Место издания:14th International Congress on Invertebrate Reproduction and Development Napoli
Первая страница:36
Последняя страница:36
Аннотация:In Arctic latitudes life cycles of marine organisms are adapted to annual
changes of temperature. Sexual reproduction is usually a seasonal event.
Each species builds gonads and produces gametes in a definite season. The
time of sexual reproduction of invertebrates usually depends on
environment. But medusozoan cnidarians prepare themselves for
reproduction in advance. Scyphozoan polyps and hydroids living on the
bottom substrata produce planktonic medusae which swim and feed to
growth and sexual reproduction. In my study I investigated life cycles of
hydrozoans and scyphozoans from the White Sea. Medusae and hydroids
with medusae buds were collected from the sea in different seasons of the
year. The annual experiments allowed to study life cycles of several species
in laboratory. As a result I determined the temperature which is needed for
medusae production in several species inhabiting the White Sea. Four
reproduction strategies were found in the studied species: 1) Species
producing medusae as a result of lowering the temperature (Catablema
vesicarium, Halitholus cirratus, Rathkea octopunctata, Bougainvillia superciliaris).
2) Species which need a long period of minimal temperature to produce
medusae (Cyanea sp., Aurelia aurita, Sarsia lovenii). 3) Species producing
medusae after a small increase of temperature in spring (Obelia longissima). 4)
Species producing medusae after increase the temperature to maximum in
summer (Stauridiosarsia producta). The results are useful to determine how
the climate changes affect marine populations.