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Zooplankton of Oman Coastal Waters Zooplankton of Oman Coastal Waters

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Date added: 04/07/2014
Date modified: 04/07/2014
Filesize: 4.36 MB
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Zooplankton of Oman Coastal Waters
Sergey A. Piontkovski1*, Asila Al-Maawali2, Ward Al-Muna Al-Manthri1,
Khalid Al-Hashmi1, and Elena A. Popova3
1College of Agricultural and Marine Sciences, Sultan Qaboos University
P.O. Box 34, Al-Khod 123, Sultanate of Oman
2 Marine Science Fisheries Centre, Ministry of Agriculture and Fisheries Wealth
P.O. Box 227, Sultanate of Oman
3Institute of Biology of the Southern Seas, 2 Nakhmov av., Crimea, Sevastopol

Monthly sampling during daytime was carried out in 2007-2011 at Bandar Al-Khyran (23.51oN, 58.72oE) which is the largest semi-enclosed bay on the southern end of the Sea of Oman with about 4 km2 in surface area and an average depth of 10 m. Zooplankton were represented by Copepoda (79%), Cladocera (9%), Oikopleuriddae (7%), Chaetognatha (3%), and Decapoda (~2%) comprising the major part of the total zooplankton abundance. Among copepods, 27 species constituted ~75% of total copepod abundance. Changes of copepod abundance have not had a pronounced seasonal pattern. Instead, a multiple peak structure in monthly fluctuations was observed, on the level of genera as well as the abundance of species. Amplitudes and timing of the copepod peak abundance were markedly different during the studied years.

Atmospheric cyclones and seasonal cycles of biological productivity of the ocean Atmospheric cyclones and seasonal cycles of biological productivity of the ocean

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Date added: 03/03/2014
Date modified: 03/03/2014
Filesize: 679.74 kB
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Atmospheric cyclones and seasonal cycles of biological productivity of the ocean
S.A. PIONTKOVSKI* AND K.A. AL-HASHMI
Sultan Qaboos University, PO Box 34, Al-Khod 123, Sultanate of Oman
Remotely sensed wind speed, translation speed, atmospheric pressure, atmospheric precipitation rate and chlorophyll-a concentration were used to verify the hypothesis that the response of the phytoplankton community to propagating atmospheric cyclones should be associated with the phase of the seasonal cycle of this community and the translation speed of a cyclone. For the 12 cyclones investigated from the Indian Ocean, Pacific Ocean and the Mediterranean Sea the maximal sustained wind speed varied twofold, whereas the translation speed of cyclones and the chlorophyll ratio (characterizing chlorophyll concentration before and after cyclone passage) varied by 10-fold.
It was shown that cyclones affecting the phytoplankton community approaching its seasonal maximum either could not stimulate or stimulated a weak response of further increase of chlorophyll-a concentration (due to explicitly available nutrients). Controversially, cyclones affecting the community approaching its seasonal minimum could induce gradual increase of chlorophyll-a concentration.
An exponential type of relationship between chlorophyll ratio and translation speed of cyclones was evaluated. In the range of translation speeds from 1 to 10 ms−1, the increase of chlorophyll-a concentration due to cyclone passage was most pronounced with regard to slow moving cyclones.

Spatial-Temporal Distribution of the Palinurid and Scyllarid Phyllosoma Larvae in Oman Coastal Water Spatial-Temporal Distribution of the Palinurid and Scyllarid Phyllosoma Larvae in Oman Coastal Water

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Date added: 12/02/2013
Date modified: 12/02/2013
Filesize: 8.07 MB
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Spatial-Temporal Distribution of the Palinurid and Scyllarid Phyllosoma Larvae in Oman Coastal Waters
Sergey Khvorov1*, Sergey Piontkovski2, and Elena Popova3
1Marine Science Fisheries Centre, Ministry of Agriculture and Fisheries Wealth
P.O. Box 227, Sultanate of Oman
2College of Agricultural and Marine Sciences, Sultan Qaboos University
P.O. Box 34, Al-Khod 123, Sultanate of Oman
3Institute of Biology of the Southern Seas, 2, Nakhimov av.-Crimea
99011, Sevastopol, Ukraine

The Bongo Net samples collected between 2005 and 2008 in the Sea of Oman and in the north-western part of the Arabian Sea (near Massirah Island) were analyzed, for a pilot assessment of seasonal and spatial distribution of the phyllosoma larvae. In the samples collected, 84% of all phyllosoma larvae were from the family Palinuridae, while the others were contributed by family Scyllaridae. All larvae of Panulirus homarus were in the first development stage and had a mean body length of 1.30±0.89mm. The phyllosoma larvae of the less abundant family Scyllaridae were in the second, third, and fourth development stages, which had a mean length of 2.3mm, 3.3mm and 4.63mm, respectively. In terms of seasonal changes, the phyllosoma larvae tend to appear in Omani waters in February, reaching their maximum numbers in April. The abundance of phyllosoma P. homarus was as much as twofold higher in the Arabian Sea compared to the Sea of Oman.

Seasonal and Interannual Changes in Epipelagic Ecosystem Seasonal and Interannual Changes in Epipelagic Ecosystem

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Date added: 08/07/2013
Date modified: 08/07/2013
Filesize: 776.08 kB
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Seasonal and Interannual Changes in Epipelagic Ecosystem of the Western Arabian Sea
S.A. Piontkovski, M.R. Claereboudt and S.Al-Jufaili
Sultan Qaboos University, CAMS, P.O. 34, Al-Khod 123, Sultanate of Oman

Remotely sensed and on board historical data were used to analyze monthly fluctuations of
sea surface temperature, wind speed, chlorophyll-a concentration and sardine landings in
the Sultanate of Oman. No major differences between summer and winter monsoon values were found for mean chlorophyll-a concentrations, although the spatial heterogeneity of the field was twice as high during the summer monsoon, due to spatial variability introduced by numerous mesoscale eddies. The chlorophyll-a, sea surface temperature, and zonal wind speed all showed significant peaks of variability at periods of 6 months and 1 year- mediated by the reverse of monsoonal winds. The analysis covering 12 years of data (1997-
2009) pointed out that the size of productive regions (with maximal chlorophyll
concentrations) has decreased and a negative correlation between chlorophyll-a
concentration and sea surface temperature was observed along both the western and eastern parts of the Arabian Sea. The spatially averaged time series of wind speed, sea surface temperature, and chlorophyll-a were synchronized between both regions. Sardines
landings were twice as high during the winter monsoon compared to the summer monsoon.
Overall, the epipelagic ecosystem of the western Arabian Sea was relatively stable, with
minor interannual changes observed during the last few decades but well pronounced
seasonal variability.

Coastal upwellings and Mesoscale Eddies of the Western Arabian Sea Coastal upwellings and Mesoscale Eddies of the Western Arabian Sea

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Date added: 07/03/2013
Date modified: 07/03/2013
Filesize: 2.33 MB
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Coastal upwellings and Mesoscale Eddies of the
Western Arabian Sea: Some Biological Implications

S.A. Piontkovski and S. Al-Jufaili
Sultan Qaboos University, CAMS,
PO Box 34, Al-Khod 123,
Sultanate of Oman

Satellite derived (SeaWIFS, MODIS, TOPEX/Poseidon, and Jason) chlorophyll-a concentration, sea surface heights, sea surface temperature, data on vertical profiles of temperature and salinity from the ARGO drifting floats, wind speed, the Dipole Mode Index, and historical data on sardine landings were employed, to analyze physical-biological coupling in the western Arabian Sea which is known for its vigorous eddy field affecting
characteristics of biological productivity.
Summer and winter monsoons impose different modes of mesoscale variability. In summer, the East Arabian Current along with the currents of the Arabian Sea interior generates a dense field of eddies, where as in winter, eddies become less developed and less numerous. Therefore, the chlorophyll distribution is more heterogeneous spatially and more variable temporally during summer monsoon. Interannual changes of eddy field bear footprints of the impact of basin-scale atmospheric anomaly (the Indian Ocean Dipole). Spatial-temporal characteristics of the eddy field are valuable tools in understanding seasonal and interannual fluctuations of sardine landings contributing ~ 50% to the fishery in the region.
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