Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: South Eastern Arabian Sea

Sortuj według:

Ogranicz wyniki do:

First recorded bloom of Akashiwo sanguinea (Dinophyceae) from the Cochin backwaters, a tropical estuarine system along the South Eastern Arabian Sea

Sathish Twinkle, Thomas Lathika Cicily, Aishwarya, Benny Niya, Padmakumar K. B.

Oceanological and Hydrobiological Studies

2020

Vol. 49, No. 4

391--397

Akashiwo sanguinea, a cosmopolitan red tide-forming dinoflagellate, is reported for the first time as a bloom from the Cochin estuary along the South Eastern Arabian Sea. Monthly sampling showed the continuous presence of A. sanguinea with occasional blooms. Blooms of A. sanguinea with the highest abundance of 2.8 × 105 cells l-1 were observed during the monsoon season (June 2019) with chlorophyll a of 17.2 mg m-3. The bloom period was characterized by higher concentrations of nitrate (26 µmol l-1) and phosphate (3.8 µmol l-1). Routine monitoring of the bloom region showed the survival of the Akashiwo sanguinea population in the temperature (26 to 30°C) and salinity (22 to 24 PSU) range indicating its eurythermal and euryhaline characteristics.

Characterization of light absorption coefficient of red Noctiluca scintillans bloom in the South Eastern Arabian Sea

Shaju S. S., Akula R. R., Jabir T.

Oceanologia

2018

No. 60 (3)

419--425

The red Noctiluca scintillans bloom was observed off Cochin in the South Eastern Arabian Sea (SEAS), affecting a very large area during July-August 2016. The surface water samples from the bloom region were collected to study the physical, biological and light absorption characteristics. The bloom affects the food chain by their voracious predation on the species of both first and second trophic levels. The N. scintillans cell density during the bloom was estimated at 4.73 × 105 cells l−1. In the phytoplankton absorption coefficient spectra, the accessory pigments displayed peaks in the 488-558 nm regions, which represent the characteristic carotenoid pigment (red colored pigment) for the bloom of red Noctiluca. Signature of the coastal upwelling was found from the salinity and temperature distribution, which was measured prior to the bloom occurrence. From the sea surface temperature (SST), it is also confirmed the presence of fresh water from the Cochin estuary. Increased productivity near coastal region, along with episodic events of strengthening of the upwelling, favors the proliferation of smaller diatoms. The plankton succession from smaller diatoms to larger diatoms and dinoflagellates, favors the proliferation of the red Noctiluca. The occurrence of blooms of red N. scintillans, which feed on phytoplankton, mainly diatoms, and other dinoflagellates, could be a threat to larvae of oil sardine during the upwelling period, and may negatively impact on the commercially important fishery of oil sardine, in this region.

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

Thomas L. C., Padmakumar K. B., Smitha B. R., Asha Devi C. R., Bijoy Nandan S., Sanjeevan V. N.

Oceanologia

2013

No. 55 (1)

185-204

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°N and 8.5°N). The maximum chlorophyll a concentration (22.7 mg m-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 (25 mg m-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 11.2 mg m-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.