College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
Curr Biol. 2019 May 6;29(9):1521-1527.e6. doi: 10.1016/j.cub.2019.03.044. Epub 2019 Apr 18.
Coral reefs harbor high productivity in nutrient-poor tropical oceans. This exceptional productivity can be explained by high recycling rates [1, 2], deep-water nutrient enrichment [3], and assimilation of external production [4]. Fishes consume this productivity through multiple trophic pathways and, as a result, dominate consumer biomass. Their reliance on pelagic versus benthic productivity pathways has been quantified from the tissues of individual fish [5, 6], but the contribution of different energetic pathways to the total productivity of coral reef fish assemblages remains unquantified. Here, we combined high-resolution surveys and individual biomass production estimates to generate the first energetic map of a full coral reef fish assemblage, from the smallest to the largest fishes [7, 8]. We found that the windward section of a coral reef on the Great Barrier Reef delivered an average fish productivity of 4.7 kg ha day, of which 41% was derived from water column photosynthesis, 29% by the epibenthic reef surface, 14% from cryptobenthic microhabitats, and 11% from adjacent sandy areas. The critical energetic contribution of pelagic subsidies would remain undetected if considering fish standing biomass alone, because the high productivity of reef planktivores originated from a relatively small biomass. Importantly, this study took place on a reef with only ∼6% of coral cover following multiple coral mortality events. Thus, our study offers hope that reefs subject to coral loss can still maintain considerable fish productivity, with planktivorous fishes providing major pelagic subsidies.
珊瑚礁在营养贫瘠的热带海洋中具有很高的生产力。这种非凡的生产力可以通过高回收率[1,2]、深水营养富集[3]和外部生产力的同化[4]来解释。鱼类通过多种营养途径消耗这种生产力，因此在消费者生物量中占主导地位。它们对浮游生物与底栖生产力途径的依赖已经从个体鱼类的组织中得到了量化[5,6]，但不同能量途径对珊瑚礁鱼类群落总生产力的贡献仍未量化。在这里，我们结合了高分辨率的调查和个体生物量生产估计，从最小到最大的鱼类[7,8]，生成了第一个完整珊瑚礁鱼类群落的能量图。我们发现，大堡礁的珊瑚礁迎风区的鱼类平均生产力为 4.7 公斤/公顷/天，其中 41%来自水柱光合作用，29%来自附生礁表面，14%来自隐生微生境，11%来自相邻的沙质区。如果只考虑鱼类的现存量，浮游生物的补充对能量的关键贡献将无法被发现，因为礁区浮游动物的高生产力源于相对较小的生物量。重要的是，这项研究是在一个珊瑚覆盖率只有约 6%的珊瑚礁上进行的，这个珊瑚礁已经经历了多次珊瑚死亡事件。因此，我们的研究表明，即使珊瑚礁失去了珊瑚，仍然可以维持相当高的鱼类生产力，浮游食性鱼类为主要的浮游生物补充。
