Physiological and ecological studies of Calanus euxinus (Hulsemann) from the Black Sea with comments on its life cycle

Arashkevich, E
Svetlichny, L
Gubareva, E
Besiktepe, S
Gücü, Ali Cemal
Kideys, AE
Ecological and physiological study of Calanus euxinus population from the Black Sea was carried out during the cruise of RN Bilim in Autumn 1996. The population was divided into two: active individuals, represented by all developmental stages, and diapausing CVs. The active CIV-CVIs underwent daily vertical migrations, while the diapausing CVs stayed at depth all day long. The population seemed to reproduce actively indicated by the large number of eggs and nauplii in the samples as well as the large proportion of spawning females (up to 80% of the total number of adult females). Egg production rate ranged from 5 to 25 eggs/female/day. The percentage of copepods with food changed with location and time; at night it varied from 10 to 97 in the upper layer, being less than 1 at the depth. Food remains was never observed in the guts of diapausing CVs. Up to 60% of gut in the upper layer, being less than 1 at the depth. Food remains was never observed in the guts of diapausing CVs. Up to 60% of gut contents consisted debris. The recognizable remains were parts of crustacean exoskeleton and dynoflagellates 10-60 mkm in size.Shipboard feeding experiments showed extremely low consumptions of chlorophyll (2.39-7.41 ng/ind/d in CVs and 5.67-14.33 ng/ind/d in females). The analysis of size classes distribution allowed the distinction of two groups among both diapausing and active CVs pointing on the heterogenity of the population. No difference between the length of males and females CVs was found. The state of gonad development differed between active and diapausing CVs. In the former gonad size ranged from 0.075 to 0.65 mm, in the latter small (0.1-0.15 mm) gonads before sex differentiation prevailed. An increase in gonad size was accompanied by a decrease in oil content. The active and diapausing CVs differed in their motor activity, respiration and excretion rates. Relationships between these indices and oxygen concentration were obtained. Under all oxygen concentrations studied, the indices for active CVs were higher than for diapausing CVs by a factor of 2 or 3.


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In October 2005 spatial distribution of live and dead Acartia clausi and Acartia tonsil was studied in the Black and Marmara Seas and near the Marmara Sea inlet of the Bosphorus, in order to understand their fate upon transportation between two seas. The morphometric characteristics in both species from all studied areas, and the decreased abundance of A. clausi and A. tonsa from the Black Sea towards the Marmara Sea indicate that the Marmara Sea Acartia populations are formed by recruitment from the Black ...
Development of Calanus euxinus during spring cold homothermy in the Black Sea
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In copepodites and adults of Calanus euxinus abundance, body length and weight, chemical composition and respiration rate in relation to age were studied during the cruise of R/V 'Knorr' in April 2003 in the southwestern Black Sea and in laboratory experiments. Data on morphology and physiology of C. euxinus collected during other seasons were also used in comparative analyses. At high concentrations of the diatom Proboscia alata during spring homothermy (6.8 to 8.5 degrees C) C. euxinus did not undertake d...
Vertical distribution of marine cyanobacteria Synechococcus spp. in the Black, Marmara, Aegean, and eastern Mediterranean seas
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The vertical distributions of the unicellular cyanobacteria Synechococcus were studied in several highly contrasting seas: the Black Sea, Sea of Marmara, Aegean Sea, and Mediterranean Sea. Cell abundances varied significantly on both vertical and horizontal scales in all physically and spatially discrete water masses. Epifluorescence microscope cell counts from all seas clearly showed that majority of the population remains suspended in the surface-mixed layer and decreases gradually towards the base of the...
Citation Formats
E. Arashkevich, L. Svetlichny, E. Gubareva, S. Besiktepe, A. C. Gücü, and A. Kideys, “Physiological and ecological studies of Calanus euxinus (Hulsemann) from the Black Sea with comments on its life cycle,” 1998, vol. 47, Accessed: 00, 2020. [Online]. Available: