RAPID: El Nino Isotopic Signature

RAPID：厄尔尼诺同位素特征

• 批准号: 1623514
• 负责人: Christopher Jazwa
• 金额: $ 0.96万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1623514&HistoricalAwards=false
• 关键词: RAPID; El; Nino; Isotopic; Signature

In this study, investigators seek insight into human responses to climate change in marine environments. In particular, they wish to understand patterns of El Niño intensity and frequency in the past, and how this influenced past human populations. As archaeologists, the investigators are well-suited to understand complex long-term human-environmental dynamics using climatological records and the material record from archaeological sites. El Niños influence human populations through changes in weather, often in the form of heavier rains and larger storms along the southwest coast of the United States, and an increase in sea surface temperature (SST). This change in SST is particularly relevant because it is accompanied by decreases in marine productivity, which often leads to large scale death of marine life along the west coast of the United States and South America. This severely affected the diet of past coastal populations who derived a large proportion of their food from the ocean. Today, El Niños can cause a collapse of fishing industries. This study will refine methods for using elements of the archaeological record to reconstruct El Niños and long-term patterns of SST in the past.A team of researchers led by Dr. Christopher Jazwa will take advantage of the current extreme El Niño and collect SST data and California mussel (Mytilus californianus) shells that contain a record of elevated water temperature. The oxygen isotope in the calcium carbonate that makes up the outer layers of California mussel shells is influenced by SST at the time it is deposited. This layer is deposited in bands over the lifetime of the mussel, so it is possible to use this signature to reconstruct patterns in SST through time. In this project, investigators will be traveling to Santa Rosa Island, CA, to collect SST data and living mussels in January, March, May, August, and November of 2016. By collecting samples and data during the El Niño and the summer/fall immediately afterward, it should be possible to obtain a signature of elevated SST in the isotopic signature of the shells. Because El Niños are difficult to predict in advance, it is essential that the researchers travel to the field quickly once the appropriate signature has been confirmed. The sampling location is adjacent to archaeological sites with evidence for at least 7500 years of human occupation. These sites include abundant evidence of fishing and shellfishing, including mussel shells. The methods developed in this study can be directly applied to mussels from archaeological collections for three purposes: 1) track past patterns in El Niño cycles; 2) determine long-term patterns in SST; and 3) assign individual shells to particular seasons during the year to understand seasonal movement of past human populations. Fieldwork and laboratory sample processing will be done with the assistance of undergraduate and graduate students, aiding in their education and development as archaeologists. Finally, research will be done in part to satisfy the goals of Channel Islands National Park to inventory the valuable cultural and environmental resources that are present there.

在这项研究中，研究人员寻求深入了解人类对海洋环境中气候变化的反应。特别是，他们希望了解过去厄尔尼诺强度和频率的模式，以及它如何影响过去的人口。作为考古学家，研究人员非常适合使用气候记录和考古遗址的材料记录来了解复杂的长期人类环境动态。厄尔尼诺现象通过天气变化对人口产生影响，其形式往往是美国西南部沿海沿着出现大雨和更大的风暴，以及海表温度升高。SST的这种变化特别相关，因为它伴随着海洋生产力的下降，这往往导致美国和南美洲西海岸沿着海洋生物的大规模死亡。这严重影响了过去沿海人口的饮食，他们的大部分食物来自海洋。今天，厄尔尼诺现象可能导致渔业崩溃。这项研究将改进使用考古记录元素重建厄尔尼诺现象和过去SST长期模式的方法。由Christopher Jazwa博士领导的研究小组将利用当前极端厄尔尼诺现象并收集SST数据和加州贻贝（Mytilus californianus）贝壳，其中包含水温升高的记录。构成加州贻贝壳外层的碳酸钙中的氧同位素在沉积时受到SST的影响。这一层是沉积在带在整个生命周期的贻贝，所以它是可能的使用这个签名，以重建模式SST通过时间。在这个项目中，研究人员将前往加利福尼亚州的圣罗莎岛，在2016年1月、3月、5月、8月和11月收集SST数据和活贻贝。通过在厄尔尼诺现象期间和紧接着的夏季/秋季收集样本和数据，应该有可能在贝壳的同位素特征中获得SST升高的特征。由于厄尔尼诺现象很难提前预测，一旦确认了适当的特征，研究人员就必须迅速前往实地。采样地点邻近考古遗址，有证据表明至少有7500年的人类居住。这些遗址包括大量的捕鱼和贝类捕捞的证据，包括贻贝贝壳。本研究中开发的方法可以直接应用于考古收藏的贻贝，用于三个目的：1）跟踪厄尔尼诺周期的过去模式; 2）确定SST的长期模式; 3）将单个贝壳分配给一年中的特定季节，以了解过去人类人口的季节性运动。实地考察和实验室样品处理将在本科生和研究生的协助下完成，帮助他们作为考古学家的教育和发展。最后，研究工作将部分地满足海峡群岛国家公园的目标，以清点那里存在的宝贵的文化和环境资源。