Calcification rate and the stable carbon, oxygen, and nitrogen isotopes in the skeleton, host tissue, and zooxanthellae of bleached and recovering Hawaiian corals
Calcification rate and the stable carbon, oxygen, and nitrogen isotopes in the skeleton, host tissue, and zooxanthellae of bleached and recovering Hawaiian corals
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DOI：
10.1016/j.gca.2006.02.014
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发表时间：
2006-06-01
影响因子：
5
通讯作者：
Grottoli, Andrea G.
中科院分区：
文献类型：
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作者：
Rodrigues, Lisa J.;Grottoli, Andrea G.
我们测试了稳定同位素作为珊瑚白化及恢复过程中生理变化记录者的有效性。将团块滨珊瑚（Montipora capitata）和扁缩滨珊瑚（Porites compressa）的碎片置于室外水箱中，将海水温度升高至30℃（处理珊瑚）持续一个月使其白化。另外的碎片在单独的水箱中保持在27℃（对照珊瑚）。一个月后（恢复0个月），测量其浮力重量，并将一部分碎片冷冻。剩余的碎片放回珊瑚礁进行恢复。在1.5个月、4个月和8个月后，收集碎片，测量浮力重量并冷冻。分析碎片的骨骼稳定碳、氧同位素组成（δ¹³Cₛ；δ¹⁸Oₛ）以及宿主组织（δ¹⁵Nₕ；δ¹³Cₕ）和虫黄藻（δ¹⁵Nₛ；δ¹³Cₛ）的氮、碳同位素组成。团块滨珊瑚白化后，其δ¹³Cₛ立即下降，但扁缩滨珊瑚没有。两种珊瑚的δ¹⁸Oₛ都没有记录到变暖事件。在恢复的其余几个月中，由于在此期间钙化作用和代谢分馏降低，处理珊瑚的δ¹³Cₛ和δ¹⁸Oₛ比对照珊瑚更富集。处理组扁缩滨珊瑚的δ¹⁵Nₕ升高可能是由于在白化和恢复过程中虫黄藻被排出。两种珊瑚处理组碎片在1.5个月时δ¹⁵Nₛ升高反映了为促进有丝分裂细胞分裂和/或叶绿素a/细胞恢复而增加了对溶解无机氮的吸收。处理组团块滨珊瑚在1.5个月时δ¹³Cₕ和δ¹³Cₛ的变化表明，相对于光合固定碳，异养获取的碳大幅增加。我们通过实验表明，珊瑚骨骼、宿主组织和虫黄藻中的同位素可用于验证白化和恢复过程中的生理变化，但它们作为骨骼记录中过去白化事件的替代指标的用途是有限的。（c）2006爱思唯尔公司。保留所有权利。
We tested the effectiveness of stable isotopes as recorders of physiological changes that occur during coral bleaching and recovery. Montipora capitata and Porites compressa fragments were bleached in outdoor tanks with seawater temperature raised to 30 degrees C (treatment corals) for one month. Additional fragments were maintained at 27 degrees C in separate tanks (control corals). After one month, (0 months recovery), buoyant weight was measured and a subset of fragments was frozen. Remaining fragments were returned to the reef for recovery. After 1.5, 4, and 8 months, fragments were collected, measured for buoyant weight, and frozen. Fragments were analyzed for stable carbon and oxygen isotopic compositions of the skeleton (delta C-13(s); delta O-18(s)) and nitrogen and carbon isotopic compositions of the host tissue (delta N-15(h); delta C-13(h)) and zooxanthellae (delta N-15(z); delta C-13(z)). delta C-13(s) decreased immediately after bleaching in M. capitata, but not in P. compressa. delta O-18(s), of both species failed to record the warming event. During the remaining months of recovery, delta C-13(s) and delta O-18(s) were more enriched in treatment than control corals due to decreases in calcification and metabolic fractionation during that time. Increased delta N-15(h) of treatment P. compressa may be due to expelled zooxanthellae during bleaching and recovery. Increased delta N-15(z) at 1.5 months in treatment fragments of both species reflects the increased incorporation of dissolved inorganic nitrogen to facilitate mitotic cell division and/or chl a/cell recovery. Changes in delta C-13(h) and delta C-13(z) at 1.5 months in treatment M. capitata indicated a large increase in heterotrophically acquired carbon relative to photosynthetically fixed carbon. We experimentally show that isotopes in coral skeleton, host tissue and zooxanthellae can be used to verify physiological changes during bleaching and recovery, but their use as a proxy for past bleaching events in the skeletal record is limited. (c) 2006 Elsevier Inc. All rights reserved.