Thesis
Manganese and nickel uptake, depuration and toxicity in the sea anemone Exaiptasia pallida and Symbiodinium spp.
Southern Cross University
Master of Science (MSc), Southern Cross University
2022
DOI:
https://doi.org/10.25918/thesis.223
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Abstract
Manganese (Mn) is a ubiquitous trace metal that is essential to living organisms and valued for the production of steels and alloys. However, Mn is potentially toxic to marine organisms at elevated levels. Land-based anthropogenic activities such as mining and dry cell batteries release Mn waste and other associated metals, such as nickel (Ni), that can threaten the health of marine species. A review of the Australian and New Zealand water quality guidelines for Mn in marine waters has identified a chronic toxicity data gap for Cnidarians exposed to Mn. Also, the synergistic and other potential cumulative impacts with other metals such as Ni are unknown. The sea anemone Exaiptasia pallida belongs to the phylum Cnidaria along with coral and jellyfish and is suitable as a model for marine laboratory testing. To understand the effects of Mn on non-calcified cnidarian, I investigated the effects of Mn uptake and depuration in the anemone E. pallida tissue and the endo-symbiotic, dinoflagellate algae - Symbiodinium spp. as well as stress-response, determined by changes in tentacle length and symbionts density. Because Ni coexists with Mn in mine tailings, I also investigated Ni alone and in combination with Mn. The results showed that anemones can accumulate Ni and Mn in the tissue, but higher concentrations were measured in the Symbiodinium spp. after 12-and 24 d of Ni or Mn exposure. Manganese in the anemones did not elicit a significant reduction in the Symbiodinium spp. density after 12- and 24 d, but tentacle retraction was significantly higher in all treatments than in controls. Mn depuration in anemones depended on the exposure concentrations but was more rapid in the symbionts than in the host anemone tissue. These results also showed that E. pallida are more sensitive to Ni after 12 d of Ni exposure alone and in a mixture with Mn. There was significant dose-dependent retraction in tentacle length after 12 d of exposure to Ni alone and when mixed with Mn. Exposure of anemones to a combination of Ni and Mn for 12 d caused a significant reduction in the Symbiodinium spp. Still, no effects on cell density were observed in both single-exposure experiments. The response of anemones to Ni and Mn alone and combined adds to knowledge on the vulnerability of symbiotic cnidarians in metal-polluted environments. Furthermore, these results reveal the importance of testing metal effects in combination before establishing safe limits for marine invertebrates.
Details
- Title
- Manganese and nickel uptake, depuration and toxicity in the sea anemone Exaiptasia pallida and Symbiodinium spp.
- Creators
- Louis Iyagbaye
- Contributors
- Amanda Reichelt-Brushett (Supervisor) - Southern Cross UniversityKirsten Benkendorff (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Master of Science (MSc)
- Theses
- Master of Science (MSc), Southern Cross University
- Publisher
- Southern Cross University
- Number of pages
- xvi, 110
- Identifiers
- 991013053013602368
- Copyright
- © L Iyagbaye 2022
- Academic Unit
- Faculty of Science and Engineering
- Resource Type
- Thesis