Spatio-temporal variation of microphytoplankton in the upwelling system of the south-eastern Arabian Sea during the summer monsoon of 2009**This investigation was conducted under the Marine Living Resources Programme funded by the Ministry of Earth Sciences, Government of India, New Delhi.

AbstractThe phytoplankton standing crop was assessed in detail along the South Eastern Arabian Sea (SEAS) during the different phases of coastal upwelling in 2009. During phase 1 intense upwelling was observed along the southern transects (8°N and 8.5°N). The maximum chlorophyll a concentration (22.7mgm −3) was observed in the coastal waters off Thiruvananthapuram (8.5°N). Further north there was no signature of upwelling, with extensive Trichodesmium erythraeum blooms. Diatoms dominated in these upwelling regions with the centric diatom Chaetoceros curvisetus being the dominant species along the 8°N transect. Along the 8.5°N transect pennate diatoms like Nitzschia seriata and Pseudo-nitzschia sp. dominated. During phase 2, upwelling of varying intensity was observed throughout the study area with maximum chlorophyll a concentrations along the 9°N transect (25mgm−3) with Chaetoceros curvisetus as the dominant phytoplankton. Along the 8.5°N transect pennate diatoms during phase 1 were replaced by centric diatoms like Chaetoceros sp. The presence of solitary pennate diatoms Amphora sp. and Navicula sp. were significant in the waters off Kochi. Upwelling was waning during phase 3 and was confined to the coastal waters of the southern transects with the highest chlorophyll a concentration of 11.2mgm−3. Along with diatoms, dinoflagellate cell densities increased in phases 2 and 3. In the northern transects (9°N and 10°N) the proportion of dinoflagellates was comparatively higher and was represented mainly by Protoperidinium spp., Ceratium spp. and Dinophysis spp

Unusual mass shoreward movement of bivalve (Mollusca) Donax scortum Linnaeus along the coastal waters off Calicut - South Eastern Arabian Sea

67-72Eutrophication and oxygen depletion are the major factors influencing the responses of benthic organisms in coastal ecosystems. Along the coastal waters of South Eastern Arabian Sea a mass shoreward movement of bivalve Donax scortum (locally referred as “eranthu”) occurred during end phase of summer monsoon upwelling. Possible reasons for this shoreward movement points to the low dissolved oxygen (0.25 ml L-1) in the bottom waters. Intense blooms of large dinoflagellate species, Noctiluca scintillans were observed a week prior to this event along these coastal waters and the crashing related decaying might have resulted in lower DO values in the region. The study discuss on the deleterious effects of hypoxic conditions caused by summer monsoon algal blooms on benthic fauna of South Eastern Arabian Sea

Unusual mass shoreward movement of bivalve (Mollusca) Donax scortum Linnaeus along the coastal waters off Calicut - South Eastern Arabian Sea

Eutrophication and oxygen depletion are the major factors influencing the responses of benthic organisms in coastal ecosystems. Along the coastal waters of South Eastern Arabian Sea a mass shoreward movement of bivalve Donax scortum (locally referred as “eranthu”) occurred during end phase of summer monsoon upwelling. Possible reasons for this shoreward movement points to the low dissolved oxygen (0.25 ml L-1) in the bottom waters. Intense blooms of large dinoflagellate species, Noctiluca scintillans were observed a week prior to this event along these coastal waters and the crashing related decaying might have resulted in lower DO values in the region. The study discuss on the deleterious effects of hypoxic conditions caused by summer monsoon algal blooms on benthic fauna of South Eastern Arabian Sea

Microphytoplankton community structure in the North Eastern Arabian Sea during Winter Monsoon

The overall attempt of the study was aimed to understand the microphytoplankton community composition and its variations along a highly complex and dynamic marine ecosystem, the northern Arabian Sea. The data generated provides a first of its kind knowledge on the major primary producers of the region. There appears significant response among the microphytoplankton community structure towards the variations in the hydrographic conditions during the winter monsoon period. Interannually, variations were observed within the microphytoplankton community associated with the variability in temperature patterns and the intensity of convective mixing. Changing bloom pattern and dominating species among the phytoplankton community open new frontiers and vistas towards more intense study on the biological responses towards physical processes. The production of large amount of organic matter as a result of intense blooming of Noctiluca as well as diatoms aggregations augment the particulate organic substances in these ecosystem. This definitely influences the carbon dynamics of the northern Arabian Sea. Detailed investigations based on time series as well as trophodynamic studies are necessary to elucidate the carbon flux and associated impacts of winter-spring blooms in NEAS. Arabian sea is considered as one among the hotspot for carbon dynamics and the pioneering records on the major primary producers fuels carbon based export production studies and provides a platform for future research. Moreover upcoming researches based on satellite based remote sensing on productivity patterns utilizes these insitu observations and taxonomic data sets of phytoplankton for validation of bloom specific algorithm development and its implementation. Furthermore Saurashtra coast is considered as a major fishing zone of Indian EEZ. The studies on the phytoplankton in these regions provide valuable raw data for fishery prediction models and identifying fishing zones. With the Summary and Conclusion 177 baseline data obtained further trophodynamic studies can be initiated in the complex productive North Eastern Arabian Seas (NEAS) ecosystem that is still remaining unexplored.Cochin University of Science & Technolog

“<i>Crab Jubilee</i>” subsequent to red tide of <i>Noctiluca scintillans</i> along the central Kerala coast (SW coast of India)

1549-1551Crab jubilee associated with red tide of Noctiluca was observed along the central Kerala coast during the summer monsoon of 2013. There was an unusual shoreward mass movement of blue swimming crab Portunus pelagicus throughout the day. Hypoxia caused by red tide of Noctiluca in the coastal waters as well as sluggish upwelling by fresh water surfacing during the intense rainfall might be the reason for this unusual coastal phenomenon

<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">First record of dinoflagellate <i style="mso-bidi-font-style:normal">Neoceratium platycorne</i> from the North Eastern Arabian Sea</span>

504-506Neoceratium platycorne (Daday) F. Gomez, D. Moreira, P. Lopez-Garcia is reported for the first time from the North Eastern Arabian Sea (NEAS). Species was observed in the open ocean subsurface waters of NEAS during the late winter monsoon period. Cell density of the <i style="mso-bidi-font-style: normal">N. platycorne was 10-15 cells L-1. This record will contribute to the phytoplankton checklist of the Indian EEZ

First report of epizoic diatom <i>Pseudohimantidium pacificum</i> on copepod <i>Corycaeus affinis</i> from North Eastern Arabian Sea

856-859Marine epizoic diatom, Pseudohimantidium pacificum Hustedt and Krasske 1941, on copepod Corycaeus affinis is reported for the first time in North Eastern Arabian Sea. It was found attached exclusively to copepod C. affinis. Light Microscope and Scanning Electron Microscopic studies were made to examine the frustule morphology. With the present report from the North Eastern Arabian Sea, the biogeographic boundary of this species can be extended to the Indian waters

Occurrence of epibiontic suctorian protozoans on marine <i>Ostracod Cypridina</i> dentata (Muller, 1906) in the North Eastern Arabian Sea

874-878The Cypridina dentata samples collected from North Eastern Arabian Sea, during spring inter monsoon were infested with protozoan epibionts in densities of 10 to 24 individuals per ostracod. Epibionts are suctorian ciliate protozoan species Acineta satyanandani and Paracineta karunakarani. Epibionts colonized the entire body surface, but were most numerous on the dorsal region of the carapace. Maximum number of epibionts was found on females, when compared to the male organisms. Live ostracod specimens infested with epibionts were less active than the uninfested ones and these results further suggest that epibiontic protozoans may also influence the activity of ostracods and therefore may play a substantial role in ostracod production and community dynamics. Epibiontic suctorians on ostracod Cypridina dentata were analysed and identified for the first time from North Eastern Arabian Sea

Subsurface bloom of dinoflagellate <em>Gonyaulax polygramma</em> Stein in the shelf waters off Mangalore- South Eastern Arabian Sea

1658-1664A monospecific bloom of thecate dinoflagellate Gonyaulax polygramma (5x 108 cells L-1) was observed from the shelf waters off Mangalore (South Eastern Arabian Sea) during late summer monsoon. The bloom was observed to be subsurface (~5m depth) with chlorophyll a maxima of 13.15 µg L-1. The species observed to be photosynthetic and no visible food vacuoles were observed within the cell. Water column stability with sufficient inorganic nutrients during the fag end of summer monsoon might have favoured the bloom species. The region observed complete exclusion of zooplankton and can suggestively due to unpalatability of the bloom species

Spatio-temporal variation of microphytoplankton in the upwelling system of the south-eastern Arabian Sea during the summer monsoon of 2009

The phytoplankton standing crop was assessed in detail along the South Eastern Arabian Sea (SEAS) during the different phases of coastal upwelling in 2009. During phase 1 intense upwelling was observed along the southern transects(8&deg;N and 8.5&deg;N). The maximum chlorophyll <i>a</i> concentration (22.7 mg m^-3) was observedin the coastal waters off Thiruvananthapuram (8.5&deg;N). Further north there was no signature of upwelling, with extensive <i> Trichodesmium erythraeum</i> blooms. Diatoms dominated in these upwelling regions with thecentric diatom <i> Chaetoceros curvisetus</i> being the dominant species along the 8&deg;N transect. Along the 8.5&deg;N transect pennate diatoms like <i> Nitzschia seriata</i> and <i>Pseudo-nitzschia</i> sp. dominated. Duringphase 2, upwelling of varying intensity was observed throughout the study area with maximum chlorophyll <i>a</i> concentrations along the 9&deg;N transect (25 mg m^-3) with <i> Chaetoceros curvisetus</i> as the dominantphytoplankton. Along the 8.5&deg;N transect pennate diatoms during phase 1 were replaced by centric diatoms like <i>Chaetoceros</i> sp. The presence of solitary pennate diatoms <i>Amphora</i> sp. and <i> Navicula</i> sp.were significant in the waters off Kochi. Upwelling was waning during phase 3 and was confined to the coastal waters of the southern transects with the highest chlorophyll <i>a</i> concentration of 11.2 mg m^-3. Along withdiatoms, dinoflagellate cell densities increased in phases 2 and 3. In the northern transects (9&deg;N and 10&deg;N) the proportion of dinoflagellates was comparatively higher and was represented mainly by <i>Protoperidinium</i> spp