Looking for a new method to measure hidrodynamics (summary of answers)

[Marcos Soares Barbeitos]

        Dear coral-listers,

        Here goes a summary of the answers I received about my mail
searching for hidrodynamics measuring methods:

        I received 15 answers. Eight of them recomended plaster of Paris,
gypsum or chalk clods, cubes or spheres as the most appropriate way to
measure water movement. Greg Boland also suggested alabaster. The references
I received are listed below:

        Shashar, N., S. Kinane, P.L. Jokiel, and M.R. Patterson. 1996.
        Hydromechanical boundary layers over a coral reef. Journal of
        Experimental Marine Biology and Ecology. 199:17-28. 

        Doty, JE, and MS Doty.  1973.  Abrasion in the measurement of water
        motion with the clod-card technique: Bull. of S. Cal. Acad. of Sci.
v.27, pp
        40-41.

        Thompson T, and E Glenn.  1994.  Plaster standards to measure water
        motion: L&O 39:7 pp. 1768-1770.

        Jokiel, P. L. and J. I. Morrissey. 1993. Water motion on coral
        reefs: evaluation of the "clod card" technique. Mar Ecol Prog
        Ser 93:175-1993.

        Komatsu, T., and Kawai, H. (1992). Measurements of time-averaged
        intensity of water motion with plaster balls. Journal of
Oceanography 48,         353-365.

        Komatsu, T., and Murakami, S. (1994). Influence of a Sargassum
        forest on the spatial diatribution of water flow. Fisheries
Oceanography 3,
        256-266.        

Craig Bingman suggested this site, where I could find some more
references about this subject, and a description of the method:

        http://www.aquariumfrontiers.com/1998/aug/features/1/default.asp

Three alternative and interesting suggestions came from Hugh
Sweatman, David Obura and Ron Hill. Their answers were:

        Hugh Sweatman <hsweatma at email.aims.gov.au>

"It seems to me that a device that relies on venturi effects to draw dye
from a container through a standard aperture might be better.  I envisaged
using small vials [film containers?] filled with ink and having two
hypodermic needles sticking out of the top, one long one to allow the
currents to draw the ink out and one short to let the water in.  Then you
could use a colorimeter to measure dilution."

        David Obura <dobura at AfricaOnline.co.ke>

"I did see an interesting method used for released larval fish from cages
- they used doughnut shaped candies/sweets (lifesavers) to hold a door
closed so that after some time (not so long) the candy was dissolved,
releasing the door.  Maybe there is some hard and resistant (and cheap)
Brazilian candy that would work!!"

        Ron Hill <Ron.Hill at noaa.gov>

"Dr. Angie McGeehee tested a device that paired copper and zinc metals (to
measure galvanic corrosion) in reef areas.  The test units need to be calibrated
for your area and temperatures but the results were pretty good, and the overall
materials are relatively easy to put together.  I think she has a publication
out on the method, I can probably get a copy to send you or I can track down her
address for you to contact her directly.  Let me know if you are interested in
further information."

        Thanks a lot for your help, and I hope that this summary may help
you in your work

        Sincerely,

        Marcos Soares Barbeitos