Omani Coast Research Articles

Primary productivity and its regulation in the Arabian Sea during 1995

Abstract The annual cycle of monsoon-driven variability in primary productivity was studied in 1995 during the Arabian Sea Expedition as part of the United States Joint Global Ocean Flux Studies (US JGOFS). This paper describes the seasonal progression of productivity and its regulation on a section which ran from the coast of Oman to about 1000 km offshore in the central Arabian Sea at 65°E. During the SW Monsoon (June–mid-September), the coolest water and highest nutrient concentrations were close to the coast, although they extended offshore to about 800 km; during the January NE Monsoon, deep convective mixing provided nutrients to the mixed layer in the region 400 – 1000 km offshore. As expected, the SW Monsoon was the most productive season (123±9 mmol C m−2 d−1) along the southern US JGOFS section from the coast to 1000 km offshore, but productivity in the NE Monsoon was surprisingly high (112±7 mmol C m−2 d−1). There was no onshore/offshore gradient in primary productivity from 150 to 1000 km off the Omani coast in 1995, and there was no evidence of light limitation of either primary productivity or photosynthetic performance (PoptB) from deep convective mixing during the NE Monsoon, deep wind mixing during the SW Monsoon or offshore Ekman downwelling during the SW Monsoon. Productivity during the Spring Intermonsoon (86±6 mmol C m−2 d−1) was much higher than in oligotrophic regions such as the tropical Pacific Ocean (29±2 mmol C m−2 d−1) or the North Pacific gyre region (32±8 mmol C m−2 d−1). The 1995 annual mean productivity (111±11 mmol C m−2 d−1) along this section from the Omani coast to the central Arabian Sea was about equal to the spring bloom maximum (107±23 mmol C m−2 d−1) during the 1989 North Atlantic Bloom Experiment (NABE) and the equatorial, 1°N–1°S wave guide maximum (95±6 mmol C m−2 d−1) in the Pacific Ocean during the 1992 EqPac study. The 1995 SW Monsoon primary productivity was similar to the mean value observed in the same region in 1994 by the Arabesque Expedition (127±14 mmol C m−2 d−1) and in 1964 by the ANTON BRUUN Expedition (115±27 mmol C m−2 d−1). During the 1995 SW Monsoon, strong, narrow and meandering current filaments extended from the region of coastal upwelling to about 700 km offshore; these filaments had levels of biomass, primary productivity, chlorophyll-specific productivity and diatom abundance that were elevated relative to other locations during the SW Monsoon. The SW Monsoon was the most productive period, but SW Monsoon primary productivity values were lower than predicted because efficient grazing by mesozooplankton kept diatoms from accumulating the biomass necessary for achieving the high levels of primary productivity characteristic of other coastal upwelling regions. The high rates of chlorophyll-specific productivity (PoptB>10 mmol C mg Chl−1 d−1) observed in the 1995 SW Monsoon, together with the observed dust flux and iron concentrations, indicate that the Arabian Sea was more iron replete than the equatorial Pacific Ocean or the Southern Ocean.

Nitrogen production in the northern Arabian Sea during the Spring Intermonsoon and Southwest Monsoon seasons

Abstract Planktonic nitrogen productivity and regeneration were measured with 15NO3, 15NH4 and 15N-urea tracers during the Spring Intermonsoon (SI) and Southwest Monsoon (SWM) seasons in the northern Arabian Sea from the Omani coast southeast to 10°N. On an areal basis, new (nitrate) productivity and the nitrogen f-ratio varied from 0.1 to 13 mmol m−2 d−1 and 0.03 to 0.4, respectively. Including urea in total nitrogen uptake lowered the f-ratio by 29% on average for individual samples, and during the SI was most important in offshore regions. The lowest nitrate productivity rates also were measured in offshore regions during the SI, where low, but detectable, nitrate levels limited uptake. The onset of the SWM was associated with an order of magnitude increase in nitrate uptake seaward of the Findlater Jet as compared to the SI. Apparently, the positive effect of the increased availability of nitrate and the Ekman transport of established phytoplankton populations to the region more than offset the degraded light conditions caused by the deep (>80 m) mixed layers. Despite the increases in offshore nitrate uptake, both a budget of surface particulate material and 234Th POC flux estimates indicated that the mid- SWM reduced the efficiency of material export from surface waters and disrupted the linkage between new production and export that was evident in the SI. In the mid-SWM, new production mainly accumulated in deeply mixed surface waters offshore, and may be responsible for the well documented lag between the onset of the SWM and export. In the coastal upwelling region, new production rates were significantly greater during the SWM only near filaments of coastal water advected offshore. Ammonium regeneration rates and concentrations increased significantly in coastal regions during the SWM, and nitrification likely was a significant sink for some of the ammonium produced there. The transport of some of the remainder of this reduced nitrogen offshore would fuel nitrogen production without having an impact on local respiration. This is one of several factors that may confound the comparison of new and net production in coastal regions during the early SWM.

New Prehistoric sites along the Omani coast from Ra's al‐Hadd to Ra's al‐Jins

The information gathered from the study of surface collections is still an extremely important source of knowledge of prehistoric Oman. The data presented here come from some sites found during a survey by the Italian‐French team working in the Ra's al‐Hadd Project. Technological, typological and typometric analyses of the lithic material are used to suggest a tentative chronology.

The upper-ocean response to monsoonal forcing in the Arabian Sea: seasonal and spatial variability

Observations from four towed profiler surveys undertaken between December 1994 and October 1995 examine the seasonal and spatial variability of the upper ocean response to the Monsoon cycle in the Arabian Sea. Although observed atmospheric forcing agrees well with modern climatologies, cross-basin patterns of mixed-layer depth and water properties observed in 1994–1995 are not entirely consistent with an upper-ocean response dominated by Ekman pumping. During the winter monsoon, the mixed-layer deepens dramatically with distance offshore. Surface cooling intensifies with offshore distance, and a one-dimensional response dominated by convective overturning could explain observed wintertime mixed-layer depths. Except for waters associated with a filament extending offshore from the Omani coast, mixed-layer depths and water properties show only modest cross-basin contrasts during the Southwest Monsoon. Filament waters differ from surrounding mid-basin waters, having shallow mixed-layers and water properties similar to those of waters upwelled near the Omani coast. In September, following the Southwest Monsoon, waters within 1000 km of the Omani coast have cooled and freshened, with marked changes in stratification extending well into the pycnocline. Estimates of Ekman pumping and wind-driven entrainment made using the Southampton Oceanographic Center 1980–1995 surface flux and the Levitus mixed-layer climatologies indicate that during the Southwest Monsoon wind-driven entrainment is considerably stronger than Ekman pumping. Inshore of the windstress maximum, Ekman pumping partially counters wind-driven entrainment, while offshore the two processes act together to deepen the mixed-layer. As Ekman pumping is too weak to counter wind-driven mixed-layer deepening inshore of the windstress maximum, another mechanism must act to maintain the shallow mixed-layers seen in our observations and in climatologies. Offshore advection of coastally upwelled water offers a mechanism for maintaining upper ocean stratification that is consistent with observed changes in upper ocean water properties. Ekman upwelling will modulate wind-driven entrainment, but these results indicate that the primary mechanisms acting inshore of the windstress maximum are wind-driven mixing and horizontal advection.

Regional variation of total microbial biomass in sediments of the deep Arabian Sea

Eight different sites from 2300 to 4420 m water depth in the Arabian Sea were sampled for a biochemical quantification of phospholipid concentrations in the sediments. This method serves as a measure of microbial biomass in marine sediments comprising all small-sized organisms, including bacteria, fungi, protozoa and metazoa. Phospholipid concentrations can be converted to carbon units as an estimate of total microbial biomass in the sediments. The average phospholipid concentrations in the surface sediments (0–1 cm) of the 4 abyssal sites ranged from 7 nmol cm −3 at the southern site (SAST, 10°N 65°E, 4425 m) to 29 nmol cm −3 at the western site (WAST, 16°N 60°E, 4045 m). The high values detected at the abyssal station WAST exceeded those in the literature for other abyssal sites and were comparable to values from the upper continental slope of the NE-Atlantic and the Arctic. At the four continental slope sites in the Arabian Sea, average phospholipid concentrations ranged from 9 to 53 nmol cm −3 with the maximum values at stations A (2314 m) and D (3142 m) close to the Omani coast. Records of particulate organic carbon flux to the deep sea are available for four of the investigated locations, allowing a test of the hypothesis that the standing stock of benthic microorganisms in the deep sea is controlled by substrate availability, i.e. particle sedimentation. Total microbial biomass in the surface sediments of the Arabian Sea was positively correlated with sedimentation rates, consistent with previous studies of other oceans. The use of the measurement of phospholipid concentrations as a proxy for input of particulate organic matter is discussed.

Aerosols over the Arabian Sea: Atmospheric transport pathways and concentrations of dust and sea salt

This paper provides an overview of dust transport pathways and concentrations over the Arabian Sea during 1995. Results indicate that the transport and input of dust to the region is complex, being affected by both temporally and spatially important processes. Highest values of dust were found off the Omani coast and in the entrance to the Gulf of Oman. Dust levels were generally lower in summer than the other seasons, although still relatively high compared to other oceanic regions. The Findlater jet, rather than acting as a source of dust from Africa, appears to block the direct transport of dust to the open Arabian Sea from desert dust source regions in the Middle East and Iran/Pakistan. Dust transport aloft, above the jet, rather than at the surface, may be more important during summer. In an opposite pattern to dust, sea salt levels were exceedingly high during the summer monsoon, presumably due to the sustained strong surface winds. The high sea salt aerosols during the summer months may be impacting on the strong aerosol reflectance and absorbance signals over the Arabian Sea that are detected by satellite each year.

Monsoon-controlled export fluxes to the interior of the Arabian Sea

As a part of the US-JGOFS Arabian Sea Process Study (ASPS), we deployed a mooring array consisting of 16 Mark-7G time-series sediment traps on five moorings, each in the mesopelagic and interior depths in the western Arabian Sea set along a transect quasi-perpendicular to the Omani coast. The array was deployed for 410 days to cover all monsoon and inter-monsoon phases at 4.25-, 8.5- or 17-day open-close intervals, all of which were synchronized at 17-day periods. Total mass flux, fluxes of organic, inorganic carbon, biogenic Si and lithogenic Al (mg m −2 day −1) were obtained from samples representing 667 independent periods. The average total mass fluxes estimated in the interior depth along this sediment trap array at Mooring Stations 1–5 (MS-1–5) during 1994-5 ASPS were 147, 235, 221, 164 and 63 mg m −2 day −1, respectively. Mass fluxes during the southwest (SW) Monsoon were always larger than during the northeast (NE) Monsoon at all divergent zone stations, but the difference was insignificant at the oligotrophic station, MS-5. Four major pulses of export flux events, two each at NE Monsoon and SW Monsoon, were observed in the divergent zone; these events dominated in quantity production of the annual mass flux, but did not dominate temporally. Export pulses were produced by passing eddies and wind-curl events, but the direct processes to produce individual export blooms at each station were diversified and highly complex. The onset of these pulses was generally synchronous throughout the divergent zone. Export pulses associated with specific biogeochemical signatures such as the ratio of elevated biogenic Si to inorganic carbon indicate a supply of deep water to the euphotic layer in varying degrees. The variability of mass fluxes at the oligotrophic station, MS-5, also represented both monsoon events, but with far less amplitude and without notable export pulses.

Seasonal variation of hydrographic and nutrient fields during the US JGOFS Arabian Sea Process Study

Between September 1994 and December 1995, the US JGOFS Arabian Sea Process Experiment collected extensive, high quality hydrographic data (temperature, salinity, dissolved oxygen and nutrients) during all seasons in the northern Arabian Sea. An analysis of this unique data suite suggests the presence of many features that are described in the canonical literature, but these new data provided the following insights. 1. Although the seasonal evolution of mixed-layer depths was in general agreement with previous descriptions, the deepest mixed-layer depths in our data occurred during the late NE Monsoon instead of the SW Monsoon. 2. The region exhibits considerable mesoscale variability resulting in extremely variable temperature-salinity (TS) distributions in the upper 1000 db. This mesoscale variability is readily observed in satellite imaging, in the high resolution data taken by a companion ONR funded project, and in underway ADCP data. 3. The densest water reaching the sea surface during coastal upwelling appeared to have maximum offshore depths of ∼150 m and σ θ’s close to the core value (∼25) for the saline Arabian Sea Water (ASW), but salinities in these upwelling waters were relatively low. The densest water found at the sea surface during late NE Monsoon conditions has σ θ’s>24.8 and relatively high salinities, suggesting that they are a source for the ASW salinity maximum. 4. Persian Gulf Water (PGW) with a core σ θ of 26.6 forms a widespread salinity maximum. Despite the considerable extent of this feature, Persian Gulf outflow water, with a salinity (4) of ∼39 at its source, can only be a minor contributor. Within the standard US JGOFS sampling grid, maximum salinities on this surface are ∼36.8 at stations near the Gulf, falling to values as low as ∼35.3 at the stations farthest removed from its influence. Even at our standard stations closest to the Gulf (N-1 and N-2), the high-salinity, low-nutrient Persian Gulf water has only a modest direct effect on nutrient concentrations. This PGW salinity maximum is associated with the suboxic portions of the Arabian Sea’s oxygen minimum zone. 5. The salinity maximum associated with Red Sea Water (RSW, core σ θ=27.2) in the JGOFS study region is clearly evident at the southermost sampling site at 10′N (S-15). Elsewhere, this signal is weak or absent and salinity on the 27.2 σ θ surface tends to increase towards the Persian Gulf, suggesting that the disappearance of this salinity maximum is due, at least in part, to the influence of the Persian Gulf outflow. 6. Inorganic nitrogen-to-phosphate ratios were lower (frequently much lower) than the standard Redfield ratio of 15/1–16/1 (by atoms) at all times and all depths suggesting that inorganic nitrogen was more important than phosphate as a limiting nutrient for phytoplankton growth, and that the effects of denitrification dominated the effects of nitrogen fixation. 7. The water upwelling off the Omani coast during the SW Monsoon has inorganic nitrogen to silicate ratios that were higher (∼2/1) than the ∼1/1 ratio often assumed as the ratio of uptake during diatom growth. 8. The temporal evolution of inorganic nitrogen-to-silicate ratios suggests major alteration by diatom uptake only during the late SW Monsoon cruise (TN050) in August–September 1995. 9. Widespread moderate surface layer nutrient concentrations occurred during the late NE Monsoon. 10. A zone of high offshore nutrient concentrations was encountered during the SW Monsoon, but instead of being associated with offshore upwelling it may represent offshore advection from the coastal upwelling zone, the influence of an eddy, or both. 11. Although our data do not contradict previous suggestions that the volume of subtoxic water may be reduced the SW Monsoon, they suggest a weaker re-oxygenation than indicated by some previous work. Similarly, they do not confirm results suggesting that secondary nitrite maxima may be common in waters with oxygen concentrations >5 μM.

Aerosols over the Arabian Sea: geochemistry and source areas for aeolian desert dust

The temporal and spatial patterns of dust concentrations and geochemistry of aerosols collected over the Arabian Sea, along with atmospheric transport models, were used to identify source areas from the surrounding desert environments. Seasonally, the highest dust levels occurred during the winter and spring, with probable source areas in India/Pakistan/Iran and the Arabian Peninsula. Spatially, the highest dust levels were found off the Omani coast and over the Gulf of Oman, where high dust levels persisted throughout the year, suggesting that the Arabian Peninsula, and perhaps Oman specifically, are the most prominent contributors to the annual dust load in the region.

Temporal variations of pCO 2 in surface seawater of the Arabian Sea in 1995

As part of the JGOFS program in the Arabian Sea we continually measured the partial pressure of CO 2 gas in surface seawater ( pCO sea 2) and in the atmosphere above the sea surface ( pCO air 2) along six similar cruise tracks in January, February, March, July, November, and December of 1995. The observed variations of pCO sea 2 reached over 260 μatm close to the Omani coast in January–February and July–August. Offshore the pCO sea 2 variations with time were relatively small (<40 μatm). The pCO air 2 shifted by 15 μatm between the northeast and southwest monsoons. In order to estimate monthly and annual mean of CO 2 flux in the Arabian Sea, we used sea surface temperature and wind speed data, given on a 2.5°×2.5° resolution, from FNMOC and interpolated the observed pCO sea 2 data both in time and space. Close to the Omani coast, the estimated monthly mean CO 2 efflux across the air–sea interface varies from 8.3 to 44 mmol m -2 month -1 during most of the year and up to 312.8 mmol m -2 month -1 during the southwest monsoon season (July/August). Overall, the annual mean CO 2 flux from the northern Arabian Sea to the atmosphere is estimated to be 0.46 mol m -2 yr -1 or 7.0 Tg C yr -1.

Strong CO2 emissions from the Arabian Sea during south‐west monsoon

The partial pressure of CO2 (pCO2) was measured during the 1995 South‐West Monsoon in the Arabian Sea. The Arabian Sea was characterized throughout by a moderate supersaturation of 12–30 µatm. The stable atmospheric pCO2 level was around 345 µatm. An extreme supersaturation was found in areas of coastal upwelling off the Omani coast with pCO2 peak values in surface waters of 750 µatm. Such two‐fold saturation (218%) is rarely found elsewhere in open ocean environments. We also encountered cold upwelled water 300 nm off the Omani coast in the region of Ekman pumping, which was also characterized by a strongly elevated seawater pCO2 of up to 525 µatm. Due to the strong monsoonal wind forcing the Arabian Sea as a whole and the areas of upwelling in particular represent a significant source of atmospheric CO2 with flux densities from around 2 mmol m−2 d−1 in the open ocean to 119 mmol m−2 d−1 in coastal upwelling. Local air masses passing the area of coastal upwelling showed increasing CO2 concentrations, which are consistent with such strong emissions.

A southwest monsoon hydrographic climatology for the northwestern Arabian Sea

This paper provides a detailed hydrographic climatology for the shallow northwestern Arabian Sea prior to and during the southwest monsoon, presented as multiple‐year composite vertical hydrographic sections based on National Oceanographic Data Center historical ocean station data. Temperature and salinity measurements are used to infer the water masses present in the upper 500 m. The hydrographic evolution depicted on bimonthly sections is inferred to result from wind‐driven physical processes. In the northwestern Arabian Sea the water mass in the upper 50 m is the Arabian Sea Surface Water. Waters from 50 to 500 m are formed by mixing of Arabian Sea Surface Water with Antarctic and Indonesian intermediate waters. The inflow of Persian Gulf Water does not significantly influence the hydrography of the northwestern Arabian Sea along the Omani coast. Nitrate has a high inverse correlation with temperature and oxygen in the premonsoon thermocline in the depth interval 50–150 m. During the southwest monsoon, coastal upwelling off Oman and adjacent offshore upward Ekman pumping alter the shallow hydrography.

Interannual variability in phytoplankton blooms observed in the northwestern Arabian Sea during the southwest monsoon

Interannual changes in the strength and seasonal evolution of the 1979 through 1982 surface level southwest monsoon winds have been related to variations in the summer phytoplankton bloom of the northwestern Arabian Sea by synthesis of satellite ocean color remote sensing with analysis of in situ hydrographic and meteorological data sets. The 1979–1981 southwest monsoon phytoplankton blooms in the northwest Arabian Sea peaked during August‐September, extended from the Omani coast to about 65°E, and appeared to lag the development of open‐sea upwelling by at least 1 month. In all 3 years the bloom was driven by spatially distinct upward nutrient fluxes to the euphotic zone forced by the physical processes of coastal upwelling and offshore Ekman pumping. Coastal upwelling was evident from May through September, yielded the most extreme concentrations of phytoplankton biomass, and along the Omani coast was limited in its impact on upper ocean biological variability to the continental shelf. Ekman pumping stimulated the development of a broad open‐ocean component of the southwest monsoon phytoplankton bloom oceanward of the Omani shelf. Phytoplankton biomass on the Omani continental shelf was increased during both the early and late phases of the 1980 southwest monsoon due to stronger coastal upwelling under the most intense southwesterly winds of the four summers investigated. Diminished coastal upwelling during the early phase of the weak 1982 southwest monsoon resulted in a coastal bloom that reached a mean phytoplankton pigment concentration that was 28% of that seen in 1980. The lack of a strong regional northwestern Arabian Sea bloom in late summer 1982 is attributed to the development of persistent, shallow temperature stratification that rendered Ekman pumping less effective in driving upward nutrient fluxes.

Manganese and iron in Indian Ocean waters

The first vertical profiles of dissolved Mn and Fe for the (NW) Indian Ocean are reported. The area is characterized by seasonal upwelling and a broad oxygen minimum zone in intermediate waters. The dissolved Fe-profile exhibits a maximum (5.1 nM) in the oxygen minimum zone, with low values both in surface waters (0.3 nM) and deep waters (around 1 nM). Mn concentrations in the surface waters are elevated (2.0-4.3 nM), and decrease rapidly in an offshore direction. Below the first 25 m, concentrations decrease dramatically (0.5-1.3 nM), indicating removal by oxidation and particle scavenging. Further down, various Mn maxima are observed which can be related to hydrographic features (sigma-θ): 1. 1. Intermediate water originating from the Red Sea lost its dissolved O 2 while flowing northward along the Omani coast and exhibits a strong Mn maximum (4.6-6.5 nM) coincident with the deep O 2 minimum. 2. 2. At the two inshore stations in the Gulf of Oman this is overlain by relatively modest Mn maxima (±2.7 nM) related to Arabian Gulf overflow water. 3. 3. Finally the strong Mn maxima (4.4-5.6 nM) in the oxygen minimum zone at the two offshore stations are related to yet another watermass. Below these various maxima, concentrations decrease gradually to values as low as 90 pM at 2000 meters depth. Towards the seafloor concentrations increase again, leading to a modest bottom water maximum (0.7-1.5 nM). The overall vertical distributions of Mn and Fe are strikingly similar, also in actual concentrations, to those previously reported for the eastern equatorial Pacific, an area also characterized by an extensive O 2-minimum zone.

Topographic Controls on Bioproductivity and Organic Carbon Deposition, Oman Arabian Sea Coastal Upwelling Region: ABSTRACT

Ocean boundary currents impinging on swallow shelves and coastal capes may undergo oceanward divergence driven by the conservation of potential vorticity. This process may result in local upwelling, enhanced primary productivity, and increased organic richness in sediments. Combined with reconstructions of past coastline configurations and models of paleo-ocean circulation, the recognition of this process should enable the hindcasting of more specific sites of organic carbon enrichment than has previously been possible. Preliminary investigations of ocean circulation along the southeastern coast of Arabia during recent southwest monsoon seasons suggest that continental shelf topography and coastal promontories act to focus upwelling. Thermal infrared NOAA advanced very high resolution radiometer images acquired during the 1981, 1982, 1983, and 1985 southwest monsoon seasons depict localized regions of depressed sea surface temperature near a major shelf break and coastal capes. These regions of cooler surface water may result from topographically focused upwelling plumes. Present work includes the development of a numerical ocean model to predict the effect of topography on the southwest monsoon current as it encounters the Omani coast. Thermal infrared and visible band satellite remote sensing is being integrated with in-situ vertical temperature profiles and sea surface temperature observations in order to assessmore » horizontal and vertical water motion and surface layer bioproductivity during the monsoonal upwelling season. The effects of topographically focused coastal upwelling on organic carbon deposition are being assessed by the mapping of the total organic carbon content of surface sea-floor sediments.« less

Survey of tar, hydrocarbon and metal pollution in the coastal waters of Oman

Quantitative beach sampling conducted after the S. W. monsoon season yielded average standing stocks of tar ranging from 5 to 2325 g m −1 of shoreline with overall average of 224 g m −1. Values are among the highest reported for any world area and show a trend of increasing levels of oil residues close to the Strait of Hormuz. Data support the premise that tanker deballasting is a major source of oil pollution on the Omani coast. Locally high levels were seen near offshore tanker loading facilities. Petroleum hydrocarbons in rock oysters increased in a south to north gradient consistent with beach tar observations. But relatively low hydrocarbon levels in biota coupled with observations of very little floating tar suggests that oil released in Omani coastal waters aggregates, sinks, and reaches the coast as heavy tar lumps. Except for elevated levels of Cd at two stations, heavy metal and chlorinated hydrocarbon concentrations were low compared to more industrialized world areas. Suggestions are made to improve the effectiveness of future pollution studies in the Gulf Region.

The Feminist Movement in the Gulf

The feminist movement in the Gulf appeared long after its Egyptian or Bilad al-Sham counterparts. This was due to the weight of social traditions, which denied women presence and participation in public life, and to the delay in starting girls’ education compared to the education of boys. Gulf states did not begin educating girls until after the oil surge, which helped them set the pillars for modern states. The first state school for girls in Bahrain was inaugurated in 1938, over a quarter of a century after the inauguration of the first boys’ school. It was not until the early ‘70s of the past century that girls’ schools were inaugurated or spread in the Sultanate of Oman and some emirates on the Omani Coast (the United Arab Emirates today).