more on A cervicornis experiments

[Juan Torres]

Dear Coral Listers:
Here is more information regarding my experiments with A cervicornis that
might answer some of the questions that were asked. Sorry I didn't give it
before.
1) The main reason of the experiment is to measure the effect of enhaced UV
radiation on two coral species: A cervicornis and P furcata. Even though I
have had these problems with A cervicornis, I did not have any problems with
P furcata. The samples from both species were collected from the same depth
at the reef (1-1.5m), tied to wire frames which are covered with plastic,
and kept acclimatizing on the reef at <1m depth for a month. After the month
they were inspected and all the colonies from both species were perfectly
fine. All  the corals were placed in the aquariums less than 30 minutes from
removing them from the reef and were maintained with aereation during the
trip to the aquariums. The aquariums have a 30 gallon capacity and only 3-4
colonies with between 6-8 branches were put inside each aquarium.
The aquariums were not covered with any mesh or shading cloth because the
PAR and UV light regime measured were similar to the ones measured from they
were ketp acclimatizing. The control aquariums are being kept under normal
(no shading) sunlight and others are under UV lamps which are turned on only
two hours during the day (between 11:00am-1:00pm) which results in an
average 5% increase in the dose the control ones are recieving. Other
aquariums are under a Hyzod panel that filters 99% of the UV radiation
reaching the aquariums. Yet, I might try covering the aquariums with some
mesh and see if this results.
2) This is an open water system, the salinity has been monitored and is
between 34-35ppt all the time, and the temperature measured with HOBO
thermometers fluctuates between 27oC at night and 29.5oC at noon, which
compares to the temperature that is currently being measured at the reef
where they were removed (between 26.7-30oC). We have not made analysis on
nutrients.
3) I believe, after reading Julian Sprung's e-mail, that it may be both
bleaching and RTN happening since it begins with a discoloration of the
colonies and after 1-2 days the tissue can be seen to hang from the skeleton
in most of the colonies.
Yet, I sincerely appreciate all the information posted and any other will be
greatly appreciated too!
Regards,
Juan L. Torres
University of PR
Dept. of Marine Sciences

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