A modern Sr/Ca‐δ18O‐sea surface temperature calibration for Isopora corals on the Great Barrier Reef
A modern Sr/Ca‐δ18O‐sea surface temperature calibration for Isopora corals on the Great Barrier Reef
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大堡礁等孢珊瑚的现代 Sr/Ca-δ18O-海面温度校准
DOI：
10.1002/2016pa002973
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
D. Potts
中科院分区：
文献类型：
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作者：
Logan D. Brenner;B. Linsley;D. Potts
等孔珊瑚（Acroporidae）是一个经常结壳的属，分支到亚块状珊瑚，在现代和化石印度-西太平洋珊瑚礁的许多浅生境中很常见。虽然丰富，但在古海洋学文献中基本上没有等孔菌。综合海洋钻探计划第325次远征从大堡礁（GBR）获取的大型孔隙岩的稀缺和等孔岩的丰富使古海洋学的注意力集中在等孔岩上。本文首次对Sr/Ca和δ 18o进行了独立的高分辨率定标，并证明了其与Porites记录的一致性。基于GBR南部Heron岛的5个现代等孔虫群落，建立了现代骨骼Sr/Ca-和δ 18 o -海表温度（SST）校准。将珊瑚Sr/Ca记录与月度海温数据配对，得到Sr/Ca-SST敏感性从（cid:1） 0.061±0.004（居中）到（cid:1） 0.083±0.007（原始）mmol/mol°C (cid:1) 1。这些敏感性处于已公布的孔隙值范围的中间，与大多数已公布的Isopora值重叠，（cid:1） 0.075±0.011至（cid:1） 0.065±0.011 mmol/mol°C (cid:1) 1。δ 18 O-SST敏感性范围为（cid:1） 0.184±0.014（中心）至（cid:1） 0.185±0.014（原始）‰°C (cid:1) 1，假设δ 18 O的所有季节变化都是由海温引起的。这些δ 18 O-SST灵敏度小于生物文石广泛接受的值（cid:1） 0.23‰°C (cid:1) 1，但处于高分辨率孔隙岩定义的灵敏度的上端，始终小于上述建立的值。我们的研究结果证实，在大型块状孔隙岩稀缺或不存在的栖息地，Isopora可以作为古海洋学记录的替代来源。
Isopora (Acroporidae) is a genus of often encrusting, branching to submassive corals that are common in many shallow habitats on modern and fossil Indo-West Paci fi c reefs. Although abundant, Isopora is largely absent from paleoceanographic literature. The scarcity of large Porites and the abundance of Isopora retrieved from the Great Barrier Reef (GBR) on Integrated Ocean Drilling Program Expedition 325 focused paleoceanographic attention on Isopora . Here we provide the fi rst independent high-resolution calibration of both Sr/Ca and δ 18 O for temperature analyses based on Isopora and demonstrate its consistency with Porites records. We developed modern skeletal Sr/Ca- and δ 18 O-sea surface temperature (SST) calibrations based on fi ve modern Isopora colonies from Heron Island in the southern GBR. Pairing the coral Sr/Ca record with monthly SST data yielded Sr/Ca-SST sensitivities from (cid:1) 0.061 ± 0.004 (centered) to (cid:1) 0.083 ±0.007 (raw) mmol/mol°C (cid:1) 1 based on reduced major axis regressions. These sensitivities are in the middle of the range of published Porites values and overlap most published values for Isopora , (cid:1) 0.075± 0.011 to (cid:1) 0.065 ±0.011 mmol/mol°C (cid:1) 1 . The δ 18 O-SST sensitivities range from (cid:1) 0.184 ±0.014 (centered) to (cid:1) 0.185 ±0.014 (raw) ‰ °C (cid:1) 1 , assuming that all seasonal variation in δ 18 O was due to SST. These δ 18 O-SST sensitivities are smaller than the widely accepted value of (cid:1) 0.23 ‰ °C (cid:1) 1 for biogenic aragonite but are at the upper end of high-resolution Porites -de fi ned sensitivities that are consistently less than the aforementioned established value. Our results validate the use of Isopora as an alternative source of paleoceanographic records in habitats where large massive Porites are scarce or absent.