The influence of turbidity on ancient and modern coral reefs

浑浊度对古代和现代珊瑚礁的影响

• 批准号: RGPIN-2021-04054
• 负责人: Zonneveld, JohnPaul
• 金额: $ 3.72万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742841
• 关键词: influence; turbidity; ancient; modern; coral

The role that turbid water has played in coral and coral reef survival through two Cenozoic hyperthermal events (temporal intervals of global warming) is investigated. Diverse coral reef systems were long considered to be phenomena limited to clear water settings. Areas of high clastic sediment input were considered to be harmful to corals due to reduced water transparency (reducing photosynthesis by coral symbionts), fine-grained sediment clogging the feeding / respiration apparatus of sessile benthic faunas and increased nutrients and particulate organics in the water column (which causes extensive algal colonization and smothering of coral taxa). Unfortunately, clear water settings provide no respite from increased water temperatures and prolonged, cloudless exposure to intense solar radiation that result from a warming climate and thus, in recent years extensive bleachings have resulted in the widespread demise of tropical corals and coral reefs. Recent studies have suggested that, rather than smothering reefs, moderate levels of turbidity (cloudiness) may lower reef stress by shielding coral taxa from high solar radiation. Several recent studies have identified turbid-system (murky water) coral reefs as refugia wherein reef biota may retreat and survive environmental crises. Despite the importance of turbid water coral reefs, they are poorly understood relative to their clear-water equivalents. The goal of this research program is to investigate the role that turbid water coral reefs play and have played in maintaining regional coral reef health and reef fauna diversity during hyperthermal events. Two hyperthermal intervals are investigated. The older interval is the Paleocene-Eocene Thermal Maximum (PETM) - Early Eocene Climate Optimum (EECO) interval (~56 to 49 million years ago), which includes the warmest interval on the earth up until the present day. Latest Paleocene to early Eocene reefs in the neoTethys region (modern southern Europe) are my focus for this research program as this area was the centre of reef diversity during the Paleogene and thick vertically continuous, reef-prone outcrop is available through both pure carbonate and mixed siliciclastic-carbonate successions. The younger interval considered is the Middle Pleistocene to Modern. Here my focus is on the northeastern coast of Sumba, Indonesia. Sumba occurs in the Coral Triangle, the most diverse marine ecosystem on the planet, hosting 76% of the world's coral species and 37% of coral fish species. extensive bleaching has resulted in the widespread demise of these tropical corals and coral reefs. The island of Sumba was chosen as it includes an one-million year record of uplifted coral reefs, includes ancient and modern turbid-water and clear-water coral reefs in close proximity and occurs on an island in the Wallacea straits (an island-rich region that occurs between the Sahul and Sunda shelves, which were subaerially exposed during the Pleistocene).

通过两次新生代超高温事件（全球变暖的时间间隔），浊水在珊瑚和珊瑚礁生存中发挥的作用进行了研究。 长期以来，多样化的珊瑚礁系统被认为是仅限于清水环境的现象。据认为，碎屑沉积物大量流入的地区对珊瑚有害，因为水的透明度降低（珊瑚共生体的光合作用减少），细粒沉积物堵塞了固着底栖动物的摄食/呼吸器官，水柱中的营养物和颗粒有机物增加（导致藻类大量定植和珊瑚分类群窒息）。不幸的是，由于气候变暖，水温升高，长时间无云暴露在强烈的太阳辐射下，因此，近年来大规模的漂白导致热带珊瑚和珊瑚礁的广泛死亡。最近的研究表明，适度的浑浊度（云量）不会使珊瑚礁窒息，反而可能通过保护珊瑚类群免受高太阳辐射而降低珊瑚礁的压力。最近的几项研究已确定浊流系统（浊水）珊瑚礁是珊瑚礁生物群可能撤退并在环境危机中幸存下来的避难所。尽管浊水珊瑚礁的重要性，但相对于清水珊瑚礁，人们对它们的了解甚少。这项研究计划的目标是调查浊水珊瑚礁在维持区域珊瑚礁健康和珊瑚礁动物多样性方面发挥的作用。研究了两个超高温区间。较老的时间段是古新世-始新世最热期（PETM）-早始新世气候最佳期（EECO）时间段（约5600万至4900万年前），其中包括地球上最温暖的时间段。在新特提斯地区（现代南欧）的最新古新世至始新世早期的珊瑚礁是我这项研究计划的重点，因为这一地区是在古近纪和厚的垂直连续的珊瑚礁多样性的中心，倾向于露头可通过纯碳酸盐岩和混合硅质碎屑碳酸盐岩继承。较年轻的时期是中更新世至现代。这里我关注的是印度尼西亚松巴岛的东北海岸。松巴发生在珊瑚三角区，这是地球上最多样化的海洋生态系统，拥有世界上76%的珊瑚物种和37%的珊瑚鱼类。大面积的白化已导致这些热带珊瑚和珊瑚礁普遍死亡。选择松巴岛是因为它包括一百万年的上升珊瑚礁记录，包括古代和现代浊水和清水珊瑚礁，并且位于Wallacea海峡（Sahul和Sunda大陆架之间的岛屿丰富区域，在更新世期间暴露在水下）的一个岛屿上。