Fischer,A.S.,Weller,R.A.,Rudnick,D.L..,Eriksen,C.C.,Lee,C.M.,Brink,K.H.,Fox,C.A.,Leben,R.R.
Mesoscale eddies, costal upwelling, and the upper-ocean heat budget in the Arabian Sea Journal Article
In: Deep-Sea Research Part II, vol. 49, no. 94, pp. 2231-2264, 2002.
Abstract | BibTeX | Tags: Arabian Sea, budget, salinity, survey, temperature, trend, Upwelling
@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}
}
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
Weller,R.A.,Fischer,A.S.,Rudnick,d.l.,Eriksen,C.C.,Dickey,T.D.,Marra,J.,Fox,C.,Leben,R.
Moored observations of upper-ocean response to the monsoons in the Arabian Sea during 1994-1995 Journal Article
In: Deep-Sea Research Part II, vol. 49, no. 253, pp. 2195-2230, 2002.
Abstract | BibTeX | Tags: Arabian Sea, depth, salinity, temperature
@article{,
title = {Moored observations of upper-ocean response to the monsoons in the Arabian Sea during 1994-1995},
author = {Weller,R.A.,Fischer,A.S.,Rudnick,d.l.,Eriksen,C.C.,Dickey,T.D.,Marra,J.,Fox,C.,Leben,R.},
year = {2002},
date = {2002-01-01},
journal = {Deep-Sea Research Part II},
volume = {49},
number = {253},
pages = {2195-2230},
abstract = {The role of surface forcing in the semiannual evolution of the upper-ocean temperature, salinity, and velocity fields in the Arabian Sea is examined. To do so, variability in the upper ocean in the central Arabian Sea was observed from an array of moorings deployed from October 1994 to October 1995. The Northeast (NE) Monsoon was characterized by moderate winds, clear skies, and dry air; sea-surface temperature (SST) dropped by 3§C; the ocean lost an average of 19.7Wm-2 and the mixed layer deepened by 100m in response. The Southwest (SW) Monsoon was accompanied by strong winds, cloudy skies, and moist air; the ocean gained an average of 89.5Wm-2 but SST dropped by 5.5§C and the mixed layer deepened to almost 80 m. The response to the NE Monsoon included daily cycling in the depth of the mixed layer in response to the diurnal cycle in the buoyancy forcing and a weak local, wind-driven response. Stronger windforcing during the SW Monsoon dramatically reduced diurnal restratification, and a clearer signal of local, wind-driven flow in the upper ocean was found. The strongest velocity signal in the upper ocean, however, was the flow associated with mesoscale geostrophic features that passed slowly through the moored array, dominating the current meter records in the first part of the NE Monsoon and again in the latter part of the SW Monsoon. One-dimensional heat and freshwater balances, which held at other times through the year, broke down during the passage of these features.},
keywords = {Arabian Sea, depth, salinity, temperature},
pubstate = {published},
tppubtype = {article}
}
The role of surface forcing in the semiannual evolution of the upper-ocean temperature, salinity, and velocity fields in the Arabian Sea is examined. To do so, variability in the upper ocean in the central Arabian Sea was observed from an array of moorings deployed from October 1994 to October 1995. The Northeast (NE) Monsoon was characterized by moderate winds, clear skies, and dry air; sea-surface temperature (SST) dropped by 3§C; the ocean lost an average of 19.7Wm-2 and the mixed layer deepened by 100m in response. The Southwest (SW) Monsoon was accompanied by strong winds, cloudy skies, and moist air; the ocean gained an average of 89.5Wm-2 but SST dropped by 5.5§C and the mixed layer deepened to almost 80 m. The response to the NE Monsoon included daily cycling in the depth of the mixed layer in response to the diurnal cycle in the buoyancy forcing and a weak local, wind-driven response. Stronger windforcing during the SW Monsoon dramatically reduced diurnal restratification, and a clearer signal of local, wind-driven flow in the upper ocean was found. The strongest velocity signal in the upper ocean, however, was the flow associated with mesoscale geostrophic features that passed slowly through the moored array, dominating the current meter records in the first part of the NE Monsoon and again in the latter part of the SW Monsoon. One-dimensional heat and freshwater balances, which held at other times through the year, broke down during the passage of these features.
Marine Science; Fisheries Center,Oman
Ecological studies in the Coastal waters of Oman and selecting of sites for aquaculture: Progress Report no:2 Technical Report
no. 401, 2001.
Abstract | BibTeX | Tags: Hydro-biology, oceanography, Oman, plankton, salinity, temperature, zooplankton
@techreport{,
title = {Ecological studies in the Coastal waters of Oman and selecting of sites for aquaculture: Progress Report no:2},
author = {Marine Science and Fisheries Center,Oman},
year = {2001},
date = {2001-01-01},
number = {401},
pages = {1-81},
publisher = {Ministry of Agriculture and Fisheries, Directorate General of Fisheries Resources, Marine Science and Fisheries Centre, Marine Ecology Laboratory},
abstract = {The report is divided into two sections: the first outlines the preliminary results of data collected in transects in 21 different sites along the coast - including temperature, salinity, dissolved 02, hydrogen ion concentration, phytoplankton production and zooplankton production. The second section includes an initial assessment of potential sites for aquaculture, including Duqm, Masirah, Quriyat, Barr al Hikmann, Likbi, Sharbitat, Mirbat, Tiwi, Khawr Jarama, and Shinas},
keywords = {Hydro-biology, oceanography, Oman, plankton, salinity, temperature, zooplankton},
pubstate = {published},
tppubtype = {techreport}
}
The report is divided into two sections: the first outlines the preliminary results of data collected in transects in 21 different sites along the coast - including temperature, salinity, dissolved 02, hydrogen ion concentration, phytoplankton production and zooplankton production. The second section includes an initial assessment of potential sites for aquaculture, including Duqm, Masirah, Quriyat, Barr al Hikmann, Likbi, Sharbitat, Mirbat, Tiwi, Khawr Jarama, and Shinas
Marine Science; Fisheries Center Oman
Ecological studies in the Coastal waters of Oman and selecting of sites for aquaculture: Progress Report no:2 Technical Report
no. 423, 2001.
Abstract | BibTeX | Tags: Hydro-biology, oceanography, Oman, plankton, salinity, zooplankton
@techreport{,
title = {Ecological studies in the Coastal waters of Oman and selecting of sites for aquaculture: Progress Report no:2},
author = {Marine Science and Fisheries Center Oman},
year = {2001},
date = {2001-01-01},
number = {423},
pages = {1-81},
publisher = {Ministry of Agriculture and Fisheries, Directorate General of Fisheries Resources, Marine Science and Fisheries Centre, Marine Ecology Laboratory},
abstract = {The report is divided into two sections: the first outlines the preliminary results of data collected in transects in 21 different sites along the coast - including temperature, salinity, dissolved 02, hydrogen ion concentration, phytoplankton production and zooplankton production. The second section includes an initial assessment of potential sites for aquaculture, including Duqm, Masirah, Quriyat, Barr al Hikmann, Likbi, Sharbitat, Mirbat, Tiwi, Khawr Jarama, and Shinas},
keywords = {Hydro-biology, oceanography, Oman, plankton, salinity, zooplankton},
pubstate = {published},
tppubtype = {techreport}
}
The report is divided into two sections: the first outlines the preliminary results of data collected in transects in 21 different sites along the coast - including temperature, salinity, dissolved 02, hydrogen ion concentration, phytoplankton production and zooplankton production. The second section includes an initial assessment of potential sites for aquaculture, including Duqm, Masirah, Quriyat, Barr al Hikmann, Likbi, Sharbitat, Mirbat, Tiwi, Khawr Jarama, and Shinas
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.
Microbial food web structure in the Arabian Sea: a US JGOFS study Journal Article
In: Deep-Sea Research Part II, vol. 47 , no. 98, pp. 1387-1422, 2000.
Abstract | BibTeX | Tags: Arabian Sea, dominance, objectives, salinity, temperature, Upwelling
@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}
}
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.
Toon,R.K.,Lohrenz,S.E.,Rathbun,C.E.,Wood,A.M.,Arnone,R.A.,Jones,B.H.,Kindle,J.C.,Weidemann,A.D.
Photosynthesis-irradiance parameters and community structure associated with coastal filaments and adjacent waters in the northern Arabian Sea Journal Article
In: Deep-Sea Research Part II, vol. 47, no. 244, pp. 1249-1277, 2000.
Abstract | BibTeX | Tags: Arabian Sea, biology, chlorophyll, Distribution, salinity, Upwelling
@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}
}
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.
Wood,A.M.,Lipsen,M.,Coble,P.
Fluorescence-based characterization of phycoerythrin-containing cyanobacterial communities in the Arabian Sea during the Northeast and early Southwest Monsoon (1994-1995) Journal Article
In: Deep-Sea Research Part II, vol. 46, no. 265, pp. 1769-1790, 1999.
Abstract | BibTeX | Tags: Arabian Sea, Distribution, Gulf of Maine, population, populations, salinity, temperature, Upwelling
@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}
}
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.
Al-Jabri,M.
Marine epilithic algal communities on artificial and natural substrates Technical Report
no. 5, 1996.
Abstract | BibTeX | Tags: Arabian Gulf, Arabian Sea, coral, developing, Green turtles, growth, Gulf of Oman, habitat, marine, monitoring, Oman, pollution, productivity, salinity, temperature, turtles
@techreport{,
title = {Marine epilithic algal communities on artificial and natural substrates },
author = {Al-Jabri,M.},
year = {1996},
date = {1996-01-01},
volume = {FSC 1580-91 },
number = {5},
pages = {1-15},
abstract = {INTRODUCTION The Epilithic Algal Community (EAC) of coral reefs are diverse assemblages of small filamentous green, red, blue-green algae ('turf species') and crustose coralline red algal. These have low biomass but show rapid growth rate (Klumpp and Mckinnon, 1989) and this algal community colonizes the reefs and serves as the primary food source for herbivores. The diversity and richness of reef fauna can also be attributed largely to the high productivity of EAC (Klumpp and Mckinnon, 1989); thus the EAC is the major source of food for herbivores such as damselfish, echinoids, surgeonfish (sohal and yellow tail), parrotfish and green turtles. The main algal functional form group (Littler et a¡.,1983) is the filamentous group. In the Arabian Sea, however, there is a diverse algal community of filamentous, sheet-group, coarsely branched group and thick leathery group due to upwelling, (Mardela, 1975, Jupp et al, 1996). The Gulf of Oman does not experience upwelling due to the summer S.W. monsoon, so in this part of Oman, because of the physical conditions prevailing, there are high salinities and temperatures in summer as well as wide temperature variation and, combined with largely sand substrates here, coral reefs are not as widely distributed as in many tropical seas and their growth and diversity is not as great. In spite of this, they still contribute a highly complex community (Sheppard and Salm, 1988). During the past three decades, many of the natural marine habitats in the world and Arabian Gulf in particular are being destroyed, degraded or are actually disappearing as a result of oil pollution, coastal infilling and other activities associated with industrial development. Because the EAC is very important for grazers, many studies on natural reefs and artificial reefs structures including oil platforms, piers, jetties and other coastal installations have been carried out (Seaman and Sprague, 1991). Artificial habitat enhancement has been practiced primarily to attract fishes in various parts of the world, however in Oman there are no studies yet that have been made to understand the mechanisms of attractive effect of artificial structures. In addition, few studies on reef coral community and no detailed study of EAC have been carried out in Oman with studies along the Gulf of Oman just mentioning few macroalgae and green filamentous algae, e.g. Entromorpha (Sheppard and Salm, 1988). On the Gulf of Oman coasts, only sparse clumps of larger macroalgae (>10cm) of sheet-group, coarsely branched and thick leathery groups are found (Mardela, 1975) with, for example, only scattered plants such as Padina and Halymenia (Cordero, 1992). In view of the importance of EAC on natural and artificial reefs this preliminary study will provide valuable baseline biological data about the growth of algae as well as the faunal assemblages that accumulate around artificial substrates. Data from this study would be useful to assist researchers in the future in monitoring herbivorous fish resources as well as the succession of communities developing on artificial reefs.},
keywords = {Arabian Gulf, Arabian Sea, coral, developing, Green turtles, growth, Gulf of Oman, habitat, marine, monitoring, Oman, pollution, productivity, salinity, temperature, turtles},
pubstate = {published},
tppubtype = {techreport}
}
INTRODUCTION The Epilithic Algal Community (EAC) of coral reefs are diverse assemblages of small filamentous green, red, blue-green algae ('turf species') and crustose coralline red algal. These have low biomass but show rapid growth rate (Klumpp and Mckinnon, 1989) and this algal community colonizes the reefs and serves as the primary food source for herbivores. The diversity and richness of reef fauna can also be attributed largely to the high productivity of EAC (Klumpp and Mckinnon, 1989); thus the EAC is the major source of food for herbivores such as damselfish, echinoids, surgeonfish (sohal and yellow tail), parrotfish and green turtles. The main algal functional form group (Littler et a¡.,1983) is the filamentous group. In the Arabian Sea, however, there is a diverse algal community of filamentous, sheet-group, coarsely branched group and thick leathery group due to upwelling, (Mardela, 1975, Jupp et al, 1996). The Gulf of Oman does not experience upwelling due to the summer S.W. monsoon, so in this part of Oman, because of the physical conditions prevailing, there are high salinities and temperatures in summer as well as wide temperature variation and, combined with largely sand substrates here, coral reefs are not as widely distributed as in many tropical seas and their growth and diversity is not as great. In spite of this, they still contribute a highly complex community (Sheppard and Salm, 1988). During the past three decades, many of the natural marine habitats in the world and Arabian Gulf in particular are being destroyed, degraded or are actually disappearing as a result of oil pollution, coastal infilling and other activities associated with industrial development. Because the EAC is very important for grazers, many studies on natural reefs and artificial reefs structures including oil platforms, piers, jetties and other coastal installations have been carried out (Seaman and Sprague, 1991). Artificial habitat enhancement has been practiced primarily to attract fishes in various parts of the world, however in Oman there are no studies yet that have been made to understand the mechanisms of attractive effect of artificial structures. In addition, few studies on reef coral community and no detailed study of EAC have been carried out in Oman with studies along the Gulf of Oman just mentioning few macroalgae and green filamentous algae, e.g. Entromorpha (Sheppard and Salm, 1988). On the Gulf of Oman coasts, only sparse clumps of larger macroalgae (>10cm) of sheet-group, coarsely branched and thick leathery groups are found (Mardela, 1975) with, for example, only scattered plants such as Padina and Halymenia (Cordero, 1992). In view of the importance of EAC on natural and artificial reefs this preliminary study will provide valuable baseline biological data about the growth of algae as well as the faunal assemblages that accumulate around artificial substrates. Data from this study would be useful to assist researchers in the future in monitoring herbivorous fish resources as well as the succession of communities developing on artificial reefs.
Thangaraja,M.
Hydro-Biology off Oman Technical Report
no. 484, 1995.
Abstract | BibTeX | Tags: Fisheries, Hydro-biology, oceanography, Oman, salinity, zooplankton
@techreport{,
title = {Hydro-Biology off Oman},
author = {Thangaraja,M.},
year = {1995},
date = {1995-01-01},
journal = {MSFC Research Report},
volume = {95-1},
number = {484},
pages = {1-151},
publisher = {Ministry of Agriculture and Fisheries, Directorate General of Fisheries Resources, Marine Science and Fisheries Centre, Marine Ecology Section},
abstract = {The report gives information on the temperature, salinity, Dissolved oxygen, phytoplankton production, zooplankton production and fish production for each of the 8 fisheries areas in Oman. It then discusses the results of time series studies (hydrography, phytoplankton, zooplankton) in Musandam, Muscat and Dhofar.},
keywords = {Fisheries, Hydro-biology, oceanography, Oman, salinity, zooplankton},
pubstate = {published},
tppubtype = {techreport}
}
The report gives information on the temperature, salinity, Dissolved oxygen, phytoplankton production, zooplankton production and fish production for each of the 8 fisheries areas in Oman. It then discusses the results of time series studies (hydrography, phytoplankton, zooplankton) in Musandam, Muscat and Dhofar.
Brock,J.C.,McClain,C.R.,Hay,W.W.
A southwest monsoon hydrographic climatology for the northwestern Arabian Sea Journal Article
In: Journal of Geophysical Research, vol. 97, no. 337, pp. 9455-9465, 1992.
Abstract | BibTeX | Tags: Antarctic, Arabian Sea, depth, oceanography, Oman, salinity, temperature, thermocline, Upwelling
@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}
}
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.
Savidge,G.,Lennon,J.,Matthews,A.J.
A shore-based survey of upwelling along the coast of Dhofar region, southern Oman Journal Article
In: Continental Shelf Research, vol. 10, no. 471, pp. 259-275, 1990.
Abstract | BibTeX | Tags: bathymetry, chlorophyll, Oman, salinity, survey, temperature, Upwelling
@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}
}
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.
Bruce,J.G.
Some details of upwelling off the Somali and Arabian coasts Journal Article
In: Journal of Marine Research, vol. 32, no. 58, pp. 419-423, 1974.
Abstract | BibTeX | Tags: Arabian Sea, oceanography, salinity, surface temperature, temperature, Upwelling
@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}
}
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.