. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SPONGE-CORAL ALLELOCHEMISTRY 235. Figure 2. After two hours of experimentally induced contact be- tween Agaricia lamarcki and Plakortis halichondroides (a, top), a bleached, necrotic area appears on the coral (b, bottom). (Salt River Canyon, St. Croix, 25 m depth; photograph by N. M. Targett). even over greater depth ranges (Porter and M uscatine, in prep.), and therefore these values for coral colonies in contact with sponges are indicative of unsustainable car- bon deficits. In all cases, the differences observed between c
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SPONGE-CORAL ALLELOCHEMISTRY 235. Figure 2. After two hours of experimentally induced contact be- tween Agaricia lamarcki and Plakortis halichondroides (a, top), a bleached, necrotic area appears on the coral (b, bottom). (Salt River Canyon, St. Croix, 25 m depth; photograph by N. M. Targett). even over greater depth ranges (Porter and M uscatine, in prep.), and therefore these values for coral colonies in contact with sponges are indicative of unsustainable car- bon deficits. In all cases, the differences observed between control and experimental coral oxygen flux patterns demon- strate significantly reduced photosynthetic capacity in coral colonies in contact with sponges or their metabo- lites. Therefore, the null hypotheses (no discernable effect) must be rejected for hypotheses (3) compensation point, (4) net production, (5) gross production, (6) noc- turnal respiration rate, and (7) integrated P/R ratio un- der either field conditions or idealized "cloudless day" illumination. Hypothesis (8) P/R ratio > is also falsi- fied. Other species of sponges (Agelas conij'era, Haliclona rubens, and 1'emngnla sp.) were also placed in contact with Agaricia lamarcki. They did not bleach the coral, thus indicating that mechanical irritation and pressure are not responsible for the effect observed with P. chondroides. Crude organic extracts were isolated from Plakortis halichondroides and coated onto synthetic cellulose pads, "tuffy ; When tied to living coral, these extract-soaked pads caused bleaching within 24 hours. Control pads (uncoated or coated with ether solvent only) produce no effect. While the exact nature of these organic compounds is still unknown, comparative thin layer chromatography of crude extracts from whole P. halichondroides and compounds isolated from waters surrounding uninjured Plakortis suggests that com- pounds in the surrounding water are the s
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
