Marine larvae...how much do we know?

[Aframomum]

Hi there,

Just thought I'd add something that I have been noticing in some of the negative posts about your salts metals' assay: many people seem to think that since you used sea urchin larvae, that the results don't correlate to any other larval survival, esp. with animals we normally raise in our tanks. I feel this is a misunderstanding amoung the reefing community and perhaps an article is in order to explain the common delicate nature shared by species in their larval stages. I did a quick search and found a few threads on marine larvae:

http://life.bio.sunysb.edu/marinebio/larvae.html
http://raven.zoology.washington.edu/embryos/embryos.html
http://www.euronet.nl/users/janpar/virtual/ocean.html

Mark

 

[rshimek]

Hi Mark,

[thanks]

The larvae of this particular species are some of the best known and well-studied animals in the world; rather like a subtidal lab rat... They have been studied in detail for well over 130 years, and much of what we know of classic embryology (including human embryology) has been found by studying these particular wee beasties.

I included in the article a link to the Woods Hole site that discusses these larvae (albiet, I would bet money that the number of people that looked at that site would be less than the fingers of one hand).

In essence in a study such as this, the larvae are like the old time canaries in a coal mine.

 

[Aframomum]

I apologize for I am one that did not take note of the link, I wonder if it was grad students that did the intense hour by hour description of the fertilized egg development. It would be interesting if anyone in a graduate program in marine biology would cater to conduct a project involving the same type of hour by hour observation that Harvey conducted on the A. punctulata . I think some of the species to test would be some of the common species found in our tanks that reproduce regularly, such as Nassarius snails, bristle worms, mysis shrimp - animals that do not require special requirments for obtaining specimens. As has been mentioned before, a control is needed to compare the results with and I feel taking some of the burden of testing off of your shoulders would be a kind jester.

Mark

P.S. - I would be thrilled to conduct such an experiment but am only an undergraduate student in the clinical laboratory program and do not think it would be a smart move to bring invertebrate larvae into a microbiology lab.

 

[rshimek]

Originally posted by Aframomum

Hi Mark,

I apologize for I am one that did not take note of the link, I wonder if it was grad students that did the intense hour by hour description of the fertilized egg development.

It was initially done as the primary research of several scientists, in effect the early work was the life's work of several folks.

It would be interesting if anyone in a graduate program in marine biology would cater to conduct a project involving the same type of hour by hour observation that Harvey conducted on the A. punctulata.

It is actually done frequently, and in fact that kind of observation is the basis of marine invertebrate embryology courses at numerous schools. I have done it, and I require it of my students, on occasion. In fact, the first laboratory exercise my invertebrate zoology students will do this summer at the Bamfield Marine Station will be an hour by hour comparison of embryonic development of a feather duster worm, and a sea urchin. The lab will run for a couple of days to get the embryos well into the feeding larval stages (after which they will be flushed down the sea water drains back into the bay).

The work is not generally difficult, but it is painstaking, and there are some obstacles that may need to be overcome (such as inducing spawing). One of the reasons that sea uchins are often used in bioassays is that they may be "spawned on demand," and while no single species is available that is "ripe" all year round, there are enough species available that the tests can be done at any time of the year. Also the urchins have been studied so intensely that deviations from normality can be noted pretty easily.