Cyclone Phailin enhanced the productivity following its passage: evidence from satellite data

This article does not have an abstract

<span style="font-size:15.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: "Times New Roman";mso-ansi-language:EN-US;mso-fareast-language:EN-US; mso-bidi-language:HI;mso-bidi-font-weight:bold" lang="EN-US">Spatio-Temporal Distribution of Physico-Chemical Parameters and Chlorophyll-<i style="mso-bidi-font-style:normal">a</i> in Chilika Lagoon, East Coast of India</span>

614-627<span style="font-size:9.0pt;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">Present study contains the current status of Chilika Lagoon water quality during pre-monsoon, monsoon and post-monsoon seasons of the year 2012. Spatial and seasonal distributions of water quality parameters viz. WT, pH, Salinity, DO, TSM, Chl-a and inorganic nutrients (NO , NO , NH, PO, SiO) were examined in this study. Twenty locations were selected covering all the ecological sectors of the lagoon. Study reveals significant spatio-temporal variation in water quality parameters. The pH of the lagoon was found to be slightly alkaline. DO concentration was controlled by photosynthetic activities of autotrophs. Results of one-way ANOVA indicated spatio-temporal variation in the nutrients especially NH  and SiO (p  was found below the pollution limit for aquatic lives. Among the nutrients SiO, was the most influencing factor regulating phytoplankton production of the lagoon throughout the year.  However, NH was found as the second influencing factor for distribution of Chl-a

<span style="font-size:15.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-US">Occurrence of a new species of toxic Cnidaria (<i style="mso-bidi-font-style: normal">Pelagia noctiluca</i><b> </b>Forskål, 1775) from estuarine waters of Rushikulya River, Western Bay of Bengal</span>

580-58

<span style="font-size:15.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language: HI;mso-bidi-font-weight:bold" lang="EN-US">First record of <i style="mso-bidi-font-style: normal">Desmoscolex falcatus</i> (Nematoda: Adenophorea: Desmoscolecida: Desmoscolecidae) from Rushikulya estuary, Odisha, India</span>

487-489<i style="mso-bidi-font-style: normal">Desmoscolex falcatus<span style="font-size:9.0pt;mso-ansi-language: EN-US" lang="EN-US"> (Nematoda: Adenophorea: Desmoscolecida: Desmoscolecidae) is reported for the first time from Rushikulya estuary. </span

First record of fourteen phytoplankton species off Rushikulya estuary, Northwestern Bay of Bengal

490-494Fourteen numbers of phytoplankton species have been reported for the first time in coastal waters off Rushikulya estuary. </span

Seasonal variation of phytoplankton community composition in coastal waters off Rushikulya Estuary, East Coast of India

508-526<span style="font-size:9.0pt;line-height: 115%;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:ar-sa"="" lang="EN-US">A total of 149 phytoplankton species were identified during the study period wherein diatoms contributed 109, dinoflagellates 28, green algae 6, cyanobacteria 4 and cocolithophores 2. A striking feature of the study is the new record of 26 species from coastal waters vicinity off Rushikulya estuary (coastal and estuarine waters extending from Rushikulya to Bahuda) and 15 species from entire coastal waters of Odisha. A contrast in phytoplankton species composition was noticed in all seasons. Diatoms found as the dominant prevailing phytoplankton group in all seasons in terms of number of species and abundance. Diatom species <i style="mso-bidi-font-style: normal">viz. Thalassiothix longissima, Skeletonema costatum, Coscinodiscus eccentricus were ubiquitous off Rushikulya estuary throughout the year. River and monsoon influence coastal waters in supplying macronutrients for phytoplankton growth. Nitrogenous nutrients were found to be controlling factor for phytoplankton growth. A linear relationship between phytoplankton abundance and chlorophyll-a was observed during three seasons. Despite the highest species abundance during premonsoon, species diversity index showed maximum for postmonsoon and monsoon periods due to preponderance of few diatom species. Species were found to be more evenly distributed during monsoon as indicated from the Pielou’s evenness (J’) index. Non-metric multidimensional scaling (MDS) ordinations based on Bray-Curtis similarities indicated that phytoplankton communities prevailed in March and April were the least similar to those on other sampling occasions.</span

Performance of operational satellite bio-optical algorithms in different water types in the southeastern Arabian Sea

The in situ remote sensing reflectance (Rrs) and optically active substances (OAS) measured using hyperspectral radiometer, were used for optical classification of coastal waters in the southeastern Arabian Sea. The spectral Rrs showed three distinct water types, that were associated with the variability in OAS such as chlorophyll-a (chl-a), chromophoric dissolved organic matter (CDOM) and volume scattering function at 650 nm (β650). The water types were classified as Type-I, Type-II and Type-III respectively for the three Rrs spectra. The Type-I waters showed the peak Rrs in the blue band (470 nm), whereas in the case of Type-II and III waters the peak Rrs was at 560 and 570 nm respectively. The shifting of the peak Rrs at the longer wavelength was due to an increase in concentration of OAS. Further, we evaluated six bio-optical algorithms (OC3C, OC4O, OC4, OC4E, OC3M and OC4O2) used operationally to retrieve chl-a from Coastal Zone Colour Scanner (CZCS), Ocean Colour Temperature Scanner (OCTS), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), MEdium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS) and Ocean Colour Monitor (OCM2). For chl-a concentration greater than 1.0 mg m−3, algorithms based on the reference band ratios 488/510/520 nm to 547/550/555/560/565 nm have to be considered. The assessment of algorithms showed better performance of OC3M and OC4. All the algorithms exhibited better performance in Type-I waters. However, the performance was poor in Type-II and Type-III waters which could be attributed to the significant co-variance of chl-a with CDOM

Not Available

Not AvailableThe present study focused on understanding the variability of optically active substances (OASs) and their effect on spectral remote-sensing reflectance (Rrs). Furthermore, the effect of atmospheric correction schemes on the retrieval of chlorophyll-a (chl-a) from satellite data was also analysed. The OASs considered here are chl-a, coloured dissolved organic matter (CDOM), and total suspended matter (TSM). Satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite was used for this study. The two atmospheric correction schemes considered were: multi-scattering with two-band model selection NIR correction (hereon referred as ‘A1’) and Management Unit of the North Sea Mathematical Models (MUMM) correction and MUMM NIR calculation (hereafter referred as ‘A2’). The default MODIS bio-optical algorithm (OC3M) was used for the retrieval of chl-a. Analysis of OASs showed that chl-a was the major light-absorbing component, with highly variable distribution (0.006–25.85 mg m–3). Absorption due to CDOM at 440 nm (aCDOM440) varied from 0.002 to 0.31 m–1 whereas TSM varied from 0.005 to 33.44 mg l–1. The highest concentration of chl-a was observed from August to November (i.e. end of the southwest monsoon and beginning of the northeast monsoon), which was attributed to coastal upwelling. The average value of aCDOM440 was found to be lower than the global mean. A significant negative relationship between aCDOM440 and salinity during the southwest monsoon indicated that much of the CDOM during this season was derived from river discharge. Spectral Rrs was found to be strongly linked to the variability in chl-a concentration, indicating that chl-a was the major light-absorbing component. Satellite-derived spectral Rrs was in good agreement with that in situ when chl-a concentration was lower than 5 mg m–3. The validation of chl-a, derived from in situ Rrs, showed moderate performance (correlation coefficient, R2 = 0.64; log10(RMSE) = 0.434; absolute percentage difference (APD) = 43.6% and relative percentage difference (RPD) = 42.33%). However the accuracy of the algorithm was still within acceptable limits. The statistical analysis for atmospheric correction schemes showed improved mean ratio of measured to estimated chl-a (‘r’ = 1.6), log10(RMSE) (0.49), APD (25.46%), and RPD (17.57%) in the case of A1 as compared with A2, whereas in the case of A2, R2 (0.56), slope (0.26), and intercept (0.27) were better as compared with A1. The two atmospheric correction schemes did not show any significant statistical difference. However the default atmospheric correction scheme (A1) was found to be performing comparatively better probably due to the fact that the concentration of TSM and CDOM was much lower to overcome the impact of chl-a.Not Availabl

Zooplankton community distribution along offshore transects of some Indian estuaries of east coast: A taxonomic investigation during a summer cruise

1781-1791<span style="font-size:9.0pt;line-height: 115%;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:ar-sa"="" lang="EN-US">Zooplankton abundance and composition were studied by selecting offshore transects of seven estuaries <i style="mso-bidi-font-style: normal">viz. Pennar, Krishna, Godavari, Gosthani, Rushikulya, Devi and Mahanadi along east coast of India during April, 2011. During the study period, sea surface temperature (SST) varied from 27.9°C to 28.3°C with an average of 28.1°C. Salinity varied from 33.0 to 35.0 PSU with an average of 34.5 PSU.  Different zooplankton groups belonging to 13 phyla were recorded from seven transects. Copepods dominated the community with 50.5 to 96.8%. Calanoids, namely Paracalanus parvus, P. aculeatus, Temora turbinata were common in all the transects studied. <span style="font-size:9.0pt;line-height:115%; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:"times="" roman";mso-ansi-language:en-gb;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"="" lang="EN-GB">The Shannon’s diversity index (H´) was found highest in Pennar (2.666) and lowest in Godavari transect (1.785). From cluster analysis and non-parametric multidimensional scaling (nMDS), it is observed that the species composition was changing from north to south of the study area. </span

Phytoplankton community structure along offshore transects of some Indian estuaries of east coast: An experience with a summer cruise

960-973This paper is based on the analyses of samples collected during a summer cruise onboard CRV ‘Sagar Paschimi’ (Cruise no.09/11) from 1st to 8th of April 2011. Species composition, abundance and distribution of phytoplankton, and water quality parameters (transparency, water temperature, salinity, pH, dissolved oxygen, nutrients viz. NO2, PO4 and chlorophyll-a) were examined in this study. A total of 123 phytoplankton species were identified. Of total, 86 species of diatoms from 44 genera, 22 species of dinoflagellates from 10 genera, 5 species of green algae from 5 genera, 4 species of cyanobacteria from 4 genera, 2 species of cocolithophores from 2 genera and 1 species of silicoflagellate were identified. Phytoplankton communities were found to vary from transect to transect. Highest and lowest values for species diversity index are associated with Godavari and Gosthani transects respectively. The highest phytoplankton abundance was found at transect Krishna (26680 cells/l) and the lowest at Godavari (9480 cells/l). Thalassiothrix longissima was quantified as the dominant species among diatoms and Dinophysis caudata among dinoflagellates. Abundance of bloom forming species Asterionellopsis glacialis was observed at transects Godavari & Mahanadi. Diversity and evenness indices of phytoplankton were found highest at Godavari transect. There exhibited a linear relationship between chlorophyll-a and phytoplankton abundance at all the transects with deviations at Gosthani and Godavari