The present study revealed proliferation of macro-algae modifying coral reef ecosystems in a different manner due to diseases and sedimentations in the Mandapam group of islands in the Gulf of Mannar. Benthic surveys ...The present study revealed proliferation of macro-algae modifying coral reef ecosystems in a different manner due to diseases and sedimentations in the Mandapam group of islands in the Gulf of Mannar. Benthic surveys were conducted with major attack of seven coral reefs diseases with high sedimentation rate, nine species of fleshy macro-algae(Turbinaria ornata, Turbinaria conaides, Caulerpa scalpelliformis, Caulerpa racemosa, Kappaphycus alvarezii, Padina gymnosphora, Sargassum wightii, Ulva reticulata and Calurpa lentillifera) proliferation against major corals life forms(Acropora branching, Acropora digitate, Acropora tabulate, coral massive, coral submassive, coral foliose and coral encrusting). The results confirm that diseased corals most favor to macro-algae growth(15.27%) rather than the sedimentation covered corals(8.24 %). In the degradation of coral life forms, massive corals were more highly damaged(7.05%) than any other forms. Within a short period of time(May to September), coral coverage shrank to 17.4% from 21.9%, macro-algae increased 23.51% and the average sedimentation rate attained 77.52 mg cm^(-2) d^(-1) with persisting coral reef diseases of 17.59%. The Pearson correlation showed that the coral cover decreased with increasing macro-algae growth, which was statistically significant(r =-0.774, n = 100, P < 0.0005). The proliferation of the various macro-algae C. scalpellifrmis, T. ornata, C. racemosa, T. conaides, U. reticulata, S. wightii, K. alvarezii, P. gymnosphora and C. lentillifera increased with percentages of 6.0, 5.8, 5.7, 4.9, 4.2, 3.7, 2.7 and 1.9, respectively. If this trend continues, the next generation of new recruit corals will undoubtedly lead to a phase shift in Gulf of Mannar corals.展开更多
Objective:To investigate the antibacterial activity of six seaweeds against twelve human bacterial pathogens using seven different solvents.Methods:Antibacterial activity was evaluated using the disc diffusion techniq...Objective:To investigate the antibacterial activity of six seaweeds against twelve human bacterial pathogens using seven different solvents.Methods:Antibacterial activity was evaluated using the disc diffusion technique on Mueller Hinton agar.Broth dilution assays are standard method used to compare the inhibition efficiency of the antimicrobial agents.Results:Among the six seaweeds tested,the antibacterial activity was higher in the brown seaweeds when compared to red and green seaweeds.Padina gymnospora was found exerting a strong antibacterial activity with a high range inhibition[(6.00±0.82)to(22.67±1.25)mm].Broth dilution assay was conducted against Salmonella sp.with the chloroform extract of Padina gymnospora and the growth inhibition was found in the range of 74.26%to 82.56%.Conclusions:Further research studies are being carried out on other species of seaweeds of different habitats in order to provide complete data of the antimicrobial potential of these algae.It is also essential to study the principle compound present in the seaweeds which is responsible for antimicrobial activity.It can be achieved by using advanced separation techniques.展开更多
基金the National Remote Sensing Center, ISRO-Hyderabad for providing financial supports
文摘The present study revealed proliferation of macro-algae modifying coral reef ecosystems in a different manner due to diseases and sedimentations in the Mandapam group of islands in the Gulf of Mannar. Benthic surveys were conducted with major attack of seven coral reefs diseases with high sedimentation rate, nine species of fleshy macro-algae(Turbinaria ornata, Turbinaria conaides, Caulerpa scalpelliformis, Caulerpa racemosa, Kappaphycus alvarezii, Padina gymnosphora, Sargassum wightii, Ulva reticulata and Calurpa lentillifera) proliferation against major corals life forms(Acropora branching, Acropora digitate, Acropora tabulate, coral massive, coral submassive, coral foliose and coral encrusting). The results confirm that diseased corals most favor to macro-algae growth(15.27%) rather than the sedimentation covered corals(8.24 %). In the degradation of coral life forms, massive corals were more highly damaged(7.05%) than any other forms. Within a short period of time(May to September), coral coverage shrank to 17.4% from 21.9%, macro-algae increased 23.51% and the average sedimentation rate attained 77.52 mg cm^(-2) d^(-1) with persisting coral reef diseases of 17.59%. The Pearson correlation showed that the coral cover decreased with increasing macro-algae growth, which was statistically significant(r =-0.774, n = 100, P < 0.0005). The proliferation of the various macro-algae C. scalpellifrmis, T. ornata, C. racemosa, T. conaides, U. reticulata, S. wightii, K. alvarezii, P. gymnosphora and C. lentillifera increased with percentages of 6.0, 5.8, 5.7, 4.9, 4.2, 3.7, 2.7 and 1.9, respectively. If this trend continues, the next generation of new recruit corals will undoubtedly lead to a phase shift in Gulf of Mannar corals.
文摘Objective:To investigate the antibacterial activity of six seaweeds against twelve human bacterial pathogens using seven different solvents.Methods:Antibacterial activity was evaluated using the disc diffusion technique on Mueller Hinton agar.Broth dilution assays are standard method used to compare the inhibition efficiency of the antimicrobial agents.Results:Among the six seaweeds tested,the antibacterial activity was higher in the brown seaweeds when compared to red and green seaweeds.Padina gymnospora was found exerting a strong antibacterial activity with a high range inhibition[(6.00±0.82)to(22.67±1.25)mm].Broth dilution assay was conducted against Salmonella sp.with the chloroform extract of Padina gymnospora and the growth inhibition was found in the range of 74.26%to 82.56%.Conclusions:Further research studies are being carried out on other species of seaweeds of different habitats in order to provide complete data of the antimicrobial potential of these algae.It is also essential to study the principle compound present in the seaweeds which is responsible for antimicrobial activity.It can be achieved by using advanced separation techniques.
