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Wyszukujesz frazę "red sea" wg kryterium: Temat


Tytuł:
Circulation and winter deep-water formation in the Northern Red Sea
Autorzy:
Manasrah, R.
Badran, M.
Lass, H.U.
Fennel, W.
Powiązania:
https://bibliotekanauki.pl/articles/49153.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Aqaba Gulf
eddy
deep-water formation
winter
circulation
Red Sea
Opis:
Water mass characteristics and circulation patterns in the Gulf of Aqaba and northern Red Sea were studied for the first time during the r/v ‘Meteor’ cruise leg 44/2 from February 21st to March 7th 1999 using temperature-salinity profiles and current observations. The deep water in the northern Red Sea had similar characteristics to the well-mixed upper 450 m of water in the Gulf of Aqaba. This indicates that the winter mixed waters of the Gulf of Aqaba contribute significantly to deep-water in the northern Red Sea. Mixing in the Gulf of Aqaba is an annually repeated event that starts with the cooling of the surface water during November–December and reaches a maximum, which in most years extends down the entire water column in March–April. Waters deeper than the mixed layer in the Gulf seems to be rather passive and play no specific role in water mass formation in the northern Red Sea. In contrast to the Gulf of Aqaba, the upper 200 m of the northern Red Sea were stratified (21.5–23.5◦C, and 40.0–40.3 PSU). Stratification at the Strait of Tiran was weak (21.6–22.0◦C, and 40.3–40.5 PSU) and disappeared abruptly in the Gulf of Aqaba (21.4–21.6◦C, and 40.6–40.7 PSU). A well-developed cyclonic gyre with a diameter of about 50–60 km and maximum velocity of about 0.4 m s−1 was observed in the stratified upper 200 m of the northern Red Sea waters. The gyre may contribute to the preconditioning for intermediate water formation in the northern Red Sea.
Źródło:
Oceanologia; 2004, 46, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nutrient flux fuels the summer primary productivity in the oligotrophic waters of the Gulf of Aqaba, Red Sea
Autorzy:
Badran, M.I.
Rasheed, M.
Manasrah, R.
Al-Najjar, T.
Powiązania:
https://bibliotekanauki.pl/articles/47744.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Aqaba Gulf
biological stress
diffusion model
chlorophyll a
oligotrophic water
primary productivity
thermohaline stratification
nutrient flux
Red Sea
Opis:
The thermohaline characteristics of the Gulf of Aqaba, Red Sea, depict a welldefined seasonal pattern of winter mixing from December to April and summer stratification from May to November. This thermohaline structure is a major controlling factor of the nutrient, chlorophyll a and primary productivity seasonal cycles. The nitrate and chlorophyll a concentration records generated down to 200 m at a vertical resolution of 25 m – weekly during 1994, 1995 and every two weeks from April 1997 through to December 2000 – are employed to assess the nitrogen flux across the summer thermocline of the Gulf of Aqaba. The flux calculations are based on a simple diffusion model that incorporates the physical stress eddy diffusivity factor Kz and a biological stress factor k. Both Kz and k are calculated using the Michaelis-Menten equation and the nitrate concentration gradient. The total nitrate flux of the Gulf of Aqaba during the seven summer months (May–November) is estimated at 0.52 moleN m−2. In relation to established primary productivity values (75.5 gC m−2 (May November)−1) and the generated chlorophyll a records, this yields an f fraction of new to total primary production of 0.50. This relatively high f value is discussed with respect to the geophysical characteristics of the Gulf of Aqaba and similar oceanic basins. The remaining 50% is accounted for by cross-sectional flow from the relatively nutrientrich coral reef coastal habitat and rapid recycling, triggered by high irradiance and water temperature.
Źródło:
Oceanologia; 2005, 47, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationships between water temperature, nutrients and dissolved oxygen in the Northern Gulf of Aqaba, Red Sea
Autorzy:
Manasrah, R.
Raheed, M.
Badran, M.I.
Powiązania:
https://bibliotekanauki.pl/articles/49092.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
stratification
nutrient
Aqaba Gulf
temperature
sea water
Red Sea
oxygen
Opis:
Five years (1998, 2000–2003) of summer records of temperature, nutrients and dissolved oxygen concentrations in the upper 400 m of the water column of the northern Gulf of Aqaba were employed to produce a simple statistical model of the relationship between temperature versus nitrate, phosphate, silicate andd issolved oxygen concentrations. Temperature profiles in the upper 400 m during summer revealeda clear thermocline in the upper 200 m. This was reflected in nutrient ando xygen concentrations as nitrate, phosphate, and silicate increasedfr om the surface to deep water while dissolved oxygen decreased. The best fit relationship between temperature versus nitrate andphosphate was inverse linear and the best fit correlation between temperature versus silicate andd issolvedo xygen was fractional. The observedn utrient concentrations were shaped by a combination of the hydrodynamics and biological factors. Deep winter mixing and high nutrient concentrations dominate during winter. Shortly after the water stratifies in spring, the nutrients are drawn down by phytoplankton during the spring bloom and remain low throughout the rest of the year. The regression equations presented here will be useful in estimating nutrient concentrations from temperature records as long as the annual natural cycle is the main driver of nutrient concentrations and external inputs are insignificant. Deviations from these relationships in the future could provide insight into modifications in the nutrient concentrations probably resulting from new nutrient sources, such as anthropogenic inputs.
Źródło:
Oceanologia; 2006, 48, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First report on Noctiluca scintillans blooms in the Red Sea off the coasts of Saudi Arabia: consequences of eutrophication
Autorzy:
Mohamed, Z.A.
Mesaad, I.
Powiązania:
https://bibliotekanauki.pl/articles/48017.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
microalga
dinoflagellate
bloom
coast
eutrophication
Saudi Arabia
Red Sea
Noctiluca scintillans
Opis:
Blooms of Noctiluca scintillans are reported for the first time in the Red Sea off the south-western coasts of Saudi Arabia. During the present study, surface water samples were collected weekly on the coasts of the Al Shuqayq region from February to April 2004–2006. The abundance of N. scintillans correlated negatively with most nutrients, as well as the cell densities of diatoms and dinoflagellate species. Microscopic examination of live cells from Noctiluca blooms showed the presence of some species of diatoms and dinoflagellates within the Noctiluca body – confirmation of its grazing on these microalgae. The presence of a Noctiluca bloom in the coastal waters off south-western Saudi Arabia could be linked indirectly to water eutrophication by an increase in prey abundance. The physico-chemical properties of Red Sea coastal waters should therefore be monitored regularly in order to minimize the formation of harmful algal blooms, which may affect all food web levels, including the human level.
Źródło:
Oceanologia; 2007, 49, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temporal variations in coral reef health at a coastal industrial site on the Gulf of Aqaba, Red Sea
Autorzy:
Al-Zibdah, M.K.
Damhoureyeh, S.A.
Badran, M.I.
Powiązania:
https://bibliotekanauki.pl/articles/47429.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Aqaba Gulf
coral reef
sponge
hydrozoan
macrobenthos
echinoderm
temporal variation
coral
macroalga
bivalve
Red Sea
Opis:
A detailed ecological study was conducted for three years (2001–03) on a 5 km stretch of well-developed coral reef facing an industrial site in the southernmost section of the Jordanian coast of the Gulf of Aqaba, Red Sea. The degree of modification associated with the prevailing ecological factors was assessed with respect to species diversity and abundance of the major groups of the macrobenthic community: corals, bivalves, hydrozoans, echinoderms, sponges and macroalgae. Three locations of two depths each – 6 and 12 m – were selected and surveyed using the visual census point-intercept method. The actual area of the survey covered about 2250 m2. Macrobenthic communities occurring close to the industrial jetty were characterized by low diversity and the obvious dominance of soft coral (16–30% cover). In the deep transects (12 m) hard coral cover was higher than that in the shallow transects (30–55%). Correlation analyses indicated that species richness increased with increasing distance from the industrial jetty. Species richness of other macrobenthos was also higher as depth increased. The results revealed that the distribution and abundance of coral, echinoderms, hydrozoans and macroalgae were correlated with the relative importance of bottom modification within the various locations in the entire study area. However, no distinct influence of location or depth on the identities of most macrobenthic species was indicated.
Źródło:
Oceanologia; 2007, 49, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Density dependent growth of the red algae Furcellaria lumbricalis and Coccotylus trancatus in the West Estonian Archipelago Sea, Northern Baltic Sea
Autorzy:
Kotta, J.
Paalme, T.
Kersen, P.
Martin, G.
Herkul, K.
Moller, T.
Powiązania:
https://bibliotekanauki.pl/articles/48839.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
Furcellaria lumbricalis
red alga
alga growth
Coccotylus truncatus
Opis:
In an in situ experiment we evaluated the growth of the red algae Furcellaria lumbricalis and Coccotylus truncatus in the Archipelago Sea. The results showed that the growth rates of both species were similar but that growth decreased with increasing algal coverage. The effects were more pronounced for C. truncatus than for F. lumbricalis. Economic analyses aiming to establish sustainable harvesting limits for F. lumbricalis in the study area should take account of the density dependent growth of these red algae.
Źródło:
Oceanologia; 2008, 50, 4; 577-585
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of the sea squirt Ecteinascidia thurstoni Herdman, 1890 (Ascidiacea: Perophoridae) along Suez Canal and Egyptian Red Sea coasts
Autorzy:
Gab-Alla, A.A.-F.A.
Powiązania:
https://bibliotekanauki.pl/articles/47709.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sea squirt
sea coast
Perophoridae
Suez Canal
seasonal rhythm
Red Sea
Ascidiacea
distribution
Ecteinascidia thurstoni
Opis:
Ecteinascidia thurstoni is a colonial sea squirt. It has a seasonal rhythm and a tropical and subtropical distribution; it is usually present during the summer months. It synthesizes a group of molecules called ecteinascidins. One of these is ET-743, a compound that has a most original anti-tumoral activity and is today considered to be one of the most promising substances effective against various solid-type tumors (currently sold under the trade name of Yondelis for the treatment of sarcomas and related tumors; it is undergoing phase II/III clinical trails for other kinds of tumors). Worldwide, Ecteinascidia species represent the only available source of this bioactive compound, which was first discovered in E. turbinata. During the present study, the ecology of E. thurstoni along the Suez Canal and Red Sea was investigated. Its populations were observed to be highly gregarious due in part to their low larval dispersal, which is very localized; larvae therefore tend to settle close to their parent colonies. It is only recorded in shallow waters (0.5–1.5 m) as an epiphyte on the pneumatophores of mangroves by the Red Sea, on the pilings of jetties, and the metal or cement banks of the Suez Canal. The morphometric characteristics (zooid length, zooid weight, colony weight) of the Suez Canal population differ significantly from those of the Red Sea. Studying the distribution of this species and locating its different populations along the Suez Canal and Red Sea could help to characterize their genetics, chemistry and bacterial communities at different isolated locations. Ultimately, this will help to define the sources of ET-743 and hence promote its biosynthesis on a commercial scale.
Źródło:
Oceanologia; 2008, 50, 2; 239-253
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineralogical and chemical composition of the mud fraction from the surface sediments of Sharm Al-Kharrar, a Red Sea coastal lagoon
Autorzy:
Basaham, A.S.
Powiązania:
https://bibliotekanauki.pl/articles/48257.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Sharm Al-Kharrar
mineralogical composition
trace element
chemical composition
mud fraction
Red Sea
surface sediment
tropical marine habitat
coastal lagoon
Opis:
Interaction between continental and marine end-members gives rise to the natural biogeochemical processes in Sharm Al-Kharrar, a lagoon in the arid Red Sea region. Twenty-nine surface sediment samples were collected from the area and their mud fraction analysed for grain size, OC, CaCO3, mineralogy and elemental composition. The mud fraction consisted of a mixture of siliciclastic/calcareous materials, dominated by silt size materials and characterised by low OC (average 0.71% ±0.13); CaCO3 varied widely, with an average of 45% ±18. Concentrations of Al, Fe, Mn, Cu, Ni, Cr, V and Ba showed a wide range of variation throughout the Sharm. The results were normalised to Al and subjected to cluster analysis in order to examine the relations between the mineralogy and the elemental composition. The contents of Al, Fe, Mn, Cu, Ni, Cr, V and Ba appeared to be influenced by the mixing of the two end-members in addition to the physiochemical processes associated with the mixing between episodic freshwater flooding and seawater. Zn was the single element that showed a slight departure from the mixing model.
Źródło:
Oceanologia; 2008, 50, 4; 557-575
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mycosporine-like amino acids in six scleractinian coral species
Autorzy:
Al-Utaibi, A.A.
Niaz, G.R.
Al-Lihaibi, S.S.
Powiązania:
https://bibliotekanauki.pl/articles/48437.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hard coral
Lithophyllor lobata
Fungia repanda
mycosporine-like amino acid
scleractinian coral
Fungia danai
Fungia scutaria
Fungia corona
Red Sea
Fungiidae
Ctenactis echinata
coral species
Opis:
Mycosporine-like amino acids (MAAs) were studied in stony coral species (Fungiidae) along the Eastern coast of the Red Sea. Six species – Fungia scutaria, F. danai, F. corona, F. repanda, Ctenactis echinata and Lithophyllor lobata – were examined for MAAs at water depths of 5, 10, 15 and 20 m. Protein and chlorophyll were also determined and showed higher contents in winter than in summer. Generally, the total content of MAAs in summer was found to be approximately three times greater than in winter. Overall, concentrations of MAAs were greatest at a depth of 5 m. Porphyra-334 was the most abundant MAA in F. scutaria and F. danai, whereas asterina-330 was either not detectable (e.g. L. lobata) or present in low concentrations (e.g. F. danai, F. repanda and C. echinata). Shinorine was not detected in F. danai or L. lobata. Both C. echinata and L. lobata had the lowest concentrations of MAAs, presumably because of their large calcareous skeletons. The variation in MAA concentrations among seasons and water depths is probably due to a number of factors, including the intensity of solar radiation, turbidity and phylogenetic variation.
Źródło:
Oceanologia; 2009, 51, 1; 93-104
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problems of metaplantation of protected species - a case study of sea holly (Eryngium maritimum L.) and dark red helleborine (Epipactis atrorubens (Hoffm.) Besser)
Problemy metaplantacji gatunków chronionych na przykładzie mikołajka nadmorskiego (Eryngium maritimum L.) i kruszczyka rdzawoczerwonego (Epipactis atrorubens (Hoffm.) Besser)
Autorzy:
Zolkos, K.
Afranowicz, R.
Bloch-Orlowska, J.
Minasiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/84940.pdf
Data publikacji:
2010
Wydawca:
Akademia Pomorska w Słupsku
Tematy:
metaplantation
protected species
sea holly
Eryngium maritimum
dark red helleborine
Epipactis atrorubens
marine ecosystem
plant species
royal helleborine zob.dark red helleborine
Opis:
In June 2005 metaplantation of Eryngium maritimum and Epipactis atrorubens, from the build area of the Gdańsk Container Terminal into Sobieszewska Island was carried out. The reason for that immediate action was the unreliable report of the influence of investment on the environment, in which the mentioned above species have not been included. Metaplantation was conducted during one day time, by 21 volunteers. Altogether, 146 individuals of Sea Holly and 184 ones of Dark Red Helleborine have been translocated. Detailed measurements of each individual were made. On the new site, all planted individuals were permanently labelled. The newly constituted populations have been taken under monitoring. With regard to species of special concern, metaplantation of threatened populations seems to be the most beneficial form of nature compensation expected from the investors. Still, there are no unambiguous procedures for its executing.
Rozwoj gospodarczy i związana z tym nasilająca się antropopresja powodują istotne przekształcenia środowiska przyrodniczego na rożnych poziomach jego organizacji: ekosystemalnym, biocenotycznym i gatunkowym. Zgodnie z obowiązującą w Polsce polityką zrównoważonego rozwoju zmiany te, często nieuniknione, powinny być poprzedzone działaniami minimalizującymi ich skutki. W związku z tym podejmowane są działania czynnej ochrony przyrody. Jedną z tych metod, która dotyczy ochrony ginących i zagrożonych gatunków roślin, jest metaplantacja. Według „Poradnika ochrony siedlisk i gatunków Natura 2000” (Sudnik- Wojcikowska i Stebel 2004) metaplantacja to: „metoda ochrony gatunków ginących, polegająca na przenoszeniu roślin i zwierząt z zagrożonych stanowisk naturalnych na stanowiska zastępcze”. W czerwcu 2005 roku przeprowadzona została metaplantacja populacji Eryngium maritimum i Epipactis atrorubens z terenu budowy terminalu kontenerowego Portu Północnego w Gdańsku na Wyspę Sobieszewską. Przygotowanie i przeprowadzenie metaplantacji musiało odbyć się bardzo szybko ze względu na rozpoczęte już prace budowlane. Tak późne rozpoczęcie starań o uratowanie lokalnych populacji obu gatunków wynikało z nierzetelnie sporządzonego raportu oddziaływania inwestycji na środowisko, w którym wyżej wymienione gatunki nie zostały uwzględnione. Metaplantację przeprowadzono w ciągu jednego dnia, a wzięło w niej udział 21 wolontariuszy. Ogółem przeniesiono 146 okazów mikołajka nadmorskiego i 184 kruszczyka rdzawoczerwonego. Wykonano szczegółowe pomiary każdego przenoszonego okazu. Na nowym stanowisku posadzono i trwale oznakowano wszystkie przeniesione rośliny. Nowo powstałe populacje objęte zostały monitoringiem. W przypadku gatunków szczególnej troski metaplantacja zagrożonych populacji wydaje się najkorzystniejszą formą kompensacji przyrodniczej, wymaganej od inwestorów. Nadal brak jest jednak jasno określonych procedur jej przeprowadzania.
Źródło:
Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline; 2010, 14
1643-0115
Pojawia się w:
Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioaccumulation of gamma emitting radionuclides in red algae from the Baltic Sea under laboratory conditions
Autorzy:
Zalewska, T.
Saniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/48962.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
bioaccumulation
environment pollution
Furcellaria lumbricalis
heavy metal
laboratory condition
macroalga
marine alga
marine organism
Polysiphonia fucoides
radionuclide
red alga
Opis:
The bioaccumulation ability of radionuclides 51Cr, 54Mn, 57Co, 60Co, 65Zn, 85Sr, 109Cd, 110mAg, 113Sn, 137Cs and 241Am in two red algae species from the southern Baltic Sea – Polysiphonia fucoides and Furcellaria lumbricalis – was determined under laboratory conditions. P. fucoides demonstrated better bioaccumulative properties towards most of the investigated radionuclides. As a result, P. fucoides can be recommended as a good bioindicator of radioactive environmental pollution. The bioaccumulation of radionuclides in F. lumbricalis was studied during an extended laboratory experiment. The initial extensive uptake of radioisotopes was followed by the rapid removal of cations; in general, concentrations tended to decrease with time. 137Cs displayed a different behaviour, its concentration in the algae increasing over time mainly due to its large ion radius; this is a factor that could be responsible for the stronger mechanical and chemical bonding of Cs+ and that could hamper the movement of ions in both directions.
Źródło:
Oceanologia; 2011, 53, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New and ‘visiting’ fish species collected off the Western coast of Poland (Baltic Sea) in 2007–2008 with a description of their parasite fauna
Autorzy:
Wiecaszek, B.
Sobecka, E.
Dudko, S.
Keszka, S.
Powiązania:
https://bibliotekanauki.pl/articles/47560.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
red mullet
Mullus surmuletus
Chelidonichthys lucerna
Trachurus trachurus
Chelon labrosus
Pomeranian Bay
Szczecin Lagoon
Lake Dabie
Baltic Sea
Polska
horse mackerel
parasite fauna
Opis:
The first occurrence of striped red mullet Mullus surmuletus in the Pomeranian Bay (in 2007) and the occurrence of three very rarely noted species (tub gurnard Chelidonichthys lucerna, Atlantic horse mackerel Trachurus trachurus, thicklip grey mullet Chelon labrosus) collected in 2007–2008 in the Pomeranian Bay, Szczecin Lagoon and Lake Dąbie are reported. Their expansion is probably due to increased sea temperatures resulting from climate change, as well as the inflow of saline water. The ‘visitors’ hosted eight pathogens from four taxonomic groups: Protozoa, Nematoda, Acanthocephala and Mollusca. Nematodes, the most numerous ones, were found in three host species. All the parasite species were new for the hosts examined; only the larvae of the acanthocephalan Corynosoma strumosum had already been recorded in one of the hosts (Chelidonichthys lucerna). The stomachs of almost all the fish examined were empty, but the species composition of the parasite fauna found showed that the fish must have ingested some food in the Pomeranian Bay.
Źródło:
Oceanologia; 2011, 53, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Occurrence and germination of dinoflagellate cysts in surface sediments from the Red Sea off the coasts of Saudi Arabia
Autorzy:
Mohamed, Z.A.
Al-Shehri, A.M.
Powiązania:
https://bibliotekanauki.pl/articles/48723.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
occurrence
germination
dinoflagellate cyst
cyst
Red Sea
Saudi Arabia
coast
toxic species
distribution
abundance
surface sediment
organic carbon
silt
clay
Cochlodinium polykrikos
Prorocentrum minimum
Dinophysis
acuminata
Alexandrium catenell
Scrippsiella trochoidea
Opis:
The distribution and abundance of dinoflagellate cyst assemblages were investigated in surface sediments from south-western Red sea coasts of Saudi Arabia at six sites during March 2010. A total of 19 taxa of dinoflagellate cysts were identified from all sites. The sampling sites showed a similar cyst assemblage, but they differed in total cyst abundance (3 to 4083 cysts g−1 dry weight). Cyst abundance was strongly correlated with sediment characteristics, the highest numbers being recorded in sediments with large contents of organic carbon, silt and clay. Cyst assemblages were dominated by cysts of potentially toxic species, including Cochlodinium polykrikos, Prorocentrum minimum, Dinophysis acuminata, Alexandrium catenella and Scrippsiella trochoidea. Most cysts germinated successfully at different rates at 15 and 25◦C. This study suggests that surface sediments from all Saudi Red Sea coasts should be monitored for the presence of dinoflagellate cysts to give ample warning of the presence and abundance of toxic species in a given area.
Źródło:
Oceanologia; 2011, 53, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The link between shrimp farm runoff and blooms of toxic Heterosigma akashiwo in Red Sea coastal waters
Autorzy:
Mohamed, Z.A.
Al-Shehri, A.M.
Powiązania:
https://bibliotekanauki.pl/articles/48811.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hemolytic activity
ichthyotoxic alga
shrimp farm
raphidophyte
Heterosigma akashiwo
Red Sea
coastal water
Saudi Arabia
phytoplankton
physicochemical characteristics
sea water
environmental factor
nutrient concentration
algal bloom
Opis:
In May 2010 a copious bloom of the raphidophyte Heterosigma akashiwo was observed for the first time in Red Sea waters off the coasts of Saudi Arabia. This bloom was confined to an area where water and phytoplankton flow freely between the sea and a shrimp farm. The phytoplankton density and physico-chemical characteristics of the sea water were therefore investigated weekly at bloom and non-bloom sites in order to gain insight into the environmental factors prevailing at the bloom site and their link with the shrimp farm runoff. The bloom site showed higher nutrient concentrations than the non-bloom site, indicating the possible role of the shrimp farm in flushing nutrients into this site. The bloom appeared on 27 May, coinciding with a decrease in salinity (<300/00) and an increase in temperature (>19◦C). The results of toxicological assays showed that both bloom samples and batch cultures of H. akashiwo were toxic to Artemia salina and exhibited haemolytic activity with respect to rabbit erythrocytes. Bloom samples showed a higher toxicity (LC50 = 8.9 × 104 cells ml−1) and haemolytic activity (EC50 = 3.64 × 104 cells ml−1) than the batch cultures (LC50 =11.6×104 cells ml−1, EC50 =5.1×104 cells ml−1). In the light of the results of this study, the link between H. akashiwo blooms and shrimp farm runoff should be considered during the monitoring of Red Sea coastal waters for the presence of harmful algal blooms.
Źródło:
Oceanologia; 2012, 54, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical distribution of zooplankton in the epipelagic zone off Sharm El-Sheikh, Red Sea, Egypt
Autorzy:
Dorgham, M.M.
Elsherbiny, M.M.
Hanafi, M.H.
Powiązania:
https://bibliotekanauki.pl/articles/48203.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hydrography
copepod
Red Sea
Sharm El-Sheikh
Egypt
plankton
zooplankton dynamics
vertical distribution
epipelagic zone
Chaetognatha
Appendicularia
Opis:
The purpose of the present study was to track the seasonal vertical distribution of zooplankton abundance in the epipelagic zone off Sharm El-Sheikh, Red Sea. Zooplankton samples were collected seasonally within the depth ranges of 0–25, 25–50, 50–75, 75–100 m at a single station off Sharm El-Sheikh City. The present study is an attempt to expand knowledge about the structure as well as the vertical distribution of the epipelagic zooplankton community in the Gulf of Aqaba in general and in its southern part in particular. The results indicate the occurrence of 52 copepod species and several species of other planktonic groups in the study area; the zooplankton standing crop fluctuated between 1124 and 4952 organisms m−3. Copepods appeared to be the predominant component, forming an average of 86.5% of the total zooplankton count, and with other groups demonstrated a markedly different seasonal vertical distribution. Twelve bathypelagic copepod species were reported during the present study, and five species were new to the area, having migrated northwards from the main basin of the Red Sea.
Źródło:
Oceanologia; 2012, 54, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł

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