The effects of nutrient status and thermal stress in the symbiotic sea anemone Exaiptasia pallida
| Author(s) | Brennan, Melanie Agnes | |
| Date Accessioned | 2020-02-13T14:14:01Z | |
| Date Available | 2020-02-13T14:14:01Z | |
| Publication Date | 2019 | |
| SWORD Update | 2020-02-03T13:23:56Z | |
| Abstract | Corals reefs are rapidly disappearing under the damage of exposure to high temperature caused by climate change, which results in bleaching (a loss of algal symbionts). Corals that feed heterotrophically on zooplankton display less stress under increased temperature and recover faster from bleaching events; however it is not understood how coral preacclimation to available nutrient levels (and in turn nutrient availability to symbionts) impacts thermal tolerance. The symbiotic sea anemone Exaiptasia pallida was exposed to two different feeding regimes: fed Artemia salina nauplii once weekly, or starved (unfed) for 31 days. In addition, another set of animals were withheld food, but were treated with low-levels of nitrate and phosphate (5 µM and 0.5 µM respectively). Anemones were subsequently heated to 32 ºC for an additional 10-14 days and continued nutrient treatment. During nutrient exposure, fed anemones maintained maximum quantum yield of photosystem II (Fv/Fm) and wet weight, while both unfed groups lost wet weight. Furthermore, starved anemones consumed more Artemia after 31 days of nutrient treatment. High temperature led to signs of bleaching stress, observed as a decline in symbiont density and a drop in Fv/Fm; however the percentage of carbon translocated to the host increased in starved anemones. Together, these results indicate that heterotrophic feeding gives symbiotic anemones a potential advantage in combating bleaching stress. However, the documented advantage of heterotrophic feeding to corals was increased symbiont density and photosynthetic efficiency of photosystem II, but in this study the observed advantage to sea anemones was maintenance of animal size and respiration rate. Understanding the ecological implications of how sessile marine invertebrates respond to bleaching will be key in understanding the ecological impacts of global warming on coral reefs. | en_US |
| Advisor | Warner, Mark E. | |
| Degree | M.S. | |
| Department | University of Delaware, School of Marine Science and Policy | |
| Unique Identifier | 1140447363 | |
| URL | http://udspace.udel.edu/handle/19716/25009 | |
| Language | en | |
| URI | https://search.proquest.com/docview/2307785130?accountid=10457 | |
| Title | The effects of nutrient status and thermal stress in the symbiotic sea anemone Exaiptasia pallida | en_US |
| Type | Thesis | en_US |