ECOLOGICAL CHARACTERISTICS OF THE DIFFERENT ECOSYSTEMS in COASTAL areas OF THE ANDAMAN ISLANDS

Coastal ecosystems are well known for their higher primary and secondary productivity and support of diverse floral and faunal communities.  Especially coral reef and seagrasses create, as well as occupy, important niches in shallow water environments.  Physico- chemical characteristics of the critical habitats (Mangrove, seagrass, dead coral bed and sandy beach) of Andaman islands were studied.  Physico-chemical parameters recorded in 18 stations showed distinct variations among different ecosystems, especially chemical parameters showed notable variations in all these ecosystems. Sediment characters showed significant variations: pH of the sediments varied between 8.1 and 8.6 in all the sampling locations and the electrical conductivity of the sediments varied between 2.1 and 4.1dSm-1. Sediment nutrients varied widely: nitrogen (22-52 kg/acre), phosphorus (10-15 kg/acre) and potassium (55-73 kg/acre). Though the physico-chemical parameters showed distinct variations among different ecosystems, they are within the optimum range reported for the specific ecosystems prevailing in the area. In general, the nutrient level of water in the seagrass and mangroves was low when compared similar ecosystems of the mainland. It is important to note that, though the ambient water quality of these ecosystems is at the optimum level reported for the respective ecosystems, proper attention should be paid to maintain the subtle nature of the ecosystems of the islands, under the post-tsunamic geomorphological variations, increasing national and international tourism activity and the changing climatic conditions

Remote sensing application in the conservation and management of coastal bio resources of the Palk Bay, Southeast coast of India

Various resources of the Palk Bay, Southeast coast of India viz. coral reefs, reef vegetation, denseseagrass beds, sparse seagrass beds, dense mangroves and sparse mangroves were classified throughvisual interpretation and digital image processing method using IRS-LISS - III (1996,2000,2002 &2004) satellite data. The resource maps were generated and reclassified after intensive ground truthverifications. The Palk Bay has shown an areal extent of 286.95 ha of reef area during 2004, whichis 177.54 ha lesser than that of the reef area of 1996. The reef vegetation composed mainly ofseaweeds, has gained over 29.44 ha and sand over reef area also has increased alarmingly i.e. 120.34ha during the same period. The study has revealed the reduction of dense seagrass beds by 785.5 habetween 1996 and 2004 while the sparse seagrass beds have gained 513.68 ha during this period. Thesparse mangrove cover area has increased to about 36.45 ha and there is also a 2.99 ha increase inthe dense mangrove cover. Various reasons for the changes have been identified and based on whichsuitable plans have been suggested for the effective conservation and management of the importantbio-resourccs of the Palk Bay

Statistical tools for studying the temporal variations in chlorophyll-a concentration along the Southwest Bay of Bengal waters

454-464Multivariate statistical analysis such as multiple linear regression (MLR) and principal component analysis (PCA) are used to study the effect of physico-chemical parameters on chlorophyll distribution along the southwest Bay of Bengal from January 2012 to June 2014. Physical properties recorded showed clear seasonal patterns in sea surface temperature (26.2 – 32.8 °C), salinity (24 – 36 PSU), pH (7.808 to 8.428), photosynthetic photon flux (522 – 1220.4 μM m-2s-1) with the minimum and maximum values during monsoon and summer seasons, respectively. In contrast, the chemical variables such as nitrite (0.15 to 2.35 μM), nitrate (1.02 to 6.58 μM), ammonia (0.11 – 5.22 μM), total nitrogen (1.04 to 11.58 μM), inorganic phosphate (0.16 – 2.97 μM), total phosphorus (0.55 – 8.60μM) and reactive silicate (2.00 to 23.95 μM) showed the minimum and maximum concentration during summer and monsoon seasons, respectively. The high and low chlorophyll (0.10 to 6.92 μg l-1) and dissolved oxygen (4.07 and 7.884 mg l-1) concentrations are observed during summer and pre-monsoon seasons, respectively. PCA found that nitrogenous nutrients and chlorophyll are positively loaded and sea surface temperature (SST) was negatively loaded in all the seasons except during summer season. Inter-comparison of modeled and in-situ chlorophyll-a (chl-a) concentration showed a significant correlation during monsoon season by 93 % of matchup with a R2 = 0.930, N = 60 and SEE = ±0.369 compared to other seasons. Regression analysis also predicted the positive influence of nitrate and ammonia and negative influence of SST with chl-a

Partial pressure of carbon dioxide (pCO2) and air-water CO2 exchange in the tropical semidiurnal estuarine system

Time-series observations of the Vellar estuary between May 2013 and December 2019 showed clear variability with respect to space and time in the distribution of nutrients, partial pressure of carbon dioxide (pCO2) and air-water CO2 exchange. Lower and higher salinities revealed significant seasonality in estuarine pCO2, as well as variations in the seasonal pattern due to the freshwater discharges during monsoon rainfall. The pCO2 attained the highest levels (8457 µatm) during monsoon which coincided with the lowest pH (7.498) and the undersaturation of pCO2 (322 µatm) was observed with maximum pH (8.182) during pre-monsoon. The Principal Component Analysis (PCA) identified four components that accounted for 77.28 % of the total variance and explained the significant influence of nutrients, chlorophyll and temperature on pCO2 distribution. Similarly, the multiple linear regression analysis showed significant influence of environmental variables on pCO2 variability with a R2 of 0.957, SEE±230.816, p < 0.001. The surveyed area of the Vellar estuary had an overall pCO2 of 1068 µatm and was supersaturated with regard to the atmospheric pCO2 throughout the year, with an average CO2 flux of 4.13±5.59 mmol C m-2 d-1 to the atmosphere. During the study period, the Vellar estuary actively supplied 650.2 mol C m-2 Y-1 to the atmosphere. Hence, the metabolic balance of the estuarine ecosystem is aided by land derived organic carbon accompanied with freshwater flows from the Vellar river, constituting the estuary as a substantial source of atmospheric CO2

Statistical tools for studying the temporal variations in chlorophyll-a concentration along the Southwest Bay of Bengal waters

Multivariate statistical analysis such as Multiple Linear Regression (MLR) and Principal Component Analysis (PCA) are used to study the effect of physico-chemical parameters on chlorophyll distribution along the southwest Bay of Bengal from January 2012 to June 2014.  Physical properties recorded showed clear seasonal patterns in sea surface temperature (26.2 – 32.8 °C), salinity (24 – 36 PSU), pH (7.808 to 8.428), photosynthetic photon flux (522 – 1220.4 µM m-2s-1) with the minimum and maximum values during monsoon and summer seasons, respectively. In contrast, the chemical variables such as nitrite (0.15 to 2.35 µM), nitrate (1.02 to 6.58 µM), ammonia (0.11 – 5.22 µM), total nitrogen (1.04 to 11.58 µM), inorganic phosphate (0.16 – 2.97 µM), total phosphorus (0.55 – 8.60 µM) and reactive silicate (2.00 to 23.95 µM) showed the minimum and maximum concentration during summer and monsoon seasons, respectively. The high and low chlorophyll (0.10 to 6.92 µg l-1) and dissolved oxygen (4.07 and 7.884 mg l-1) concentrations are observed during summer and pre-monsoon seasons, respectively. PCA found that nitrogenous nutrients and chlorophyll are positively loaded and Sea Surface Temperature (SST) was negatively loaded in all the seasons except during summer season. Inter-comparison of modeled and in-situ chlorophyll-a (chl-a) concentration showed a significant correlation during monsoon season by 93 % of matchup with a R2 = 0.930, N = 60 and SEE = ±0.369 compared to other seasons. Regression analysis also predicted the positive influence of nitrate and ammonia and negative influence of SST with chl-a

Development of a DNA Barcoding System for Seagrasses: Successful but Not Simple

Seagrasses, a unique group of submerged flowering plants, profoundly influence the physical, chemical and biological environments of coastal waters through their high primary productivity and nutrient recycling ability. They provide habitat for aquatic life, alter water flow, stabilize the ground and mitigate the impact of nutrient pollution. at the coast region. Although on a global scale seagrasses represent less than 0.1% of the angiosperm taxa, the taxonomical ambiguity in delineating seagrass species is high. Thus, the taxonomy of several genera is unsolved. While seagrasses are capable of performing both, sexual and asexual reproduction, vegetative reproduction is common and sexual progenies are always short lived and epimeral in nature. This makes species differentiation often difficult, especially for non-taxonomists since the flower as a distinct morphological trait is missing. Our goal is to develop a DNA barcoding system assisting also non-taxonomists to identify regional seagrass species. The results will be corroborated by publicly available sequence data. The main focus is on the 14 described seagrass species of India, supplemented with seagrasses from temperate regions. According to the recommendations of the Consortium for the Barcoding of Life (CBOL) rbcL and matK were used in this study. After optimization of the DNA extraction method from preserved seagrass material, the respective sequences were amplified from all species analyzed. Tree- and character-based approaches demonstrate that the rbcL sequence fragment is capable of resolving up to family and genus level. Only matK sequences were reliable in resolving species and partially the ecotype level. Additionally, a plastidic gene spacer was included in the analysis to confirm the identification level. Although the analysis of these three loci solved several nodes, a few complexes remained unsolved, even when constructing a combined tree for all three loci. Our approaches contribute to the understanding of the morphological plasticity of seagrasses versus genetic differentiation

Occurrence and Distribution of Actinomycetes in Marine Environs and their Antagonistic Activity against Bacteria that is Pathogenic to Shrimps

The mean population density of actinomycetes in water samples from eight stations off Little Andaman Island in India ranged from 0.29 x 103 CFU/ml at station 2 (Naval Area) to 0.45 x 103 CFU/ml at station 4 (Chandra Nallah). Density in sediment samples ranged from 1.21 x 103 CFU/g at station 2 (Naval area) to 3.29 x 103 CFU/g at station 6 (Buttler Bay). Forty-one strains were isolated and tested for their antagonistic activity against Vibrio alginolytics, V. harveyi, and V. parahaemolyticus, bacteria that are highly pathogenic to shrimps. Over 60% of the strains (26) exhibited varying degrees of antagonistic activity. Among them, six showed good activity and were tentatively identified as Streptomyces xantholiticus, S. aureofasciclus, S. galtieri, S. vastus, S. galbus, and S. rimosus. Results suggest that actinomycetes from the marine environment can be used as bio-control agents in shrimp culture systems to control diseases caused by bacteri- al pathogens

<span style="font-size:15.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-US">Improved fixing and image interpretation techniques for counting chromosomes in Seagrass<i style="mso-bidi-font-style:normal"> Halodule pinifolia </i>(Miki) den Hartog.</span>

1977-1980Cytogenetics is a pioneer technique used to differentiate the plants at species level including seagrasses. Present study consists an improved technique for staining of chromosomes of seagrass Halodule pinifolia (2n= 44). By modifying and updating old methods, an improved technique for counting chromosomes has been developed. Image interpretation techniques applied in the study in Photoshop CS2 ver.9 allowed to read the chromosomes apparently with high accuracy