Hydrobiological responses of the North Eastern Arabian Sea during late winter and early spring inter-monsoons and the repercussions on open ocean blooms

2016 ◽  
Vol 97 (7) ◽  
pp. 1467-1478 ◽  
Author(s):  
K. B. Padmakumar ◽  
Lathika Cicily Thomas ◽  
K. G. Vimalkumar ◽  
C. R. Asha Devi ◽  
T. P. Maneesh ◽  
...  
Keyword(s):  
Water Column ◽  
Arabian Sea ◽  
Early Spring ◽  
Winter Monsoon ◽  
Late Winter ◽  
Biological Production ◽  
Noctiluca Scintillans ◽  
The North ◽  
North Eastern ◽  
Eastern Arabian Sea

Winter cooling and persistent mixing for more than a quarter of year (November to early March) along the North Eastern Arabian Sea (NEAS) results in nutrient enrichment of the euphotic column thereby triggering biological production. Hydrographic characteristics of NEAS during Late Winter Monsoon (LWM) and Early Spring Inter Monsoon (ESIM) and the influence on biological production are overviewed here. Winter convective mixing signatures were evident during LWM with low SST (24°C), high SSS (36.4), deep mixed layers (>100 m) and increased surface nitrate (~1 µM). Open ocean waters observed high chlorophyll a (1–2 mg m−3) and microphytoplankton abundance (1.2–1.5 × 104 cells l−1). Diatoms and green Noctiluca scintillans were the major microphytoplankton identified. ESIM observed gradual stabilization of water column with curtailment of winter signatures and strengthening of Noctiluca scintillans blooms. Mesozooplankton biomass was higher during LWM and decreased towards ESIM with intensification of Noctiluca blooms. However during ESIM, abundance of gelatinous zooplankton occurred in the bloom region. Inter-annual variations were observed in the biological responses along with the hydrographic changes. Thus the convective process during winter monsoon and stabilization of the water column during ESIM plays a significant role in the production pattern of NEAS.

scholarly journals <sup>15</sup>N enrichment in the surface Particulate Organic Nitrogen of the north-eastern Arabian Sea from the middle to the waning phase of the winter monsoon: possible causes

2007 ◽  
Vol 4 (1) ◽  
pp. 245-264
Author(s):  
S. Kumar ◽  
R. Ramesh
Keyword(s):  
Water Column ◽  
Arabian Sea ◽  
Organic Nitrogen ◽  
Subsurface Layer ◽  
The North ◽  
North Eastern ◽  
Eastern Arabian Sea ◽  
Nitrogen Isotopic Composition ◽  
Hydrographic Conditions ◽  
N Enrichment

Abstract. A temporal increase of ~5‰ in the average nitrogen isotopic composition (δ15NPON) of surface particulate organic nitrogen was observed in the open north-eastern Arabian Sea during January to late February-early March 2003, despite the presence of T. erithraeum (up to ~11%), a diazotroph that fixes atmospheric N2, in the latter period. Hydrographic conditions and residence time of nitrate in the water column suggested that this increase could be a combined effect of denitrification in the subsurface layer and inefficient utilization of nitrate entrained in the water column during January.

Hydrography and biogeochemistry of the north western Bay of Bengal and the north eastern Arabian Sea during winter monsoon

2008 ◽  
Vol 73 (1-2) ◽  
pp. 76-86 ◽  
Author(s):  
K.K. Balachandran ◽  
C.M. Laluraj ◽  
R. Jyothibabu ◽  
N.V. Madhu ◽  
K.R. Muraleedharan ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Arabian Sea ◽  
Winter Monsoon ◽  
The North ◽  
North Eastern ◽  
Eastern Arabian Sea ◽  
Western Bay Of Bengal ◽  
North Western

What controls the initiation of algal bloom during the winter monsoon in the Arabian Sea??

2021 ◽  
Author(s):  
Lakshmi Shenoy
Keyword(s):  
Water Column ◽  
Mixed Layer ◽  
Arabian Sea ◽  
Mixed Layer Depth ◽  
Chlorophyll Concentration ◽  
Winter Monsoon ◽  
Physical Interaction ◽  
Stoichiometric Ratio ◽  
Noctiluca Scintillans ◽  
Northern Arabian Sea

&lt;p&gt;A winter monsoon cruise was undertaken in the northern Arabian Sea to understand the bio-physical interaction responsible for the occurrence of phytoplankton bloom in the region. The observation shows strong convective mixing with a dense and deeper mixed layer (MLD: 100-140 m) and well-oxygenated upper water column (&gt;95% saturation). The chlorophyll concentration was low (0.1 -0.3 &amp;#181;g/l) despite having ample nitrate (~2.5 &amp;#181;M) in the surface layer. The region, however, was deprived of micro phytoplankton, especially diatomic species and Noctiluca Scintillans, and was dominated by the picophytoplankton (77%-85%). The mean Si/N ratio in the upper 100 m was 0.72 indicating &amp;#8220;Silicate stressed&amp;#8221; condition for the proliferation of diatoms. Even a deeper mixed layer could not penetrate into the silicicline (~150m) which was deeper than the nitracline (~110m). In addition, the euphotic depth (~49m) was much shallower than the mixed layer depth suggesting the Sverdrup critical depth limitation in the northern Arabian Sea. We further show that the bloom initiated only when the mixed layer shoals towards the euphotic zone. Our observations suggest that two primary factors, the stoichiometric ratio of nutrients, especially Si/N ratio, in the mixed layer and re-stratification of the upper water column, govern the phytoplankton blooming in the northern Arabian Sea during the later winter monsoon.&lt;/p&gt;

Symbiosis between the stramenopile protist Solenicola setigera and the diatom Leptocylindrus mediterraneus in the North Eastern Arabian Sea

Symbiosis ◽  
2012 ◽  
Vol 56 (2) ◽  
pp. 97-101 ◽  
Author(s):  
K. B. Padmakumar ◽  
Lathika Cicily ◽  
Anu Shaji ◽  
T. P. Maneesh ◽  
V. N. Sanjeevan
Keyword(s):  
Arabian Sea ◽  
The North ◽  
North Eastern ◽  
Eastern Arabian Sea

Psammonema kuriani (Nematoda: Desmodoroidea), a novel species from the margin of the north-eastern Arabian Sea

2015 ◽  
Vol 96 (7) ◽  
pp. 1469-1473
Author(s):  
Jini Jacob ◽  
P.R. Anilkumar ◽  
Rosamma Philip ◽  
Damodaran Rayaroth
Keyword(s):  
Deep Sea ◽  
Arabian Sea ◽  
Novel Species ◽  
Estuarine Sediments ◽  
Indian Ocean Region ◽  
The North ◽  
North Eastern ◽  
Eastern Arabian Sea ◽  
Ocean Region ◽  
First Time

A novel species of nematode belonging to the rare genus Psammonema Verschelde & Vincx, 1995 is described from the continental margin of the north-eastern Arabian Sea (214 m). Psammonema kuriani sp. nov. shows a different position of the lateral alae compared with the original genus diagnosis, hence an emended genus diagnosis is given. The genus Psammonema was previously described from the estuarine sediments of Indian Ocean region and the present study reports the genus from the deep sea for the first time.

scholarly journals Subsurface chlorophyll maxima in the North Eastern Arabian sea: Simulation on impact of warming

2020 ◽  
Vol 110 ◽  
pp. 105858
Author(s):  
H. Midhun shah ◽  
B.R. Smitha ◽  
A.A. Mohamed Hatha ◽  
M. Sudhakar
Keyword(s):  
Arabian Sea ◽  
The North ◽  
North Eastern ◽  
Eastern Arabian Sea
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