Although resource availability is important for coral reef nutrient cycling and trophic ecology, it is poorly understood how particulate resources may change following an oceanic heat stress event. Here, carbon and nitrogen concentrations and stable isotope values (δ13C and δ15N) of particulate organic matter (POM; 10 and 30 m) were compared from before and after the 2016 mass coral bleaching event in the Maldives, Indian Ocean. To characterize the trophic status of the post-bleaching water column, dissolved inorganic nutrients across shallow to mesophotic coral reefs (10–50 m) and plankton δ13C and δ15N were measured. Eight months after the mass bleaching, an oligotrophic water column with decreased particulate organic nitrogen and variable yet increased mean δ13C of POM was observed. Elemental and isotopic data of particulate resources from pre- and post-bleaching revealed three oceanographic regimes related to ocean mixing. This study highlights the importance of characterizing water column biogeochemistry to understand nutrient cycling in coral reef ecosystems especially post-disturbance.

中文翻译：

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珊瑚白化事件后珊瑚礁水体的生物地球化学变异性和营养状态

尽管资源可用性对珊瑚礁养分循环和营养生态很重要，但人们对海洋热应激事件后颗粒资源可能如何变化知之甚少。在这里，比较了印度洋马尔代夫 2016 年大规模珊瑚白化事件前后的颗粒有机物（POM；10 和 30 m）的碳和氮浓度以及稳定同位素值（δ13C 和 δ15N）。为了表征漂白后水柱的营养状态，测量了浅层到中光珊瑚礁（10-50 m）和浮游生物 δ13C 和 δ15N 的溶解无机养分。大规模漂白后 8 个月，观察到一个贫营养水柱，其中颗粒有机氮减少，POM 的平均 δ13C 变化但增加。漂白前后颗粒资源的元素和同位素数据揭示了三种与海洋混合相关的海洋学制度。这项研究强调了表征水柱生物地球化学以了解珊瑚礁生态系统中营养循环的重要性，尤其是在受到干扰后。