NOPR Collection:

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

2022-06-17T07:13:33Z

Title: Partial pressure of carbon dioxide (pCO2) and air-water CO2 exchange in the tropical semidiurnal estuarine system Authors: Shanthi, R; Poornima, D; Saravanakumar, A; Thangaradjou, T; Choudhry, S B; Roy, R Abstract: 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. Page(s): 7-17

Studies on nutritional composition of three colour forms of Kappaphycus alvarezii (Doty) Doty

2022-06-17T07:10:58Z

Title: Studies on nutritional composition of three colour forms of Kappaphycus alvarezii (Doty) Doty Authors: Kumar, K Suresh; Kumari, Sushma; Rao, P V Subba Abstract: Biochemical composition of seaweeds is known to vary with species and environment. Kappaphycus alvarezii is an important commercial source of carrageenans (gel-forming and viscosifying polysaccharides). The nutritional and mineral composition of three (brown, green and pale yellow) colour forms of edible seaweed K. alvarezii is investigated in the current study. The brown colour form of this seaweed contained highest ash content of (25.99±0.22 %), crude fibre (21.0±0.68 %), and protein (8.92±0.41 %), while, the green form had highest carbohydrate (22.0±0.00 %) and sulphate (5.89±0.00 %) content. On the other hand, the pale yellow colour form had highest lipid content (0.72±0.00 %). Amongst the 17 minerals analyzed, highest total mineral macro-elements (viz. Na, K, Ca and Mg) were recorded in the brown form (18.8±0.71 g/100 g d wt) followed by the pale yellow (17.3±1.07 g/100 g d wt) and green colour form (11.9±1.22 g/100 g d wt). The micro-elements varied within the three colour forms; however, the brown colour form had maximum micro-element content (P, Cd, Pb, As, Hg, Cr, Zn, Cu, Fe, Mn, Co, Mo and Ni; 19.96±0.24mg/100 g d wt), followed by green (8.6±0.64 mg /100 g d wt) and pale yellow form (7.15±0.58mg /100 g d wt). On the basis of this study, it could be said that these three colour forms (i.e. brown, green and pale yellow) of Kappaphycus alvarezii could be utilized as a condiment in the omnivorous diet; however, a daily intake of 5.68 g d wt is recommended in case of the brown form, while in case of the green and pale yellow form a maximum daily intake of 9.55 and 10.5 g d wt, respectively is recommended. The study also reveals that the three colour-forms differed in their nutritional and mineral composition. Page(s): 18-25

Bioluminescent bacterial flora of Nigerian coastal fish species

2022-06-17T07:08:58Z

Title: Bioluminescent bacterial flora of Nigerian coastal fish species Authors: Agwu, O A; Aguta, O J Abstract: The scarcity of studies on bioluminescent bacteria in fish species along the coastal and marine environment of Nigeria prompted the assessment of abundance of bioluminescent bacteria and possible isolation on three common coastal fish species (Drepane africana, Sardinella maderensis and Mugil cephalus) displaying luminescence. The population of the luminescent bacteria among the three fish species ranged from 2.95×105 to 6.68×106 cfu ml-1 and the corresponding percentage to the heterotrophic bacteria was between 0.01 and 0.34 %. The surface water had 2.00×105 cfu ml-1 with 0.20 % ratio to heterotrophic bacteria. The predominant luminescent bacteria observed were gram-negative short rod. Further study of these bacteria showed that growth and light emission occurred concurrently without the exhibition of lag phase; however, maximum luminescence was observed at mid-exponential growth phase suggesting quorum sensing phenomenon. The 16S rRNA gene sequence showed 92.81 % homology to Vibrio campbelli, Vibrio harveyi and Vibrio rotiferianus. This study highlights the occurrence of bioluminescent bacteria in skin of tropical coastal fish species in Nigerian coastal waters and also serves as a fundamental basis for future studies on the biotechnological application of this unique characteristics. Page(s): 26-32

First record of the genus Caprella and species Caprella danilevskii Czerniavski, 1868 (Amphipoda: Corophiida: Caprellidae) from Arabian Sea, North Indian Ocean

2022-06-20T05:32:38Z

Title: First record of the genus Caprella and species Caprella danilevskii Czerniavski, 1868 (Amphipoda: Corophiida: Caprellidae) from Arabian Sea, North Indian Ocean Authors: Gaikwad, S; Sautya, S Abstract: The genus Caprella (Amphipoda: Caprellidae) has been recorded from all over the world oceans, whereas the species C. danilevskii Czerniavski, 1868 was only limited to southern parts of the Indian Ocean. Here, the occurrence of the genus Caprella and species C. danilevskii is described from the coastal waters of India for the first time, thus extending the distribution of this species to the northern Indian Ocean. The specimens of C. danilevskii were collected from macroalgae located at the rocky intertidal coast at Veraval, Gujarat, India. A detailed description of the specimen from the Indian region was provided, including explicit morphometric relations among the male and female sexes. Some abnormalities and special characters were observed in the population, which have not been discussed prior to this study. The species C. danilevskii could represent an introduction in the coastal waters of India; however it cannot be ignored that the species was present earlier or could have been overlooked. Page(s): 33-44