Century-old coral reveals significant ocean and climate changes
太平洋的西部边界流, which forms a critical regulator of sea surface temperature and weather patterns, 随着地球变暖而显著增强, 根据一项新的电子游戏正规平台, co-authored by Assistant Professor of Earth and Environmental Sciences 王星辰(托尼), 发表于期刊 自然地球科学.
这项电子游戏正规平台 provides the first evidence that the western boundary current in the South Pacific has significantly strengthened during the 20th century in response to global warming, contributing to an intensified equatorial undercurrent, 据王说, who uses stable isotopes to better document and understand the biogeochemical cycles in the modern and past oceans.
Records drawn from coral samples also showed a pronounced recurring pattern of variable ocean-atmosphere climatic conditions – known as decadal oscillation – indicating that periods of enhanced western boundary current correspond to periods of increased sea surface temperatures in the eastern equatorial Pacific, 根据报告, 王准备, 台湾大学的任皓佳和她的团队, 以及台湾中央电子游戏正规平台院的合作者, 加州大学, 加州大学伯克利分校, 德克萨斯大学奥斯汀分校, 以及夏威夷太平洋大学.
Professor of Earth and Environmental Sciences 王星辰(托尼)
“This result confirms the significant role of the western boundary current in controlling the heat balance of the equatorial ocean, 正如气候模型预测的那样,王说.
The team examined the historical clues embedded in century-old coral, probing the chemical components of tropical coral’s skeleton for data on environmental and climatological conditions in the past, much like examining the rings that mark the year-by-year development of trees. 这项电子游戏正规平台, titled “Increased tropical South Pacific western boundary current transport over the past century,” explored how global warming has led to the strengthening of the western boundary current in the South Pacific, which has had a significant effect on the broader global climate.
王说 that the team set out to better understand how the western boundary current has changed as the climate has warmed. The ocean acts as the largest heat reservoir in the Earth’s climate system, 王说.
“More than 90 percent of the global warming heat has been absorbed by the ocean,王说. “The circulation of the ocean plays a key role in redistributing the ocean’s energy and in doing so, 调节全球和区域气候. This means that the strengthening of the western boundary current has an effect on weather events that take place hundreds if not thousands of miles away.”
He added, “The tropical Western Pacific Ocean is the largest warm pool in the world. It is particularly important for a climate phenomena known as El Niño.”
潜水员收集珊瑚样本, illustrative of the process used by researchers in climate studies. (王星辰)
El Niño， 美国国家海洋和大气管理局已经正式宣布它将于6月抵达, has been closely associated with increased flooding and rain across the Americas and the Pacific.
The western boundary current system in the tropical Pacific Ocean transports water into the equatorial region and regulates its sea surface temperature, 影响El Niño和La Niña的活动. 然而, due to the limited availability of long-term observational data from satellites and instruments, it has been unclear whether the western boundary current is strengthening or weakening in the context of global warming, 王说.
The researchers collected a century-long coral sample from the Solomon Sea and used a mass spectrometer to analyze the isotopic composition of nitrogen – namely the ratio of nitrogen-15 and nitrogen-14 – preserved in the coral sample, which served as a proxy for western boundary current changes, 根据报告.
电子游戏正规平台中使用的珊瑚样本的x射线图像.
The coral records also showed a pronounced decadal oscillation, indicating that periods of enhanced western boundary current correspond to periods of increased sea surface temperatures in the eastern equatorial Pacific.
王说 the findings indicate that the continued strengthening of the western boundary current will keep playing a significant role in the global climate and the extreme weather events that have become increasingly common in the 21st century.
“We were a bit surprised that the western boundary current has indeed strengthened under global warming,王说. “It implies that the western boundary current will continue to play an important role in regulating tropical and global climate in the future. 例如, enhanced western boundary current might make it easier to develop strong El Niño events, 比如我们现在正在经历的.”
王说 the next steps in this research will continue to use coral samples to study ocean circulation changes and how those changes interact with the climate system, 无论是现在还是过去.
Christopher Kerwin is a sophomore in the Morrissey College of Arts and Sciences