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

造礁珊瑚的生长和沉积历史提供了其生长环境的良好记录，利用从冲绳珊瑚礁采集的活珊瑚，对珊瑚钙化与海水文石饱和状态（Ω）之间的关系进行了实验室研究实验。在25℃下，烧杯中培养的块状珊瑚Porites Iutea的钙化率随着Ω_<文石>值(1.08-7.77)的增加而呈线性增加。 Ω 的钙化率 (c) 的增加趋势表示为方程 c=aΩ+b (a, b : 常数) 当 Ω 大于 4 时，珊瑚样品在夜间发生钙化，表明存在钙化现象。这项研究强烈表明，黄滨滨珊瑚的钙化取决于周围海水的 Ω，由于 pCO_2 增加而导致海水饱和状态的降低可能会通过减少珊瑚的造礁能力来降低。珊瑚的钙化率。F … More unafuti 环礁的钻芯由英国皇家学会珊瑚礁探险队于 1896 年 8 月收集，已使用质谱岩芯测定的高精度 ^<14>C 和 Sr 同位素测量值确定了年代。顶部是全新世珊瑚礁沉积物，反映出自 8 ka 以来珊瑚礁生长了 26.4m，其下方是更新世珊瑚礁-泻湖沉积物由一系列推断的26.4 m、30 m、〜65 m和〜80 m（分别为〜0.1 Ma、〜0.2 Ma、〜0.3 Ma和〜0.6 Ma）的间断分隔开，反映了与晚第四纪海洋相关的环礁碳酸盐沉积物反过来，~80 m 以下的底层层序包括额外的更新世礁泻湖沉积物的上部部分，具有较高的水位。堆积速率 >100 m/Ma，并且下部的严重白云石化的 Sr 同位素数据提供了白云石形成的最大（最古老）年龄，并且根据前体 CaCO_3 的同位素记忆程度，反映了来自前体 CaCO_3 的持续成岩作用。 ~2.3 Ma（即最古老的白云岩）或在 ~1 Ma 的一个或多个离散成岩事件中，并且可能在 ~2 Ma 珊瑚礁序列。我们还对中途岛环礁的年代学进行了研究，并希望发表这种深部取芯项目的费用很高，因此很难为科学目的获得岩芯。因此，沉降区域深层岩心记录的海平面特征非常罕见和珍贵。这两种方法对于全球警报和海平面上升之间的相关性特别有用。来自两种截然不同方法的此类信息的混合。可能会澄清海平面的升降变化。