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Response of coral-reef development and coral growth for global warming and sea-level rise

珊瑚礁发育和珊瑚生长对全球变暖和海平面上升的响应

基本信息

批准号：
15510006
负责人：
OHDE Shigeru
金额：
$ 2.37万
依托单位：
University of the Ryukyus
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15510006/
关键词：
Coral reef Sea-level rise Global warming Chronology Strontium isotope Funafuti atoll Okinawa Midway atoll ミッドウエイ環礁

项目摘要

The growth and depositional history of reef-buildings corals provide excellent records of the environment in which they grew. Using living corals collected from Okinawan coral reefs, laboratory experiments were performed to investigate the relationship between coral calcification and aragonite saturation state (Ω) of seawater at 25℃. Calcification rate of a massive coral Porites Iutea cultured in a beaker showed a linear increase with increasing Ω_<aragonite> values (1.08-7.77) of seawater. The increasing trend of calcification rate (c) for Ω is expressed as an equation, c=aΩ+b (a, b : constants). When Ω was larger than 4, the coral samples calcified during nighttime, indicating an evidence of dark calcification. This study strongly suggests that calcification of Porites lutea depends on Ω of ambient seawater. A decrease in saturation state of seawater due to increased pCO_2 may decrease reef-buildings capacity of corals through reducing calcification rate of corals.The drill core of F … More unafuti Atoll, collected by the Royal Society Coral Reef Expedition in 1896-8, has been dated using high-precision ^<14>C and Sr isotope measurements determined by mass spectrometry. The core top is a Holocene reef deposit, reflecting 26.4m of reef growth since 8 ka, and is underlain by Pleistocene reef-lagoonal deposits separated by a series of inferred hiatuses at 26.4 m, 30 m,〜65 m and 〜80 m(〜0.1 Ma,〜0.2 Ma,〜0.3 Ma and 〜0.6 Ma, respectively), reflecting atoll carbonate deposits associated with late Quaternary sea-level changes. In turn, the underlying sequence below 〜80 m comprises an upper section of additional Pleistocene reef-lagoonal deposits, having a high accumulation rate >100 m/Ma, and a heavily dolomitized lower section. Sr isotope data in the lower section provide maximum (oldest) ages for dolomite formation and, depending on the extent of the isotopic memory from precursor CaCO_3, reflect ongoing diagenetic alteration from 〜2.3 Ma (i.e., the oldest dolomite) or in one or more discrete diagenetic events at 〜1 Ma, and possibly at 〜2 Ma. The coral reef sequence reflects interaction between atoll carbonate sedimentation, tectonic subsidence, and eustatic sea-level change. We also performed the chronology of Midway atoll and would like to publish the results. Such deep coring projects are expensive and cores are therefore difficult to obtain for scientific purposes. The sea-level signatures recorded by deep cores in subsiding areas are therefore rare and precious.These two methods are especially useful for correlations between global warning and sea-level rise. A blending of such information from two very different approaches might clarify eustatic sea-level changes. Less

礁石珊瑚的生长和沉积历史为它们生长的环境提供了极好的记录。利用从冲绳珊瑚礁采集的活珊瑚，进行了实验室实验，研究了珊瑚钙化与海水文石饱和状态(Ω)在25℃时的关系。在烧杯中养殖的大型珊瑚藻类的钙化率随海水Ω_lt；文石和Gt；值的增加呈线性增加。Ω的钙化速率(C)的增加趋势表示为：c=aΩ+b(a，b：常数)。当Ω大于4时，珊瑚样本在夜间钙化，表明暗钙化的证据。这项研究有力地表明，黄褐斑的钙化依赖于周围海水的Ω。PCO_2升高导致海水饱和状态降低，可能通过降低珊瑚的钙化率来降低珊瑚的造礁能力。F…钻芯英国皇家学会珊瑚礁探险队于1896-1808年收集的莫纳富提环礁，已经用高精度的碳和锶同位素测量方法测定了它们的年代。岩心顶部为全新世生物礁沉积，反映了8ka以来26.4m的生物礁生长，下部为更新世生物礁-泻湖沉积，中间隔着26.4m、30m、~65m和~80m(分别为~0.1 Ma、~0.2 Ma、~0.3 Ma和~0.6 Ma)的一系列推断海平面，反映了与晚第四纪海平面变化有关的环礁碳酸盐沉积。80m以下的下伏层序由上一段更新世附加礁泻湖沉积组成，具有较高的堆积速率&100m/Ma，下段为严重白云岩化。下部的锶同位素数据提供了白云岩形成的最大(最古老)年龄，并根据前驱CaCO3的同位素记忆程度，反映了~2.3 Ma(即最古老的白云岩)以来正在进行的成岩蚀变，或在~1 Ma或可能在~2 Ma发生的一次或多次离散成岩事件。珊瑚礁序列反映了环礁碳酸盐沉积、构造沉降和海平面变化之间的相互作用。我们还完成了中途环礁的年表，并希望公布结果。这种深部取心项目成本高昂，因此很难获得用于科学目的的岩心。因此，沉降区深部岩心记录的海平面特征是罕见和珍贵的。这两种方法对于全球预警和海平面上升之间的关联特别有用。将来自两种截然不同的方法的这类信息混合在一起，可能会澄清海平面的变化。较少