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Efflorescence of the Potentially Harmful Dinoflagellate Prorocentrum micans in the Oum Er Rbia Estuary – North Atlantic Moroccan Coasts

Bengriche Rachida, Bouchafra El Mostafa, Chaouite Jamila, Moncef Mohammed

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 6

250--256

EN

The present work addressed the study an episode of red waters of great extent, which was observed off the Oum Er Rbia estuary in spring 2019. The responsible species was Prorocentrum micans. The study was carried out on three stations with different characteristics, distributed in the estuary upstream and downstream of an urban wastewater discharge. The cell densities observed were maximum in March 2019. Some environmental parameters (temperature, salinity, dissolved oxygen, chlorophyll (a) and pheopigments) were simultaneously recorded. The P. micans densities increased from downstream to upstream with cell concentrations of 1.03×105 cell/l in S3, 9.1×106 cell/l in S2 and 14.11×107 cell/lin S1. The contribution of P. micans to the total dinoflagellates density was higher and reached 99.54% in station S1. These blooms would be associated with high concentrations of chlorophyll (a) and pheopigments, which equaled 40 μg/l and 909 μg/l, respectively, and dissolved oxygen supersaturations (17.05 mg/l). This phenomenon also corresponded to a marked decrease in salinity. According to the application of the Kruskal-Wallis test, the difference was found to be significant between the three stations (p = 0.0034). In addition, densities were higher in surface waters than in bottom waters at all three stations. However, this difference did not appear to be statistically significant (p > 0.05).

2

Inhibitory effects of the brown macroalga Turbinaria ornata on cyst germination and progeny cells of five harmful dinoflagellate species

Mohamed Zakaria, Alamri Saad, Hashem Mohamed

Oceanologia

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2022

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No. 64 (1)

63--74

EN

This study investigates the inhibitory effects of thalli and their extracts of the macroalga Turbinaria ornata on the germination of dinoflagellate cysts, previously isolated from Red Sea surface sediments. The experiments were conducted on cysts of five harmful dinoflagellate species including Alexandrium catenella, Cochlodinium polykrikos, Dinophysis accuminata, Prorocentrum cordatum and Scrippsiella trochoidea. The results showed neither macroalgal thalli nor their extracts had direct impact on the cyst germination of all species. Instead, these macroalgal materials remarkably affected the germling viability and culturability of progeny cells of these cysts. Dry macroalgal thalli exhibited stronger inhibitory effects on germling viability and cell culturability (IC50= 0.235–0.543, 0.385–1.43 mg mL−1, respectively) than fresh thalli (IC50=2.201–4.716, 2.17–7.18 mg mL−1, respectively). The macroalgal ethanol extract was approximately 2-5 times more effective (IC50 = 0.012–0.047 and 0.024–0.089 mg mL−1, respectively) than aqueous extract (IC50 = 0.04–0.1 and 0.054–0.207 mg mL−1, respectively) against the germling viability and vegetative progeny cells of all cyst species. Among different species, A. catenella and C. polykrikos germlings were more sensitive to macroalgal thalli and their extracts than those of S. trochoidea, P. cordatum and D. acuminata. Meanwhile, progeny cells of A. catenella exhibited the highest sensitivity to all macroalgal materials. Our results suggest that the use of T. ornata may be a promising strategy for inhibiting the division of progeny cells of dinoflagellate cysts and impairing the recurrence of HABs in confined coastal areas.

3

Estimation of diatom and dinoflagellate cell volumes from surface waters of the Northern Indian Ocean

Chitari R. R., Anil A. C.

Oceanologia

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2017

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No. 59 (3)

389--395

EN

Phytoplankton samples collected from the Northern Indian Ocean (Bay of Bengal, northern Arabian Sea, and Dona Paula Bay Goa, west coast of India), were utilized to quantify changes in cell size, cell volume and carbon per cell of diatoms and dinoflagellates. The dataset from the Bay of Bengal also provides inter- and intra-annual variations (April 2008 to March 2010). The variations in cell size and volume were large in regions influenced by the riverine influx or terrigenous inputs. An interregional comparison of commonly available forms (8 species) points out that cell volumes are highest in the North Atlantic and lowest in the Mediterranean. The information provided will be useful in estimation of carbon biomass and biogeochemical studies.

4

Growth rates of dinoflagellates along the Karachi coast assessed by the size fractionation method

Munir S., Siddiqui P. J. A., Naz T., Burhan Z. U., Morton S.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 3

326--334

EN

The in situ growth rates of dinoflagellates along the Karachi coast off Pakistan was studied by the size fractionated method during winter (February 2006) and summer (May 2007). The growth rate per day ranged from -2.87 to 2.3 d–1(20 species) in winter and from 1.20 to 1.95 d–1 (13 species) in summer. Growth rates (μmax d–1) of the dominant species were as follows: Prorocentrum gracile, Prorocentrum minimum, Prorocentrum arcuatum (1.0-1.10), Protoperidinium steinii (0.92), Gonyaulax spinifera (0.69), Dinophysis acuminata (2.3), Dinophysis caudata (0.92), Ceratium lineatum, Prorocentrum micans (1.95), Gyrodinium sp. (1.88), Ceratium furca (1.70), and Alexandrium ostenfeldii (1.34). The declining growth rates were observed for Pyrophacus stein (-1.10), Scrippsiella trochoidea (-1.61 to -0.82), Prorocentrum donghaiense (-1.94) and Karenia mikimotoi (-2.48). Our results suggest that a higher temperature induce an increase in dinoflagellate growth rates.

5

Integrated palaeontological characteristics (ammonites, ostracods, foraminifers, dinocysts) of the Berriasian deposits of central Crimea

Savelieva J., Feodorova A., Shurekova O., Arkadiev V.

Volumina Jurassica

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2014

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Vol. 12, no. 1

129--162

EN

The Berriasian deposits of the central Crimea have been studied in order to compose a composite sequence of the stage with detailed palaeontological characterization. The Berriasian includes the Bedenekyrskaya Formation (packstones), Bechku Formation (siltstones, sandstones) and Kuchkinskaya Formation (sponge packstones, clays, siltstones, and coral-algal bioherm framestones). The Jacobi, Occitanica and Boissieri zones were identified based on ammonites found in the sections. A micropalaeontological analysis determined the following: 6 foraminiferal assemblages, the Costacythere khiamii – Hechticythere belbekensis and Costacythere drushchitzi – Reticythere marfenini ostracod assemblages, and a Phoberocysta neocomica dinocyst assemblage. Palaeoecological analysis of the ostracod and foraminiferal associations indicates a moderately warm marine basin with normal salinity and shallow depths (tens of meters). Only the sponge horizon was probably deposited in a deeper-water environment.

6

Annual phytoplankton dynamics in the Gulf Saint Vincent, South Australia, in 2011

Leterme S.C., Jendyk J. G., Ellis A. V., Brown M. H., Kildea T.

Oceanologia

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2014

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No. 56 (4)

757--778

EN

Phytoplankton communities are the basis of many marine and freshwater food webs. Their composition fluctuates depending on hydrochemical conditions, such as light, temperature, salinity, pH, nutrients and turbulence. This study investigates the effect of changing environmental conditions on the coastal phytoplankton community of the Gulf St Vincent in South Australia. This is the first study simultaneously investigating the phytoplankton communities and their environment in this area and is essential to set up the baseline of future studies. In total, 179 phytoplankton species were identified and enumerated between January and December 2011. Phytoplankton communities were numerically dominated by chlorophytes during 6 months of the survey and an intense bloom (representing 62% of the overall phytoplankton community) of the diatom Cylindrotheca closterium was observed in February. Our results suggest that in the coastal waters of the Gulf St Vincent, the variability in environmental conditions is driven by temperature, wind speed/direction and the changing levels of phosphorus. However, the variability observed during autumn and winter months seems to be driven by changing levels of nitrogen and silica. In this shallow environment, the wind speed is proportional to the stress at the ocean floor and should directly influence the resuspension of sediment and associated nutrients. Nutrient ratios were observed to investigate potential phytoplankton nutrient limitation patterns. These ratios indicated that nitrogen was usually the limiting nutrient, which is typical of marine systems. Since nutrient enrichment is generally the main factor driving the succession and composition of phytoplankton communities in coastal waters, further work is now needed to identify the sources of nutrients in this region where river runoff is limited and evaporation is high relative to precipitation.

7

Composition of protozoan communities at two sites in the coastal zone of the southern Baltic Sea

Rychert K., Spich K., Laskus K., Pączkowska M., Wielgat-Rychert M., Sojda G.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

268--276

EN

Protozoan communities were studied in the coastal zone of the southern Baltic Sea. Stable environmental conditions and typical, bimodal seasonal changes in the protozoan biomass were observed at the sampling site in Sopot (2003–2004). At the sampling site in Ustka (2007–2008), strong benthic resuspension and irregular impacts of fresh water resulted in atypical seasonal changes in the protozoan biomass with a summer peak only. The mean annual biomass had similar values at both sites: 43.2 μg C dm−3 in Sopot and 38.6 μg C dm−3 in Ustka. The protozoan community in Sopot was dominated by ciliates (48% of the biomass), whereas in Ustka — by heterotrophic nanoflagellates (53%).

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Occurrence and germination of dinoflagellate cysts in surface sediments from the Red Sea off the coasts of Saudi Arabia

Mohamed Z.A., Al-Shehri A.M.

Oceanologia

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2011

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No. 53 (1)

121-136

EN

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

9

Palaeoenvironmental changes preceding the Middle Miocene Badenian salinity crisis in the northern Polish Carpathian Foredeep Basin (Borków quarry) inferred from foraminifers and dinoflagellate cysts

Peryt D., Gedl P.

Geological Quarterly

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2010

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Vol. 54, No 4

487-508

EN

Study of foraminiferal and dinoflagellate cyst assemblages and palynofacies occurring in 2 m-thick marls cropping out beneath a giant gypsum intergrowth unit in the Borków gypsum quarry in Southern Poland, one of the key Badenian evaporite sections in the Polish Carpathian Foredeep Basin, has shown the presence of 49 species of benthic foraminifers and 11 species of planktonic ones, and 51 dinoflagellate (including 8 redeposited ones). The composition of the foraminiferal fauna and its isotopic signal indicate temperature-stratified, nutrient-rich and thus less-oxygenated marine water. Changes in the relative abundance of epifaunal and infaunal species indicate a clear environmental change during the deposition of the marls. A middle to outer shelf marine, well-ventilated environment with moderate primary productivity existed during the deposition of the bottom part of the marls. Subsequently, infaunal bottom-dwellers became dominant due to a massive increase in food supply to the sea bottom and shallowing of the sea to inner - middle shelf depths, and than a decreasing trend of a relative abundance of the infaunal morphogroups is observed until the top of the marls that were deposited in an inner shelf environment with moderate primary productivity. The calculated palaeotemperatures for particular foraminifer taxa (Globigerina spp., Cibicidoides and Bulimina elongata) show a slight upsection decrease and a decrease in the temperature differences between the bottom and intermediate water beds. Palynofacies are composed of elements of mixed origin, including terrestrial, marine (mainly dinoflagellate cysts) and elements of uncertain derivation (structureless organic matter). The palynological content of most samples indicates their deposition in an open-marine marine environment, in the stable marine conditions of an open shelf basin with no salinity fluctuations. The sample just below the gypsum contains no dinoflagellate cysts, perhaps due to a drastic change in the photic zone leading to a complete collapse of the dinoflagellate flora. Very rare occurrence of planktonic foraminifers in that sample suggest the shallowing of the basin accompanied by a decrease in the temperature gradient between the upper (warmer) and lower (colder) water beds. A shallow, cold water marine environment is indicated for the topmost foraminiferal assemblage.

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First report on Noctiluca scintillans blooms in the Red Sea off the coasts of Saudi Arabia: consequences of eutrophication

Mohamed Z.A., Mesaad I.

Oceanologia

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2007

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No. 49 (3)

337-351

EN

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.

11

The composition, abundance and distribution of dinoflagellates in the Gulf of Gdańsk in the years 1992-1994

Pliński M., Dobron K.

Oceanological Studies

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1999

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Vol. 28, No. 1-2

41-49

EN

The quantitative and qualitative analysis of dinoflagellates from samples taken in the years from 1992 to 1994 in the Gulf of Gdansk has been done. The following species was identified: Hetero-capsa triquetra, Dinophysis norvegica, D. acuminata, Peridinium balticum, P. aciculiferum, P. pellucidum, P. curvipes, P. brevipes, Peridiniella catenata, Gonyaulax triacanta, Prorocentrum micans. The highest quantity of dinoflagellates was observed in May 1994.