{"title":"Holocene paleoenvironmental change based on diatom records from the continental shelf of the Chukchi Sea in the Arctic Ocean","authors":"Young-Suk Bak, Seung-Il Nam","doi":"10.1007/s12303-023-0040-7","DOIUrl":null,"url":null,"abstract":"<p>Diatom assemblages from ARA2B-1A taken in the Chukchi Sea shelf were analyzed to reconstruct paleoenvironmental changes during the last 10 ka BP. The main factors controlling the distribution of diatom in the Chukchi Sea are the relatively warm and nutrient-rich Pacific water inflow after the opening of the Bering Strait. Based on the selected diatoms, three diatom assemblage zones are identified. The diatom assemblage zone I shows a rare or very low abundance, which corresponds to the early Holocene (10–8 ka BP). The diatom assemblage zone II corresponds to the mid-to-late Holocene (8–2 ka BP). It is a seasonal sea-ice environment with relatively abundant diatom valves and <i>Chaetoceors</i> resting spores, as well as sea-ice species, cold-water species, coastal species, and upwelling species. The diatom assemblage zone III corresponds to the late Holocene (2–0 ka BP), and the the sea-ice species generally decreased compared to zone II, while the coastal species <i>Paralia sulcata</i> occurred abundantly. In particular, the <i>Thalassiosira antarctica</i>, a cold-water species, increased distinctly during this time interval. After ∼2 ka BP, <i>T. antarctica</i> rapidly increased while sea-ice species rarely appeared, indicating limited open-marine environments. In particular, after 1 ka BP, <i>T. antarctica</i> decreased while the sea-ice species increased, suggesting that the sea-ice increased again before the recent global warming of the Arctic, the late Holocene.</p>","PeriodicalId":12659,"journal":{"name":"Geosciences Journal","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geosciences Journal","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s12303-023-0040-7","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Diatom assemblages from ARA2B-1A taken in the Chukchi Sea shelf were analyzed to reconstruct paleoenvironmental changes during the last 10 ka BP. The main factors controlling the distribution of diatom in the Chukchi Sea are the relatively warm and nutrient-rich Pacific water inflow after the opening of the Bering Strait. Based on the selected diatoms, three diatom assemblage zones are identified. The diatom assemblage zone I shows a rare or very low abundance, which corresponds to the early Holocene (10–8 ka BP). The diatom assemblage zone II corresponds to the mid-to-late Holocene (8–2 ka BP). It is a seasonal sea-ice environment with relatively abundant diatom valves and Chaetoceors resting spores, as well as sea-ice species, cold-water species, coastal species, and upwelling species. The diatom assemblage zone III corresponds to the late Holocene (2–0 ka BP), and the the sea-ice species generally decreased compared to zone II, while the coastal species Paralia sulcata occurred abundantly. In particular, the Thalassiosira antarctica, a cold-water species, increased distinctly during this time interval. After ∼2 ka BP, T. antarctica rapidly increased while sea-ice species rarely appeared, indicating limited open-marine environments. In particular, after 1 ka BP, T. antarctica decreased while the sea-ice species increased, suggesting that the sea-ice increased again before the recent global warming of the Arctic, the late Holocene.
通过分析在楚科奇海大陆架采集的 ARA2B-1A 硅藻群,重建了公元前 10 千年的古环境变化。控制楚科奇海硅藻分布的主要因素是白令海峡开口后相对温暖和营养丰富的太平洋海水流入。根据所选硅藻,确定了三个硅藻集合区。硅藻集合区 I 的硅藻数量稀少或极少,与全新世早期(10-8 ka BP)相对应。硅藻集合区 II 与全新世中晚期(8-2 ka BP)相对应。这是一个季节性的海冰环境,硅藻瓣膜和Chaetoceors静止孢子以及海冰物种、冷水物种、沿岸物种和上升流物种相对丰富。硅藻集合区 III 与全新世晚期(2-0 ka BP)相对应,海冰物种与区域 II 相比普遍减少,而沿岸物种 Paralia sulcata 则大量出现。特别是冷水物种 Thalassiosira antarctica 在这一时期明显增加。公元前 2 ka 年以后,T. antarctica 迅速增加,而海冰物种却很少出现,这表明开放海洋环境有限。特别是在公元前 1 ka 年之后,蚁囊虫减少,而海冰物种增加,这表明在最近的北极全球变暖之前,即全新世晚期,海冰再次增加。
期刊介绍:
Geosciences Journal opens a new era for the publication of geoscientific research articles in English, covering geology, geophysics, geochemistry, paleontology, structural geology, mineralogy, petrology, stratigraphy, sedimentology, environmental geology, economic geology, petroleum geology, hydrogeology, remote sensing and planetary geology.