@article{,

title = {Ecosystem state change in the Arabian Sea fuelled by the recent loss of snow over the Himalayan-Tibetan Plateau region},

author = {Goes, Joaquim I.,Tian, Hongzhen,Gomes, Helga do Rosario,Anderson, O. Roger,Al-Hashmi, Khalid,deRada, Sergio,Luo, Hao,Al-Kharusi, Lubna,Al-Azri, Adnan,Martinson, Douglas G.},

url = {https://www.nature.com/articles/s41598-020-64360-2},

doi = {https://doi.org/10.1038/s41598-020-64360-2},

issn = {2045-2322},

year  = {2020},

date = {2020-01-01},

journal = {Scientific Reports},

volume = {10},

number = {102},

pages = {7422},

abstract = {The recent trend of global warming has exerted a disproportionately strong influence on the Eurasian land surface, causing a steady decline in snow cover extent over the Himalayan-Tibetan Plateau region. Here we show that this loss of snow is undermining winter convective mixing and causing stratification of the upper layer of the Arabian Sea at a much faster rate than predicted by global climate models. Over the past four decades, the Arabian Sea has also experienced a profound loss of inorganic nitrate. In all probability, this is due to increased denitrification caused by the expansion of the permanent oxygen minimum zone and consequent changes in nutrient stoichiometries. These exceptional changes appear to be creating a niche particularly favorable to the mixotroph, Noctiluca scintillans which has recently replaced diatoms as the dominant winter, bloom forming organism. Although Noctiluca blooms are non-toxic, they can cause fish mortality by exacerbating oxygen deficiency and ammonification of seawater. As a consequence, their continued range expansion represents a significant and growing threat for regional fisheries and the welfare of coastal populations dependent on the Arabian Sea for sustenance.},

keywords = {Arabian Sea, HAB, harmful algae, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Warming of the Eurasian landmass is making the Arabian Sea more productive},

author = {Goes, Joaquim I,Thoppil, Prasad G,do R Gomes, Helga,Fasullo, John T},

issn = {0036-8075},

year  = {2005},

date = {2005-01-01},

journal = {Science},

volume = {308},

number = {379},

pages = {545-547},

abstract = {The recent trend of declining winter and spring snow cover over Eurasia is

causing a land-ocean thermal gradient that is particularly favorable to stronger

southwest (summer) monsoon winds. Since 1997, sea surface winds have been

strengthening over the western Arabian Sea. This escalation in the intensity of

summer monsoon winds, accompanied by enhanced upwelling and an increase

of more than 350% in average summertime phytoplankton biomass along the

coast and over 300% offshore, raises the possibility that the current warming

trend of the Eurasian landmass is making the Arabian Sea more productive.},

keywords = {Arabian Sea, Climate change, monsoon, Oman, productivity, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Variability of water properties, heat and salt fluxes in the Arabian Sea, between the onset and wane of the 1995 southwest monsoon},

author = {Beal,L.M.,Chereskin,T.K.,Bryden,H.L.,Ffield,A.},

year  = {2003},

date = {2003-01-01},

journal = {Deep-Sea Research Part II},

volume = {50},

number = {42},

pages = {2049-2075},

abstract = {We investigate the variability of the circulation,water masses,heat and salt fluxes in the Arabian Sea over the course of the southwest monsoon. Two zonal sections taken along 8§30'N in 1995 as part of the Indian Ocean WOCE hydrographic program are used. The first was occupied in early June at the onset of the southwest monsoon winds,the second in late September,at the wane of the monsoon. The September section was found to be generally warmer (+0.32§C) and saltier (+0.04) than in June,despite a 50mm drop in mean sea level. Therefore,the common assumption that an increase in sea-surface height follows an increase in heat content (the hydrostatic response) does not hold. Instead,we conclude that the heat content increases due to the advection of Arabian Sea Surface Water and Red Sea Water onto the section from the north,and the drop in sea level is due to a loss of mass,rather than heat,from the water column. There are large uncertainties involved in diagnosing the heat-flux divergence across the Arabian Sea, because the seasonal variability of the water masses and circulation in the basin mean that our data are not representative of a steady state. We treat each section separately and find an oceanic heat export of -0.72PW in June and -0.19PW in September,implying a basin cooling rate of about -0.36PW in June and a slight heating of 0.12PW in September. In June the mass and heat balances are dominated by the Ekman transport and the Somali Current,with very flat density surfaces resulting in a small interior geostrophic transport. By September the Ekman transport has reduced,and it is primarily the interior transport that balances a strong Somali Current. There are two main overturning cells in June and September: A shallow one of approximate magnitude 15 Sv in June and 0 Sv in September, which reaches depths of no more than 500m and is driven by Ekman divergence at the surface; and a deep cell of magnitude 1 Sv representing a weak inflow and subsequent upwelling of Circumpolar Deep water. The deep cell implies a basin-averaged upwelling velocity of 3.2x10-5 cm s-1 through 2200 m.},

keywords = {Arabian Sea, density, depth, Indian Ocean, Oceanic, Red Sea, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Distribution, annual cycle, and vertical migration of acoustically derived biomass in the Arabian Sea during 1994-1995},

author = {Ashjian,C.J.,Smtih,S.L.,Flagg,C.N.,Idrisi,N.},

year  = {2002},

date = {2002-01-01},

journal = {Deep-Sea Research Part II},

volume = {49},

number = {299},

pages = {2377-2402},

abstract = {The distinguishing characteristic that sets the Arabian Sea apart from other oceanic regions is the regular oscillation of monsoonal atmospheric conditions that produces predictable periods of upwelling or convective mixing, with associated biological response, during the Southwest and Northeast monsoons, respectively. This oscillation is also evident in cycles of standing stocks of zooplankton and micronekton. The vertical distribution and spatial pattern of zooplankton and micronekton biomass were estimated using an acoustic Doppler current profiler along a 1000-km transect extending from the continental shelf of Oman to the central Arabian Sea during ten cruises on the R/V Thomas G. Thompson (November 1994-December 1995). The influence of the Southwest Monsoon, and accompanying upwelling and enhanced acoustically derived biomass, was the dominant feature in the spatial-temporal distributions of both zooplankton and micronekton near the Omani coast. The diel vertical migration of predators (myctophids, pelagic crabs), and the seasonal changes in the strength of this signal, was the most significant pattern observed in the vertical distribution of biomass and imparted a strong day-night signal to the integrated upper water-column biomass. Significant differences in the magnitude of integrated upper water-column biomass, both zooplankton (day) and migrator-zooplankton (night), were seen between inshore and offshore of the atmospheric Findlater Jet. A station located in the central Arabian Sea demonstrated seasonal changes in biomass over the year, despite being quite far from the influence of the monsoonal oscillations. Predation pressure was greater offshore of the Findlater Jet than in the region inshore of the Jet or in the central Arabian Sea. The pelagic community of the Arabian Sea may have evolved life history strategies to coincide with the predictable monsoonal cycle},

keywords = {acoustic, Arabian Sea, diel, Distribution, history, life history, migration, myctophids, Oceanic, Oman, predation, seasonal change, stocks, Upwelling, zooplankton},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Microbial community dynamics and taxon-specific phytoplankton production in the Arabian Sea during the 1995 monsoon seasons},

author = {Brown,S.L.,Landry,M.R.,Christensen,S.,Garrison,D.,Gowing,M.M.,Bidigare,R.R.,Campbell,L.},

year  = {2002},

date = {2002-01-01},

journal = {Deep-Sea Research Part II},

volume = {49},

number = {57},

pages = {2345-2376},

abstract = {As part of the US JGOFS Arabian Sea Process Study in 1995, we investigated temporal and spatial patterns in microbial dynamics and production during the late Southwest (SW) Monsoon (August-September 1995) and the early Northeast (NE) Monsoon (November-December 1995) seasons using the seawater-dilution technique. Experiments were coupled with population assessments from high-performance liquid chromatography, flow cytometry, and microscopy to estimate further taxon-specific phytoplankton growth, grazing and production. Dilution estimates of total primary production varied substantially, from 7 to 423 mg Cl-1 d-1, and were generally in good agreement with rate estimates from 14C-uptake incubations. Both primary production and secondary bacterial production were, on average, 2.5xhigher during the SW Monsoon than the NE Monsoon. Relative to the total community, photosynthetic prokaryotes contributed 23% and 53% of production during the SW and NE Monsoons, respectively. Prochlorococcus spp. production was well balanced by grazing losses, while >50% of Synechococcus spp. production during the SW Monsoon appeared to escape grazing by protists. Diatoms comprised >30% of primary production at a high biomass station during the SW Monsoon but <30% at all stations during the NE Monsoon. Growth rates of Synechococcus spp. and diatoms appeared to be limited by inorganic nitrogen concentrations, while Prochlorococcus spp., dinoflagellates and Phaeocystis spp. were not. Losses to protistan grazing were strongly correlated with phytoplankton biomass and production. Despite sufficient prey levels, protistan biomass was modest and constant across the region during both seasons. Of the larger taxa, diatoms were grazed the least effectively with only 50% of daily production accounted for by protistan grazing. Combined estimates of protistan and mesozooplankton grazing at upwelling stations during the SW Monsoon leave ~10% of primary production unaccounted for and available for sinking and/or lateral advection. Similarly high rates of net production at northern coastal stations during the NE Monsoon suggest that this area also may contribute to regional export flux},

keywords = {Arabian Sea, assessment, growth, population, prey, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Mesoscale eddies, costal upwelling, and the upper-ocean heat budget in the Arabian Sea},

author = {Fischer,A.S.,Weller,R.A.,Rudnick,D.L..,Eriksen,C.C.,Lee,C.M.,Brink,K.H.,Fox,C.A.,Leben,R.R.},

year  = {2002},

date = {2002-01-01},

journal = {Deep-Sea Research Part II},

volume = {49},

number = {94},

pages = {2231-2264},

abstract = {Estimationof 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 upper ocean heat budget in the Arabian Sea},

keywords = {Arabian Sea, budget, salinity, survey, temperature, trend, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Zooplankton spatial distributions in coastal waters of the northern Arabian Sea, August 1995},

author = {Hitchcock,G.L.,Lane,P.,Smith,S.,Luo,J.G.,Ortner,P.B.},

year  = {2002},

date = {2002-01-01},

journal = {Deep-Sea Research Part II},

volume = {49},

number = {387},

pages = {2403-2423},

abstract = {The spatial distribution of zooplankton biomass was surveyed in coastal waters of the northern Arabian Sea during the 1995 Southwest Monsoon (August) on cruise MB 95-06 of the NOAA Ship Malcolm Baldrige.  Vertical patterns of displacement volumes from a limited set of paired day-night MOCNESS tows suggest there was little diel vertical migration in the coastal waters off the southern Arabian Peninsula. Zooplankton biomass varied from 5.2 to 15.1 9 dw m(-2) (178-517mM Cm-2) in the upper 200-300m of Omani coastal waters. Distributions of acoustic backscatter were mapped in eight daytime acoustic Doppler current profiler transects in coastal waters off Oman and Somalia. Several transects contained maxima in acoustic backscatter that coincided with cool, fresh surface features that were several tens of kilometers wide. Although there was considerable scatter in the relationship between acoustically determined biomass (ADB) of zooplankton and surface temperature, there was a trend of increased biomass in the cool surface temperatures of the Omani upwelling zone. Acoustic transects crossed two filaments that extended seaward from upwelling centers off Oman and Somalia. Estimated zooplankton ADB exported from the upwelling zones in the surface features was on the order of 300 kg dw s( -1 ). The physical and biological characteristics of filaments maintain zooplankton associated with upwelling areas, such as Calanoides carinatus, as they are advected offshore from coastal upwelling zones. (C) 2002 Published by Elsevier Science Ltd.},

keywords = {acoustic, Arabian Sea, displacement, Distribution, migration, Oman, surface temperature, temperature, trend, Upwelling, zooplankton},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Primary productivity and its regulation in the Arabian Sea during 1995},

author = {Barber,R.T.,Marra,J.,Bidigare,R.C.,Codispoti,L.A.,Halpern,D.,Johnson,Z.,Latasa,M.,Goericke,R.,Smith,S.L.},

year  = {2001},

date = {2001-01-01},

journal = {Deep-Sea Research Part II},

volume = {48},

number = {323},

pages = {1127-1172},

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 1000km offshore in the centralArabian 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 - 1000km o!shore. As expected, the SW Monsoon was the most productive season (123ñ9mmolC m-2d-1) along the southern US JGOFS section from the coast to 1000km offshore, but productivity in the NE Monsoon was surprisingly high (112ñ7mmol C m-2d-1). There was no onshore/offshore gradient in primary productivity from 150 to 1000km o! the Omani coast in 1995, and there was no evidence of light limitation of either primary productivity or photosynthetic performance (PBopt) 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 (86ñ6mmolC m-2d-1) was much higher than in oligotrophic regions such as the tropical Pacific Ocean (29ñ2 mmolC m-2 d-1) or the North Pacific gyre region (32ñ8 mmolC m-2 d-1). The 1995 annual mean productivity (111ñ11mmolC m-2 d-1) along this section from the Omani coast to the central Arabian Sea was about equal to the spring bloom maximum (107ñ23mmolC m-2 d-1) during the 1989 North Atlantic Bloom Experiment (NABE) and the equatorial, 1§N-1§S wave guide maximum (95ñ6mmolC 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 (127ñ14mmolC m-2 d-1) and in 1964 by the ANTON BRUUN Expedition (115ñ27 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 700km 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 effcient 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 (PBopt>10mmolC 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 },

keywords = {abundance, Arabian Sea, Atlantic, location, North Atlantic, Oman, Pacific Ocean, performance, productivity, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Heterotrophic bacterioplankton in the Arabian Sea: Basinwide response to year-round high primary productivity},

author = {Ducklow,H.W.,Smith,D.C.,Campbell,L.,Landry,M.R.,Quinby,H.L.,Steward,G.F.,Azam,F.},

year  = {2001},

date = {2001-01-01},

journal = {Deep-Sea Research Part II},

volume = {48},

number = {90},

pages = {1303-1323},

abstract = {Heterotrophic bacterial abundance and productivity were measured during five and four cruises, respectively, in the northwest Arabian Sea as part of the US JGOFS Process Study, which provided a new view of seasonal bacterial dynamics in that part of the basin influenced by monsoonal forcing. In this paper, surface layer data are used to address two questions concerning the influence of the monsoon cycle on bacterial dynamics: (1) Is there a bacterial bloom in the SW Monsoon? and (2) Is bacterial production low during the oligotrophic Spring Intermonsoon? An extensive comparison of epifluorescence microscopy and flow cytometry, unprecedented at this scale, detected essentially the same heterotrophic bacterial populations and distributions, with some between-cruise di!erences. Use of the two methods allowed us to extend our observations in space and time. Bacterial productivity, both in the surface layer and integrated over the euphotic zone, was elevated less than 2-fold during the Southwest Monsoon. Levels of bacterial abundance and production were low during the Northeast Monsoon, then increased in March during the Spring Intermonsoon. There was some stimulation of abundance or production inshore in response to coastal upwelling. In general, the basin was enriched in bacterial biomass >5 ' 108  cells l-1 throughout the year, relative to other tropical regimes, presumably in response to overall high PP and DOC levels. Seasonally uniform DOC levels may be regulated in part by intense bacterial utilization rates, but also reflect seasonal consistency in PP.},

keywords = {abundance, Arabian Sea, Distribution, population, populations, productivity, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Nitrogen production in the northern Arabian Sea during the Spring Intermonsoon and Southwest Monsoon seasons},

author = {Sambrotto,R.N.},

year  = {2001},

date = {2001-01-01},

journal = {Deep-Sea Research Part II},

volume = {48},

number = {470},

pages = {1173-1198},

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.  },

keywords = {Arabian Sea, budget, impact, population, populations, productivity, respiration, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Arabian Sea phytoplankton during Southwest and Northeast Monsoons 1995: composition, size structure and biomass from individual cell properties measured by flow cytometry},

author = {Shalapyonok,A.,Olson,R.J.,Shalapyonok,L.S.},

year  = {2001},

date = {2001-01-01},

journal = {Deep-Sea Research Part II},

volume = {48 },

number = {221},

pages = {1231-1261},

abstract = {As part of the US JGOFS Arabian Sea Process Study, we determined the abundance, size distributions and carbon biomass of autotrophic phytoplankton in the Arabian Sea during summer Southwest and fall Northeast Monsoon seasons of 1995 (R/V Thomas G. Thompson cruises TN 049 and TN 053). Flowcytometry of 60-ml samples was used to enumerate and determine scattering and fluorescence properties of Prochlorococcus sp., Synechococcus sp., and eukaryotic phytoplankton with cell equivalent spherical diameter up to 40 æm. Cellular forward light scattering was calibrated against Coulter size using 22 phytoplankton cultures spanning the size range 0.8-40 æm, grown exponentially in natural sunlight. The phytoplankton community structure was strongly linked to water-mass characteristics, and was affected by both intense monsoon-related environmental forcing and widespread and dynamic mesoscale structures; the magnitude of spatial variability was similar to that between seasons for all three phytoplankton groups. Prochlorococcus was numerically dominant in the more oligotrophic, stratified areas with surface nitrate concentrations below 0.1 æM and surface temperatures above 27§C. Its abundance was significantly greater during the NE Monsoon and was inversely correlated with the abundance of the two other groups. Synechococcus and eukaryotic phytoplankton cell concentrations covaried at most locations, were highest in areas of intense, monsoon-related mixing, and changed less between seasons than Prochlorococcus. The bulk of biomass of all three groups was located within the mixed layer. Only eukaryotes formed notable subsurface maxima at several offshore locations where Prochlorococcus dominated the mixed layer. Dramatically elevated eukaryotic phytoplankton concentrations in the nutrient-rich upwelling areas were due to the blooming of smaller (<3 æm) cells. Surprisingly, stratified, offshore, nutrient-depleted areas had concentrations of 10-40 æm phytoplankton cells similar to or even higher than upwelling areas. Thus, the mean eukaryotic cell size and the relative contribution of large nanoeukaryotes to the phytoplankton biomass were highest in offshore waters. Eukaryotes accounted for most of the phytoplankton carbon biomass - from about 50 to 80% on average during both seasons. Both Prochlorococcus and large (10 æm) nanoeukaryotes reached their greatest biomass contributions - up to 40% each - in the offshore oligotrophic locations. For the SW and NE Monsoon cruises, flow cytometrically-measured phytoplankton was estimated at 1.1 and 2.2 gCm-2 on average and comprised 33 and 38% of POC, respectively. Diel variability in cellular carbon content accounted for 52% of the observed variability in cellular carbon content for Prochlorococcus, 26% for Synechococcus, and 14% for eukaryotic phytoplankton cells at the surface.},

keywords = {abundance, Arabian Sea, diel, Distribution, location, surface temperature, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {A principal component analysis of sea-surface temperature in the Arabian Sea},

author = {Wilson-Diaz,D.,Mariano,A.J.,Evans,R.H.,Luther,M.E.},

year  = {2001},

date = {2001-01-01},

journal = {Deep-Sea Research Part II},

volume = {48 },

number = {263},

pages = {1097-1114},

abstract = {Spatial and temporal variability in sea-surface temperature (SST) is analyzed by the method of principal component analysis (PCA). Variability of satellite-derived SST from the NOAA/NASA Advanced Very High Resolution Radiometer (AVHRR) Pathfinder data over the Arabian Sea is compared to the PCA of the mixed-layer temperature fields from two different Indian Ocean models. Climatological model output is compared to Pathfinder's "averaged" year using data from 1987 to 1990. A 5-year analysis with data and model output (from 1985 to 1989) is also done. The first mode in all the studies accounts for 58.2-95.8% of the SST variability, and is identified with the seasonal warming and cooling associated with the Indian Monsoon. The second mode accounts for 20.6-31.1% and corresponds to the radiative heating of the basin. Time series of the basin's mean SST shows that the models lag Pathfinder SST by approximately one month. The climatological models fail to reproduce the SST variability, in both space and time, of the Arabian Sea. The Luther-Ji model, forced by interannual monthly winds, does much better. The main discrepancies are likely due to the models' forcing fields underestimating the strength of the monsoon, and the vertical thermal structure not being adequate to represent the real ocean, especially in upwelling areas.},

keywords = {Arabian Sea, Indian monsoon, Indian Ocean, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Geographical differences in seasonality of CZCS-derived phytoplankton pigment in the Arabian Sea for 1978-1986},

author = {Banse,K.,English,D.C.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {322},

pages = {1623-1677},

abstract = {In situ measurements of phytoplankton chlorophyll in the Arabian Sea were taken largely along temporally and spatially unevenly distributed sections, scarce especially prior to the operation of NASA's Coastal Zone Color Scanner (CZCS). Herein, the CZCS pigment observations between late 1978 and mid-1986 north of 10§N, including the outer Gulf of Oman, are depicted for 14 subregions beyond the continental shelves as daily means, often only five days apart. To eliminate bias from electronic overshoot, the data were reprocessed with a more conservative cloud screen than used for NASA's Global Data Set. The pattern, derived from the older in situ observations, of one period with elevated chlorophyll almost everywhere during the Southwest Monsoon (SWM) and one additional late-winter bloom in the north, is confirmed. The differing nitrate silicate ratios in freshly entrained water in the central and northern Arabian Sea seem to lead to different succession and perhaps to differing vertical fluxes, and during winter favor blooms only in the north. The spatial pigment pattern in the outer Gulf of Oman is not an extension of that of the northwestern Arabian Sea. The seasonal physical forcing explains much of the timing of pigment concentration changes, but not the levels maintained over long periods. From the CZCS observations it is unclear whether the period of high phytoplankton productivity expected during the SWM in the open Arabian Sea lasts for about two or four months. During this entire season, chlorophyll values in the upper layers rarely exceed 1-2 mg m-3 outside the zone influenced by the Arabian upwelling. Near 15§N, however, fluxes into sediment traps at 3 km depth indicate an onset of high primary production very soon after the arrival of the SWM and suggest a long period of high production in the open sea. The partial temporal disconnect during the SWM between pigment changes in the upper part of the euphotic zone and of fluxes into the traps is disconcerting. For future modeling of plankton production in the open Arabian Sea, the use of two size classes of phytoplankton is recommended. The utility of satellite-derived pigment concentrations (as opposed to temporal changes of pigment) for testing such models is questioned.},

keywords = {Arabian Sea, chlorophyll, depth, Gulf of Oman, lead, Oman, plankton, productivity, timing, trap, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Microbial food web structure in the Arabian Sea: a US JGOFS study},

author = {Garrison,D.L.,Gowing,M.M.,Hughes,M.P.,Campbell,L.,Caron,D.A.,Dennett,M.R.,Shalapyonok,A.,Olson,R.J.,Landry,M.R.,Brown,S.L.,Liu,H.-B.,Azam,F.,Steward,G.F.,Ducklow,H.W.,Smith,D.C.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47 },

number = {98},

pages = {1387-1422},

abstract = {One of the main objectives of the Joint Global Ocean Flux Studies (JGOFS) program is to develop an understanding of the factors controlling organic carbon production in the ocean and the time-varying vertical flux of carbon from surface waters (US JGOFS (1990) US JGOFS Planning Report Number 11; Sarmiento and Armstrong (1997) US JGOFS Synthesis and Modeling Project Implementation Plan). A considerable amount of evidence suggests that carbon cycling and the potential for exporting carbon from ocean systems is a function of food web structure. As part of the US JGOFS Arabian Sea Studies, the biomass of planktonic organisms, ranging from heterotrophic bacteria through microplankton-sized organisms, was estimated using a variety of methods including flow cytometry and microscopy. This is a first attempt to combine biomass data from a number of sources, evaluate the structure of the food web, examine changes in food web structure in relation to seasonal or spatial features of the study area, and look for indications of how changing structure affects carbon-cycling processes. Biomass in the upper 100 m of the water column ranged from approximately 1.5 to >5.2 gC m-2. Heterotrophic bacteria (Hbac) made up from 16 and 44% of the biomass; autotrophs comprised 43-64%; and the remainder was made up of nano- and microheterotrophs. Autotrophs and nano- and microheterotrophs showed a general pattern of higher values at coastal stations, with the lowest values offshore. Heterotrophic bacteria (Hbac) showed no significant spatial variations. The Spring Intermonsoon and early NE Monsoon were dominated by autotrophic picoplankton, Prochlorococcus and Synechococcus. The late NE Monsoon and late SW Monsoon periods showed an increase in the larger size fractions of the primary producers. At several stations during the SW Monsoon, autotrophic microplankton, primarily diatoms and Phaeocystis colonies, predominated. Increases in the size of autotrophs were also reflected in increasing sizes of nano- and microheterorophs. The biomass estimates based on cytometry and microscopy are consistent with measurement of pigments, POC and PON. Changes in community structure were assessed using the percent similarity index (PSI) in conjunction with multidimensional scaling (MDS) or single-linkage clustering analysis to show how assemblages differed among cruises and stations. Station clustering reflected environmental heterogeneity, and many of the conspicuous changes could be associated with changes in temperature, salinity and nutrient concentrations. Despite inherent problems in combining data from a variety of sources, the present community biomass estimates were well constrained by bulk measurements such as Chl a, POC and PON, and by comparisons with other quantitative and qualitative studies. The most striking correlation between food web structure and carbon cycling was the dominance of large phytoplankton, primarily diatoms, and the seasonal maxima of mass flux during the SW Monsoon. High nutrient conditions associated with upwelling during the SW Monsoon would explain the predominance of diatoms during this season. The sinking of large, ungrazed diatom cells is one possible explanation for the flux observations, but may not be consistent with the observation of concurrent increases in larger microzooplankton consumers (heterotrophic dinoflagellates and ciliates) and mesozooplankton during this season. Food-web structure during the early NE Monsoon and Intermonsoons suggests carbon cycling by the microbial community predominated.},

keywords = {Arabian Sea, dominance, objectives, salinity, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The fate of upwelled waters in the Great Whirl, August 1995},

author = {Hitchcock,G.L.,Key,E.L.,Masters,J.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {111},

pages = {1605-1621},

abstract = {The Great Whirl is a large, anticyclonic gyre that develops of the northern Somali coast during the Southwest Monsoon. In August 1995 the NOAA Ship Malcolm Baldrige surveyed the seaward edge of the upwelling zone associated with this gyre. The fate of recently upwelled water was followed by mapping surface property distributions along a cool surface feature that extended seaward along the northern edge of the Great Whirl. Surface properties (T, S, and chlorophyll a), surface velocity (ADCP), and XBT and CTD casts were interpreted in relation to the trajectories of three instrumented surface drifters deployed in the feature. Cool surface waters correspond in space to the shoaling of the upper thermocline and offshore advection from the coast. Surface chlorophyll a concentrations decreased from 2 to 3 æg l-1 in the Upwelling zone to 0.5-1.5 æg l-1 in the surface feature and contiguous waters. Maximum surface velocities in the Great Whirl were 250 cm s-1 with velocities >100 cm s-1 along the northern perimeter of the gyre. Decorrelation time-scales for u and v velocity components, and chlorophyll a fluorescence, from the drifters were on the order of 4 to 7 days. These times are comparable to those over which the drifters were ejected from the Great Whirl into the Socotra Gyre. Decorrelation times for sea-surface temperature were somewhat longer (10 days). All three platforms passed between the Somali coast and Socotra within a week of their deployment and then traveled east into the northern Arabian Sea.},

keywords = {Arabian Sea, chlorophyll, Distribution, temperature, thermocline, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The upper-ocean response to monsoonal forcing in the Arabian Sea: seasonal and spatial variability},

author = {Lee,C.M.,Jones,B.H.,Brink,K.H.,Fischer,A.S.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {398},

pages = {1177-1226},

abstract = {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 o!shore 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 isconsistent 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.},

keywords = {Arabian Sea, depth, survey, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The Oman upwelling zone during 1993, 1994 and 1995},

author = {Shi, W,Morrison, John M,Böhm, Emanuele,Manghnani, Vijayakumar},

issn = {0967-0645},

year  = {2000},

date = {2000-01-01},

journal = {Deep Sea Research Part II: Topical Studies in Oceanography},

volume = {47},

number = {472},

pages = {1227-1247},

abstract = {Satellite-derived sea-surface temperature, TOPEX/POSEIDON (T/P) sea-level anomalies

(SLAs), model wind data, and hydrographic data are used to characterize the upwelling along

the Oman coast during the US Joint Global Ocean Flux Study (US JGOFS) Arabian Sea

Process Study (ASPS) in 1995 as well as to look at interannual variability in the upwelling over

the period 1993}1995.

Empirical orthogonal function (EOF) analysis of the satellite-derived sea-surface temperature

(SST) at the locations of the US JGOFS standard stations shows the "rst mode, which

represents a biannual variability, contributes 67% of the total variance. In addition, the SST

shows the upwelling `fronta moving o!shore with the development of Southwest (SW) Monsoon

in early June 1995, reaching a maximum distance of approximately 120 km by late August

1995. Finally, SST shows the persistence of cold upwelling waters for nearly a month after the

end of the SW Monsoon within the bays along the Oman coast.

TOPEX/POSEIDON SLAs indicate that with the onset of the SW Monsoon, a 30-cm drop

in steric height is observed along the Oman coast associated the presence of the cool upwelled

waters. This drop in steric height sets up a horizontal pressure gradient and results in

a compensating along-shore, northeastward-#owing, geostrophic current (East Arabian

Current; EAC) during the SW Monsoon. Similarly, the altimeter data slow an o!shore decrease

in steric height during the Northeast (NE) Monsoon, indicating a seasonal reversal in direction

of the EAC with #ow to the southwest. Subsurface temperature data indicate that the actual

uplifting of isotherms associated with the upwelling can be found to a distance of approximately

260 km from the shore and to a depth of 150}200 m. Using along-track altimetry data, we

estimate that, for a region 260 km in o!shore distance and 600 km alongshore, 2.2]106,

1.4]106 and 0.55]106 m3 s~1 were upwelled through the 100 m level with upwelling velocities

O (2.0]10~5 m s~1), during the SW Monsoons of 1993, 1994 and 1995, respectively. The

reduced upwelling in the summer of 1995 is attributed to a reduction in wind-stress curl along

the Arabian coast when compared to 1993 and 1994. ( 2000 Elsevier Science Ltd. All rights

reserved.},

keywords = {Arabian Sea, Hydro-biology, Interannual variability, oceanography, Oman, sea surface temperature, seasonal variation, Sultanate of Oman, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Photosynthesis-irradiance parameters and community structure associated with coastal filaments and adjacent waters in the northern Arabian Sea},

author = {Toon,R.K.,Lohrenz,S.E.,Rathbun,C.E.,Wood,A.M.,Arnone,R.A.,Jones,B.H.,Kindle,J.C.,Weidemann,A.D.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {244},

pages = {1249-1277},

abstract = {Comparisons were made among size-fractionated photosynthesis-irradiance (P-E) parameters, chlorophyll a size distributions, and accessory pigment composition of natural phytoplankton assemblages in filaments, coastal upwelling waters, and an oligotrophic region of the northern Arabian Sea during the Fall Intermonsoon in 1995. Differences between P-E parameters, PBmax and àB, were observed between filaments and adjacent waters and were associated with differences in phytoplankton community structure. In a southern filament and coastal upwelled waters, the majority of the estimated biomass (chlorophyll a) was present in the larger (2-20 and 20-200 æm) size fractions; dominant accessory pigments were 19'-butanoyloxyfucoxanthin and peridinin. In higher salinity waters, high percentages of chlorophyll a and lutein/zeaxanthin were observed in the smallest size-fraction (<2 æm). Whole water values of PBmax ranged from 1.77 to 2.31 (g C g chl a-1 h-1) when the majority of the biomass was in the largest fractions. Higher values (more than 4.48 g C g chl a-1 h-1) were determined in whole water samples for communities comprised primarily of small cells. A size dependence was also observed in the value of àB, 0.017 or greater (g C g chl a-1 h-1)/(æmol quanta m-2 s-1) for whole water samples at stations dominated by small cells and 0.013 when derived from stations dominated by large cells. The observed pattern of larger phytoplankton associated with upwelling and filament waters was consistent with previous investigations and was, for the most part, comparable to findings in the California Current system. Our results show that differences in taxonomic composition and photosynthetic characteristics were indeed present between filament waters and other distinct regions; these results suggest that taxonomic variations may be associated with size-related variations in P-E parameters. Our findings provide a unique data set describing filament biology in the northern Arabian Sea during the Fall Intermonsoon thus adding important details in efforts to model biogeochemical processes in this region. },

keywords = {Arabian Sea, biology, chlorophyll, Distribution, salinity, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Iron speciation in the Arabian Sea},

author = {Witter,A.E.,Lewis,B.L.,Luther III,G.W.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {264},

pages = {1517-1539},

abstract = {Fe(III) speciation was measured in seawater collected as part of the United States Joint Global Ocean Flux (US JGOFS) Arabian Sea Process Study, Cruise TN045, March 14-April 10, 1995. The Fe-binding capacity of organic seawater ligands was measured in filtered seawater (<0.4 æm) collected from surface depths and throughout the oxygen minimum zone (OMZ). Seawaters from three stations on the southern line (S2, S9, and S11) were examined. Total Fe concentrations measured at the three sites ranged from: 1.25 ñ 0.21 nM to 1.30 ñ 0.01 nM (S2); 1.67 ñ 0.50 nM to 2.63 ñ 0.54 nM (S9); and 1.40 ñ 0.11 nM to 1.70 ñ 0.29 nM (S11). Cathodic stripping voltammetry (CSV) with 1-nitroso-2-napthol (1N2N) as the competitive ligand (pH 6.9) was used to determine conditional stability constants and Fe-binding ligand concentrations in seawater. Conditional stability constants for FeL complexes ranged from log KFeL = 21.6 ñ 0.1 to 22.5 ñ 0.9 at the three sites. Total ligand concentrations ranged from 1.47 ñ 0.06 nM to 6.33 ñ 1.16 nM over all sites, but increased by a factor of 2-3 from the surface to the oxygen minimum zone (OMZ), suggesting that Fe-binding ligands may be produced during organic matter degradation. Ligand concentrations were consistently higher than total iron concentrations at every site measured, with an average "excess" ligand concentration of 2.15 ñ 1.50 (n = 10). "Excess" ligand concentrations in the OMZ were 2 to 20 times higher than surface waters (upper 100 m). Formation-rate constants (kf ) and dissociation-rate constants (kd) between added Fe3+ and seawater ligands were measured using a kinetic approach at ambient seawater pH, allowing independent calculation of the conditional stability constant, since K = kf/kd. Using the kinetic approach, conditional stability constants ranged from log KFeL = 20.5 ñ 0.1 to 22.9 ñ 0.1. Although log K values are comparable in magnitude to those reported in the Pacific and Northwestern Atlantic Oceans, measured total ligand concentrations in the Arabian Sea are higher. This suggests that in areas that receive high Fe inputs through upwelling and/or atmospheric deposition, marine organisms may produce 'excess' ligands to keep Fe soluble in seawater for extended intervals.  },

keywords = {Arabian Sea, Atlantic, Atlantic Ocean, depth, marine, oxygen minimum, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Patterns of co-variability between physical and biological parameters in the Arabian Sea},

author = {Bartolacci,D.M.,Luther,M.E.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {40},

pages = {1933-1964},

abstract = {The relationship between physical forcing and biological response observed in the Arabian Sea for the years 1978-1986 were examined. Spatial and temporal patterns of variability in a climatological time-series of three possible physical forcing parameters and CZCS-derived phytoplankton pigment concentration during the annual cycle were quantified using single and joint empirical orthogonal function (EOF) and singular-value decomposition (SVD) analyses. Monthly composites of the NASA regional pigment data were interpolated to fill data voids and binned corresponding to the physical flux data. Nearly all the spatial-temporal analyses consistently partitioned a large portion of the variability using only 1 or 2 dominant modes and indicated a lag in the timing of the peak pigment concentration behind the maxima in physical forcing. In all cases, major modes of variability resembled the Southwest Monsoon pattern, with the Northeast Monsoon contributing very little to the total variance and covariance. The Joint EOF and SVD analyses incorporated subtle features surrounding the peak Southwest Monsoon phenomena. Correlation maps of the joint EOF analysis depicted differences in spatial variability of pigment concentration associated with stress and curl, showing areas of curl-driven upwelling distinct from coastal upwelling, with possible off-shore advection of the curl-induced high pigment waters.},

keywords = {Arabian Sea, timing, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Picophytoplankton dynamics and production in the Arabian Sea during the 1995 Southwest Monsoon},

author = {Brown,S.L.,Landry,M.R.,Barber,R.T.,Campbell,L.,Garrison,D.L.,Gowing,M.M.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {56},

pages = {1745-1768},

abstract = {Phytoplankton community structure is expected to shift to larger cells (e.g., diatoms) with monsoonal forcing in the Arabian Sea, but recent studies suggest that small primary producers remain active and important, even in areas strongly influenced by coastal upwelling. To better understand the role of smaller phytoplankton in such systems, we investigated growth and grazing rates of picophytoplankton populations and their contributions to phytoplankton community biomass and primary productivity during the 1995 Southwest Monsoon (August-September). Environmental conditions at six study stations varied broadly from openocean oligotrophic to coastal eutrophic, with mixed-layer nitrate and chlorophyll concentrations ranging from 0.01 to 11.5 æM NO3 and 0.16 to 1.5 æg Chl a. Picophytoplankton comprised up to 92% of phytoplankton carbon at the oceanic stations, 35% in the diatom dominated coastal zone, and 26% in a declining Phaeocystis bloom. Concurrent in situ dilution and 14C-uptake experiments gave comparable ranges of community growth rates (0.53-1.05 d-1 and 0.44-1.17 d-1, to the 1% light level), but uncertainties in C:Chl a confounded agreement at individual stations. Microzooplankton grazing utilized 81% of community phytoplankton growth at the oligotrophic stations and 54% at high-nutrient coastal stations. Prochlorococcus (PRO) was present at two oligotrophic stations, where its maximum growth approached 1.4 d-1 (two doublings per day) and depth-integrated growth varied from 0.2 to 0.8 d-1. Synechococcus (SYN) growth ranged from 0.5 to 1.1 d-1 at offshore stations and 0.6 to 0.7 d-1 at coastal sites. Except for the most oligotrophic stations, growth rates of picoeukaryotic algae (PEUK) exceeded PRO and SYN, reaching 1.3 d-1 offshore and decreasing to 0.8 d-1 at the most coastal station. Microzooplankton grazing impact averaged 90, 70, and 86% of growth for PRO, SYN, and PEUK, respectively. Picoplankton as a group accounted for 64% of estimated gross carbon production for all stations, and 50% at highnutrient, upwelling stations. Prokaryotes (PRO and SYN) contributed disproportionately to production relative to biomass at the most oligotrophic station, while PEUK were more important at the coastal stations. Even during intense monsoonal forcing in the Arabian Sea, picoeukaryotic algae appear to account for a large portion of primary production in the coastal upwelling regions, supporting an active community of protistan grazers and a high rate of carbon cycling in these areas.  },

keywords = {Arabian Sea, chlorophyll, growth, impact, Oceanic, population, populations, productivity, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Arabesque: An overview},

author = {Burkill,P.H.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {340},

pages = {529-547},

abstract = {This special issue reports the results of ARABESQUE, a UK-led, international programme of upper-ocean biogeochemistry in the Arabian Sea region, conducted during two contrasting seasons.  The seasons studied here were the waning of the southwest monsoon in August/September and the intermonsoon-northeast monsoon transition in November/December 1994.  Biogeochemical studies were carried out along three transects in the Gulf of Oman and the Arabian Sea.  the main ARABESQUE transect, 1590km in length, lay orthagonal to the southern Oman coast and spanned a range of conditions that encompassed coastal seasonal upwelling through to oceanic aseasonal oligotrophy of the central Arabian Sea.  Surface mixed-layer hydrography, PAR, wind speed and direction fields and research results obtained during two seasonal studies are summarised in this paper which also serves and an introductory overview to ARABESQUE.},

keywords = {Arabian Sea, Gulf of Oman, length, Oceanic, oceanography, Oman, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The role of seasonal and diel changes in mixed-layer depth on carbon and chlorophyll distributions in the Arabian Sea},

author = {Gardner,W.D.,Gundersen,J.S.,Richardson,M.J.,Walsh,I.D.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {97},

pages = {1833-1858},

abstract = {The e!ects of changes in the mixed-layer depth on the distribution of particulate organic carbon (POC) and chlorophyll a were examined in the Arabian Sea during the Northeast Monsoon (January and December), Spring Intermonsoon (February-March), and Southwest Monsoon (July and August) of 1995. POC distributions were derived from profiles of beam attenuation calibrated with POC, and chlorophyll a distributions were derived from calibrated fluorescence profiles. Depth of the seasonal mixed layer (Då of 0.125 kg m-3  from surface density) increased with distance offshore during both monsoons, especially in the southern Arabian Sea where the range was 10-80 m nearshore to 80-120 m offshore. The deepest seasonal mixed layers occurred during the Northeast Monsoon. During the Spring Intermonsoon the seasonal mixed layer was only 10-40 m. Variations in the depth of the diel mixed layer (Då of 0.03 kg m-3  from surface density) were up to 90 m during the Northeast Monsoon, but were seldom over 20 m during the Southwest Monsoon. During the Spring Intermonsoon when mixed layers and diel variations in the mixed layer were small, nutrients became depleted, producing oligotrophic conditions plus a strong deep chlorophyll a maximum (>2 mg chl m-3) below the mixed layer. The chlorophyll a maximum was centered at ~ 50 m, which is significantly beneath the effective depth of satellite color sensing. When mixing is active throughout the diel cycle, particulate organic carbon (POC) and chlorophyll distributions are quite uniform within the mixed layer. Nighttime increases in mixed layer depths can mix POC and chlorophyll a produced during the day downward and can entrain new nutrients to enhance primary production. Although mixing from diel variations may be effective in redistributing components within the mixed layer and may be an important mechanism for removing particles from the mixed layer, regional upwelling of nutrients and diatom blooms appear to dominate over diel mixed layer dynamics in the production and export of carbon in the Arabian Sea.},

keywords = {Arabian Sea, chlorophyll, density, depth, diel, Distribution, nearshore, Oceanic, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Seasonal variations in the distribution of Fe and Al in the surface waters of the Arabian Sea},

author = {Measures,C.I.,Vink,S.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46 },

number = {153},

pages = {1597-1622},

abstract = {Concentrations of dissolved Al and Fe in the surface mixed layer were measured during five cruises of the 1995 US JGOFS Arabian Sea Process Study, Concentrations of both Al and Fe were relatively uniform between January and April, the NE Monsoon and the Spring Intermonsoon period, ranging from 2 to 11 nM Al (mean 5.3 nM) and 0.5 to 2.4 nM Fe (mean 1.0 nM). In July/August, after the onset of the SW Monsoon, surface water Al and Fe concentrations increased significantly (Al range 4.5-20.1 nM; mean = 10 nM, Fe range 0.57-2.4 nM; mean = 1.3 nM), particularly in the NE part of the Arabian Sea, as the result of the input and partial dissolution of eolian dust. Using the enrichment of Al in the surface waters, we estimate this is the equivalent to the deposition of 2.2-7.4 g m-2 dust, which is comparable to values previously estimated for this region. Approximately one month later (August/September), surface water concentrations of both Al and Fe were found to have decreased significantly (mean Al 7.4 nM, mean Fe 0.90 nM) particularly in the same NE region, as the result of export of particulate material from the euphotic zone. Fe supply to the surface waters is also affected by upwelling of sub-surface waters in the coastal region of the Arabian Sea during the SW Monsoon. Despite the proximity of high concentrations of Fe in the shallow sub-oxic layer, freshly upwelled water is not drawn from this layer and the NO3/Fe ratio in the initially upwelled water is below the value at which Fe limitation is through to occur. Continued deposition of eolian Fe into the upwelled water as it advects offshore provides the Fe required to raise this ratio above the Fe limitation value.  },

keywords = {Arabian Sea, Distribution, seasonal variation, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Remotely sensed features in the US JGOFS Arabian Sea Process Study},

author = {Shi,W.,Morrison,J.M.,B”hm,E.,Manghnani,V.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {226},

pages = {1551-1575},

abstract = {TOPEX/POSEIDON altimeter data and wind data are used to calculate the geostrophic transport and Ekman transport in the northern Arabian Sea within the upper 500 m. In the summer, the upper 500-m layer in the northern Arabian Sea is horizontally divergent, with a transport going out of the northern Arabian Sea across 15.75§N reaching a maximum of 10 x 106 m3 s-1 in late June. In the winter, it is horizontally convergent, with a transport within the upper 500 m layer across 15.75§N reaching about 5 x 106 m3 s-1 into the northern Arabian Sea. The mean net transport for 1993-1995 out of the northern Arabian Sea across 15.75§N within the upper 500 m is estimated to be 0.74 x 106 m3 s-1. Most of the deep water upwelling across the 500 m depth, which compensates for the loss of waters in the upper 500-m layer, occurs in the eastern part of the northern Arabian Sea. The North Equatorial Current is found to deflect into the Arabian Sea during the NE Monsoon and the Spring Intermonsoon periods. In addition, estimates are made of the net transport into and out of the region encompassed by the US Joint Global Ocean Flux Study (JGOFS) Arabian Sea Process Study. The total transport out of the US JGOFS region is approximately 3.5-4.0 x 106 m3 s-1 in July of 1995 in the upper 500 m. Analysis of the mean sea surface height for the Arabian Sea shows a periodic change with the seasonal monsoon, with a typical depression of the ocean surface during the summer indicative of Arabian Sea cooling. The yearly change of the averaged sea surface height at 15.75§N is of the order of 15 cm. Rossby wave propagation also was observed at 15.75§N in the sea surface height fields.},

keywords = {Arabian Sea, depth, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Fluorescence-based characterization of phycoerythrin-containing cyanobacterial communities in the Arabian Sea during the Northeast and early Southwest Monsoon (1994-1995)},

author = {Wood,A.M.,Lipsen,M.,Coble,P.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {265},

pages = {1769-1790},

abstract = {Scanning fluorescence spectroscopy was used to investigate the spatial and temporal variability in the fluorescence signature of phycoerythrin-containing organisms in the Arabian Sea during the early Northeast and early Southwest Monsoon (1994-1995). Phycoerythrin (PE) emission spectra were relatively invariant among all the samples collected on either cruise; the relatively symmetrical PE emission peaks showed maxima at wavelengths ranging from 563-572 nm. PE excitation spectra always showed either a strong shoulder or a peak at wavelengths absorbed maximally by phycourobilin (PUB) chromophores as well as a peak at wavelengths absorbed maximally by phycoerythrobilin (PEB) chromophores. Thus, the Arabian Sea appears to be different from the Black Sea or Gulf of Maine in that PUB-lacking forms of PE rarely, if ever, dominate the PE signal. Fluorescence excitation signatures differed in the relative excitation of PE emission by wavelengths absorbed by PUB (~495 nm, ExPUB) and bywavelengths absorbed by PEB (~550 nm, ExPEB); these were distinguished by having either very low (~0.6), very high (~1.8), or intermediate ExPUB:ExPEB ratios. The distribution of samples with different PE fluorescence signatures was investigated extensively during the early Southwest Monsoon, and communities characterized by the low ExPUB:ExPEB ratios were closely associated with cooler (24-27§C), fresher (35.7-36.25 psu) water influenced by coastal upwelling. In general, "ambient" surface water of the Arabian Sea during the early Southwest Monsoon was of intermediate temperature (27-29§C) and salinity (36.15-36.4 psu) and showed intermediate or high values for ExPUB :ExPEB. This suggests that the PE fluorescence signature can be used to follow the fate of upwelling-influenced water masses and the populations they transport.  },

keywords = {Arabian Sea, Distribution, Gulf of Maine, population, populations, salinity, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Biohydro-optical classification of the northwestern Indian Ocean},

author = {Brock,J.C.,Sathyendranath,S.,Platt,T.},

year  = {1998},

date = {1998-01-01},

journal = {Marine Ecology Progress Series},

volume = {165},

number = {338},

pages = {1-15},

abstract = {An approach to a partial solution to the general problem of defining biogeochemical provinces for the accurate estimation of global-ocean primary production and realistic structuring of epipelagic plankton ecosystem models is presented for the northwestern Indian Ocean.  This is accomplished through use of a new technique, biohydro-optical classification, that applies a rudimentary submarine light budget incorporating climatologies of incident light, mixed layer thickness, and chlorophyll to recognize fundamental modes of tropical plankton ecosystems.  The three types of biohydro-optical classes found in the  Arabian Sea, Typical Tropical, Mixed-Layer Bloom, and Transitional, are shown to evolve thorough the spring intermonsoon (March through May) summer southwest monsoon (June thorough August), and fall intermonsoon (Sep through Nov)  under climatic forcing and in response to the resulting biological variability. Virtually all of the open Arabian Sea is within the Typical Tropical Class at the close of the spring intermonsoon.  This class type is intended to identify the maximum (DCM) maintained by active algal growth, and light-rich oligotrophic shallow zone containing phytoplankton association which depends largely on regenerated nutrients. At the close of the southwest monsoon in August, a mixed layer bloom province covers much of the northern Arabian Sea. This province class corresponds to the ecosystem mode represented by tropical regions undergoing marginal or mid-ocean upwelling and greatly simplifies regional extrapolation of the local primary production algorithm.  At the onset of the fall intermonsoon, the mixed layer algal bloom province in the northern and western Arabian Sea is superseded by a transitional province, which persists through the fall intermonsoon.  We interpret the upper layer of the fall intermonsoon transitional province in the Arabian Sea as a special case of the shallow regenerative plankton ecosystem of oligotrophic ocean areas, where rates of zooplankton-driven nutrient regeneration and recycled production, key processes in the upper layer of the classic 2-layer euphotic zone or oligotrophic low-latitude oceans, reach extreme values.Note on diagrams/maps in paper:Of all the regions of the nw Arabian Sea, the coastal areas off Oman and Yemen are most often in the Transitional or Mixed layer bloom classes.  The Gulf of Masirah maintains a mixed layer bloom class thorughout the year, even when other coastal areas of Oman switch to a Transitional class.},

keywords = {Arabian Sea, chlorophyll, ecosystem, Gulf of Masirah, Indian Ocean, Oman, plankton, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {A comparison of phytoplankton populations of the Arabian Sea during the Spring Intermonsoon and Southwest Monsoon of 1995 as described by HPLC-analyzed pigments},

author = {Latasa, Mikel.,Bidigare, Robert. R.},

year  = {1998},

date = {1998-01-01},

journal = {Deep-Sea Research II},

volume = {45},

number = {141},

pages = {2133-2170},

keywords = {Arabia, Arabian Sea, Iran, Pakistan, Phytoplankton, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Seasonal variation of hydrographic and nutrient fields during the US JGOFS Arabian Sea Process Study},

author = {Morrison, John M,Codispoti, LA,Gaurin, S,Jones, B,Manghnani, V,Zheng, Z},

issn = {0967-0645},

year  = {1998},

date = {1998-01-01},

journal = {Deep Sea Research Part II: Topical Studies in Oceanography},

volume = {45},

number = {419},

pages = {2053-2101},

abstract = {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 },

keywords = {Arabian Sea, Nutrient cycling, Oman, productivity, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Seasonal response of zooplankton to monsoonal reversals in the Arabian Sea},

author = {Smith,S.,Roman,M.,Prusova,I.,Wishner,K.,Gowing,M.,Codispoti,L.A.,Barber,R.,Marra,J.,Flagg,C.},

year  = {1998},

date = {1998-01-01},

journal = {Deep-Sea Research Part II},

volume = {45},

number = {478},

pages = {2369-2403},

abstract = {The US JGOFS Arabian Sea Process Study was designed to provide a seasonally and spatially resolved carbon budget for a basin exhibiting some of the highest and lowest concentrations of plant biomass in the world's ocean. During the US JGOFS Process Study in the Arabian Sea (September 1994-January 1996), the absolute maximum in biomass of epipelagic zooplankton in the entire study was observed during the Southwest Monsoon season inshore of the Findlater Jet in the area of upwelling. The greatest contrast between high and low biomass in the study area also was observed during the Southwest Monsoon, as was the strongest onshore-offshore gradient in biomass. Lowest biomass throughout the study was observed at the most offshore station (SI5), outside the direct influence of the monsoon forcing. The greatest day/night contrastsing biomass were observed nearshore in all seasons, with nighttime biornass-exceeding daytime in the Northeast Monsoon season, but daytime exceeding nighttime in the Southwest Monsoon season. The diel vertical migration patterns in general reversed between the monsoons at all stations in the southern part of the study area. Virtually, no diel vertical migration of zooplankton took place in any season at the station with strong, persistent subsurface suboxic conditions (N7), suggesting that these conditions suppress migration. Based on the distribution of biomass, we hypothesize that inshore of the Findlater Jet, zooplankton grazing on phytoplankton is the dominant pathway of carbon transformation during both monsoon seasons, whereas offshore the zooplankton feed primarily on microplankton or are carnivorous, conditions that result in reduction of the carbon flux mediated by the zooplankton. Predation by mesopelagic fish., primarily myctophids, may equal daily growth of zooplankton inshore of the Findlater Jet during all seasons. This suggests that the food web inshore of the Findlater Jet is well integrated, may have evolved during past periods of intensified upwelling, and has a distinctly annual cycle. (C) 1998 Elsevier Science Ltd. All rights reserved.},

keywords = {Arabian Sea, Distribution, migration, predation, Upwelling, zooplankton},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The 1994-1996 Arabian Sea Expedition: An integrated, interdisciplinary investigation of the resonse of the northwestern Indian Ocean to monsoonal forcing},

author = {Smith,S.L.,Codispoti,L.A.,Morrison,J.M.,Barber,R.},

year  = {1998},

date = {1998-01-01},

journal = {Deep-Sea Research Part II},

volume = {45},

number = {235},

pages = {1905-1915},

abstract = {This document outlines the aims and methodology used in the JGOFS cruise and reports some of the initial results.  Relevant quotes:  The response of hte Arabian Sea to sustained southwest winds of high intesity during hte summer is clear and direct.  TEH area of upwelling, identified by cool sst observed by the AVHRR images increases markedly form early to mid-june and remins in this configuration with variability assocated with changes in wind strength until mid-September.  Once thew SW monsoon winds relax in id september, the upwelling may collapse quickly.  Although the mean wind strenght is much lower, the situation is more or less reversed during hte winter months when cool, dry winds associated with the NE monsoon blow over hte ARabian SEa.},

keywords = {Arabian Sea, history, Indian Ocean, Upwelling, zooplankton},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Monsoon climate and Arabian Sea coastal upwelling recorded in massive corals from southern Oman},

author = {Tudhope,A.W.,Lea,D.W.,Shimmield,G.B.,Chilcott,C.P.,Head,S.},

year  = {1996},

date = {1996-01-01},

journal = {Palaios},

volume = {11},

number = {486},

pages = {347-361},

abstract = {Corals living in the coastal waters of southern Oman experience the influence of the seasonally reversing Asian monsoon system.  The objective of the research reported here is to assess the potential for using the skeletal chemistry of these corals to investigate past variability in the monsoon climate.  To this end, 20-year long, monthly resolution geochemical records are presented for cores from two massive Porites  corals, located 20 km apart near Marbat on the Arabian Sea coast of southern Oman.  We consider four aspects of skeletal chemistry: oxygen and carbon isotopic composition, barium content and the nature and occurence of annual fluorescent bands within the coral skeletons.  Coral skeletal ë18O documents variations in sea surface temperature which have regional and basin-wide significance.  In particular, the ë18O of coral skeleton precipitated during the period of the NE monsoon is strongly correlated with annual rainfall anomalies in India, whilst that precipitated during the period of the SW monsoon appears to provide information on variability in the strength of coastal upwelling.   The stable carbon isotope composition and barium content of these particular corals display strong annual cycles, but do not appear to directly record interannual climatic/oceanographic variability.  It is concluded that corals on the coast of southern Oman have great potential to provide high-resolution, century-long records of oceanographic and climatic variability associated with the operation of the monsoon climate system.},

keywords = {Arabian Sea, coral, India, Oman, surface temperature, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Interannual variability in phytoplankton blooms observed in the northwestern Arabian Sea during the southwest monsoon},

author = {Brock,J.C.,McClain,C.R.},

year  = {1992},

date = {1992-01-01},

journal = {Journal of Geophysical Research},

volume = {97},

number = {52},

pages = {733-750},

abstract = {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 65øE, 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.},

keywords = {Arabian Sea, plankton, productivity, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {A southwest monsoon hydrographic climatology for the northwestern Arabian Sea},

author = {Brock,J.C.,McClain,C.R.,Hay,W.W.},

year  = {1992},

date = {1992-01-01},

journal = {Journal of Geophysical Research},

volume = {97},

number = {337},

pages = {9455-9465},

abstract = {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 5(}-150 m. During the southwest monsoon coastal upwelling off Oman and adjacent offshore upward Ekman pumping alter the shallow hydrography.},

keywords = {Antarctic, Arabian Sea, depth, oceanography, Oman, salinity, temperature, thermocline, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Cetacean observations from the Somali Democratic Republic, September 1985 through May 1987},

author = {Small,J.A..,Small,G.J.},

year  = {1991},

date = {1991-01-01},

journal = {CEtaceans and Cetacean Research in the Indian Ocean Sanctuary: UNEP - Marine Mammal Technical Report No.3},

number = {476},

pages = {179-210},

abstract = {Two vessels operated along the Gulf of Aden and northern Indian Ocean coasts of Somalia from Aug. 1985 through May 1987.  Their fishing activities carried them on a routine basis from Djibouti to the Horn of Africa and, on many cruises, into the Indian Ocean as far south as 8øN.  The frequent and regular presence of these vessels afforded a unique opportunity for research since few previous surveys along the Somalian coast were transitory and/or of short duration.  There were 398 sightings of cetaceans representing at least 14 species: blue whale, Bryde's whale, sperm whale, melon-headed whale, false killer whale, killer whale, short-finned pilot whale, Indo-Pacific humpback dolphin, common dolphin, bottlenose dolphin, Risso's dolphin, spotted dolphin, striped dolphin and spinner dolphin (NO humpback whales!!).  Sightings locations and related environmental data are discussed. Some trends between years were seen in the occurrence and location of blue, killer and short-finned pilot whales.},

keywords = {Antarctic, Blue whale, bottlenose dolphin, Bryde's whale, cetacean, cetaceans, Common dolphin, dolphin, false killer whale, Gulf of Aden, Humpback Whale, humpback whales, Indian Ocean, killer whale, location, marine, megaptera novaeangliae, melon-headed whale, migration, occurrence, Oman, Pacific Ocean, Risso's dolphin, sanctuaries, Southern Hemisphere, sperm whale, Spinner dolphin, spotted dolphin, stocks, Striped dolphin, survey, trend, Upwelling, whale, whales, whaling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Some features of the upwelling off Oman},

author = {Elliott,A.J.,Savidge,G.},

year  = {1990},

date = {1990-01-01},

journal = {Journal of Marine Research},

volume = {48},

number = {365},

pages = {319-333},

abstract = {Hydrographic and ADCP data were collected in the coastal waters of Oman during the 1987 summer monsoon.  the minimum surface temperatures, up to 5§C below ambient offshore values, were found close to the coast and in the vicinity of the Kuria Muria Islands.  Strong surface gradients were observed near Ras al Hadd at the entrance to the Gulf of Oman where the geostrophic surface flow exceeded 1.0m/s.  The alongshore flux in the top 300m of a region extending 100km from the coast was estimated to be 10 x 106 m3/s.  Evidence for an offshore filament of cool water was found in both current and temperature data.},

keywords = {Gulf of Oman, oceanography, Oman, plankton, surface temperature, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {A shore-based survey of upwelling along the coast of Dhofar region, southern Oman},

author = {Savidge,G.,Lennon,J.,Matthews,A.J.},

year  = {1990},

date = {1990-01-01},

journal = {Continental Shelf Research},

volume = {10},

number = {471},

pages = {259-275},

abstract = {A shore-based survey of hydrographic variables along the southern Oman coast between 16ø55'N, 53ø55'E and 170Z3'N, 55ø17.5'E was carried out between August and November 1985 during the southwest monsoon season and the succeeding period marked by the onset of the northeast winds. During the monsoon season strong evidence of upwelling based on temperature and nutrient data was apparent for the eastern half of the survey area which was distinguished by severe coastal relief and a steeply shelving bathymetry. The upwelled water appeared to be advected westwards into the shallower waters of Salalah Bay which comprised the western part of the survey area. Maximum stratification as inferred from increased temperatures and decreased nutrient concentrations was recorded at the western end of Salalah Bay. Marked increases in chlorophyll a were apparent within the Bay at the boundary between the stratified and upwelled water but concentrations were low within the main bodies of the two water types. The upwelling process was discontinuous in time but the intensity of the upwelling was not apparently related to variation in wind strength; only minimal variations in the velocity of the prevailing southwest wind were recorded during the major part of the survey period. Regular diurnal changes of variable amplitude were observed for all properties sampled with the exception of salinity.},

keywords = {bathymetry, chlorophyll, Oman, salinity, survey, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Some details of upwelling off the Somali and Arabian coasts},

author = {Bruce,J.G.},

year  = {1974},

date = {1974-01-01},

journal = {Journal of Marine Research},

volume = {32},

number = {58},

pages = {419-423},

abstract = {Surface temperature and salinity maps from measurements during the period of maximum coastal upwelling in the Arabian Sea are given.  The region of coldest, temperature <14 §C and freshest, salinity ,35.15 % surface water of Ras Mabber (9§ N Somali coast) shifted northeastward during a 10 day period.  Off the Arabian coast the upwelled water was not as cold (minimum 18§C) or fresh (minimum 35.7%) and was found between 16§N and 20§N.},

keywords = {Arabian Sea, oceanography, salinity, surface temperature, temperature, Upwelling},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {On the ecology and feeding habits of the euphausiids (Crustacea) in the Arabian Sea (Zur Okologie und Eranhrungsbiologie der Euphausiaceen (Crustacea) im Arabischen Meer)},

author = {Weigmann,R.},

year  = {1970},

date = {1970-01-01},

journal = {Meteor Forschungsergeb.},

volume = {5},

number = {498},

pages = {11-52},

abstract = {In the present paper, the ecology and feeding habits of euphausiids are described. The samples were taken at the time of the NE-monsoon (1964/65) by R. V. 'Meteor' in the Arabian Sea and adjacent waters. 24 spp were determined. According to distribution of the spp, the following marine areas can be distinguished: Arabian Sea: 24 spp, dominant are Euphausia diomedeae, E. tenera, E. distinguenda,  Stylocheiron carinatum. Gulf of Aden: 1 0 spp, dominant are Euphausia diomedeae, E. distinguenda.  Red Sea: 6 spp, dominant are Euphausia diomedeae, E. distinguena. Gulf of Oman: 5 spp, dominant are Euphausia distinguenda, Pseudeuphausia latifrons. Persian Gulf: 1 sp- Pseudeuphausia latifrons. The total number of euphausiids indicate the biomass of this group. High densities of euphausiids (200-299 and > 300 individuals/l00 m super(3)) occur in the innermost part of  the Gulf of Aden, in the area south of the Euqator near the African east coast, near Karachi (Indian west coast) and in the Persian Gulf.   Comparison with data relating to production biology confirms that these are eutrophic zones which coincide with areas in which upwelling occurs at the time of the NE-monsoon. The central part of the Arabian Sea differs from adjacent waters by virtue of less dense euphasiid populations (>199 individuals/lOO m super(3)). Measurements relating to production biology demonstrate a relatively low concentration of primary food sources. Food material was ascertained by analysis of stomach content. The following omnivorous species were examined: Euphausia diomedeae, E. distinguenda, E. tenera, Pseudeuphausia latifronts and Thysanopoda tricuspidata. Apart from crustacean remains large numbers  of Foraminifera, Radiolaria, tintinnids, dinoflagellates were found in the stomachs. Quantitatively crustaceans form the most important item in the diet. Food selection on the basis of size an form appears to be restricted to certain genera of tintinnids. The genera Stylocheiron and Nematoscelis are predators. Only crustacean remains were found in the stomachs of Stylocheiron abbreviatum, whereas Radiolaria, Foraminifera and tintinnids occurred to some extent in Nematoscelis sp. Different euphauisiids occupy different positions in the food chain in the Arabian Sea. In omnivorous species the position is variable, since they not only feed by filtering autotrophic and heterotrophic Protista, but also by predation on zooplankton. Carnivorous spp without filtering apparatus feed exclusively on zooolankton of the size of copepods. Only these spp are well established as occupying a higher position in food chain. The parasrtlc protozoan Thalassomyces fagei was found on Euphausia diomedeae, E. tenera, E. distinguenda and E. sanzoi.},

keywords = {Arabian Sea, biology, density, diet, Distribution, ecology, Euphausiid, feeding, Gulf of Aden, Gulf of Oman, marine, Oman, population, populations, predation, Red Sea, Upwelling, zooplankton},

pubstate = {published},

tppubtype = {article}

}