Efficiency of the transport system of the hydroid Dynamena pumila (L., 1758) under different abiotic impacts

Biology Bulletin Reviews. 2022. Vol. 12. No. 3. P. 266–278.

V. S. Dementyev, Marfenin N. N.

Abstract—In the article, the efficiency (range and volume) of the transport of food particles suspended in
hydroplasm along the stolon of the colonial hydroid Dynamena pumila inhabiting the littoral is determined
with respect to four environmental factors: the temperature (10, 15, 20, 25, 28°С), salinity (26, 20, 15, 10‰),
air exposure (duration 5, 10, 20, 30 min), and the presence or absence of water exchange. The capacity for
efficient transport is determined based on the estimated length of local hydroplasma flows that form a chain
continuous integral hydroplasmic flows. Local flows covering one or two stolon modules are theoretically
sufficient for the generation of joint extended hydroplasmic flows and are thus equally represented for almost
all values of the studied environmental factors, except for 28°C and 10‰. This means that the transport sys-
tem of D. pumila is equally effective in a wide range of temperature and salinity changes, as well as during
extended air exposure and the maintenance of colonies in stagnant water. The highest efficiency of colony
integration is achieved at 15–20°С, 26–20‰ and after air exposure for 5–10 min. In terms of the degree of
integration, there is almost no difference in the number of colonies in nonflowing and flowing conditions.
The transfer of colonies from one cuvette with water to another does not affect the intensity of the hydroplas-
mic flow system.

Keywords: temperatures, assessment of environmental factors, Salinity, air exposure, water exchange, digestion, distribution of food