The importance of zooplankton to the daily metabolic carbon requirements of healthy and bleached corals at two depths
The importance of zooplankton to the daily metabolic carbon requirements of healthy and bleached corals at two depths
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DOI：
10.1016/j.jembe.2008.09.015
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发表时间：
2008-12-15
影响因子：
2
通讯作者：
Grottoli, Andrea G.
中科院分区：
文献类型：
--
作者：
Palardy, James E.;Rodrigues, Lisa J.;Grottoli, Andrea G.
三种夏威夷珊瑚的漂白和未漂白碎片暴露在I米和6米深浮游动物的浓度增加和周围环境中，以确定浮游动物对珊瑚每日碳收支的贡献。记录了捕获的每个浮游动物的大小和分类分组，并确定了不同大小类别浮游动物的相对输入。利用一种改进的方法计算了异养对动物呼吸(CHAR)的贡献，该方法包括了所有大小类浮游动物的比例贡献。结果表明，物种、深度和漂白处理对珊瑚摄食率的比例影响在环境浮游动物浓度和增强浮游动物浓度之间没有显著差异。在所有评估的条件下，珊瑚捕获的浮游动物的大小和组合都相同，并且优先捕获下午400分以下的浮游生物。无论处于何种漂白状态，斑孔鱼的摄食率都随着深度的增加而增加。未漂白珊瑚的摄食率随深度的增加而增加，但漂白珊瑚的摄食率并不随深度增加。在深度范围内，相对于未漂白的碎屑，漂白的头状单孢子虫的摄食率增加，P压缩性降低，而R lobata的取食率保持不变。因此，珊瑚对同一干扰的摄食反应可能会有很大的不同。计算的CHAR值表明，浮游动物的异养碳在珊瑚的日碳收支中所起的作用比先前估计的要大得多，在健康时占某些珊瑚物种每日代谢碳需求的46%，在漂白时占147%。因此，在所有实验条件下，异养获取的碳对珊瑚的日碳收支做出了重要贡献。这些结果表明，自养和异养碳对珊瑚能量需求的相对重要性与珊瑚的漂白状态和环境有关，应该从100%光自养到100%异养的连续体来考虑。(C)2008爱思唯尔B.V.保留所有权利。
Bleached and non-bleached fragments of three species of Hawaiian corals were exposed to enhanced and ambient concentrations of zooplankton at I and 6 m depth to determine the contribution of zooplankton to the coral's daily carbon budget. The size and taxonomic grouping were recorded for every zooplankton captured and the relative input of zooplankton of different size classes was determined. The contribution of heterotrophy to animal respiration (CHAR) was calculated using an improved method that included the proportionate contribution of zooplankton from all size classes. Results show that the proportionate effects of species, depth and bleaching treatments on coral feeding rates were not significantly different between ambient and enhanced zooplankton concentrations. Corals captured the same size and assemblage of zooplankton under all evaluated conditions, and preferentially captured plankters smaller than 400 pm. Feeding rates of Porites lobata increased with depth regardless of bleaching status. Feeding rates of Porites compressa increased with depth in non-bleached corals, but not in bleached corals. Within depth, feeding rates of bleached Montipora capitata increased, P compressa decreased and R lobata remained unchanged relative to non-bleached fragments. Therefore, the feeding response of corals to the same disturbance may vary considerably. Calculated CHAR values show that heterotrophic carbon from zooplankton plays a much larger role in the daily carbon budget of corals than previously estimated, accounting for 46% of some coral species' daily metabolic carbon requirements when healthy and 147% when bleached. Thus, heterotrophically acquired carbon made an important contribution to the daily carbon budget of corals under all experimental conditions. These results suggest that the relative importance of autotrophic and heterotrophic carbon to a coral's energetic needs is mediated by a coral's bleaching status and environment, and should be considered on a continuum, from 100% photoautotrophy to 100% heterotrophy. (C) 2008 Elsevier B.V. All rights reserved.