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Applied sciences1
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Biology1
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Frontiers in Marine Science1
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Hidrobiologia1
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International Journal of Limnology1
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Journal of Experimental Marine Biology and Ecology1
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Journal of Marine Science and Engineering1
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Journal of the Black Sea / Mediterranean Environment1
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Marine Pollution Bulletin1
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Mitochondrial DNA Part B1
A new record of potentially ichtyotoxic haptophyte species, Prymnesium parvum f. patelliferum, in the Sea of Marmara during a large-scale mucilage event in June 2021
Eker-Develi, Elif | Tekdal, Dilek
A non-calcifying haptophyte species, Prymnesium parvum f. patelliferum (Green, Hibberd & Pienaar) Larsen, is reported for the first time in the Sea of Marmara from the mucilage event on 11 June 2021. The species was identified with a light microscope and scanning electron microscope. In addition, the 18S rRNA gene was partially sequenced in this study. Amplified gDNA of the expected size was sequenced and analyzed via bioinformatics applications. Results of the analysis vigorously recommended that a 672 bp PCR product was component of a small subunit ribosomal RNA gene sequence. The isolate was named MEUE1, and the partial 18S rRNA sequence of MEUE1 was submitted to the NCBI database (accession number OQ740296). Sequence analysis of isolated culture also verified that it was P. parvum f. p...
The response of phytoplankton assemblages to environmental parameters in the Azad Dam Lake in the west of Iran.
Eker-Develi, Elif
Seasonal variations of phytoplankton abundance, species composition, and their interaction with environmental parameters were investigated in the Azad Dam Lake, in the West of Iran during 2015–2016. Sampling was conducted seasonally at five stations in the lake.Multivariate statistical analyses were carried out to define the abiotic variables influencing phytoplankton community composition. A total of 51 taxa of phytoplankton belonging to six phyla were identified. Bacillariophyta (diatoms) were most diverse with 22 taxa, comprised more than 90%of the total density. Despite the low Shannon–Wiener index (H0) diversity (0.10–1.54), pointing out the dominant density of Bacillariophyta resulted in high water quality. Statistical analysis showed seasonal phytoplankton assemblages differences i...
Marker pigments and carbon biomass of phytoplankton on the northeastern Mediterranean Sea coast
Eker-Develi, Elif
Marker pigments are used to determine taxonomic composition and biomass of microalgae in different oceanic regions. However, sometimes discrepancies are encountered between microscopy and marker pigment based approaches principally because of altering environmental factors influencing diversity of phytoplankton. In the present investigation, marker pigments from HPLC-CHEMTAX analysis concurrent with carbon biomass estimated by microscopy were investigated during 2015–2016 at weekly intervals in the eastern Mediterranean Sea coast. Counting nanoplankton (in particular non-calcifying haptophytes and prasinophytes) in live samples provided a better correlation between microscopy and pigment-based results than in fixed samples. Nanoplankton and picoplankton constituted ~56% of chlorophyll a ba...
Enhancing microalgae classification accuracy in marine ecosystems through convolutional neural networks and support vector machines
Eker Develi, Elif
Accurately classifying microalgae species is vital for monitoring marine ecosystems and managing the emergence of marine mucilage, which is crucial for monitoring mucilage phenomena in marine environments. Traditional methods have been inadequate due to time-consuming processes and the need for expert knowledge. The purpose of this article is to employ convolutional neural networks (CNNs) and support vector machines (SVMs) to improve classification accuracy and efficiency. By employing advanced computational techniques, including MobileNet and GoogleNet models, alongside SVM classification, the study demonstrates significant advancements over conventional identification methods. In the classification of a dataset consisting of 7820 images using four different SVM kernel functions, the line...
New records of haptophyte species from the Northeastern Mediterranean Sea for algal flora of Turkey.
Eker-Develi, Elif
Chrysochromulina alifera, Chrysochromulina lanceolata, Chrysochromulina parkeae, Haptolina cf. ericina, Umbellosphaera irregularis, Umbellosphaera tenuis, Umbilicosphaera foliosa, Syracosphaera molischii, Rhabdosphaera clavigera var stylifera and Ophiaster formosus were recorded for the first time along the Turkish coasts. Non-calcified haptophyte species Chrysochromulina alifera, C. lanceolata, C. parkeae and H. cf. ericina were observed in live samples since formaldehyde damages cells. Among them only C. alifera could be observed with SEM. Either SEM pictures or light microscope images of other species were presented. Although previously reported along Turkish coasts Syracosphaera pulchra was a coccolithophore species most frequently observed after Emiliania huxleyi in the study area. Sc...
The response of phytoplankton assemblages to environmental parameters in the Azad Dam Lake in the west of Iran.
Eker-Develi, Elif
Seasonal variations of phytoplankton abundance, species composition, and their interaction with environmental parameters were investigated in the Azad Dam Lake, in the West of Iran during 2015–2016. Sampling was conducted seasonally at five stations in the lake.Multivariate statistical analyses were carried out to define the abiotic variables influencing phytoplankton community composition. A total of 51 taxa of phytoplankton belonging to six phyla were identified. Bacillariophyta (diatoms) were most diverse with 22 taxa, comprised more than 90%of the total density. Despite the low Shannon–Wiener index (H0) diversity (0.10–1.54), pointing out the dominant density of Bacillariophyta resulted in high water quality. Statistical analysis showed seasonal phytoplankton assemblages differences i...
Antioxidant Capacity and Protein contents of Five Marine Microalgae
Yaman Halil | Eker-Develi Elif | Keles Yuksel
Antioxidant capacity, chlorophyll, marker pigment, and protein contents of four diatoms (Helicotheca tamesis, Haslea silbo, Nitzschia navis-varingica, and Asterionellopsis glacialis) and one cyanobacterium (Spirulina subsalsa) have been investigated. N. navis-varingica exhibited the highest chlorophyll a, fucoxanthin, ascorbic acid, and total antioxidant capacity (TAC) among the five species studied. Cupric-reducing antioxidant capacities of N. navis-varingica and H. silbo were higher than other species studied. A. glacialis exhibited the highest total superoxide dismutase (SOD) activity, H. silbo displayed the highest ascorbate peroxidase (APX) activity, and Spirulina subsalsa had the maximum phenolic and protein contents. Overall, compared to other studies in the literature, the...
Moringa oleifera Lam. as a bioflocculant for harvesting microalgae grown on agricultural wastewaters for feed production
Eker-Develi, Elif | Tekdal, Dilek
Harvesting impacts the costs of microalgae production and affects the characteristics of the final product. Therefore, this study evaluated Moringa oleifera seed powder (MP) as a bioflocculant compared to two chemicals (Aluminium Sulphate—AS and Iron Chloride—IC) to harvest a mixed microalgae culture (Chlorella vulgaris and Desmodesmus sp.) grown on digestate. MP was the most stable flocculant but resulted in the lowest harvesting efficiency of 75%, compared to 94% for AS and 100% for IC. Process parameters such as pH, duration of mixing, grinding method for obtaining the powder, and granulometry had no significant effect on the harvesting efficiency of MP, reinforcing that this is a robust flocculant. The use of a water extraction step increased the harvesting efficiency of MP to ...
Morphology, molecular genetics and potential importance for mucilage events of the new coccolithophorid Ochrosphaera neapolitana in the Sea of Marmara
Eker-Develi, Elif | Tekdal, Dilek
The coccolithophorid Ochrosphaera neapolitana was reported for the first time from samples obtained during a large-scale mucilage event in the Sea of Marmara in May 2022 in a previous study. We also found this species in our samples obtained about a year ago (i.e., in June 2021). In our study, O. neapolitana was further isolated and produced in the laboratory as a monoculture for further investigations using electron microscopy and molecular methods. Ochrosphaera neapolitana was identified using a small sub-unit (SSU) rRNA sequence and subsequent phylogenetic analysis. During the laboratory experiments, O. neapolitana was surprisingly observed to produce conspicuous levels of mucilage as a skim layer in mono- or multi-species cultures, mainly comprising other diatom species. This o...
Impact of environmental factors on phytoplankton composition and their marker pigments in the northern Adriatic Sea
Eker-Develi, Elif
Phytoplankton composition, abundance and carbon biomass were investigated at monthly intervals during 2006—2007 at a coastal site, “Acqua Alta”an oceanographic tower, in the northern Adriatic Sea. Results were compared with chlorophyll a concentrations of phy- toplankton classes attributed by HPLC-CHEMTAX analysis. Changes in the taxonomic structure were associated with environmental parameters. The total carbon biomass of phytoplankton was positively correlated with the temperature and negatively correlated with silicate concen- trations. Nutrient concentrations were higher in the winter—spring period than in the summer- autumn period. The highest carbon biomass and abundance of phytoplankton were observed during summer—autumn months. Diatoms were the group that had the highest contributi...
A gene-rich and compact chloroplast genome of the green alga Nephroselmis pyriformis (N.Carter) Ettl 1982 from the shores of Mersin (Eastern Mediterranean Sea).
Eker-Develi, Elif | Tekdal, Dilek
We report the complete chloroplast genome of the MED1 strain of Nephroselmis pyriformis from the Eastern Mediterranean Sea. At 111,026 bp, this genome is smaller and more compact than those of Nephroselmis olivacea and Nephroselmis astigmatica, and in contrast to the latter taxa, its inverted repeat contains no complete protein-coding genes. It encodes 3 rRNAs, 33 tRNAs and 94 proteins. Maximum likelihood analysis of a concatenated set of chloroplast genes from green algae belonging to deep-diverging lineages positioned the three Nephroselmis species in a strongly supported clade in which N. pyriformis is sister to N. astigmatica.
A novel cosmopolitan species of blue diatoms
Eker-Develi, Elif
Specimens of a new species of blue diatoms from the genus Haslea Simonsen were discovered in geographically distant sampling sites, first in the Canary Archipelago, then North Carolina, Gulf of Naples, the Croatian South Adriatic Sea, and Turkish coast of the Eastern Mediterranean Sea. An exhaustive characterization of these specimens, using a combined morphological and genomic approach led to the conclusion that they belong to a single new to science cosmopolitan species, Haslea silbo sp. nov. A preliminary characterization of its blue pigment shows similarities to marennine produced by Haslea ostrearia, as evidenced by UV–visible spectrophotometry and Raman spectrometry. Life cycle stages including auxosporulation were also observed, providing data on the cardinal points of this s...
Phytoplankton and pigment composition during an Emiliania huxleyi bloom in the Black Sea
Eker-Develi, Elif
Alterations in composition and carbon biomass of phytoplankton community are closely related to seasonal variations, anthropogenic inputs and ultimately climatic changes in a longer perspective. Accuracy of the collected data is important to determine changes occurring in phytoplankton community composition. An intercomparison exercise of haptophyte abundance obtained by microscopy was performed by three research laboratories based on samples taken from 2 to 11 June 2016, in the western and central Black Sea. Total carbon biomass of phytoplankton groups was estimated by one of the three laboratories based on microscopy. Phytoplankton group composition was also determined with marker pigments. Carbon biomass of large sized diatoms and dinoflagellates was correlated with CHEMTAX deri...
Phytoplankton distribution in the Caspian Sea during March 2001
Soydemir, Nuray | Eker, Elif
Phytoplankton abundance, biomass and species composition of the Caspian Sea were evaluated by using samples collected from the Iranian (southern Caspian Sea) and southern Kazakhstan (eastern Caspian Sea) surface waters inMarch 2001. A total of 45 taxa were found in the samples (20 diatoms, 17 dinoflagellates and 8 others). Abundance and biomass of diatoms were high at the eastern stations, while dinoflagellates were dominant in terms of both biomass and abundance in the southern region. Average abundance and biomass were 40 000 ± 35 000 cell l)1 and 580 ± 690 lg l)1 . The mean biomass value found here for the Middle and southern Caspian Sea in March are difficult to compare with the past due to limited information, but seems higher than previously registered values. Higher chloroph...
Diatoms isolated from the marine mucilage in the Sea of Marmara in 2021
Tekdal Dilek | Eker-Develi Elif
This study presents five new records of diatoms based on light and electron microscopy results from the surface water of the Sea of Marmara coast during a large-scale mucilage event in 2021. Three of these diatoms are small nanoplanktic; Cyclotella cryptica, Nitzschia amabilis, Thalassiosira pseudonana, and the two of them are larger diatoms; Conticribra weissflogii and Entomoneis cf. pusilla. In addition, a species frequently seen in mucilage samples in the Adriatic Sea and the the Sea of Marmara, Cylindrotheca closterium, was also isolated and described. The chloroplast rbcL region, SSU, and 18S rDNA of C. closterium, C. cryptica and N. amabilis were amplified using primers in other previous studies. The rbcL, SSU, and 18S rDNA partial sequences were submitted to the NCBI database. Molec...
Editorial: Phytoplankton dynamics under climate change
Eker-Develi, Elif
Phytoplankton plays an important role in ocean processes, and is well-known to have an enormous positive impact on climate change ormore specifically on global warming, by reducing atmospheric CO2 levels through the sinking of produced organic and inorganic matter to the deep ocean (Falkowski, 2012; Beardall and Raven, 2013). However, climate change, with consequences of elevated seawater temperatures and decreased pH levels (Beardall and Raven, 2013), influences phytoplankton dynamics, changing phytoplankton composition, geography and biomass in the oceans (Falkowski and Oliver, 2007; Boyd et al., 2015; Jonkers et al., 2019). Temperature increases could also drive temporal shifts in the onset of the regular annual blooms, their composition, duration and amplitude as well asmismatc...