A second series was composed of three heads each of Montastrea annularis , 

 Montastrea cavernosa , Agaricia agaricites , and Meandrina meandrites . 

 These were dosed with 1 ppm, 100 ppb, and concentrations of the 

 organochlorine mixture, and observations made on the response of predators 

 and symbionts to the dosed heads and on the coral's feeding behavior, 

 clearing of siltation, polyp expansion and contraction. Shallow holes were 

 drilled in these specimens, and coral tissue removed from 1/2" diameter 

 circles, to observe recruitment of invertebrates on the newly exposed sur- 

 face or repair of the breach by the coral. 



A third series of experiments was conducted on respiration of individual 

 coral heads. Corals were selected for undamaged condition, size (maximum 

 diameter 17.5 cm), ease of dislocation from the dead base, and absence of 

 associated invertebrates. The heads were gently pried free from their dead 

 bases and placed in the plexiglass respiration chamber. 



Because only one respiration chamber was available, we were unable to obtain 

 simultaneous comparisons between dosed and undosed heads, thereby insuring 

 identical light regimes. Rather, we obtained a respiration history of 48 

 to 72 hours for each head, dosed the heads with 1 ppm organochlorine mixture 

 for the standard 3 hour period, and recorded post-dose respiration for 24 

 to 96 hours. We recorded incident light at the site of the experiments, 

 and were able to compare oxygen uptake rates for both pre-dose (control) 

 and post-dose periods (1 to 3 hours) of identical incident light. Dark 

 period respiration rates were compared for time of night; day period rates 

 had to be compared for average incident light per hour- long periods because 

 of wide daily fluctuations in light level. 



Additional controls were run for each coral species to determine the effects 

 of pure, uncontaminated acetone on respiration rates. Coral heads were 

 subjected to as much as twice the quantities of acetone used in organochlorine 

 doses with no observable change in the base rate. 



At the termination of the acetone control runs, the coral tissue was removed 

 from the skeleton by jets of water from a dental Water-Pik, and the bare 

 coral skeleton again run in the respirometer . No oxygen uptake or generation 

 was observed. 



Because a closed respirometer was used, the chamber was manually opened and 

 flushed at 1 to 4 hour intervals. This is necessary because during daylight 

 hours, p02 increases to concentrations two to three times greater than 

 ambient, and at night nearly all the oxygen may be removed from the chamber. 



RESULTS 



Preliminary studies, done prior to the TEKTITE mission, included an analysis 

 of the present levels of organochlorines and experimental assessment of the 

 uptake rates in a coral (Acropora cervicornis) from Key West, and a non reef 

 forming coral from Woods Hole (Astrangia danae) . The Acropora had 3 to 12 

 ppb ( of total weight of tissue) DDT, 260 to 320 ppt dieldrin, and 200 to 320 

 ppt DDE plus PCBs . Astrangia showed detectable quantities of dieldrin only: 

 220 ppt. Both of these species rapidly concentrated an experimental dose of 

 these same types of organochlorines (pure recrystallized p, p'-DDT, dieldrin. 



VI-231 



