Intertidal physiology

A place for questions and discussion on physiological adaptations and their responses to intertidal life (in Sea Slugs).

Authorship details
Rudman, W.B., 2000 (March 28) Intertidal physiology. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

Re: Heat shock in sea slugs

April 2, 2000
From: Roni Rogers

I just wanted to send out a thank you to Bill, Cynthia and Dave for responding to my question. The study I am doing is for an undergraduate project out at the Bodega Harbor Mudflats. If I find out anything interesting I will let you know.

Roni Rogers

Rogers, R., 2000 (Apr 2) Re: Heat shock in sea slugs. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Roni,
Look forward to your results,
Bill Rudman.

Re: Heat shock in sea slugs

March 28, 2000
From: Cynthia D. Trowbridge

Dear Roni and Bill,

Hi. Our lab group (Menge/Lubchenco) has been looking at environmental stress, including heat stress, on intertidal species for many years. Some people have looked at heat shock proteins; others have looked at RNA:DNA ratios in mussels, whelks, littorines, etc.; still others have taken ecological approaches. There is a theoretical paper on the ecological consequences of stress in terms of interspecific interactions (competition, herbivory, etc.):

Bruce Menge & Annette Olson (1990) in Trends of Ecology and Evolution (sorry, I can't recall the title).

In terms of opisthobranchs, I have a paper on desiccation stress and how it affects ascoglossan-algal interactions (Placida dendritica in Oregon & New Zealand plus Elysia viridis in Scotland):
•Trowbridge, C.D. (1998) Stenophagous, herbivorous sea slugs attack desiccation-prone, green algal hosts (Codium spp.): Indirect evidence of prey-stress models (PSMs)? J. Exp. Mar. Biol. Ecol. 230: 31-53.

It is one of the first demonstrations that desiccation-stressed seaweeds are more vulnerable to herbivore attack than unstressed conspecifics. Although the mechanism is common in terrestrial systems, there are few recorded cases for marine systems.

In terms of the nudibranch you ask about, [Hermissenda crassicornis] in Oregon it is common intertidally during daytime low tides on emergent substrata. During the summer, we generally have periodic upwelling so animals are not highly stressed during low tides. On days (and even summers) when upwelling does not occur frequently, the intertidal zone really gets damaged by desiccation stress. Whether it is due to heat stress, high light stress, water-loss stress, or some combination of the three remains to be understood.

Stress can compromise chemical and structural defenses of species. As Bill said, I am not clear why you are asking about how stress would affect predation by conspecifics. If you were asking how stress affects fish and crab predation on nudibranchs or affects interspecific competition among slugs for food resources, I would consider those excellent ecological questions. Anyway, good luck with your project.



Trowbridge, C., 2000 (Mar 28) Re: Heat shock in sea slugs. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Re: heat shock studies

March 28, 2000
From: Dave Behrens


Concerning your message: Years of studies have been done on several dozen intertidal species at the Thermal Effects lab at the Diablo Canyon Nuclear Power Plant, in Central California. The Cal State University, San Luis Obispo, library has all the reports. Black and Red abalone were among the species, but I am sure no
Branch's were studied.

I think I can get you in touch with someone that might be able to help you, if you are interested.

Dave Behrens

Behrens , D., 2000 (Mar 28) Re: heat shock studies. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Heat shock in sea slugs

March 27, 2000
From: Roni Rogers

I am doing a project on Hermissenda crassicornis to see if heat stress during low tides affects their ability to defend themselves against other members of their own species. Has any research ever been done with this organism or any other intertidal species? I have only found one paper on barnacles.

Roni Rogers.

Rogers, R., 2000 (Mar 27) Heat shock in sea slugs. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Roni,
There has been a lot of work done over the years on heat stress, effect of heat etc on intertidal animals but its a bit outside the scope of the Sea Slug Forum. Most animals subject to stress in the intertidal are those which are uncovered at lowtide which is not the case with most intertidal sea slugs which live in tidepools. A very few sacoglossan sea slugs live in very high tidal pools which heat up at low tide but these are able to stand quite high temperatures.

Hermissenda crassicornis doesn't fit into that category. I can't imagine under normal conditions that it would experience heat stress. I also didn't know it was considered to be in grave danger of attack from other members of its own species. Quite a few glaucid aeolids will attack others of their own species in captivity, but this is probably a consequence of being kept in artificial, unnatural conditions of overcrowding.

Have you any evidence that Hermissenda suffers heat stress in natural conditions or that it attacks others of its own species? If you haven't, I can't quite see the point of the experiment.

Best wishes,
Bill Rudman.

Rudman, W.B., 2000 (Mar 27). Comment on Heat shock in sea slugs by Roni Rogers. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from