Historical timescale records of coral growth and skeletal carbonate deposition under conditions of high turbidity and terrigenous sediment influence

高浊度和陆源沉积物影响条件下珊瑚生长和骨骼碳酸盐沉积的历史时间尺度记录

• 批准号: NE/F01077X/1
• 负责人: Christopher Perry
• 金额: $ 8.17万
• 依托单位: Manchester Metropolitan University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF01077X%2F1
• 关键词: Historical; timescale; records; coral; growth

There is a general perception that corals (and coral reefs) are highly susceptible to riverine inputs of terrigenous sediment, and that high rates of such inputs will negatively impact reef health and vitality (usually evidenced by low coral cover and/or high partial mortality rates). In coral reef settings where such inputs have been limited in the past and where corals are not adapted to deal with frequent sediment loading and reduced light penetration, this perception is likely to have considerable validity and may lead, over time, to shifts in coral community structure. However, there is an increasing body of sedimentological, geomorphological and palaeoecological data demonstrating not only long-term (>1,000 year) persistence of coral communities under conditions of high terrigenous sediment input and high turbidity, but also clear evidence of active and rapid reef-accretion. Under these conditions corals seem to be sufficiently adapted to these environmental conditions that coral cover is often high and well-developed reef structures can form. This has been demonstrated at sites in Thailand, Indonesia, Mozambique and at a range of sites along the nearshore (innermost shelf) areas of the Great Barrier Reef (GBR), Australia. An apparent paradox thus exists between the perceived negative effects of high turbidity and terrigenous sediment inputs on coral communities (which are widely referred to in the scientific literature) and the increasing sedimentary and palaeoecological evidence for historical timescale persistence of corals and of reef-building in these settings. This raises an intriguing question about coral carbonate production in these environments and about the nature of skeletal carbonate deposition. Are these coral communities able to produce reef structures, despite high terrigenoclastic sediment input and high turbidity regimes, because of particularly high coral growth and calcification rates? Little data exists from nearshore reefs of this type and there has been no attempt to quantify and compare these processes over temporal and spatial scales. This project thus aims to quantify coral extension (growth) and calcification rates, and to quantify the microskeletal characteristics (i.e., the size and density of key skeletal elements in the coral skeleton) from two of the dominant coral species associated with reef-building within nearshore, turbid-zone settings along the central GBR coastline. The focus for the research will be the two best-studied turbid-zone reefs in the region; Paluma Shoals and Lugger Shoal. Extensive datasets are available on the sedimentary environments, hydrodynamic conditions and contemporary community structures in each locality. In addition, radiocarbon (14C) date-constrained growth models exist for each site that allow data to be placed in a reliable chronological framework. Specifically, we will gather data on a massive coral species (Porites lobata) that makes a major contribution to contemporary reef-flat coral communities in both settings, and a branching coral species (Acropora pulchra) which previous research has demonstrated to have been a major framework contributor throughout the growth history of these reefs. The research will utilise novel Computerised (Axial) Tomography (CT) scanning and established Scanning Electron Microscopy (SEM) approaches to quantify coral growth rates and styles of coral skeletal deposition in these samples. Between-site comparisons will be made against data collected from the same species of Porites and Acropora that were collected from clear water sites at Low Isles during the 1928-1929 Great Barrier Reef Expedition. This extensive and well-catalogued coral repository is stored at the NHM and CT methodologies will allow us to examine the skeletal structures of these corals using non-destructive techniques.

人们普遍认为，珊瑚（和珊瑚礁）极易受到河流输入的陆源沉积物的影响，而这种输入的高比率将对珊瑚礁的健康和活力产生负面影响（通常表现为珊瑚覆盖率低和/或部分死亡率高）。在过去这种投入有限的珊瑚礁环境中，珊瑚不适应处理频繁的沉积物负荷和减少的光线穿透，这种看法可能相当有效，并可能随着时间的推移导致珊瑚群落结构的变化。然而，越来越多的沉积学、地貌学和古生态资料表明，在高陆源沉积物输入和高浊度的条件下，珊瑚群落不仅长期（100 - 1000年）持续存在，而且有明确的证据表明，珊瑚礁的活跃和快速增生。在这些条件下，珊瑚似乎充分适应了这些环境条件，珊瑚覆盖率通常很高，并且可以形成发育良好的珊瑚礁结构。这已经在泰国、印度尼西亚、莫桑比克和澳大利亚大堡礁（GBR）近岸（最内层大陆架）地区的一系列地点得到了证明。因此，高浊度和陆源沉积物输入对珊瑚群落的负面影响（在科学文献中被广泛提及）与越来越多的沉积和古生态证据表明，在这些环境中珊瑚的历史时间尺度持久性和珊瑚礁建设之间存在明显的矛盾。这就提出了一个有趣的问题，即在这些环境中珊瑚碳酸盐的产生以及骨架碳酸盐沉积的性质。由于珊瑚生长和钙化率特别高，尽管陆生碎屑沉积物输入和浊度很高，但这些珊瑚群落是否能够产生珊瑚礁结构？这种类型的近岸珊瑚礁的数据很少，也没有尝试在时间和空间尺度上量化和比较这些过程。因此，本项目旨在量化珊瑚的延伸（生长）和钙化率，并量化两种主要珊瑚物种的微骨骼特征（即珊瑚骨架中关键骨骼元素的大小和密度），这些物种与沿GBR中部海岸线近岸浑浊带设置的珊瑚礁建设有关。研究的重点将是该地区两个研究得最好的浑浊带珊瑚礁；Paluma浅滩和Lugger浅滩。在每个地方都有关于沉积环境、水动力条件和当代群落结构的大量数据集。此外，每个站点都存在放射性碳（14C）日期约束增长模型，可以将数据放置在可靠的时间框架中。具体来说，我们将收集大量珊瑚物种（Porites lobata）的数据，这些物种对两种环境下的当代礁滩珊瑚群落做出了重大贡献，以及一种分支珊瑚物种（Acropora pulchra）的数据，此前的研究已经证明，它在这些珊瑚礁的整个生长历史中一直是主要的框架贡献者。该研究将利用新的计算机轴向断层扫描（CT）扫描和已建立的扫描电子显微镜（SEM）方法来量化这些样本中珊瑚的生长速度和珊瑚骨骼沉积的样式。地点之间的比较将与1928-1929年大堡礁考察期间从低岛清澈水域收集的同一物种的Porites和Acropora的数据进行比较。这个广泛和分类良好的珊瑚库储存在国家海洋博物馆，CT方法将使我们能够使用非破坏性技术检查这些珊瑚的骨骼结构。

项目成果

Mid-Holocene sea surface conditions and riverine influence on the inshore Great Barrier Reef

• DOI: 10.1177/0959683614534739
• 发表时间: 2014-06
• 期刊: The Holocene
• 作者: R. Roche;C. Perry;S. Smithers;M. Leng;C. Grove;H. Sloane;Catherine Unsworth

Recurrent patterns of coral community and sediment facies development through successive phases of Holocene inner-shelf reef growth and decline

全新世内陆架礁生长和衰退的连续阶段中珊瑚群落和沉积相发育的循环模式

• DOI: 10.1016/j.margeo.2011.09.012
• 发表时间: 2011
• 期刊: Marine Geology
• 影响因子: 2.9
• 作者: Perry C

Evidence for the episodic "turn on" and "turn off" of turbid-zone coral reefs during the late Holocene sea-level highstand

全新世晚期海平面高位期间浑浊带珊瑚礁间歇性“开启”和“关闭”的证据

• DOI: 10.1130/g30444.1
• 发表时间: 2010
• 期刊: Geology
• 影响因子: 5.8
• 作者: Perry C

Spatial variation in porosity and skeletal element characteristics in apical tips of the branching coral Acropora pulchra (Brook 1891)

分支珊瑚 Acropora pulchra 顶端孔隙度和骨骼元素特征的空间变化（Brook 1891）

• DOI: 10.1007/s00338-010-0679-1
• 发表时间: 2010
• 期刊: Coral Reefs
• 影响因子: 3.5
• 作者: Roche R