A System to Test the Effects of Air Exposure on Gelatinous Egg Masses in Simulated Intertidal and Subtidal Conditions
Many marine organisms deposit egg masses in the intertidal and subtidal. Their distribution determines the amount of air exposure they receive. Oxygen is one of the factors affecting embryo development in egg masses and is potentially provided more easily in air than in water. It has been predicted that there is no difference in the development rate of embryos in gelatinous egg masses exposed to air, as in the intertidal, or submerged, as in the subtidal. However, this prediction has never been assessed in either a laboratory or field study.
For a laboratory setting we designed and constructed a system in which to simulate the amount of air exposure occurring in the intertidal and subtidal. Our system consisted of two pumps connected to digital timers that simulated a tidal cycle in a tank. The intertidal and subtidal were represented by two grids placed at different heights in the tank. We developed a simple technique that allowed us to transfer egg masses deposited at other locations to the grids. We chose the nudibranch Dendronotus frondosus to test the prediction of no difference in development of embryos in intertidal and subtidal egg masses. We were unable to obtain egg masses from D. frondosus to use in our system. We successfully reached our primary objective by designing and constructing a cost efficient system to study the effects of air exposure on embryonic development in invertebrate egg masses.
Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant
- A system to test the effects of air exposure on gelatinous egg masses in simulated intertidal and subtidal conditions (2000). Darya Hahn and Marc Pellaud. Advisors: Chad Sisson and Larry Harris.