Thesis
The lethal and sublethal effects of selected trace metals on various life stages of scleractinian corals
Southern Cross University, School of Resource Science and Management
Doctor of Philosophy (PhD), Southern Cross University
1998
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Abstract
The effects of trace metals including copper, lead, nickel, zinc and cadmium,· on the fertilization success, larval survival, larval motility, larval settlement and gamete development of several species of scleractinian corals were investigated in this study. Studies were also done on the uptake of copper and zinc by adult corals and the metal partitioning between the symbiotic zooxanthellae, tissue, gametes and skeleton.
Copper was the most toxic metal tested for all life stages of corals. Copper ECso values for coral fertilization success were between 14.93 μg/L and 39.69 μg/L. The motility of coral larvae and larval settlement success were both inhibited by copper at similar concentrations to those that inhibited fertilization success. Larval survival was not greatly affected by copper up to 24 hours exposure and LCso values were 248 μg/L to 260 μg/L for 6 hours and 121 μg/L to 136 μg/L for 24 hours. After longer exposures to copper the LC50 values for larval survival (34.08 μg/L to 87 .31 μg/L) were more similar to the ECso values for larval motility for the same exposure times (21.91 μg/L).
Lead was also toxic to coral fertilization success and ECso values were between 1453 μg/L and 2467 μg/L. The lead ECso values for larval motility (72 hour 2900 μg/L) were similar to values for fertilization success, however larval survival was much less sensitive at all exposure times and the 72 hour LCso value was 9890 μg/L. Other metals tested including zinc, nickel and cadmium were less toxic to fertilization success, larval motility and larval. survival than lead or copper.
Copper was also toxic at low concentrations to adult corals and short exposures (up to 64 hours) of low concentrations of copper (2 μg/L to 200 μg/L) affected gamete development. In addition, analysis of metal concentrations in zooxanthellae indicate that they are likely to play an important role in the uptake and loss of trace metals in corals.
This is the first detailed study of trace metal toxicity to early life stages of scleractinian corals and it clearly shows that very low concentrations of some trace metals affect critically important life stages of scleractinian corals. Repeated successful spawning years are necessary for long term maintenance of reef coral populations, and therefore quantifying the effects of contaminants on fertilization success, larval survival and larval settlement is important. This study provides new baseline information for managers and policy makers on the effects of metals on sensitive life stages of scleractinian corals, and therefore makes useful contributions for determining biologically appropriate water quality criteria and waste discharge levels in coral reef areas.
The techniques used and developed in this study are sensitive, cost effective and they provide meaningful data on critical developmental life stages of scleractinian corals. These techniques can be used for determining the toxicity of other pollutants and combinations of pollutants to corals in the future.
Details
- Title
- The lethal and sublethal effects of selected trace metals on various life stages of scleractinian corals
- Creators
- Amanda Jean Reichelt-Brushett
- Contributors
- Peter L Harrison (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Doctor of Philosophy (PhD)
- Theses
- Doctor of Philosophy (PhD), Southern Cross University
- Publisher
- Southern Cross University, School of Resource Science and Management
- Number of pages
- xviii, 231
- Identifiers
- SCU1479; 991012821293502368
- Copyright
- © Amanda J Reichelt-Brushett 1998
- Academic Unit
- Faculty of Science and Engineering
- Resource Type
- Thesis