@article{,

title = {Monsoonal forcing of calcification in the Arabian Sea},

author = {Balch,W.M.,Drapeau,D.T.,Fritz,J.J.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {18},

pages = {1301-1337},

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

keywords = {abundance, Arabian Sea, stocks, trap},

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 = {Annual biomarker record for export production in the central Arabian Sea},

author = {Prahl,F.G.,Dymond,J.,Sparrow,M.A.},

year  = {2000},

date = {2000-01-01},

journal = {Deep-Sea Research Part II},

volume = {47},

number = {200},

pages = {1581-1604},

abstract = {The record for plankton biomarkers in sediment trap samples from a one-year experiment in the central Arabian Sea (AS4: 15§59'N 61§30'E) shows variations that reflect changing biological conditions in surface waters. Particulate fluxes of C37-39 alkenones, highly branched C25 isoprenoids (HBI), dinosterol, nC28 12-hydroxy fatty acid, 24-ethylcholesterol, and C30-34 series of pentacyclic triterpanols all displayed distinct maxima at the start and stop of the Northeast (NE) and Southwest (SW) Monsoons. Surface mixing conditions changed rapidly at these times, altering light and nutrient availability, thereby triggering these biomarker signals of export production. Temporal offsets noted in individual biomarker concentrations (per g total organic carbon) at the start of the SW Monsoon suggest succession occurs in the phytoplankton community contributing to organic matter export. Comparable offsets were neither apparent at the start of the less dynamic NE Monsoon nor at the end of the NE or SW Monsoons. Broad concentration maxima for HBI also were observed at the beginning and end of the time-series during the relatively quiescent Fall Intermonsoon period when such features were conspicuously absent for other biomarkers. HBI are reputed biomarkers of Rhizoselenia and Haslea spp., two recognized dominants of diatom biomass in the Arabian Sea. These peaks in biomarker concentration could reflect either changes in the relative proportion of specific organisms that contribute to the upper ocean productivity or enhanced preservation of the biomarkers during times of high export production. In either case, the biomarker record in sediment traps reflects important changes in the biological condition of the upper ocean. All biomarkers except HBI were measurable in surface sediments deposited beneath the trap site. Comparison with concentrations in average sediment trap particles showed each was sensitive to significant ( ~ 99%) degradation, displaying depletion factors relative to TOC of ò4. Clearly, consequences of such high levels of early diagenetic recycling must be considered carefully when conclusions about changes in export production from surface waters in past oceans are drawn from stratigraphic analysis of biomarkers in marine sediments.  },

keywords = {Arabian Sea, depletion, marine, plankton, productivity, trap},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Monsoon-controlled export fluxes to the interior of the Arabian Sea},

author = {Honjo,S.,Dymond,J.,Prell,W.,Ittekkot,V.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {388},

pages = {1859-1902},

abstract = {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 quasiperpendicular 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.},

keywords = {Arabian Sea, depth, pulses, trap},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Demersal fisheries of the Arabian Sea, the Gulf of Oman and the Arabian Gulf},

author = {Siddeek,M.S.M.,Fouda,M.M.,Hermosa,G.V.Jr.},

year  = {1999},

date = {1999-01-01},

journal = {Estuarine, Coastal and Shelf Science},

volume = {49},

number = {474},

pages = {87-97},

abstract = {The demersal fisheries of the Arabian Sea, the Gulf of Oman and the Arabian Gulf are reviewed. The region comprises eight countries: Oman, United Arab Emirates (U.A.E.), Qatar, Saudi Arabia, Bahrain, Kuwait, Iraq and Iran. Over 350 commercial fish species, eight shrimp species, two spiny lobster species, one shovel nose lobster species, one cuttlefish species, one crab species, and one abalone species support the demersal fisheries in the continental shelves of the three regions. Artisanal and industrial vessels with over 120 000 fishermen were involved in demersal fisheries. Fishing boats include fish and shrimp trawlers (wooden and steel hulled), large wooden boats (dhow) with inboard engines, small dhows with outboard engines, and fiberglass boats. Fishing gear consists of trawls, bottom gill nets, traps (wire mesh and plastic types), barrier traps, hand lines, and bare hands and knives (to dislodge abalone). Demersal fish (primarily Lethrinidae, Sparidae, Serranidae, Siganidae, Sciaenidae, Stromateidae, Lutjanidae, Trichiuridae, and Nemipteridae) and shrimp (primarily Penaeus semisulcatus, Metapenaeus affinis, Parapenaeopsis stylifera, and Penaeus merguiensis) were the two commercial demersal resources. Approximately 198 000-214 000 tonnes (t) of demersals were landed annually during 1988-1993, accounting for nearly 40% of the total marine landings (475000-552000 t). This percentage, however varied among countries: 25% in Oman, 32% in U.A.E., 71% in Qatar, 52% in Saudi Arabia, 56% in Bahrain, 55% in Kuwait, close to 100% in Iraq, and 41% in Iran. Fishing effort on certain stocks may have been below the optimum level (e.g. certain Omani demersal fish), near the optimum level (e.g. Omani shrimp), or above the optimum level ( e.g. Arabian Gulf shrimp and demersal fish). Overexploitation led to restriction of fishing effort by limiting fishing licenses, regulating fishing gear (mesh size) and capture size, closing fishing areas, restricting fishing season, and banning certain fisheries. However, fisheries management was hampered by lack of appropriate management regulations, enforcement and data on most stocks. Pollution and degradation of nursery areas were also affecting the productivity of fisheries resources. To achieve sustainable demersal fisheries, maintaining a healthy marine environment, reducing fishing effort, and strictly enforcing closed seasons and closed areas are needed. These measures are being implemented with varying degrees of success by all the countries.},

keywords = {Arabian Gulf, Arabian Sea, enforcement, Fisheries, fishing gear, Gulf of Oman, management, marine, nets, Oman, pollution, productivity, regulations, trap, trawlers},

pubstate = {published},

tppubtype = {article}

}