scholarly journals Size-fractionated primary production in the south-eastern Black Sea

Oceanologia ◽  
2021 ◽  
Author(s):  
Ertugrul Agirbas ◽  
Mustafa Bakirci
Keyword(s):  
Primary Production ◽  
Black Sea ◽  
The South ◽  
South Eastern

scholarly journals Phytoplankton community composition in the south-eastern Black Sea determined with pigments measured by HPLC-CHEMTAX analyses and microscopy cell counts

2014 ◽  
Vol 95 (1) ◽  
pp. 35-52 ◽  
Author(s):  
Ertugrul Agirbas ◽  
Ali Muzaffer Feyzioglu ◽  
Ulgen Kopuz ◽  
Carole A. Llewellyn
Keyword(s):  
Black Sea ◽  
High Performance ◽  
Phytoplankton Community ◽  
Phytoplankton Community Structure ◽  
The South ◽  
Coastal Station ◽  
Chl A ◽  
South Eastern ◽  
Cell Counts ◽  
Offshore Station

The phytoplankton community structure and abundance in the south-eastern Black Sea was measured from February to December 2009 using and comparing high performance liquid chromatography pigment and microscopy analyses. The phytoplankton community was characterized by diatoms, dinoflagellates and coccolithophores, as revealed by both techniques. Fucoxanthin, diadinoxanthin, peridinin and 19′-hexanoyloxyfucoxanthin were the main accessory pigments showing significant correlation with diatom-C r2 = 0.56–0.71, P < 0.05), diatom-C (r2 = 0.85–0.91, P < 0.001), dinoflagellate-C (r2 = 0.39–0.88, P < 0.05) and coccolithophore-C (r2 = 0.80–0.71, P < 0.05), respectively. Microscopy counts indicated a total of 89 species, 71% of which were dinoflagellates, 23% were diatoms and 6% other species (mainly coccolithophores). Pigment-CHEMTAX analysis also indicated the presence of pico- and nanoplankton. Phytoplankton carbon (phyto-C) concentrations were highest in the upper water column, whereas chlorophyll-a (Chl-a) showed a deep maximum. Average phyto-C was higher at the coastal station (291 ± 66 µg l−1) than at the offshore station (258 ± 35 µg l−1), not statistically different (P > 0.05). The coastal station also had higher Chl-a concentrations (0.52–3.83 µg l−1) compared to the offshore station (0.63–2.55 µg l−1), not significant (P > 0.05). Our results are consistent with other studies and indicate that the southern Black Sea is shifting towards mesotrophy with the increasing prevalence of dinoflagellates compared to diatoms.

scholarly journals Population parameters of the pontic shad, Alosa immaculata Bennett, 1835 in the Fatsa coast of the south-eastern Black Sea

2019 ◽  
Vol 36 (4) ◽  
pp. 319-324
Author(s):  
İsmet Balık
Keyword(s):  
Black Sea ◽  
Maximum Yield ◽  
Total Mortality ◽  
Reference Points ◽  
Growth Equation ◽  
Fishing Mortality ◽  
Population Parameters ◽  
The South ◽  
South Eastern ◽  
Exploitation Rate

The aim of this study is to estimate population parameters of pontic shad, Alosa immaculata Bennett, 1835 in the Fatsa coast of the south-eastern Black Sea. A total of 314 pontic shad specimens were collected from study area using artisanal fishing gears from March 2013 to February 2014. In the study, parameters of the von Bertalanffy growth equation were found as L∞=43.05 cm; k=0.430 per year and t0=-0.451 year. The growth performance index (Φ') was estimated as 2.90. The total mortality (Z), natural mortality (M), fishing mortality rates (F) were calculated as 1.33 year-1, 0.75 year-1 and 0.58 year-1, respectively. The annual instantaneous fishing mortality rate was greater than both the target (Fopt=0.375 year-1) and limit (Flimit=0.50 year-1) biological reference points. Similarly, the present level of exploitation rate (E=0.43) was higher than the exploitation ratio for maximum yield per recruit (Emax=0.375) suggesting that overexploitation occurred. These results showed that this species has been over-exploited in the Fatsa coast of the south-eastern Black Sea. Measures should be taken to reduce the current exploitation rate for sustainable fishing of pontic shad in the Fatsa coast of the south-eastern Black Sea.

scholarly journals Seasonal changes in abundance, lipid and fatty acid composition of Calanus euxinus in the South-eastern Black Sea

2017 ◽  
Vol 64 (3) ◽  
Author(s):  
N. Sen Ozdemir ◽  
A. M. Feyzioglu ◽  
F. Caf ◽  
I. Yildiz
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Black Sea ◽  
Lipid Content ◽  
Seasonal Changes ◽  
Total Lipid Content ◽  
Trophic Levels ◽  
The South ◽  
South Eastern

Seasonal changes in abundance, lipid and fatty acid composition of Calanus euxinus Hulsemann, 1991 were analysed monthly during the period from March 2012 to February 2013. The highest abundance of C. euxinus was recorded in February (847 ind. m-3) during the sampling period. Female and male C. euxinus peaked in February (587 ind. m3, 169 ind. m-3, respectively). However, copepodites peaked in November (107 ind. m-3). Average total lipid content was determined as percentage (%) and per individual (mg ind-1). It was proportionally highest in February (7.03%) and lowest in September (3.02%). However, average lipid content per individual was highest in February (0.11 mg ind-1) and lowest in September and November (0.04 mg ind-1). Major fatty acids in C. euxinus were identified as 16:0, 16:1 n-7, EPA and DHA. ΣSFA, ΣMUFA, ΣPUFA and ΣHUFA were observed to be correlated with temperature. ΣSFA and ΣMUFA increasedwith the rise in temperature (r2=0.74, r2=0.73, p<0.05, respectively) whereas ΣPUFA and ΣHUFA increased as temperature decreased (r2=-0.73, r2=-0.80, respectively, p<0.05). Additionally, while ΣPUFA and ΣHUFA increased (r2=0.61, r2=-0.68, respectively, p<0.05), ΣMUFA decreased (r2=-0.68, p<0.05) as chlorophyll-a increased. It was observed that the degree of unsaturation increased as temperature decreased. Results of the study revealed that C. euxinus has rich lipid content as well as fatty acid composition and it plays an important role in the South-eastern Black Sea ecosystem functionalities especially having key role in energy fluxes to higher trophic levels.

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