Rebecca Smith ’12 researching prehistoric climate change to better predict the world to come

对新巴黎人注册网站大多数人来说, 在缅因州参观一个美丽的地方意味着欣赏风景, 晒太阳, 也许还会留意当地的野生动物. 贝基·史密斯(Becky Smith)的想法有些不同. 当她回到自然世界的时候, she’s more interested in knowing what that particular spot looked like millions of years ago. 

Becky’s interest in science first emerged in Waynflete’s Astrophysics and Marine Biology electives. Becky credits these two courses—taught by educators David Vaughan and Wendy Curtis—with sparking her fascination with earth science. 爱丽丝·布洛克也激发了她对俄罗斯历史的热情, which led Becky to consider pursuing the subject at the college level. 贝茨学院为她提供了一个足球学校的招生机会, 然而, 因为学校没有开设俄罗斯历史课程, 贝基决定新巴黎人注册网站地质学. 

在贝茨的时候, 贝基在加利福尼亚的沙漠中进行田野调查, 内华达, 德州, 和墨西哥, eventually moving into a more intensive form of field mapping in Montana, where she measured the age and spatial distributions of rock formations in specific areas. (的 resulting maps reveal how a region has changed over geologic time—millions to billions of years.) While energy companies conduct this type of research when searching for new oil fields, 贝基纯粹是为了科学. “这是一种全新的体验，我很喜欢，”她回忆道. 

Becky’s undergraduate work also focused on coprolites (fossilized feces), particularly those left behind thousands of years ago by now-extinct giant sloths. 通过检查粪化石, researchers can reconstruct details of the environment in which the sloths once lived. 贝基很感兴趣. “这是最酷的事情，”她说. “I began to realize that I was truly curious about what Earth looked like millions of years ago.” 

在获得地质学学位后, 外加地球化学和古生物学的辅修课程, Becky entered the graduate program at the University of Massachusetts at Amherst. She began to research the fossilized remains of ancient phytoplankton in order to reconstruct changes in ocean currents through time. 

浮游植物, 它们产生了地球上一半的氧气, 是生活在海洋表层的微生物吗. 当这些微小的海洋生物死亡时, 它们的有机化合物下沉到海底, 它们在哪里留下脂质(油)残留物. 经过数百万年, these organic compounds—known as biomarkers—accumulate in layers of sediments on the ocean floor. Since phytoplankton adjust their chemical compositions to different ocean temperatures, lipids from warm surface waters contain different organic compounds from those produced in 寒冷的水域. 通过从海洋沉积物中提取脂质样品, paleoclimatologists and biogeochemists can learn about the ocean temperatures in which the source organisms once lived. 这些脂质, which are collected every few centimeters from deep-sea marine sediment cores, allow scientists to reconstruct how sea surface temperatures have changed over millions of years. “这是一项有趣的工作，”贝基说. “通过研究这些时期, we will be able to better understand baseline climate behavior on Earth, which improves the climate models capable of predicting where we’re heading in the future.” 

Becky recently completed a nine-week research expedition in the Central South Pacific as part of the International Ocean Discovery Program. 的 JOIDES决议, 一艘470英尺长的科考船, 航行到南极绕极流(ACC)区域, 地球上唯一不受大陆阻碍的洋流. ACC在南极洲周围快速移动, 在太平洋之间混合和重新分配洋流和热量, 大西洋, 和印度洋. “ACC本质上就像一个巨大的搅拌碗, 将洋流输送到世界各地,贝基说。. “它对全球气候有重大影响.”

的 ACC had until recently been considered too remote for study by geologists (the region is well known as one of the stormiest places on the planet). 尽管存在这些挑战, core drillers deployed over three miles of piping from the ship’s drilling rig down to the ocean floor, then penetrated a further 300 meters down to extract ancient sediment samples. 船员们经常不得不在波涛汹涌的海面上进行精确的工作. “的 analogy the drillers use is hitting a dime with a piece of string from the top of the Empire State Building, 贝基说。. “他们的能力令人惊叹.” 

While Becky did complete some initial analyses in the ship’s chemistry lab, 真正的工作从陆上开始. In January 2020, Becky and her colleagues will gather for a “sampling party” at 德州 A&米大学. Each scientist will collect samples from the specific cores that interest them, 然后把他们带回本国大学进行分析. Though they will use these core samples to independently test their hypotheses, 研究人员将继续合作, 通过视频会议保持定期联系.

的 scientists’ efforts will eventually result in the production of a complete climate record of the central South Pacific—and the dynamics of the ACC—over the past five to eight million years. 的se studies will provide crucial information for climate modelers to reconstruct periods in Earth’s history under similar-to-modern CO2 条件. In order to understand where climate is heading under the influence of humans, models need to incorporate information on how Earth functions on a long-term scale. 

在她与来自世界各地的科学家们的合作中, Becky has learned that the United States is one of the few countries where there is any significant skepticism about climate change. “Irrespective of personal opinions, change is already happening,” she says. “And it’s the people living in poor coastal communities—those who have no voice and no financial means to adapt—who are already being displaced due to rising ocean levels.“许多否认者认为气候变化是周期性的——二氧化碳2 varies over long timescales, and that what we see today is nothing out of the ordinary. 而气候变化确实遵循循环模式, scientific data has shown a massive deviation from normal cycles since the onset of the Industrial Revolution. In the context of natural cyclicity, the Earth should actually be entering a glacial period. “Humans are causing global warming at a speed that is unprecedented,” Becky says. “大多数物种都无法适应这种变化速度.” Global warming is not about damaging the Earth, which is actually very resilient. “It’s the destruction of species and ecosystems that should really worry us.”