通过温度、物种属性和形态特征预测热带珊瑚鱼类的碳酸盐排泄和矿物成分
Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes
作者：Mattia Ghilardi, Michael A. Salter, Valeriano Parravicini, Sebastian C. A. Ferse, Tim Rixen, Christian Wild, Matthias Birkicht, Chris T. Perry, Alex Berry, Rod W. Wilson, David Mouillot, Sonia Bejarano
期刊：Nature Communications
Anthropogenic pressures are restructuring coral reefs globally. Sound predictions of the expected changes in key reef functions require adequate knowledge of their drivers. Here we investigate the determinants of a poorly-studied yet relevant biogeochemical function sustained by marine bony fishes: the excretion of intestinal carbonates. Compiling carbonate excretion rates and mineralogical composition from 382 individual coral reef fishes (85 species and 35 families), we identify the environmental factors and fish traits that predict them. We find that body mass and relative intestinal length (RIL) are the strongest predictors of carbonate excretion. Larger fishes and those with longer intestines excrete disproportionately less carbonate per unit mass than smaller fishes and those with shorter intestines. The mineralogical composition of excreted carbonates is highly conserved within families, but also controlled by RIL and temperature. These results fundamentally advance our understanding of the role of fishes in inorganic carbon cycling and how this contribution will change as community composition shifts under increasing anthropogenic pressures.
Fig. 5 | Family-level correlations among the probabilities of excretion of five carbonate polymorphs by reef fishes. Estimates are posterior medians and 95% credible intervals of correlation coefficients derived from 6,000 posterior draws of a Bayesian multivariate hurdle-lognormal model after controlling for temperature and relative intestinal length (Eq. 9). LMC, low-magnesium calcite; HMC, highmagnesium calcite; MHC, monohydrocalcite; ACMC, amorphous calcium magnesium carbonate. Data underlying the figures are available in the Zenodo repository.
人类活动的压力正在重塑全球珊瑚礁。为合理预测关键珊瑚礁功能的预期变化，需充分了解其驱动因素。本文聚焦一项由海洋硬骨鱼类维持的生物地球化学功能，即肠道碳酸盐排泄，研究了其决定因素。虽然相关研究较为缺少，但该功能却十分重要。本文通过收集382条珊瑚礁鱼（样本隶属85种、35科）的碳酸盐排泄率和矿物成分数据，发现了可预测这两项数据的环境因素和鱼类特征。本文发现，鱼类体重和相对肠道长度（relative intestinal length, RIL）是碳酸盐排泄的最强预测指标。同体积较小、肠道较短的鱼类相比，体积更大和肠道更长的鱼类每单位质量排泄的碳酸盐比例很少。同一鱼类种群中，排泄碳酸盐中的矿物成分得以高度保留，但也受到相对肠道长度（RIL）和温度的控制。以上结果从根本上进一步促进我们了解鱼类在无机碳循环中的作用，以及这一作用在未来日益增长的人类活动压力会如何随着鱼类群落构成发生变化。
