Does nutrient enrichment contribute to coral bleaching? A Fijian case study

Coral bleaching;Nutrient enrichment;Multiple stressors;Fiji

Miller, Ellen ; Savage, Candida ; Davy, Simon

University of Otago

关键词: Coral bleaching;    Nutrient enrichment;    Multiple stressors;    Fiji;   

Others  :  https://ourarchive.otago.ac.nz/bitstream/10523/4456/1/MillerEllen2013MSc.pdf

美国|英语

来源: Otago University Research Archive

【 摘 要 】

This study investigated the effects of nutrient enrichment and thermal stress on the cellular and photosynthetic response of a dominant, reef-building coral in Fiji. Porites cylindrica corals were collected from Votua, Fiji, placed in individual mesocosms, and enriched with one of three concentrations of labelled nitrate (15NO3-) for two weeks.Then, colonies were gradually heated above the identified bleaching threshold for Fijian corals for a final seven days.Stable isotope values confirmed that enrichment had a significant impact on symbiotic algal populations (Symbiodinium spp.) within P. cylindrica colonies, and demonstrated rapid uptake and cycling of nutrients between algae and coral host.Regression analysis showed a strong, positive relationship between algae populations and nitrate concentration exposure.While no visual bleaching events were observed in this experiment, there was a tendency for corals in highly enriched seawater to lose proportionately more symbiotic algae than control samples after exposure to heat stress, suggesting greater potential for bleaching events in nutrient-enriched waters.