Arabian Sea

This paper describes the current state of knowledge in the study of Indo-Arabian stone anchors in the western Indian Ocean, Red Sea and Arabian Gulf, and speculates on what they may be able to tell us about the provenance, size and handling of Arab and Indian ships and shipping during the period sixth-sixteenth centuries AD.

Seasonal evolution of surface mixed layer in the Northern Arabian Sea (NAS) between 17° N–20.5° N and 59° E-69° E was observed by using Argo float daily data for about 9 months, from April 2002 through December 2002. Results showed that during April - May mixed layer shoaled due to light winds, clear sky and intense solar insolation. Sea surface temperature (SST) rose by 2.3 °C and ocean gained an average of 99.8 Wm−2. Mixed layer reached maximum depth of about 71 m during June - September owing to strong winds and cloudy skies. Ocean gained abnormally low ∼18 Wm−2 and SST dropped by 3.4 °C. During the inter monsoon period, October, mixed layer shoaled and maintained a depth of 20 to 30 m. November - December was accompanied by moderate winds, dropping of SST by 1.5 °C and ocean lost an average of 52.5 Wm−2. Mixed layer deepened gradually reaching a maximum of 62 m in December. Analysis of surface fluxes and winds suggested that winds and fluxes are the dominating factors causing deepening of mixed layer during summer and winter monsoon periods respectively. Relatively high correlation between MLD, net heat flux and wind speed revealed that short term variability of MLD coincided well with short term variability of surface forcing.

This paper summarizes our results on the changes in pelagic calci"cation and the standing stock of calcium carbonate associated with the SW Monsoon and NE Monsoon (cruises TN049 and TN053 of the U.S. JGOFS study, respectively) in the northern portion of the Arabian Sea. Mean calci"cation was &3X greater during the SW Monsoon than during the NE Monsoon. Calci"cation per coccolithophore was 7}10X higher, and the ratio of calci"cation to photosynthesis (C/P) was 40}45% higher during the SW Monsoon. The turnover time of PIC was not statistically di!erent between the two cruises (&4.5 d averaged over the euphotic zone). Turnover time of POC increased signi"cantly between TN049 and TN053 (from &3 to 6 d over the euphotic zone). We discuss vertical sections of coccolithophore abundance, carbon standing stocks and carbon "xation. Coccolithophore calci"cation was usually about 1}5% of community photosynthesis. The ratio of calci"cation to photosynthesis spanned almost 2 orders of magnitude, and was not signi"cantly di!erent from the ratio of the PIC and POC standing stocks. We compare surface PIC and POC production rates to sediment trap #uxes from the same region.

This paper presents an overview of the significance of the use of molecular biomarkers as diagnostic and prognostic tools for marine pollution monitoring. In order to assess the impact of highly persistent pollutants such as polychlorinated biphenyls (PCB), polychlorinated dibenzo-dioxins (PCDD), polychlorinated dibenzo-furans (PCDF), polynuclear aromatic hydrocarbons (PAH), tributyltin (TBT) and other toxic metals on the marine ecosystem a suite of biomarkers are being extensively used worldwide. Among the various types of biomarkers, the following have received special attention: cytochrome P4501A induction, DNA integrity, acetylcholinesterase activity and metallothionein induction. These biomarkers are being used to evaluate exposure of various species of sentinel marine organisms (e.g. mussels, clams, oysters, snails, fishes, etc.) to and the effect of various contaminants (organic xenobiotics and metals) using different molecular approaches [biochemical assays, enzyme linked immuno-sorbent assays (ELISA), spectrophotometric, fluorometric measurement, differential pulsed polarography, liquid chromatography, atomic absorption spectrometry]. The induction of the biotransformation enzyme, cytochrome P4501A in fishes (Callionymus lyra, Limanda limanda, Serranus sp., Mullus barbatus) and mussels (Dreissena polymorpha) by various xenobiotic contaminants such as PCBs, PAHs, PCDs is used as a biomarker of exposure to such organic pollutants. The induction of cytochrome P4501A is involved in chemical carcinogenesis through catalysis of the covalent bonding of organic contaminants to a DNA strand leading to formation of DNA adduct. Measurement of the induction of cytochrome P4501A in terms of EROD (7-ethoxy resorufin O-deethylase) activity is successfully used as a potential biomarker of exposure to xenobiotic contaminants in marine pollution monitoring. In order to assess the impact of neurotoxic compounds on marine environment the evaluation of acetylcholinesterase activity in marine organisms is used as a biomarker of exposure to neurotoxic agents such as organophosphorus, carbamate pesticides etc. Metallothioneins (MTs) are induced by toxic metals such as Cd, Hg, and Cu by chelation through cysteine residues and are used in both vertebrates and invertebrates as a biomarker of metal exposure. The measurement of the levels of DNA integrity in marine organisms such as Sea stars (Asterias rubens) from the North Sea and the marine snails (Planaxis sulcatus) from the Arabian Sea along the Goa coast exposed to environmental xenobiotic contaminants clearly indicated the extent and the nature of pollution at the sampling sites along coastal environment.

The Arabian Sea Blue Whale (Balaenoptera musculus arabica Khalaf, 2021): A New Subspecies from the Arabian Sea and Western Indian Ocean.

By: Sharif Prof.Dr.Sc. Norman Ali Bassam Ali Taher Mohammad Ahmad Ahmad Mostafa Abdallah Mohammad Khalaf-Prinz Sakerfalke von Jaffa.

Abstract: There are four distinct subspecies of blue whales living in the Indian Ocean: the Antarctic Blue Whale Balaenoptera musculus intermedia Burmeister, 1871 of the Antarctic Zone and Southern Ocean, the Pygmy Blue Whale Balaenoptera musculus brevicauda Ichihara, 1966 found in the Indian Ocean and South Pacific Ocean, the Northern Indian Ocean Blue Whale Balaenoptera musculus indica Blyth, 1859, found in the Northern Indian Ocean (Khalaf, May 2020), and the newly discovered unnamed subspecies Balaenoptera musculus un-named subsp., from the Arabian Sea and the Western Indian Ocean which was recognized as a new population with a previously unreported song-type. The novel song-type was recorded off Oman in the Arabian Sea/northern Indian Ocean, off the western Chagos Archipelago in the equatorial central Indian Ocean, and off Madagascar in the southwestern Indian Ocean (Cerchio et al., 2020). Blue whale subspecies are characterized each with a diagnostic song-type. The newly discovered population was scientifically named as a subspecies based on its novel song-type. It was given the name Balaenoptera musculus arabica Khalaf, 2021.

Reference: Khalaf-Prinz Sakerfalke von Jaffa, Prof. Dr. Sc. Norman Ali Bassam Ali Taher Mohammad Ahmad Ahmad Mostafa Abdallah Mohammad (January 2021). The Arabian Sea Blue Whale (Balaenoptera musculus arabica Khalaf, 2021): A New Subspecies from the Arabian Sea and Western Indian Ocean. Gazelle: The Palestinian Biological Bulletin. ISSN 0178 – 6288. Volume 39, Number 193, 01 January 2021, pp. 17-46. Published by Prof. Dr. Norman Ali Khalaf Department for Environmental Research and Media, National Research Center, University of Palestine, Gaza, State of Palestine. https://cetacea-5.webs.com/arabian-sea-blue-whale & https://issuu.com/dr-norman-ali-khalaf/docs/arabian_sea_blue_whale

1) Why did you choose to come to Canada? Tell about the conditions before coming and what attracted you here.

"Because Canada is an experiment - think about this, English and French couldn’t defeat each other and so made a nation together. Hence the “other” becomes an essential part of who you are. I thought that would be a fertile ground to strike roots - to do here what I was doing back home in Bombay (oops! Mumbai) – architecture, poetry and calligraphy (though I miss the Arabian Sea as I grew up in a house on its coast)."

Read more…
2) How was the move itself?
3) How easy/hard was it for you to get involved in architecture in Canada? What helped you find success?
4) What would you suggest to new immigrants who wish to get into the field

Interviewed by Rotem Yaniv;
Canadian Immigrant (online magazine)
November 2009

Cross Reference. See also:
"Between Two Tongues: Falling at The Speed of Light" in the Articles Section
"Impossible Toronto"  in the Articles Section
"Meditation on Clockfaces" in the Articles Section
"Flying Into Watercity" in the Articles Section
"The Travelling Nonvegetarian" in the Poetry Section

Particle fluxes measured continuously for one year at three locations in the Arabian Sea using time-series sediment traps show that lithogenic sedimentation processes are strongly coupled to biological processes. The vertical flux of lithogenic matter is controlled by episodic production and fluxes of biogenic matter.

Sediment traps were deployed on the Northwest Shelf (NWS) of Australia in November 1996, to determine fluxes of organic matter and inorganic elements from the photic zone to deeper waters in a transect extending from Exmouth Shelf to Exmouth Plateau. Infiltrex II water samplers collected particulate and dissolved organics from the water column near the trap sites. Surface sediments and sediment cores were also collected over the study region. Lipid biomarkers were used to determine the sources of organic carbon and its cycling processes on the NWS.Dry weight fluxes from the traps ranged from 124 to 616 mg m−2 day−1and particulate organic carbon (POC) fluxes ranged from 22 to 42 mg m−2 day−1. The biogenic lipids consisted of biomarkers indicative of marine zooplankton, phytoplankton and bacteria, plus traces of land plant markers. A large contribution of unresolved complex material (UCM), which is indicative of petroleum, was detected at four times the biogenic hydrocarbon flux at shallow stations, and up to seven times the biogenic hydrocarbon flux at the most offshore station.There is essentially no river input, and only trace aeolian-derived material to contribute to primary production on the NWS of Australia. Most of the organic matter produced are rapidly recycled in the water column and the small fraction of lipids that settle to the sediments is already partially degraded and undergoes further rapid degradation in the surface sediments. Natural oil seeps also provide utilisable organic carbon to the system. The production and vertical flux rates of organics determined in this study are comparable to those reported in studies of shallow traps in oceanic areas from long-term studies in the Arabian Sea, and other coastal margins such as the Bay of Biscay (France) and California (USA).In offshore areas, most “living” lipid materials passed through the GFF filters thus invalidating POC estimates based on high volume sampling. To adequately assess living (particulate) carbon, gentle filtration of low volume seawater samples is more accurate, as shown by this solid phase absorption study of individual lipid biomarkers.

Transfers of some important biogenic atmospheric constituents, carbon dioxide (CO 2), methane (CH 4), molecular nitrogen (N 2), nitrous oxide (N 2 O), nitrate ðNO À 3 Þ, ammonia (NH 3), methylamines (MAs) and dimethylsulphide (DMS), across the air-sea interface are investigated using published data generated mostly during the Arabian Sea Process Study (1992-1997) of the Joint Global Ocean Flux Study (JGOFS). The most important contribution of the region to biogeochemical fluxes is through the production of N 2 and N 2 O facilitated by an acute, mid-water deficiency of dissolved oxygen (O 2); emissions of these gases to the atmosphere from the Arabian Sea are globally significant. For the other constituents, especially CO 2 , even though the surface concentrations and atmospheric fluxes exhibit extremely large variations both in space and time, arising from the unique physical forcing and associated biogeochemical environment, the overall significance in terms of their global fluxes is not much because of the relatively small area of the Arabian Sea. Distribution and air-sea exchanges of some of these constituents are likely to be greatly influenced by alterations of the subsurface O 2 field forced by human-induced eutrophication and/or modifications to the regional hydrography.

We describe a new micro-scale method of measuring the penetration resistance of the sur"cial layers of slope and abyssal plain sediments within and below the OMZ on the Oman continental slope. The micro-scale load resistance penetrometer (MLRP) continuously measures the penetration resistance (q) of a cylindrical probe driven at constant velocity into cores of sediment recovered by sub-coring box core samples. Measurements are recorded at 0.8 mm depth intervals into the sediment by an automated data acquisition system. These provide continuous depth pro"les of penetration resistance (q) and its variability (qr) in sur"cial sediments (0}100 mm). The results represent the "rst published application of this technique to slope and abyssal plain sediments. The q data divide the stations into shallow OMZ (SOMZ) stations (391}854 m), deep OMZ (DOMZ) stations (987}1285 m), and abyssal non-OMZ (ANOMZ) stations (3392}3396 m). One station (688 m) was anomalous. Penetration resistance (q) was positively related to shear strength and inversely related to water content, but not to bioturbation measured as burrow numbers. Relaxation and pull-out data were obtained from three stations. Three patterns of qr were observed, consisting of well-con"ned data, data containing large negative and positive spikes, and data showing a progressive down-core increase in spikes. Four additional measures of q variability were de"ned, which show statistically signi"cant relationships with burrow numbers. An increase in bioturbation, estimated by burrow numbers, is associated with a decrease in micro-scale variability in q. This is related to (J.M.H. Murray) 0967-0645/00/$ -see front matter 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 7 -0 6 4 5 ( 9 9 ) 0 0 1 0 5 -8 the activity of burrowing macrofauna. Our results are discussed in the context of biogeotechnical modi"cations of sedimentary environments.

Although most data suggest that the India–Eurasia continental collision began approx 45–55 Myr ago, the architecture of the Himalayan–Tibetan orogen is dominated by deformational structures developed in the Neogene period (< 23 Myr ago). The stratigraphic record and thermochronometric data indicate that erosion of the Himalaya intensified as this constructional phase began and reached a peak around 15 Myr ago. It remained high until approx 10.5 Myr ago and subsequently slowed gradually to approx 3.5 Myr ago, but then ...

More than 2000 measurements of atmospheric and dissolved methane (CH4) were performed in the central and northwestern Arabian Sea as part of the German JGOFS Arabian Sea Process Study during three cruises in March, May/June, and June/July 1997. Mean CH4 saturations in the surface waters of the central Arabian Sea were in the range of 103-107%. Significantly enhanced saturations were observed in the coastal upwelling area at the coast of Oman (up to 156%) and in an upwelling filament (up to 145%). The CH4 surface concentrations in the upwelling area were negatively correlated to sea surface temperatures. Areaweighted, seasonally adjusted estimates of the sea-air fluxes of CH 4 gave annual emissions from the Arabian Sea of 11-20 Gg CH4, suggesting that previously reported very high surface CH4 concentrations might be atypical owing to the interannual variability of the Arabian Sea and that the emissions derived from them are probably overestimates.

The concentration rare earth elements and Yttrium (REE + Y) were determined in coral sands from Kavaratti Island, Arabian Sea, India. Chondrite-normalized REE + Y patterns show: (1) high REE concentration particularly light REE (LREE) enrichment; (2) consistent negative Ce anomaly; (3) nearly chondritic Y/Ho ratios. All these features are consistent with the geochemistry of well oxygenated seawater with significant terrestrial contribution. The seawater composition of Nd/Yb ratio inferred from the coral record point to the dominance of LREE more than the heavy REE (HREE). The high terrestrial input rich in LREE and property of adsorption/scavenging processes of LREE than that of HREE may be the cause. Terrigenous contributions were detected on the basis of cooccurring trace element concentrations (Sc, Hf and Th) and Y/Ho ratio. Except for La, the REE distribution coefficients, KD(REE)s, are between 100 and 300. KDs are high comparing to the other elements in biogenic calcite which is attributed to detrital contamination during elemental incorporation. This study may not reflect original seawater chemistry but it can be a good proxy to indicate proximity of corals to terrigenous input sources.

The surficial sediments from the upper continental slope of the eastern Arabian Sea, impinged by the oxygen minimum zone (OMZ, 150-1200 m water depth), show varying concentrations of the biogenic element phosphorus (P, 0.1-0.2%) in the northern and southern areas even though total organic carbon concentrations are relatively constant (TOC, 2-5%;. To understand this discordance, 17 surface sediment samples from shelf, slope and deep sea of the eastern Arabian Sea were investigated using a five-step sequential extraction scheme to delineate the process responsible for P enrichment in OMZ. High fractions of organic phosphorus (P org 10-26%), biogenic phosphorus (P bio 36-48%), relatively low molar C org /P org ratios (322-447), and C org /P reactive ratios close to Redfield Ratio in OMZ sediments of the SE Arabian Sea suggest accumulation under high surface production and low residence time of labile forms of P due to high sedimentation rates. Despite higher productivity in surface waters, low fractions of P org (8-13%; less than deep-sea sediments of the study area 12-13%), P bio (25-33%), relatively high molar C org /P org ratios (341-508), and C org /P reactive ratios less than Redfield Ratio in OMZ sediments from the NE Arabian Sea may indicate a higher degree of regeneration and diagenetic transformation of labile forms of P to other phases. Authigenic phosphorus (P aut ) fraction varies by a factor of 2-8 in sediments from the OMZ when compared to well-oxygenated deep-sea sediments of the study area. While the P total remains constant, significant P transformation seems to occur in NE Arabian Sea, which is suggested by high P aut fraction ($50%) compared to low P aut fraction (10-39%) in the SE Arabian Sea sediments. Supply rates of phosphorus, variable rates of P dissolution under varying dissolved oxygen contents in the bottom waters, and early diagenetic transformation of P within the sediments seem to influence P geochemistry in sediments overlain by the OMZ in the eastern Arabian Sea. r

This report summarises the status of coral reefs in the ROPME Sea Area which includes Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates (UAE); there are no coral reefs in Iraq. The region can be split into three parts according to the local marine climate, which strongly influences the nature of the coral communities: the Persian/Arabian Gulf

The Lakshadweep group of islands is scattered in the Arabian Sea about 200 to 400 km off the west coast of Kerala. The general topography of islands is hummocky to flat with steeper shore on the east. The coralline islands are fringed by beach material all around the island. They are largely composed of course sand, disintegrated corals, shell fragments and uncemented pebbles, shingles, cobbles and boulders. The western side of most of the islands are fringed by coralline reef enclosing the lagoon. The erosion is more pronounced towards the eastern side. In case of Kavaratti island, the sediment concentration is more towards the northeast and southwest part of the lagoon. The average width of the reef is about 200-300 m. The uppermost part of the reef is punctured byspurs, grooves and scour channels and they are basically erosive in origin. The direction of spurs and grooves suggest paleo-winds and currents from southeastern direction. Two to three submarine terraces were mapped from the aerial photographs. These might have been formed due to eustatic changes of the sea level.

In this study, we investigate phosphorus (P) and iron (Fe) cycling in sediments along a depth transect from within to well below the oxygen minimum zone (OMZ) in the northern Arabian Sea (Murray Ridge). Pore-water and solid-phase analyses show that authigenic formation of calcium phosphate minerals (Ca-P) is largely restricted to where the OMZ intersects the seafloor topography, likely due to higher depositional fluxes of reactive P. Nonetheless, increased ratios of organic carbon to organic P (Corg/Porg) and to total reactive P (Corg/Preactive) in surface sediments indicate that the overall burial efficiency of P relative to Corg decreases under the low bottom water oxygen concentrations (BWO) in the OMZ. The relatively constant Fe/Al ratio in surface sediments along the depth transect suggest that corresponding changes in Fe burial are limited. Sedimentary pyrite contents are low throughout the ~25 cm sediment cores at most stations, as commonly observed in the Arabian Sea OMZ. However, pyrite is an important sink for reactive Fe at one station in the OMZ. A reactive transport model (RTM) was applied to quantitatively investigate P and Fe diagenesis at an intermediate station at the lower boundary of the OMZ (bottom water O2: ~14 μmol L−1). The RTM results contrast with earlier findings in showing that Fe redox cycling can control authigenic apatite formation and P burial in Arabian Sea sediment. In addition, results suggest that a large fraction of the sedimentary Ca-P is not authigenic, but is instead deposited from the water column and buried. Dust is likely a major source of this Ca-P. Inclusion of the unreactive Ca-P pool in the Corg/P ratio leads to an overestimation of the burial efficiency of reactive P relative to Corg along the depth transect. Moreover, the unreactive Ca-P accounts for ~85% of total Ca-P burial. In general, our results reveal large differences in P and Fe chemistry between stations in the OMZ, indicating dynamic sedimentary conditions under these oxygen-depleted waters.

Arthropods
ISSN 2224-4255
arthropods@iaees.org

Volume 9, Number 4, 1 December 2020

Cover Pages

[Front Pages (142K)] [Back Pages (63K)]
Articles

Biochemical characterization of digestive carbohydrases in Moroccan locust, Dociostaurus maroccanus Thunberg (Orthoptera: Acrididae)
Arthropods, 2020, 9(4): 119-128
Bahareh Rafiei, Mohammad Ghadamyari, Sohrab Imani, et al.
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Wing characters for morphological study on the honey bee (Apis mellifera L.) populations among six provinces of Iran
Arthropods, 2020, 9(4): 129-138
Shahram Dadgostar, Jamasb Nozari, Gholamhossein Tahmasbi
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Morpho-taxonomic study of some planktonic caught megalopal stages collected from northern Arabian Sea
Arthropods, 2020, 9(4): 139-154
Muhammad Aslam
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Microhabitat preference and biology of Holconia insignis (Thorell, 1870) (Araneae:Sparassidae) in banana plantation agroecosystem
Arthropods, 2020, 9(4): 155-163
Akamu Jude Ewunkem, Christophe Parr Mbua, Nelson Neba Ntonifor
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Latitudinal gradient in species richness of Sphaerotherium
Arthropods, 2020, 9(4): 164-170
Mark Cooper
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First record of some jumping spiders (Arachnida: Araneae: Salticidae) from Pench National Park, Maharashtra State, India
Arthropods, 2020, 9(4): 171-174
Pawan U. Gajbe
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We describe an improved tree-ring reconstruction of mean warm-season (November-April) temperatures for Tasmania from Huon pine. This record extends back to 1600 BC and is based on a tree-ring chronology that was processed to retain as much low-frequency variance as possible. The resulting reconstruction explains 46.6% of the variance and verifies significantly when compared to withheld instrumental data. Cross-spectral analysis of actual and estimated temperatures over the 1886-1991 common period indicates that most of the unexplained variance is at periods < 12 years in length. At periods > 12 years, the squared coherency ranges between 0.6-0.8, and the cross-spectral gain indicates that the amplitude of the reconstruction is a nearly unbiased estimate of the true temperature amplitude. Therefore, this reconstruction should be especially useful for studying multi-decadal temperature variability in the Tasmanian sector of the Southern Hemisphere over the past 3592 years. To this end, we examined the time evolution of low-frequency temperature amplitude fluctuations and found evidence for a 35% amplitude reduction after AD 100 that persisted until about AD 1900. Since that time, the low-frequency temperature amplitude has systematically increased. We also show how this reconstruction is related to large-scale sea surface temperatures (SST) in the Indian Ocean and eastward to the dateline. Pointwise correlations between the Tasmanian record and SSTs reveal a relationship that extends across the southern Indian Ocean and towards the Arabian Sea. This pattern is largely determined by inter-decadal temperature variability, with correlations in this > 10-year bandwidth commonly exceeding 0.6 over most of the southern Indian and southwestern Pacific sectors. A rotated empirical orthogonal function analysis reveals that the pattern of pointwise correlations found between the temperature reconstruction and SSTs is largely explained by the linear combination of three orthogonal modes of SST variability.

This report summarises the status of coral reefs in the ROPME Sea Area which includes Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates (UAE); there are no coral reefs in Iraq. The region can be split into three parts according to the local marine climate, which strongly influences the nature of the coral communities: the Persian/Arabian Gulf

The Arabian Peninsula is separated from Africa by the Red Sea and from Iran by the Persian Gulf and the Oman Sea, and is bounded on the south by the Arabian Sea and the Gulf of Aden. Geologically, it consists of crystalline Precambrian basement overlain by low-dipping Phanerozoic sedimentary and volcanic rocks, and originated 25-30 million years ago as a consequence of rifting along the line of the eventual Red Sea and Gulf of Aden. At the present time, the northern part of the Arabian plate moves northwest, with respect to the Eurasian plate, at a rate of 20±3 mm/yr. The United Arab Emirates is a part of Arabian Peninsula and lies at its northeastern part. Fujairah and the area under study is located in Northeastern Emirates. Based on geological data, mountains in the west of Fujairah consist of ophiolites. These ophiolites continue towards the south and southeast along the seashore with Quaternary deposits in the east.

This study focuses on applying remote sensing technology to identify and assess seasonal and intra-annual variation of phytoplankton availability. A standard MODIS algorithm for Chlorophyll-a, is used to obtain a variation of phytoplankton with the help of MODIS time series images from April 2011 to March 2012 that describe the situation for a whole year, we also used periodical data for each three months, i.e.

Cores 255 and B-3GC from the southern and northern Okinawa Trough, respectively, were studied for determining the variability of the Kuroshio Current on centennial scales during the Holocene based on detailed AMS 14 C dates, stable isotope, and planktonic foraminiferal distribution. The main flow of the Kuroshio Current was inferred to reenter the Okinawa Trough at V7.3 calendar (cal.) kyr BP, leading to abrupt changes in sedimentation rate, remarkably increased abundance of the Kuroshio Current indicator Pulleniatina obliquiloculata, increased sea surface temperature (SST) and depth of thermocline (DOT). During V4.6^2.7 cal. kyr BP, the abundance of P. obliquiloculata sharply decreased, corresponding to a decreases in SST and DOT, implying that the influence of the Kuroshio Current weakened at that time, possibly as a result of the intensified winter monsoon. Significantly, the Kuroshio Current proxies (e.g. the difference in SST between the southern and northern Okinawa Trough) display periodicities of V1500 yr and V700^800 yr (ascribed to the second harmonic of the 1500 yr cycle in oceanic thermohaline circulation) during the Holocene. The Holocene events (at V0.6, 1.7, 3.3, 4.6, 5.9, 8.1, 9.4 cal. kyr BP) in the Okinawa Trough appear to be the most recent manifestation of the millennial scale climate cycle, recorded in the North Atlantic, Arabian Sea marine sediment cores and Greenland ice cores, suggesting global climatic tele-connections. ß

Monthly sampling of phytoplankton, chlorophyll a, temperature, salinity and nutrients was carried out in the Sea of Oman and in the Arabian Sea, from 2004 and onwards. In addition to time series data, historical data from 1976 to 2003 were collected from the Ministry of Agriculture and Fisheries Wealth reports. Annual averages of algal blooms occurrence along the coast of Oman showed three major components of seasonal and interannual fluctuations-the seasonal cycle, interannual fluctuations with approximate period of 8 years, and the interannual rising tendency. The dominant algal blooms species comprise both diatoms and dinoflagellates, with obvious dominance of Noctiluca scintillans followed by Cochlodinium polykrikoides and Prorocentrum sp.

The distribution, biomass, and diversity of living (Rose Bengal stained) deep-sea benthic foraminifera ('30 m) were investigated with multicorer samples from seven stations in the Arabian Sea during the intermonsoonal periods in March and in September/October, 1995. Water depths of the stations ranged between 1916 and 4425 m. The distribution of benthic foraminifera was compared with dissolved oxygen, % organic carbon, % calcium carbonate, ammonium, % silica, chloroplastic pigment equivalents, sand content, pore water content of the sediment, and organic carbon #ux to explain the foraminiferal patterns and depositional environments.

In the modern ocean, oxygen minimum zones (OMZs) are potential traces of a primitive ocean in which Archean bacteria lived and reduced chemical anomalies occurred. But OMZs are also keys to understanding the present unbalanced nitrogen cycle and the oceans' role on atmospheric greenhouse control. OMZs are the main areas of nitrogen loss (as N 2 , N 2 O) to the atmosphere through denitrification and anammox, and could even indirectly mitigate the oceanic biological sequestration of CO 2 . It was recently hypothesized that OMZs are going to spread in the coming decades as a consequence of global climate change. Despite an important OMZ role for the origin of marine life and for the biogeochemical cycles of carbon and nitrogen, there are some key questions on the structure of OMZs at a global scale. There is no agreement concerning the threshold in oxygen that defines an OMZ, and the extent of an OMZ is often evaluated by denitrification criteria which, at the same time, are O 2 -dependent.

Although the confrontation between the Ottoman and Portuguese navies in the sixteenthcentury Indian Ocean is commonly described as a struggle between "indigenous Muslims" and "European intruders," in reality the seafarers of both fleets were overwhelmingly Mediterranean in origin. Yet despite these shared origins, the crews of Ottoman and Portuguese ships nevertheless conceived of themselves in different ways: the Portuguese as part of a blood-based "nation," and the Ottomans as part of a cosmopolitan "empire." And ultimately, this difference profoundly influenced relations between the two powers. Since the Ottomans, unlike any of the indigenous peoples of the Indian Ocean, were so obviously racially and ethnically similar to the Portuguese, their self-confident cosmopolitanism posed a threat to the underpinnings of Portuguese ethnic solidarity, just as the strength of their navy posed a threat to Portuguese hegemony at sea.

On average 1-2 tropical cyclones form over the Arabian Sea each year, and few of these storms are intense enough to be classified as very severe or super cyclonic storms. As such, few studies have explicitly identified the seasonal to interannual changes in environmental conditions that are associated with Arabian Sea tropical cyclogenesis. However, over the last 30 yr several intense Arabian storms did form and make landfall, with large impacts, which motivates this new study of the basin. The conclusions of earlier studies are visited by utilizing modern observational and reanalysis data to identify the large-scale features associated with Arabian tropical cyclone variability on seasonal time scales. Then year-to-year changes in environmental conditions that are related to interannual variability in Arabian storms during the pre-and postmonsoon periods are elucidated. The analysis of the relationship between large-scale environmental variables and seasonal storm frequency supports conclusions from work completed more than 40 yr prior. Investigation of the year-to-year changes in premonsoon storm frequency suggests that May (June) storms are associated with an early (late) onset of the southwest monsoon. The findings also demonstrate that November cyclones (the month when the majority of postmonsoon cyclogenesis occurs) primarily form during periods when the Bay of Bengal experiences a broad region of high sea level pressure, implying that November storms form in either the Arabian Sea or the Bay of Bengal but not in both during the same year. Finally, the analysis of changes in a genesis potential index suggests that long-term variability in the potential for a storm to form is dictated by changes in midlevel moisture.

In natural conditions, the Indus River had one of the largest sediment loads in the world, building an extensive delta on the high-energy coast of the Arabian Sea. However, water and sediment discharge have been drastically altered in the Indus since the early 1960s, when several barrages were built along the river to feed the world's largest irrigation system. A digital terrain model based on detailed 19th century surveys has been constructed to assess the morphology of the Indus shelf. Comparison of the digital terrain model to a 1950s Pakistani bathymetric survey allowed an estimation of the natural sedimentation regime before extensive human-induced changes. Digital analysis of the Indus delta coastline based on satellite imagery was used to explore the effects of the drastic decrease in sediment delivery following extensive dam building.

The paper highlights the main problems encountered in operating salt gradient solar ponds in the Arabian Gulf region, characterized by hot, windy, and dusty environment. These problems are excessive erosion of the gradient zone, the formation of sizeable localized convective zones, the deterioration of pond water clarity and the high rates of surface evaporation. These weather-related problems severely impair the

Agarose was prepared from a red alga Gracilaria dura occurring in the Arabian Sea at the west coast of India. The agarose has been characterized by studying its physicochemical properties as well as by FTIR, 13 C NMR and CP-MAS spectra, inductively coupled plasma (ICP) spectrophotometric and rheological measurements. This agarose had gel strength 2200 g cm À2 , gelling temperature 6 35°C, sulphate content 6 0.25%, ½a 45 589 À 22 and M w 1.25 · 10 5 g mol À1 . These properties were benchmarked against those of the commercially available agarose products of Sigma (A0576) and Fluka, and were found to be comparable.

Particulate organic carbon (POC) is vertically transported to the oceanic interior by aggregates and their ballasts, mainly CaCO 3 and biogenic opal, with a smaller role for lithogenic aerosols through the mesopelagic zone. Diel migrating zooplankton communities effect vertical transport and remineralization of POC in the upper layers of the ocean. Below 1.5 km, the presence of zooplankton is reduced and thus the aggregates travel mainly by gravitational transport. We normalized the fluxes of POC, CaCO 3 , and biogenic opal from data published on samples collected at 134 globally distributed, bottom-tethered, time-series sediment trap (TS-trap) stations to annual mole fluxes at the mesopelagic/bathypelagic boundary (m/b) at 2 km and defined them as F m/b C org , F m/b C inorg , and F m/b Si bio . Using this global data set, we investigated (1) the geographic contrasts of POC export at m/b and (2) the supply rate of P CO 2 to the world mesopelagic water column. F m/b C org varies from 25 (Pacific Warm Pool) to 605 (divergent Arabian Sea) mmolC m À2 yr À1 ; F m/b C inorg varies from >8 (high latitude Polar Oceans) or 15 (Pacific Warm Pool) to 459 (divergent Arabian Sea) mmolC m À2 yr À1 ; and F m/b Si bio , the most spatially/temporally variable flux, ranges from 6 (North Atlantic Drift) to 1118 (Pacific Subarctic Gyre) mmolSi m À2 yr À1 . The oceanic region exhibiting the highest POC flux over a significantly large region is the area of the North Pacific Boreal Gyres where the average F m/b C org = 213, F m/b C inorg = 126, and F m/b Si bio = 578 mmol m À2 yr À1 . F m/b C org and F m/b C inorg are particularly high in large upwelling margins, including the divergent Arabian Sea and off Cape Verde. One of the data sets showing the lowest flux over a significant region/basin is F m/b C org = 39, F m/b C inorg = 69, and F m/b Si bio = 22 mmol m À2 yr À1 in the North Pacific subtropical/tropical gyres; Pan-Atlantic average fluxes are similar except F m/b Si bio fluxes are even lower. Where C org /C inorg and Si bio /C inorg are <1 defines the ''Carbonate Ocean", and where these ratios are P1 defines the ''Silica Ocean". The Carbonate Ocean occupies about 80% of the present world pelagic ocean between the two major oceanographic fronts, the North Pacific Polar Front and the Antarctic Polar Front, and the Silica Ocean is found on the polar sides of these fronts. The total global annual fluxes of F m/b C org , F m/b Based on our global F m/b C inorg and recently estimated global primary production of PIC, 36-86 teramolC yr À1 of PIC is assumed to be dissolved within the upper 2 km of the water column.

The traditional architecture of Kerala, a state in India lying along its southwest coast, is known for its use of natural and passive methods for a comfortable indoor environment. Although there have been attempts to analyze the traditional architecture of Kerala, they were focused only on qualitative approach. An investigation was thus initiated by the authors to understand the passive environment control system of Kerala traditional architecture in providing better thermal comfort, by continuously monitoring thermal comfort parameters of a typical traditional residential building over a period of time. The inferences of the first phase of the investigation carried out during winter and summer seasons, lasting about half of the year have already been published. This paper illustrates the inferences of the second phase of the investigation that is carried out during the rainy season of the year. A comparative analysis with the results of the winter and summer periods is also incorporated. The investigation has revealed that, when the outside ambient temperature is below normal, the building system tries to maintain the indoor air temperature at a higher but comfortable level and when the outside temperature is above normal, the indoor is kept at a lower but comfortable level. It is found that a continuous gentle wind flow is maintained inside the building irrespective of the wind outside. The required level of thermal comfort is achieved by maintaining a balanced level of temperature and relative humidity along with a continuous and controlled airflow inside the building irrespective of seasons.

Electricity is backbone for almost all economic activities in present times and it is a proven fact that access of this precious perishable commodity to people bears direct impact on pace of development of the country. The country's development is measured in terms of per capita consumption of electricity which in turn depends on electricity generated. India has the fifth largest installed power capacity in the world (the first four are -US, Japan, China and Russia -in that order), and is one of the top power consumers. India has an installed power capacity of approximately 150 MW for the year 2009, which is 4% of the global capacity. The per capita power consumption (per year) in India has increased to 720 KWh (or units) from 15.6 kWh as on 31.03.2003, which is less than 5% of the per capita consumption in USA, and less than 20% than that of China. The global per capita consumption of power is about 2,340 KWh (or Units). The peak power shortage of 9.9% has been plaguing Indian power sector as on January 2010. As a result regulators worldwide are now implementing new regulating schemes and organizational reforms in an effort to improve the efficient operation of the electric utilities. Reforms and restructuring are taking place in the electricity sector by introducing competition in the electricity supply industry, wherever, it is technologically feasible and India is not exception to these reforms. In this paper, a case study of Tamil Nadu has been carried out, which is bordered on the north by the states of Andhra Pradesh and Karnataka and on the west by the state of Kerala. Kanyakumari, the southernmost tip of this land is the meeting point of the Bay of Bengal, the Arabian Sea and the Indian Ocean. In India, Tamil Nadu state ranks third in Electricity generation, Transmission and Distribution. Tamil Nadu is the first state in the country to achieve 100 % electrification of all villages as early as 1992. With the enactment of Electricity Act 2003, there has been tremendous improvement in the areas of transmission and distribution, tariff rationalization and in availability of power supply.

Here we describe a new elasmobranch assemblage consisting of isolated dental material from the Aquitanian near-shore marine deposits of the Shuwayr and Warak formations at Sharbithat, in eastern Sultanate of Oman. The faunal composition clearly indicates affinities to other early Miocene elasmobranch-bearing localities worldwide. This assemblage is predominantly composed of large and common pelagic sharks as well as teeth attributable to a new species of fantail stingray, Taeniurops tosii, as old as the oldest undisputable fossil records of Taeniurops. The study of this fossil assemblage presented here improves the knowledge of the ancient elasmobranchs that frequented the eastern Arabian coasts during the closure of the Neotethys and the birth of the Arabian Sea.

The larviparous oyster Ostrea nomades from two different localities was examined histologically and found to be mostly hermaphroditic. However, pure males, pure females and indifferent oysters were also found. The hermaphrodites of O. nomades were classified into three categories: ambisexual, predominantly female and predominantly male. Gonadal development appears to take place throughout the year with increasing activity and ripening in the winter months, leading to immediate spawning and later resorption. The number of brooding larvae of O. nomades was low at both collection sites.

In the central and eastern Arabian Sea (EAS), biomass and production of phytoplankton are known to vary spatially and seasonally whereas, biomass of mesozooplankton (MSP) is reported to be constant. This apparent contradiction has been called 'Arabian Sea Paradox'. However, it is important to note that the paradox is based on a very limited seasonal data (from 5 to 7 locations). Therefore, we reconsidered the paradox based on intensive in-situ observations at 37-40 locations in the EAS. In agreement with the known seasonal difference in phytoplankton standing stock in the EAS, we analysed the MSP data in two ways using two-way nested ANOVA. In 'basin scale' analysis, MSP data from the EAS were pooled and seasonal and inshore-offshore variations were analysed for the entire region. In 'regional scale' analysis, MSP data were analysed separately for (a) northern region (north of 15°N) and (b) southern region (15°N and south of it). Satellite data of chlorophyll a, SST and wind speed were also analysed to show the major differences in oceanographic features in the northern and southern EAS. The analyses showed prominently high chlorophyll a (av. 1 mg m − 3 ) in the northern region during most of the year through winter convection, open ocean upwelling and lateral advection from the Arabian coast. On the other hand, chlorophyll a was low (av. 0.2 mg m − 3 ) in the southern region during most of the year mainly due to thermohaline stratification. The MSP biomass was distributed almost in a similar way as that of phytoplankton stock with statistically significant spatial and seasonal variations in the northern and southern regions. In this paper, we review the 'paradox of MSP' and present clear and new evidences to show that this concept is not logically applicable for EAS.

In the present paper, we have carried out analysis of surface chlorophyll-a concentration in the seas around India obtained using the Indian Remote Sensing satellite IRS-P4 Ocean Colour Monitor (OCM) data. The focus was given to southwest Bay of Bengal where such studies are scanty. The study portraits the chlorophyll-a pattern during July 1999-June 2000. The monthly sea surface temperature (SST) trend and wind patterns using NOAA-NCEP and Quickscat Scatterometer data, respectively, were studied, to elucidate their impact on chlorophyll distribution. This helped to decipher how the reversing monsoon wind induces algal blooming in the surface waters of the study area. Several features like eddies, algal blooms and coastal plumes were observed. Highest mean chlorophyll was observed in January (northeast monsoon) and lowest in May (summer inter monsoon). Adjacent Arabian Sea water found predominantly productive than the Bay of Bengal water. Higher wind speed around 10 m/s in southwest and northeast monsoon shows about two fold increase in chlorophyll concentration to 1.0-2.0 mg/m 3 and the SST has shown gradient and decrease of about 1-2ºC in the BoB and off southern India, respectively.

During the second phase of the Arabian Sea Monsoon Experiment (ARMEX-II), extensive measurements of spectral aerosol optical depth, mass concentration, and mass size distribution of ambient aerosols as well as mass concentration of aerosol black carbon (BC) were made onboard a research vessel during the intermonsoon period (i.e., when the monsoon winds are in transition from northeasterlies to westerlies/ southwesterlies) over the Arabian Sea (AS) adjoining the Indian Peninsula. Simultaneous measurements of spectral aerosol optical depths (AODs) were made at different regions over the adjoining Indian landmass. Mean AODs (at 500-nm wavelength) over the ocean (ϳ0.44) were comparable to those over the coastal land (ϳ0.47), but were lower than the values observed over the plateau regions of central Indian Peninsula (ϳ0.61). The aerosol properties were found to respond distinctly with respect to change in the trajectories, with higher optical depths and flatter AOD spectra associated with trajectories indicating advection from west Asia, and northwest and west-coastal India. On average, BC constituted only ϳ2.2% to total aerosol mass compared to the climatological values of ϳ6% over the coastal land during the same season.

This paper focuses on the characteristics of the oxygen minimum zone (OMZ) as observed in the Arabian Sea over the complete monsoon cycle of 1995. Dissolved oxygen, nitrite, nitrate and density values are used to delineate the OMZ, as well as identify regions where denitri"cation is observed. The suboxic conditions within the northern Arabian Sea are documented, as well as biological and chemical consequences of this phenomenon. Overall, the conditions found in the suboxic portion of the water column in the Arabian Sea were not greatly di!erent from what has been reported in the literature with respect to oxygen, nitrate and nitrite distributions. Within the main thermocline, portions of the OMZ were found that were suboxic (oxygen less than &4.5 M) and contained secondary nitrite maxima with concentrations that sometimes exceeded 6.0 M, suggesting active nitrate reduction and denitri"cation. Although there may have been a reduction in the degree of suboxia during the Southwest monsoon, a dramatic seasonality was not observed, as has been suggested by some previous work. In particular, there was not much evidence for the occurrence of secondary nitrite maxima in waters with oxygen 0967-0645/99/$ -see front matter 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 7 -0 6 4 5 ( 9 9 ) 0 0 0 4 8 -X concentrations greater than 4.5 M. Waters in the northern Arabian Sea appear to accumulate larger nitrate de"cits due to longer residence times even though the denitri"cation rate might be lower, as evident in the reduced nitrite concentrations in the northern part of the basin. Organism distributions showed string relationships to the oxygen pro"les, especially in locations where the OMZ was pronounced, but the biological responses to the OMZ varied with type of organism. The regional extent of intermediate nepheloid layers in our data corresponds well with the region of the secondary nitrite maximum. This is a region of denitri"cation, and the presence and activities of bacteria are assumed to cause the increase in particles. ADCP acoustic backscatter measurements show diel vertical migration of plankton or nekton and movement into the OMZ. Daytime acoustic returns from depth were strong, and the dawn sinking and dusk rise of the fauna were obvious. However, at night the biomass remaining in the suboxic zone was so low that no ADCP signal was detectable at these depths. There are at least two groups of organisms, one that stays in the upper mixed layer and another that makes daily excursions. A subsurface zooplankton peak in the lower OMZ (near the lower 4.5 M oxycline) was also typically present; these animals occurred day and night and did not vertically migrate.

Estimation of the terms in the upper-ocean heat budget from a moored array in the central Arabian Sea shows periods when a rough balance between the temperature trend and the horizontal advection of heat exists. Altimetry and sea-surface temperature imagery are used to demonstrate that these episodes of strong horizontal advection are associated with mesoscale features. During the wintertime Northeast (NE) Monsoon these are capped-off mesoscale eddy features generated during the previous summertime Southwest (SW) Monsoon and have little horizontal transport of heat within the mixed layer. During the SW Monsoon the major contribution is strong offshore export of coastally upwelled water in a filament with a strong surface presence. Temperature and salinity properties from the moored array and a SeaSoar survey during the formation of the coastal filament confirm the offshore transport of the upwelled water mass to the site of the moored array, more than 600 km offshore. Estimates of the filament section heat flux are several percent of the total estimated heat flux due to upwelling along the Arabian Peninsula, and remote sensing data show that similar mesoscale variability along the coast is enhanced during the SW Monsoon. This points to the importance of mesoscale-modulated transports in not only the observed heat budget at the moored array, but in the overall upperocean heat budget in the Arabian Sea. r