailing in the CES |
| Description: | J. Earth Syst. Sci. 122, No. 6, December 2013, pp. 1557–1570 |
| URI: | http://dyuthi.cusat.ac.in/purl/4622 |
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| Core sediment b ... Estuarine System (CES).pdf | (585.2Kb) |
| Abstract: | Information on the distribution of dissolved Folin phenol active substances (FPAS) such as tannin and lignin in the seawater along the west coast of India is provided. Notable amounts of FPAS (surface concentrations: 80 f.1gll to 147 f.1gll and bottom concentrations: 80 f.1gll to 116 f.1gll) were detected in the seawater along the coast. The distribution pattern brings about a general depth-wise decrease. A seaward decrease was observed in the southern stations whereas reverse was the case in northern stations. A significant negative correlation was observed between FPAS concentration and dissolved oxygen in sub-surface samples. The appreciable amounts of FPAS detected in the coastal waters indicate the presence of organic matter principally originating from terrestrial (upland and coastal marsh) ecosystems in the marine environment. In this context, they may be used as tracers to determine the fate of coastalborn dissolved organic matter in the ocean and to determine directly the relationship between allochthonous and autochthonous organic matter |
| Description: | Journal of Oceanography, Vol. 57, pp. 29 to 36, 2001 |
| URI: | http://dyuthi.cusat.ac.in/purl/4610 |
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| Dissolved Folin ... he West Coast of India.pdf | (547.2Kb) |
| Abstract: | Distribution of toxic metal in the sediment core is an important area of research for environmental impact studies. Sediment cores were collected from two prominent region(C1 and C2) of CE and subjected to geochemical analysis to determine distribution of toxic metals (Cd, Co, Cr, Cu and Pb ), texture characteristics, total organic carbon (TOC) and CHNS. Statistical analysis was done to understand the interrelationship between the components. In the studied cores, metal contamination level was identified for Pb, Cu; Cr, in C1 and C2 respectively. The metal distribution depends on the granulometric factor, geogenic mineral components and anthropogenic input. Correlation analysis (CA) and Principal component(PCA) analysis also support these results |
| Description: | Research Journal of Chemical Sciences,Vol. 3(4), 65-69, April (2013) |
| URI: | http://dyuthi.cusat.ac.in/purl/4619 |
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| Environmental G ... hin Estuary (CE),India.pdf | (116.9Kb) |
| Abstract: | Hydrographic characteristics of the southwest coast of India and its adjoining Cochin backwaters (CBW) were studied during the summer monsoon period. Anomalous formation of anoxia and denitrification were observed in the bottom layers of CBW, which 5 have not been previously reported elsewhere in any tropical estuarine systems. The prevalent upwelling in the Arabian Sea (AS) brought cool, high saline, oxygen deficient and nutrient-rich waters towards the coastal zone and bottom layers of CBW during the high tide. High freshwater discharge in the surface layers brought high amount of nutrients and makes the CBW system highly productive. Intrusion of AS waters seems 10 to be stronger towards the upstream end ( 15 km), than had been previously reported, as a consequence of the lowering of river discharges and deepening of channels in the estuary. Time series measurements in the lower reaches of CBW indicated a low mixing zone with increased stratification, 3 h after the high tide (highest high tide) and high variation in vertical mixing during the spring and neap phases. The upwelled waters 15 (O2 40 μM) intruded into the estuary was found to lose more oxygen during the neap phase (suboxic O2 4 μM) than spring phase (hypoxic O2 10 μM). Increased stratification coupled with low ventilation and presence of high organic matter have resulted in an anoxic condition (O2 = 0), 2–6 km away from barmouth of the estuary and leads to the formation of hydrogen sulphide. The reduction of nitrate and formation of nitrite 20 within the oxygen deficient waters indicated strong denitrification intensity in the estuary. The expansion of oxygen deficient zone, denitrification and formation of hydrogen sulphide may lead to a destruction of biodiversity and an increase of green house gas emissions from this region |
| Description: | Biogeosciences Discuss., 7, 1751–1782, 2010 |
| URI: | http://dyuthi.cusat.ac.in/purl/4598 |
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| Formation of an ... uthwest coast of India.pdf | (6.957Mb) |
| Abstract: | The distribution of three important dissolved forms of nitrogen, viz. nitrate, nitrite and urea in the surface and bottom water samples collected from 27 selected hydrographic profiles, in the Arabian Sea, along the west coast of India is described. Of the three forms, nitrate concentrations were the highest and comparatively higher concentrations were observed in the bottom water. Decomposition of organic matter resulting in the release of the thermodynamically stable nitrogen species, i.e. nitrate, may be the major factor resulting in higher nitrate concentrations at these depths, where the water is also characterized by low values of dissolved oxygen and temperature. The significant positive correlation between A.O.U. and nitrate of the bottom water samples emphasizes the role of oxidative decomposition of organic matter which plays an active role in reducing the oxygen concentrations below the theoretical values since at this depth ( 200 m) the net production is taken to be zero. This is also evidenced by the negative correlation of nitrate with dissolved oxygen and temperature, for the bottom samples |
| Description: | Chemistry and Ecology, 2002, Vol. 18(3–4), pp. 233–244 |
| URI: | http://dyuthi.cusat.ac.in/purl/4613 |
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| Forms Of Nitrog ... Waters Of Arabian Sea.pdf | (187.6Kb) |
| Abstract: | Phosphorus fractionation was employed to find the bioavailability of phosphorus and its seasonal variations in the Panangad region of Cochin estuary, the largest estuarine system in the southwest coast of India. Sequential extraction of the surficial sediments using chelating agents was taken as a tool for this. Phosphate in the water column showed seasonal variations, with high values during the monsoon months, suggesting external runoff. Sediment texture was found to be the main factor influencing the spatial distribution of the geochemical parameters in the study region. Similarly, total phosphorus also showed granulometric dependence and it ranged between 319.54 and 2,938.83 μg/g. Calcium-bound fraction was the main phosphorus pool in the estuary. Significant spatial variations were observed for all bioavailable fractions; iron-bound inorganic phosphorus (5.04–474.24 μg/g), calcium-bound inorganic phosphorus (11.16–826.09 μg/g), and acidsoluble organic phosphorus (22.22–365.86 μg/g). Among the non-bioavailable phosphorus, alkalisoluble organic fraction was the major one (51.92– 1,002.45 μg/g). Residual organic phosphorus was K. R. Renjith (B) · N. Chandramohanakumar · M. M. Joseph Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science and Technology, Kochi 682016, Kerala, India e-mail: renjithaqua@gmail.com comparatively smaller fraction (3.25–14.64% of total). The sandy and muddy stations showed distinct fractional composition and the speciation study could endorse the overall geochemical character. There could be buffering of phosphorus, suggested by the increase in the percentage of bioavailable fractions during the lean premonsoon period, counteracting the decreases in the external loads. Principal component analysis was employed to find the possible processes influencing the speciation of phosphorus in the study region |
| Description: | Environ Monit Assess (2011) 174:299–312 |
| URI: | http://dyuthi.cusat.ac.in/purl/4601 |
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| Fractionation a ... tuary, Southwest India.pdf | (437.1Kb) |
| Abstract: | Geochemical characteristics of surficial sediments in the Panangad region of Cochin estuary, the largest brackish-water humid ecosystem in the south-west coast of India, were analysed. Temporal variations in nutrient stoichiometry, seasonal characteristics of redox elements Fe and S, and the phosphorus geochemistry were employed for the purpose. The stoichiometric analysis pointed towards autochthonous origin of organic matter, possibility of nitrogen limitation, and allochthonous modification of redox conditions. Seasonal variations were not statistically significant for all the geochemical parameters, whereas significant spatial variations were observed with lower values at sandy stations, suggesting that the texture of the sediments is the main factor influencing the sediment geochemistry. Significant inter-relations between the geochemical parameters also suggest a common control mechanism. Based on these geochemical characteristics, the study region can be effectively categorized into two distinct zones, viz. (1) erosion and transportation and (2) deposition zones |
| Description: | Chemistry and Ecology Vol. 23, No. 4, August 2007, 337–345 |
| URI: | http://dyuthi.cusat.ac.in/purl/4602 |
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| Geochemical cha ... uary, south-west India.pdf | (271.9Kb) |
| Abstract: | Southern Ocean (SO) is the fourth largest Ocean comprising the southern portions of the Atlantic Ocean, Indian Ocean and Pacific Ocean. Sediment core sample (660 34’S and 580 40’E)was collected onboard O.R.V Sagar Nidhi from January to March 2010 in the Fourth Southern Ocean expedition cruise launched by the National Centre for Antarctic and Ocean Research, Goa . Sedimentary records from this area reveal the sensitivity and climatic variability’s of the region over a large time scale. Organic matter (OM) and textural behaviour of the samples were analyzed and processed concurrently. Distribution of OM, Total Organic Carbon (TOC), Protein, Lipid and Carbohydrate along with the trace metal was highlighted. Textural variation was in the array of Sand >Clay >Silt. Sand content ranges from 30.29% to 80.11%. The order of relative distribution of OM was Lipid >Protein > TOC > Carbohydrate. The average concentrations of TOC, Protein, Lipid and Carbohydrate were 2.2 mg/g, 1.2 mg/g, 3.3 mg/g and 1.1mg/g respectively. Protein to carbohydrate ratio and lipid to carbohydrate ratio were also encountered to understand the respective freshness and nutritional quality of the sediments. Trace metal distribution showed the average concentration was maximum for Mn and minimum for Co. |
| Description: | Research Journal of Chemistry and Environment Vol.17(2) February (2013) |
| URI: | http://dyuthi.cusat.ac.in/purl/4616 |
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| Geochemistry of ... from antarctic region.pdf | (151.5Kb) |
| Abstract: | The present paper deals with the chemistry, isolation, separation, characterisation and stabilisation of the Marigold oleoresin and its application as a natural food colorant. Marigold (Tagetes Erecta L), an ornamental plant belonging to the composite family, has a rich source of natural antioxidant-Lutein. A natural pigment, xanthophylls offer an alternative to synthetic dyes as a food colorant, due to its non-toxicity. Chromatographic separations of saponified and unsaponified oleoresin were performed and Trans-Lutein identified as the major constituent. Well-preserved flowers exhibit a high yield of Xanthophyll content (105.19 g/Kg) in contrast to the unpreserved flower sample (54.87 g/Kg), emphasizing the significance of flower preservation in the extraction of xanthophyll. The stability and amount of xanthophyll also increased from 105.19 g/Kg to 226.88 g/Kg on saponification and subsequent purification with Ethylene Dichloride |
| Description: | Modern Applied Science,Vol 3,No 2,february 2009 |
| URI: | http://dyuthi.cusat.ac.in/purl/4609 |
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| Isolation, Stab ... ower- Tagetes Erecta-L.pdf | (575.2Kb) |
| Abstract: | Kerala is one of the smallest states in India which is situated in the south west coast of the country. Sediment samples from four prominent areas of Kerala Coast were collected and analyzed for nutrients. Variation of nutrients was highlighted according to the distributional characteristics of the designated sites. Nutrient trend in Cape, Trivandrum, Kollam was in the order as Ammonia > Nitrite >Nitrate, where as Cochin showed the trend as Ammonia > Nitrate > Nitrite. Greater concentration of ammonia in the entire sediments showed the ammonification of nitrogen compounds |
| Description: | INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 3, No 5, 2013 |
| URI: | http://dyuthi.cusat.ac.in/purl/4617 |
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| Nutrient dynami ... iments of Kerala coast.pdf | (289.1Kb) |
| Abstract: | Distribution and chemistry of major inorganic forms of nutrients along with physico-chemical parameters were investigated. Surface sediments and overlying waters of the Ashtamudi and Vembanad Lakes were taken for the study, which is situated in the southwest coast of India. High concentrations of dissolved nitrogen and phosphorus compounds carried by the river leads to oxygen depletion in the water column. A concurrent increase in the bottom waters along with decrease in dissolved oxygen was noticed. This support to nitrification process operating in the sediment-water interface of the Ashtamudi and Vembanad Lake. Estuarine sediments are clayey sand to silty sand both in Ashtamudi and Vembanad in January and May. Present study indicates that the sediment texture is the major controlling factor in the distribution of these nutrient forms. For water samples nitrite, inorganic phosphate was high in Vembanad in January and May compared to Ashtamudi. For sediments, enhanced level of inorganic phosphate and nitrite was found in Vembanad during January and May. It had been observed that the level of N and P is more in sediments. A comparative assessment of the Ashtamudi and Vembanad Lake reveals that the Vembanad wetland is more deteriorated compared to the Ashtamudi wetland system |
| Description: | Indian Journal of Marine Sciences Vol. 38(4), December 2009, pp 451-456 |
| URI: | http://dyuthi.cusat.ac.in/purl/4615 |
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| Nutrient dynami ... lakes of Kerala, India.pdf | (1.039Mb) |
| Abstract: | Present study consists the quantization of specific metals-- Cr, Cd, Pb, Zn and Cu observed in the experimental bivalve, Villorita species. Bivalve specimens were collected seasonally from the identified three hot spots of Vembanad Lake. Soft tissue concentrations of metals are very sensitive in reflecting changes in the ambient environment and hence important in assessing the environmental quality. Concentrations of Zn in bivalves were fairly high compared to other metals. All the stations showed a maximum concentration during premonsoon and minimum during the other two seasons. Levels of Pb, Cu, Zn, Cd and Cr are between 0-6.17mg/kg, 0-17.224mg/kg, 1.916-255.163mg/kg, 0.325-4.133mg/kg, and 0-15.233mg/kg respectively |
| Description: | Indian Journal of Geo-Marine Sciences Vol. 40 (3), June 2011, pp 424-429 |
| URI: | http://dyuthi.cusat.ac.in/purl/4611 |
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| Quantization of ... in the Cochin estuary.pdf | (321.3Kb) |
| Abstract: | The fertility of the coastal and estuarine waters is of great concern because of its influence on the productivity of these waters. Seasonal variations in the distribution of organic carbon, total nitrogen and total phosphorus in the sediments of Kuttanad Waters, a part of the tropical Cochin Estuary on the south west coast of India, are examined to identify the contribution of sediments to the fertility of the aquatic systems. The adjoining region has considerable agricultural activity. The fresh water zones had higher quantities of silt and clay whereas the estuarine zone was more sandy. Organic carbon, total phosphorus and total nitrogen were higher in the fresh water zones and lower in the estuarine zones. Total phosphorus and organic carbon showed the lowest values during monsoon periods. No significant trends were observed in the seasonal distributions of total nitrogen. Ratios of C/N, C/P and N/P, and the phosphorus and nitrogen content indicate significant modification in the character of the organic matter. Substantial amounts of the organic matter can contribute to reducing conditions and modify diagenetic processes |
| Description: | Internat. Rev. Hydrobiol. 88, 2003, 2, 179–186 |
| URI: | http://dyuthi.cusat.ac.in/purl/4599 |
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| The Ratios of C ... stem of Southern India.pdf | (132.1Kb) |
| Abstract: | The mangroves of Kerala are fast disappearing due to developmental activities.There are very few studies conducted in the chemical aspects of these ecosystems.The main objective of this study is to assess the spatial and seasonal variation of hydrographical as well as nutrients in mangrove ecosystems along Kerala coast. Five sampling sites least intervened by industries were selected for the study. Sampling was done for a period of six months in monthly intervals. A monsoonal hike of dissolved nutrients was observed in all ecosystems except in the constructed mangrove wetland. The constructed wetland exhibited a different hydrography and nutrient level in all seasons. The mangrove forest in this area consists of the species Bruguiera gymnorrhiza which has been planted since forty years. |
| Description: | Journal of Wetlands Ecology, (2009) Vol. 3, pp 32-42 |
| URI: | http://dyuthi.cusat.ac.in/purl/4604 |
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| Seasonal Variab ... Coast Of Kerala, India.pdf | (259.4Kb) |
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