摘要
在孤树岛礁(OTIR)进行的耗资数百万美元的营养富集对珊瑚礁的影响试验(ENCORE)表明,珊瑚礁营养负荷的增加对海藻生长的作用很少或几乎没有作用,海藻生长的增加可能对珊瑚礁的功能和稳定性的相关影响也是如此。然而,对OTIR礁湖中营养浓度与珊瑚礁建议营养阈值浓度(NTC)的比较表明,包括对照区在内的所有地区,在ENCORE期间营养呈饱和状态,所以,不要指望与海藻生长有关的测量在不同处理间会有任何差异。因此,ENCORE的结果对建议NTC提供了强有力的支持,同时也支持海藻生产力,继而是珊瑚礁功能对背景营养浓度的小变化敏感的生态原理。ENCORE的主要结论,即添加营养没有引起"原始的"OTIR从珊瑚群落向海藻占优势的礁转变,这一结论与在ENCORE末期进行试验的小环礁的礁壁和礁顶上有大量的大型海藻生长的事实矛盾。
The results from the multimillion dollar Enrichment of Nutrients on Coral Reefs Experiment (ENCORE) on One Tree Island Reef (OTIR) suggest that increased nutrient loads to coral reefs will have little or no effect on the algal growth rates and,hence,on the associated effects that increased algal growth might have on the functioning and stability of coral reefs. However,a comparison of the concentrations of nutrients within the OTIR lagoon with the proposed nutrient threshold concentrations (NTC) for coral reefs suggests that all sites,including the control sites,were saturated with nutrients during ENCORE,and,hence,one would not expect to get any differences between treatments in the algal-growth related measurements. Thus,ENCORE results provide strong support for the proposed NTCs and support the ecological principle that algal productivity and,consequently, the functioning of coral reefs are sensitive to small changes in the background concentrations of nutrients.The principal conclusion of ENCORE,namely that the addition of nutrients did not cause the 'pristine' OTIR to convert from coral communities to algal dominated reefs,is contrary to the fact that there was prolific macroalgal growth on the walls and crests of the experimental microatolls by the end of ENCORE.
